Disputationes metaphysicae

1. Various opinions.—Ailly a stranger to the preceding opinion.—On this matter there was an old opinion asserting that created things operate nothing, but that God effects everything at their presence, and that action is attributed to fire, water, etc., on account of appearance, and because God, as it were, made a pact not to effect such effects except at the presence of such things. This opinion is reported by Averroes, IX Metaph., comm. 7, and bk. XII, comm. 18; and by Albert, II Phys., tract. II, c. 3; and by St. Thomas, III Cont. Gent., c. 69, and I, q. 105, a. 5, and In II, dist. 1, q. 1, a. 4; yet they cite no definite author for it. Philo, however, seems to incline towards it, bk. II of the Allegories, when he says that God is the sole efficient cause; and in the book On the Cherubim and the Flaming Sword, when he says that it is proper to God to effect, but to the creature to suffer. But these things could easily be understood by antonomasia, as can other utterances of the philosophers, which we shall report later, dealing with the action of God. This opinion is also commonly attributed to Peter of Ailly, In IV, dist. 1, a. 1, at the end; there, however, he openly confesses that secondary causes act truly and properly by their own power and from the nature of the thing, and not by the will of God alone; he adds, however, at the same time, that it is true that the creature does nothing except by the will of God, and with God Himself also acting, indeed acting so that it may act, and consequently with God doing even more than if He acted alone; which things pertain to the necessity of the divine concurrence and can have a true and a false sense, as we shall see later in the proper disputation. Gabriel, however, favours this opinion more, In IV, dist. 1, q. 1, a. 3, dub. 3, where he reckons this opinion probable and adduces in its favour those words of I Cor. 12¹: God worketh all in all; and II Cor. 3: Not that we are sufficient to think any thing of ourselves, as of ourselves: but our sufficiency is from God. He himself, however, does not dare to assert that opinion.

2. Reasons for the preceding opinion.—I see no foundation for this opinion which is of any weight; the chief one, however, seems to have been that whatever efficiency is attributed to the creature is so much taken away from the divine power of the Creator; for either God operates all things, or not; the latter derogates from the divine efficacy; whence we shall show below that it is wholly false and erroneous, because it implies that something exists and does not depend on God. If, however, God effects all things, I ask further whether He does so immediately and with sufficient power, or only mediately and with insufficient power. The latter derogates from the divine perfection. If, however, the former is true, every other efficiency is superfluous, because one sufficient and efficacious cause is enough for the effect. Hence, since nature does nothing in vain, it conferred no power of operating on created things. And I confirm this: whatever God is supposed to do with a secondary cause, He will be able to do by Himself alone, for this at least pertains to His infinite power, as will be evident below; therefore in fact He does so. The consequence is evident, both because this better befits the divine power and efficacy, and especially because this seems necessary in order that a creature be made. Which I prove thus: the creature has an essential dependence on God alone, since without Him it cannot be made, and without any other whatever it can be made; therefore a creature cannot exist without this essential dependence which it has on God alone, because it cannot exist without what is essential to it; therefore every creature is through dependence on God alone; therefore it is through the efficiency of God alone, for efficiency and dependence are either the same or correlatives; therefore no creature has efficiency upon another, and consequently there is no secondary cause that effects anything.

3. Second opinion.—The second opinion denies that corporeal creatures can effect anything, but grants it of spiritual ones. St. Thomas, in the places cited, reports this from Avicebron, in the book Fons vitae, who said that no body is active, but that a certain power of a spiritual substance existing intimately in bodies effects all the actions which seem to be done through bodies. His foundation seems to have been that the agent must be intimately present to the patient; but bodies cannot be so present to one another, for quantity impedes that intimate entering of one thing into another which action requires. Hence he said that quantity not only is not active, but even impedes action; and it is confirmed, because corporeal substance is the lowest of all and the most unlike the first agent, and therefore neither has it a lower substance subject to it, on which it could act, nor can it have likeness to God in acting. Wherefore Augustine, V De Civit., c. 9, expressly says that corporeal causes are not to be numbered among efficient causes.

4. Third opinion.—The third opinion was that corporeal things can effect accidents, yet not substances, but that created spiritual substances can effect certain lower substances. St. Thomas reports this in the same place, from Avicenna, bk. I Sufficient., c. 10, and bk. IX of his Metaph., cc. 4 and 5, who seems to have held two errors in this matter. One is that one created spiritual substance can create another; for the first uncreated cause immediately effects only one intelligence, and that the most perfect, while that one creates a second, and the second a third, and so on down to the lowest. The other error asserts that this lowest spiritual substance infuses substantial forms into matter disposed by the proximate corporeal agents, which are not sufficient to effect substantial forms. His foundation as to the former part was that from one there is not, proximately and immediately, anything but one. As to the latter part, however, which more concerns the present matter, it was that these corporeal agents do nothing except by means of accidents, which are insufficient principles for effecting substantial forms. And he confirms this, because it is established by experience that many substances are generated which do not have proximate causes sufficient to introduce such forms, as when animals are generated from putrefaction by reason of accidental dispositions which concur by chance or fortuitously; therefore it is a sign that there is, as it were, some superior spiritual power ready to induce substantial forms whenever the accidental dispositions sufficiently concur; therefore all substantial generations take place from that power.

First assertion, concerning the efficiency of created causes

5. It must be said, however, first, that created agents truly and properly effect effects connatural and proportioned to themselves. This truth I judge to be not only most evident to sense and reason, but also most certain according to Catholic doctrine. Hence, just as on account of the former ground St. Thomas called the opposite opinion foolish, on account of the latter we can call it rash and erroneous; and therefore it is deservedly rejected by all philosophers and theologians. For Aristotle, although he never expressly reported or refuted the opposite opinion, yet everywhere supposes as most evident that natural causes do something. Indeed, all the ancient philosophers, whose opinions he himself reports in I Phys. and I Metaph., and elsewhere, often suppose that natural causes effect something; and therefore they laboured in explaining what they can do and from what, since from nothing nothing is made. Plato too, whom I cited from Damascene in the preceding disputation, in this sense calls natural causes instruments of the first cause, because they have a power of acting derived from it and dependent on it. In which sense Trismegistus² also said that the world is the instrument of God and has received seeds from Him in order to produce all things. And in the same way Philo, in the book On the Congress for the Sake of Learning, said that God permitted this lowest genus of things to sow and to beget. These philosophers were followed by the Commentator and other later writers. Among the Fathers, Augustine, bk. III De Trinit., cc. 7, 8 and 9, seems in his manner of speaking to have imitated the said philosophers when he says that God has placed in the elements and in other created causes the seminal reasons of things. These are nothing else than the active and passive principles of generations and of natural motions, which God placed in created things, as St. Thomas elegantly expounded, I, q. 115, a. 2, and In II, dist. 18, q. 1, a. 2; where also Durandus, Hervaeus, Giles and others; and Capreolus, In I, dist. 42, a. 3. Again, the same Augustine, VII De Civ., c. 30, speaking of God, says: Thus He administers all things which He created, that He also allows them to exercise and perform their own motions. This opinion all the scholastics confirm and celebrate, wherever they dispute either of the efficiency of causes or of the freedom of man; they may be seen in the places cited, and In II, dist. 1, where especially Durandus, q. 5.

6. The assertion is proved by experience.—Absurdities from the opposite conclusion.—And it is proved first by experience; for what is better known to sense than that the sun illuminates, fire heats, water cools? But if they say that we experience indeed that these effects take place when these things are present, yet not that they are produced by them, they plainly destroy all the force of philosophical argumentation, because we cannot otherwise experience the emanation of effects from causes, or gather causes from effects. And to this experience the common consent and voice of all bears witness, who think thus about these things. Secondly, I argue from the drawbacks; for according to that opinion living things cannot be distinguished from non-living ones, because some things would no more have the principle of their actions than others. Then nature would have given in vain to diverse things the various qualities and powers which we experience in them. Indeed, we could not even gather from action the variety of such qualities in the elements, and consequently not in other things either. For if fire does not heat, but God at the presence of fire, He could equally naturally heat at the presence of water; therefore from that action we cannot gather that fire is hot any more than water. For if God could, equally consonantly with the natures of things, have made a pact about heating at the presence of water, let us suppose He did so; then it would not be permitted to gather from the heating that water is hot; therefore neither can we now infer that it is cold, or that fire is hot.

7. Someone may say that that pact was not wholly arbitrary, but founded in some way in the natures of things, not because they are active, but because they have qualities like those to be produced; and so we gather that fire is hot because God heats at its presence, since this pact was founded on such a quality of fire. But this cannot be said philosophically; both because by the same reasoning, according to the natures of things, God ought to have produced whiteness at the presence of whiteness, since, if of itself heat is not a more active quality than whiteness, then from the nature of the thing that pact is no more due to heat than to whiteness. And the same argument can be made about any other quality whatever, indeed about quantity, and about substance, and about anything at all. And also because that has no place in equivocal causes, in which there is no like form or quality, nor is it necessarily more eminent, if they are going to do nothing. Moreover, according to that opinion the dispositions of the earth, rains, prayers, the motions of the heavens, etc., are superfluous, if all these do nothing; but it would suffice, for wheat to exist, that God should generate wheat at the presence of wheat; and so of other things. Moreover, a similar argument is made from the various organs and instruments with which God has composed bodies, especially living ones; for, just as some appear from their very disposition fitted for receiving, so also others are fitted for acting, all of which would be superfluous if these things did nothing. Finally, for this reason Aristotle said very well, II De Caelo, c. 3, and I Ethic., c. 7, that all things are for the sake of their operation; wherefore nothing is more repugnant to the institution of things and their end than to be lacking all efficiency. Moreover, if created things did nothing among themselves, from the nature of the thing all would be equally incorruptible, because they could suffer nothing from a created agent; in vain, therefore, would God have ordained so many motions of the heavens and so great a multitude of causes so that the species of these lower things might be preserved for a long time through the succession of generations and corruptions; for the same things created from the beginning would remain more easily for ever, if God Himself corrupted nothing, because the things themselves would not fight with one another nor corrupt one another. Many similar drawbacks can easily be devised, from which it is understood that the whole order of nature fights against that opinion.

8. The a priori reason for the conclusion.—Thirdly, there is the a priori reason: because to have a power of acting is not repugnant to created things, but rather is most consonant with their perfection; therefore, since God founded each thing perfect in its nature, it must not be denied that He created such things as have a connatural power of acting. The antecedent is proved, because not every power of acting requires infinite perfection; therefore the finite power of a creature will suffice for it to be able to have some efficacy. The antecedent is evident, because no probable reason persuades the necessity of infinite perfection for every action. Rather, as we shall see below, theologians have laboured much to find a reason which proves that infinite power is required for creating; for other actions and changes, therefore, such power is not required, especially in those agents which do not act without dependence on a superior.

9. An objection is met.—You will say that in this very thing a repugnance is found, namely, that something should be an agent and yet dependent in acting on a superior agent; and that therefore infinite power is required in every agent, because, if it acts, it acts by its own power alone and without dependence on another. This objection touches the foundation of the contrary opinion, of which we must speak at length below in treating of the necessity of the divine concurrence; now it is briefly answered by denying the assumption; for just as it is not repugnant to be and to be dependently on another, so it is not repugnant to act and to act dependently on another. For why should it be? Is it because it is repugnant that the same action should be at once from several total causes? But this is false, if those causes are of diverse orders and essentially subordinated. Wherefore, so far is this efficiency of secondary causes from derogating from the divine efficacy or authority, that rather it commends and declares it in the highest degree. For, as St. Thomas argues above, God so communicated His goodness to created things that He also gave them an inclination and power to communicate to others what they participate of the goodness of God Himself, imparting it to each according to its capacity. Because, as Plato said to this purpose in the dialogue On Nature, God is good, and is touched by no envy, nor does He begrudge anyone; and therefore He made all things good and like Himself in the appetite of communicating themselves according to their capacity. Hence some things communicate themselves materially, others formally; it is not repugnant, therefore, that they should also communicate themselves efficiently.

10. Whether God, effecting with secondary causes, does more than if He acted alone.—Therefore what Ailly said above, namely, that God does more by effecting with secondary causes than if He effected all things by Himself alone, is true presuppositively (so to speak), but false formally; that is, if the secondary cause effects something, God is supposed both to have effected the secondary cause itself and to have communicated to it active perfection, in which He shows His power more, and then to act with the secondary cause whatever it itself does; and so presuppositively He does more. But through the very action with which He acts with the secondary cause, He does not do more, nor equally, than if He acted by Himself alone, because He does not apply the whole efficacy necessary to act alone. Hence in such a mode of acting, although He acts with sufficient power in the notion of first cause, yet not with power sufficient in every genus. Nor is this an imperfection in God, because it is not from His need or impotence, but from the voluntary and most prudent application of His power. In which sense what Ailly said is also true, namely, that secondary causes do nothing except by the will of God; for they require, as we shall say below, the concurrence of God, which God supplies not by necessity, but by will; that will, however, is not wholly absolute (miracles being set aside), but is accommodated to the natures of things and as it were from a certain debt of just distribution; and therefore this voluntariness does not hinder such efficiency from being simply natural to created things. Just as they also have the power of acting itself from the will of God, yet not from a will wholly superadded and as it were merely gratuitously joined to the will by which He wills such creatures to exist; but these volitions are connected according to the natural debt and connection of the things themselves. Hence, that God willed fire to heat and water to cool is not merely voluntary, but in its own way due, on the supposition that He willed to create such things. We are speaking, however, of the connatural power of acting; for of the supernatural and infused power there is another account, which does not concern us. And thus at the same time the conclusion laid down has been proved and the foundation of the first opinion solved.

11. What is touched on in the confirmation about essential dependence is to be treated ex professo below in the disputation on creation; now I say only that an equivocation is committed in that proposition: the creature depends essentially on God alone; for that proposition can be understood positively and negatively. Understood positively, it gives this sense: the creature essentially demands to depend on God alone; and this is not true, speaking universally, although perhaps it can be verified of some action or of some thing on account of a special condition, which pertains to the special questions on creation, or on grace, etc. Understood negatively, however, its sense is that the notion of creature, as such, does not essentially demand dependence except on God. And this is true, because by virtue of this it is not excluded that in fact, or according to some mode of production, it can have dependence on God and on some creature, as is evident per se.

The same assertion treated from supernatural principles

12. So far the conclusion laid down has been treated philosophically; but since we said that it also has certainty according to the doctrine of faith, it is necessary to add a few things on this part. This certainty is gathered, then, first from the manner of speaking of divine Scripture, Gen. 1: Let the earth bring forth the green herb; and let the earth bring forth the living creature; where Basil, hom. 9, notes that by virtue of these and similar words natural things received the efficacy of continually effecting the generations and corruptions of things; which Ambrose pursues more at length, bk. III Hexam., from c. 8, and bks. V and VI, almost throughout. Hence, in Mark 4, Christ says: And other fell upon good ground, and brought forth fruit, etc.; and below: For the earth of itself bringeth forth fruit, first the blade, then the ear, afterwards the full corn; and Luke 21: When they now shoot forth their fruit, etc.; and in Wis. 16 it is attributed to a miracle that fire, forgetful of its power, did not consume the just and their garments; and there it is attributed to water that it extinguishes all things, and to serpents that they have venomous teeth for killing, and it is attributed to the divine power if sometimes they are impeded from these actions. Moreover, there are other truths of faith which cannot subsist without this principle. The first and chief is the truth of free choice, which can consist only in a power and mode of acting, as we shall show below. Hence the Council of Trent, sess. VI, can. 4, condemns those who say that created free choice does nothing at all and behaves merely passively. By which definition it plainly condemns the first opinion reported above and defines our conclusion. And (what convinces the matter a fortiori) the Council wills that the human will has efficiency not only in natural operations, but also in supernatural ones, or the free works of grace. From which, by the way, those testimonies are understood which Gabriel adduced to the contrary, in which the discourse is specially of the works of grace, which are so attributed to God as the primary cause that our cooperation is not excluded. For in the same place Paul says both that we are not sufficient of ourselves and that our sufficiency is from God. And he who in one place says that God works in us, in others says that He cooperates with us and that we are cooperators with the grace of God.

13. Nor does the reason taken from the efficiency of the act of sin have less efficacy; for if the secondary cause does not effect, but God at its presence, we do not make evil volitions, but God alone infuses them into us at the presence of objects, which is blasphemous and erroneous, not only because then we would not sin freely, but also because then we would sin not from ourselves but from God. Moreover, an excellent theological reason is taken from the definitions of the Councils concerning the mystery of the Incarnation, by which they teach that there are in Christ two operations and two principles of operating, or operative powers, on which one may read Damascene, III De Fide, c. 15. All which and similar things cannot be true if in created nature there is no power of acting. Finally, from the creation of the rational soul arises an excellent argument, because according to the contrary opinion it is no less true that a man generating creates the rational soul than that fire generates fire; for, just as God at the presence of fire makes fire, and the action is attributed to the fire only because it is a condition sine qua non, and, it being posited, God infallibly makes it, so God at the presence of human seed infallibly creates the soul, and not without that condition. But the consequent is an error in faith.

Second assertion

14. What efficiency Augustine denies to bodies.—I say secondly: not only incorporeal substances, but corporeal ones too, can have physical and true efficiency. This follows from the preceding by almost the same demonstration and with the same certainty; for the experiences, reasons and testimonies adduced proceed both of natural and material causes and of immaterial ones. Indeed, if the discourse be of efficiency through transient action, it is better known and more evident to us that bodies act than that incorporeal substances do. Wherefore nothing need be added in confirmation of this conclusion. Nor is the foundation of the contrary opinion of any weight, because, in order that one body act upon another, it is not necessary that it be penetratively together with it in the same place, but it is enough that they be sufficiently near, as experience itself shows and as is to be declared more at length below. Wherefore, although quantity is not active, yet it does not wholly impede action, just as matter too is not active, yet does not impede the action of the form. For quantity seems to be compared to qualities as matter to form. Hence neither impedes, but rather contributes in its own way to action, if not by acting, at least by sustaining and connaturally applying the principle of acting. To the confirmation, however, it is answered that corporeal substance according to its whole self is not in the lowest order, nor supremely distant from God, but only according to prime matter; and therefore of that we confess that it has no proper power of acting; but according to form, bodies have greater perfection and likeness to God; and therefore according to it they can have the power of effecting. Augustine, however, in the words cited speaks of efficient causes which in some way act of themselves, that is, which have dominion over their actions and can apply themselves to acting. For thus he says: Corporeal causes, which are made rather than make, are not to be numbered among efficient causes, since they can do what the wills of spirits do from them.

Third assertion

15. I say thirdly: although created causes cannot effect a substance according to its whole self, or per se primo, they can nevertheless, from presupposed substantial matter, generate a substance by educing a substantial form. This efficacy, however, is to be attributed to corporeal causes rather than to created spirits. The first part of this assertion is most certain, because created causes cannot create anything, as we shall show in treating of creation; but a substance per se primo and according to its whole self cannot be made except through creation; for it cannot be made from a presupposed subject, because no subject is presupposed to the whole substance, since it is a being complete per se; therefore it must necessarily be made from nothing, and hence through creation. And hence it is that a created spiritual substance cannot procreate another like itself, either in species or in grade, because such a substance, since it is simple in essence, cannot be made except through creation. And for the same reason material substance, as regards matter, cannot be effected by a created cause, whether incorporeal or corporeal; and in this sense we say that a substance according to its whole self and per se primo, that is, as to its whole entity and presupposing nothing of the substance, cannot be effected by a created cause; but on this matter more is to be said in what follows.

16. Substantial forms are made by corporeal supposits.—The second part of the conclusion, however, about the eduction of the substantial form by the proper efficiency of secondary causes, is not so evident and certain as are the foregoing ones about efficiency absolutely, because the effecting of this form is less sensible, and therefore less known to us, than the efficiency of accidents, and because in explaining this efficiency there is no small difficulty, as we shall see in the following section. Nevertheless this part is the more probable, especially taken absolutely and without descending to particular modes of explaining this efficiency. And it is proved, first, because, just as we see fire heat, so we see it generate fire, and the sun produce minerals, and the earth, by the action also of the sun, bring forth grass, etc. Secondly, because, since these things are not made by creation but by generation, neither on the part of the thing made nor from the mode in which it is made is infinite power required for their effecting; therefore such power does not exceed the capacity of created causes; therefore it has been communicated to them by the first cause and is connatural to them. But on this part more in the following section; for it cannot be exactly proved and defended unless the mode of this efficiency is first declared.

17. Spiritual substances cannot effect substantial forms.—The third part of the conclusion, namely, that this efficiency is not to be attributed to created spirits, is evident from the fact that they are disproportioned to an action of this kind; whereas corporeal causes are more proportioned and accommodated. Among created things, however, it is not enough that something be more perfect in order that it can effect something less perfect, unless it is established from elsewhere that it contains it eminently; but created spirits, although they are more perfect than bodies, yet since they are limited to their proper grade, and each to signifying its proper perfections, do not contain corporeal things eminently; and since they are not forms in matter, but wholly abstract, they are disproportioned to inducing forms into matter; on which matter too we shall say more below, in treating of created intelligences, where we shall show that they can effect neither substantial forms nor qualities in bodies; for they cannot alter bodies at the nod of their will. But if they cannot do this, much less will they be able to induce a substantial form into matter; for he who does not have the power of disposing matter, much less can have the power of informing it. Corporeal agents, however, since they can alter and dispose matter, are more proportioned to be able to inform it, either by educing from it or by introducing into it a substantial form, according to the capacity and quality of the form.

18. To the foundation of Avicenna, therefore, as to the former point, we deny that from the first cause only one intelligence or one effect could proceed, because the first cause does not act by necessity of nature so as to be determined to one effect, but is an intellectual agent, having in itself the exemplars of infinite things, whose effecting it defines by its will and choice. The foundation of the second error, however, raises a difficulty pertaining to the following section.

1. Matter is the principle quo of no action.—We ask at the same time about the principal and about the proximate or instrumental principle, because the one cannot be sufficiently explained without the other. It is established, first, from what has been said, that the discourse is only of a corporeal cause, because created spirits can effect no substance, as has been said. Again, since in a created substance there are matter, form and accidents, it is established, secondly, among all, that matter is not the principle of this effecting—the principle quo (I say), or formal principle; for the principle quod is the supposit, as in the other actions; the material supposit, however, although it consists of matter and form and subsistence, and moreover has accidents, yet does not have the power of acting from matter, which is not active, as we have often said. We make no mention of subsistence, however, because it is only a certain mode and terminus of the nature, naturally preceding indeed every action, yet not per se conferring power to act, as we shall say more at length below in treating of subsistence. The whole controversy, therefore, is brought back to the substantial form and its accidents or natural properties.

2. No accident is the principal cause of a substance.—Of which it is established, thirdly, that an accidental form cannot be the principal principle of producing a substance, in which almost all agree. For Major, In IV, dist. 12, is commonly cited to the contrary, but he does not contradict it, nor does anyone else whom I have seen. Nor can there be any reason for doubting, because the principal cause, as we have shown, must be either nobler than, or certainly not less noble than, the effect; for since no one gives what he does not have, how can an imperfect form have in itself, or communicate to its supposit, the principal power of effecting a more perfect form, which it can contain neither formally nor eminently? But the accidental form is more imperfect than the substantial; therefore it cannot be the principal principle of educing it. And this will be more evidently established from what is to be said, both in treating thoroughly of the first opinion and also in confirming our last assertion.

3. The substantial form is the principal principle quo by which the efficient acts.—From this it further follows that, if in a material substance there is some principal principle quo for effecting substance, it can only be the substantial form; for when the enumeration is made, nothing else remains. And this too seems to be received by the common consent of all, because, since the form is the principal act of the supposit and that which principally gives being, it must also be the principal principle of operating, since operation follows being. Finally, because the substantial form cannot be an instrumental principle; therefore it will be the principal principle. The consequence is evident, because neither is there a middle, nor can the form be wholly excluded from the notion of principle, since it is the source of all being and of all properties. The antecedent is evident, because the substantial form does not presuppose another of which it could be the instrument, since it is the first and chief of all; I speak, however, within the same supposit; for if a lower form be compared to a higher, it could be called its instrument, as was touched upon above and we shall touch upon in what follows. And hence also almost all hold it as ascertained that accidents are instruments of the substantial form for producing substance, because the substantial form does not produce a like substance by itself alone and immediately, but using accidents, as seems established by experience and as the argument made for Avicenna in the preceding section proves.

4. These things being posited, then, two things remain to be explained: first, how an accident is an instrument for producing a substance; secondly, how the substantial form is the principal principle for educing a like form. Hence there are two chief difficulties: the first is whether an accident is an instrument in such a way that it immediately attains the eduction of the substantial form itself, or whether it is called an instrument only because it operates dispositively towards the induction of the substantial form, which is the effect chiefly intended by the principal agent. The second is, supposing that the accident attains immediately, whether the substantial form also inflows proximately with it, or only remotely and as it were radically.

First opinion concerning the efficiency of accidents with respect to substance

5. Concerning the first, there is a first opinion, that accidents are instruments only in this latter way, that is, concurring only dispositively; which can be understood either of the accidents which are received in the patient and are themselves the formal dispositions of matter—in which way Philoponus seems to have understood it, II Phys., text 27, and therefore he reduces these instruments to the material cause. In which he speaks both against Aristotle and against reason. For Aristotle reduces seed and similar instruments to the efficient cause, and deservedly, because nothing is called an instrument except what inflows into the effect through some action; and therefore things are properly called instruments of no cause except the efficient. It must be understood otherwise, therefore, of the accidents which are in the agent itself and are the faculties through which it proximately operates, and effectively induces dispositions into the patient, through which it gradually prepares the matter until it becomes proximately capable of the substantial form; and in this way they are instruments for inducing the substantial form, not because they immediately attain or effect it—for their action stops and is terminated in the effecting of accidents perfectly like themselves—but because, as they are subordinated to their proper form, their action tends to the production of a like substantial form. This opinion was held by Scotus, In I, dist. 37, and In II, dist. 17, and more at length In IV, dist. 12, q. 3, whom Ockham follows, In II, q. 23. The chief foundation is that an accident, since it is a being more imperfect than the substantial form, cannot in any way effect it. Some answer that, although an accident is more imperfect in the notion of being, nevertheless in the notion of active principle it can be more apt, and in that sense can be called more perfect in acting. But this is not rightly said, because the power of acting, especially in an accident, is nothing other than its entity; or if it is distinguished in some way, at least by reason, it follows upon it and is commensurate with it; therefore an accident cannot be nobler in acting than it is in being. Otherwise, under the same distinction, someone could say that an accident is the principal principle of producing substance, because, although it is not nobler in being, it can be nobler in action, which is absurd. Moreover, we could never gather from the nobility of the action the nobility of the efficient cause as to its being. And (as Scotus argues) one could say of God Himself that He is nobler in action, although not in being.

6. The more frequent reply of the Thomists is examined.—The more frequent reply, therefore, is that an accident, although it is less noble and therefore cannot by its own power attain the production of substance, can nevertheless, in the power of its substantial form, of which it is the property and power of acting, immediately attain its eduction. But Scotus presses, asking what that power is in whose force and efficacy the accident is said to attain. For it is either something distinct from the accident or not. If it is not distinct, then substance can no more be made in its power than in the power of the accident. If it is distinct, it is either an accident or a substance; if an accident, the same argument proceeds, whether it be called absolute or respective; indeed it will be much less active if it is respective than if absolute. If, however, it is a substance, it will be none other than the substantial form; and thus the form itself will rather be the power of acting and the principle by which the accident attains the eduction of the accidental form¹, than conversely. The Thomists commonly answer, from Cajetan, I, q. 53, a. 3, and q. 77, a. 1, that when the accident is said to make substance in the power of the substance, that in the power is not to be taken transitively, but intransitively, because the sense is not that some power is added to the accident by which it produces substance, but that the accident, by its entity, because this is a certain power of the substance, can attain substance. But this reply does not seem to weaken the force of the argument, because, since heat by its nature is the power and faculty of the substance, when it is said to act in the power of the substance nothing else is said than that heat by its nature has such activity; but this seems naturally repugnant, for an ignoble form cannot be a natural power sufficient to produce a better form.

7. And, lest we seem to stop at words, in order to explain the difficulty which is in the thing itself, I ask whether that action by which the substantial form is educed from the potency of matter proceeds immediately from heat alone, for example, and from the substantial form only remotely and radically, inasmuch as the heat flows from it; or whether it is an action immediately from both forms, from the one as principal and from the other as instrumental. If this latter sense is asserted, the difficulty touched upon in the argument ceases indeed; for in this way there is no drawback in a more imperfect form concurring instrumentally to a more perfect effect; and then that in the power is very well expounded, for it signifies: that is, actually inflowing as aided by a superior power. But then other difficulties arise no less grave. The first, because the experiences which seem to prove that accidents attain the effecting of substance prove that accidents alone effect it, because either the substance does not exist, as when the accidents of consecrated wine generate wine—and the same argument, although less efficacious, is commonly made of red-hot iron generating fire—or certainly because the substance is not applied, as in the sun inducing the substantial forms of mineral things in the bowels of the earth, from which it is very far distant. The second, because according to that interpretation the substantial form is now posited as the immediate principle of some action, which exceeds its perfection. For, because it is disproportioned to this, it therefore received from nature accidental forms through which to act. Whence arises a third argument, which Scotus and Ockham indicated; for if this immediate influx must necessarily be granted to the substantial form, the immediate influx of the accidental form is superfluous. For if the generation is univocal, the substantial form, which is supposed to inflow immediately, has the perfection and proportion required to be a sufficient proximate principle for producing a form like itself; for since heat is in this way sufficient to effect like heat, why will not the substantial form be so for a like form, since it is now supposed that immediate influx is not repugnant to it? But if the generation is equivocal, since the form of the generator is more eminent, with greater reason will it be sufficient for a like action.

8. But if on account of these difficulties the former member is chosen, as seems also to be more frequently received, there remains in the first place, in its force, the difficulty touched upon; for it cannot be understood how a less noble instrument, by itself alone and through the power connatural to it, without the partnership of a nobler agent, should effect a nobler effect. For what does it matter that that instrument is the power of another? For it has from this only either that it is cut off from another, as seed from an animal—and from this the power does not grow, which is as great as the perfection which it receives in itself, not as great as the perfection of that from which it receives it—or certainly it has that it is substituted in place of another for acting, as gravity in place of the generator; and this is what appears wonderful and repugnant, namely, that nature should substitute an imperfect power so that by itself alone and without the actual help of a superior power it should, in place of the principal agent, effect a nobler effect. And moreover there are other difficulties against that way of speaking. The chief is that it follows that substantial forms have no proper activity, but concur only as it were per accidens to every action. For if God, for example, only produced and conserved heat, and afterwards did not immediately inflow into the action proceeding from the heat, He would not be a cause per se, but per accidens, of that action; therefore similarly, if the substantial form is so related to every action of heat, it cannot truly be called the efficient principle per se of the action, but at most will be called the remote principal principle, and by extrinsic denomination, namely, because the proximate principle of acting takes its place, or (to speak more truly) supplies its impotence; for in truth the form itself has of itself no activity. But this seems absurd; otherwise substance would never be per se active or generative of what is like it, nor would there be any action from a created substantial supposit except by reason of the accidents; but this is repugnant to the perfection of substance. For, as Scotus argues, In II, dist. 16, if some accidental form is immediately productive of what is like it, why will not some substantial form be so too? It seems also to be against Aristotle, II Phys., c. 7; for there he attributes a threefold causality to the form: formal, final and efficient; therefore, just as the first and the second belong properly and per se to the form, so also the third.

Second, opposed opinion concerning the activity of accidents with respect to substance

9. The second opinion affirms that accidents are instruments of substance for producing substance in such a way that they proximately and per se attain the production of the substantial form in the power of the other forms whose instruments they are. This is the opinion of St. Thomas, I, q. 45, a. 8, ad 2 and 3, and q. 77, a. 1, ad 3 and 4, and q. 115, a. 1, ad 5; and III, q. 77, a. 3; of Cajetan above; Ferrariensis, IV Cont. Gent., c. 66; and Capreolus, In I, dist. 3, q. 3, a. 2, and In IV, dist. 12, q. 1, a. 3; Giles, Quodl. III, q. 1, ad 2, and in the Hexaemeron, p. II, c. 11; Henry, Quodl. XIV, q. 1; Hervaeus, Quodl. III, q. 12. And this seems to be the common opinion of the Peripatetics. For Aristotle everywhere signifies that natural action and generation take place by means of accidents; whence, I De Generat., c. 7, he says that action, at any rate corruptive action, is only between contraries; but contrariety properly is only between qualities; and in the book On Sense and the Sensible he says that nothing acts or suffers inasmuch as it is fire or water or anything similar, but inasmuch as it undergoes contrariety, that is, inasmuch as it is affected by contrary qualities. Where Alexander observes that, according to the Peripatetic opinion, fire does not put forth action inasmuch as it is fire, but inasmuch as it is hot, that is, not through the form of fire, but through heat. Likewise, II De Anima, text 10, and VII Metaph., text 31, and bk. III De Generat. Animal., Aristotle teaches that seed is the instrument by which one animal effectively generates another. The Commentator too, bk. VII Metaph., comm. 22 and 31, and XII Metaph., comm. 18, says that it belongs to the same power to prepare matter and to induce form; since, therefore, it is established that substance uses accidents to prepare matter, it must be said that through the same it induces the form.

10. Reasons for the second opinion.—The reasons by which this opinion is confirmed are chiefly these: first, because the substantial form is not per se immediately active, but through a power which is a quality distinct from it; therefore neither does it induce the substantial form except by means of an accidental power. The antecedent is evident, first, by induction; for we see that each substance uses accidents for all its other actions, which is true not only of material, but also of created spiritual substances; therefore it is a sign that it exceeds the perfection and limitation of a created substance to be at once the principal and the proximate principle of its actions. Likewise, because the substantial form of itself is determined only to giving being formally; but to actions it is an undetermined principle, because it can almost always effect several actions, to which it is determined through accidents; and therefore it is not the proximate principle of action through itself, but through accidents; therefore the same must be said of the action by which it produces substance.

11. The second reason, which confirms the last inference of the preceding, is that the action through which the substantial form is educed is not properly an action co-distinct from the motion of alteration, which is ordered and tends to it, but is as it were its terminus; and therefore they are not counted as two actions, but as one and the same; but the whole alteration which tends to generation takes place by means of accidents, as is evident per se; therefore the substantial generation itself also takes place by means of accidents. The major is evident, because the substantial form, which is educed from the potency of matter by means of motion, results in the matter by virtue of the motion itself; therefore, speaking physically, it is made by the same action and by means of the same instrument. And it is confirmed, for accidents are the instruments for expelling the substantial form of the thing corrupted; therefore also for effecting the form of the thing generated.

12. The third reason: because proper action takes place only between contraries; therefore only that is the proper principle of such action which properly has a contrary; but such is a quality, and not a substantial form; therefore.

13. Various experiences for the second opinion.—Fourthly and chiefly, this opinion is founded on experiences; for substances are often generated by means of accidents when there is no substantial form from which the action could be, because it is either far distant or does not exist at all. Scotus answers that the fact that a form is sometimes distant does not prevent it from inflowing into the eduction of a form, because by its force and efficacy it can attain distant places. And in this way he thinks that the forms of mineral things are immediately educed by the form of the sun. But when no form is found proportioned or applied within the sphere of its activity, then he says that the eduction of the form is made immediately by the first cause, to which it belongs to supply the defects of lower agents. And in this way he says animals are more frequently generated, not only those which come from putrefaction, but also those which come from seed, in which the power is imperfect and insufficient to educe the soul from the potency of matter. But the former part of this reply is repugnant to the Aristotelian principle that agent and patient must be together, of which a little below. The latter part, however, savours of the opinion of Plato, who says that substantial forms are induced by separated ideas; for if it is true that Plato posited ideas only in the divine mind, it was the same as saying that substantial forms are effected by the first cause. Which also Philoponus taught, I Phys., at the end, where he says that substantial forms come from the universal artificer of nature. Themistius, however, in his bk. I De Anima, c. 24, and bk. III, c. 52, says that they come from the soul of the world. Avicenna, as we cited above, says that they come from the lowest intelligence. From whom Scotus differs in that he says not all forms, but several and the more perfect even of the material ones, are made by a separated agent; which also seems a greater drawback; for since all these forms are educed from the potency of matter, infinite power is not required for their effecting; why then do some of the forms have the power to effect forms like themselves, and not others, and especially those which are more perfect? Wherefore this experience is what most seems to confirm this opinion; for the reasons are certainly not so efficacious, as we shall soon see.

14. But before we settle this point, it is necessary to propose the second, which we touched upon in the reason made above in favour of the former opinion, and which matters much for understanding and rightly defending the latter opinion, although it seems to have been almost wholly passed over by its authors, namely: supposing that accidents are instruments attaining immediately and per se the eduction of the substantial form, whether they are instruments separated from the forms themselves as to causality, or conjoined. And consequently, whether the substantial form is said to be the principal principle of this action only remotely and radically, or also proximately and per se, actually inflowing. And indeed all the authors of the latter opinion seem to judge that accidents are separated instruments; for the reasons and experiences adduced, if they prove anything, most persuade this, for accidents seem to generate substance even when there is no substance concurring with them. And so think, besides the authors cited, Paludanus, In IV, dist. 12, q. 4, a. 1, concl. 3; and there Richard, a. 3, q. 2; and Thomas of Strasbourg, q. 1; Major, q. 1; Hispalensis, q. 1, a. 3, notab. 3; Albert, a. 16. All of whom speak of the sacramental species, which remain without substance; and they attribute to them that they have the same efficiency in the power of the substance which they can have when they are conjoined; which Giles also declares at length, theor. 48 on the Eucharist; Zimara too, theor. 114, treating copiously of that proposition of Averroes, that the agent disposing the matter and introducing the form is the same, thinks that the whole action is immediately from the qualities, and from the form only inasmuch as it communicates its power of acting to the quality. The same at length Cajetan, I, q. 53, a. 3. Nevertheless this opinion has the difficulties touched on above in confirming the opinion of Scotus in the preceding point, because it does not appear how the substantial form can transfuse (so to speak) its whole power of acting into the accidental form, so that even when the substantial form perishes (if need be), and the accidental alone is conserved, the latter alone could effect a substantial form more perfect than itself, since it neither actually has so perfect a being, nor is actually helped by a superior form.

First assertion, for the resolution of the question

15. On account of these difficulties I judge it difficult to pass judgment between these opinions; yet I shall briefly propose what I think. I say first, therefore, that it is not to be denied that accidents are instruments for producing substance in such a way that they proximately and per se attain the eduction of the substantial form. It is proved, first, from the common opinion of so many philosophers, which is not easily to be rejected where no evident reason to the contrary occurs. Secondly, because experience, on which philosophy chiefly relies, confirms this much, and there is nothing that is repugnant, as will be evident in solving the objections to the contrary. Thirdly, because otherwise it will often be necessary to attribute the whole efficiency of substance to universal causes, or even to the first, which in philosophy is to be avoided so far as can be done, because the right disposition of the universe demands that whatever can conveniently and connaturally be done through secondary causes be done through them. Fourthly and finally, because this mode of efficiency is consonant with the nature of the accidental form, which is given to substance not only for ornament and beauty, but also for exercising its actions, as is established of other actions by induction.

16. You will say that the account is different for this action and for the others; for the other actions are accidental, as intellection, vision, heating, etc. But this action is substantial, that is, per se primo terminated to a substantial terminus; and therefore, although accidents are apt instruments for the other actions, they are not for this one, because the proximate principle of acting must be proportioned to the action, and therefore, if the action is of a superior order, the principle must be so too. As, for example, because intellection is a spiritual action, nature would not have given an apt principle for it if it had conferred a material potency or instrument, even though the soul, which is the principal principle, is spiritual; thus, then, for a substantial action an accident will not be an accommodated instrument, even though the form is substantial. To this it can be answered from Cajetan, I, q. 54, a. 3, that substantial generation is not a proper operation or action, but is the terminus of the preceding motion or alteration, and therefore the principle of the alteration is a most apt instrument or principle of the generation. Some moderns so embrace this reply that they found on it almost the whole probability of the opinion of St. Thomas about this efficiency of accidents; and they think that before Scotus no one posited this action as distinct from alteration. I wonder, however, that they could be induced into this opinion, which seems to me contrary both to the doctrine of Aristotle and to their own principles and to evident reason. For Aristotle, in the whole of I Phys. and I De Generat., chiefly aims at distinguishing substantial generation from alteration; and in V Phys., when he says that there is motion properly so called per se in three predicaments, he says that towards substance there is not motion but change, because it is not from subject to subject, but from being in potency to being simply. Hence in the same places he distinguishes the principles of generation from the principles of the other motions, which are proper matter, as it is pure potency, and substantial form, and privation.

17. Whether and how generation is the terminus of alteration.—Next, other authors use words equivocally when they say that generation is the terminus of motion or alteration; for it can be called terminus intrinsically and properly, and thus it is plainly false; for such a terminus of alteration is nothing but the quality which is made through it; indeed, universally it is impossible that an action be the terminus of some motion, because it is of the intrinsic notion of action that it be a way, and that it be made not through another action, but through itself. In another way it can be called the terminus of successive motion as an instantaneous change extrinsically terminating the motion. Which can be understood in two ways. First, that it be a certain indivisible change, or a certain mutatum esse, which reductively pertains to the same motion and in reality is of the same notion as the mutata esse which continue the motion. And this cannot be said of generation with respect to the preceding alteration, because it is neither of the same order as the alteration nor in any way reduced to it. And moreover, because the change terminating a motion within its notion or latitude contributes something to consummating the terminus of the motion within its proper notion and entity; as the mutatum esse in which local motion first is not, consummates that Ubi which is made by such motion, and in that instant begins to be, whereas before it was not yet; and the same holds proportionally in alteration, because in that instant some terminus of the quality is made which before was not. But through generation there is not made some terminus of a quality intrinsically and within its proper genus pertaining to its consummation, but a new form of a higher notion is made. Therefore generation cannot in this way be called the terminus of motion or alteration. In another way, therefore, it can be called a terminus only extrinsically, on account of immediate consecution or concomitance. And this sense is true; yet this does not prevent generation from being a distinct action; for thus illumination is the terminus of a motion, and is a proper action. And the creation of the rational soul can in this way be called the terminus of generation with respect to the preceding alteration, which no one will deny to be a distinct action; and a fortiori the same holds of the union of that soul to the body, since this is an action posterior to the creation of the soul. If, therefore, the generation of a man is an action distinct from alteration, although it is its terminus in that way, the same a fortiori will hold in the rest. And this is most necessary if we suppose (as the said authors suppose) that in the instant of generation the whole preceding alteration and its intrinsic terminus cease to be; for thus generation cannot be called its terminus except because it immediately follows after that alteration; therefore it cannot but be a new action, because the immediate consecution of one thing after another does not take away the newness and distinction of the action.

18. Hence finally I argue a priori, because generation is really and essentially distinct from the whole preceding alteration; therefore it is per se a proper and new action. The antecedent is evident, because it is the eduction of a new form really distinct from the preceding, and it takes place in a distinct subject, namely, immediately in prime matter; whereas alteration takes place either in the whole composite or at least in the matter by means of quantity. Finally, because the whole alteration precedes in duration, and according to a probable opinion its intrinsic terminus too does not remain. The consequence is proved, because that action is the eduction of a new form, which per se primo tends to a new composite one per se; therefore it is per se a new action. They will perhaps say that it is not a proper action, but a certain resultance from the prior alteration. But this cannot be said, especially if we suppose that the accidents which preceded in the thing corrupted do not remain in the thing generated; for a form is not said to result from some action except inasmuch as it results from its terminus, because each action proximately stops in its terminus. Hence nothing results from it mediately except inasmuch as it results from its terminus; if, therefore, in the instant of generation neither the alteration nor its terminus remains, how can the substantial form result from it? They will perhaps say: because it naturally succeeds to it. But this is not to result, for resultance implies some mode of efficiency through natural emanation, which cannot be between things which proximately succeed one another, when to one perishing another succeeds; otherwise the form of the thing generated could also be said to result from the form of the thing corrupted. Wherefore this succession does not take away the necessity of a new action, but most requires it, so that by virtue of it a form may be introduced by which the other is expelled, and consequently the accidents, if they depended on it.

19. Hence they also speak less consistently who, while they otherwise think that the accidents which were in the thing generated do not remain in the thing corrupted, say that the substantial form results in matter by the instrumental power of the accidents which are introduced through motion, as soon as they arrive at a certain terminus; for if those no longer exist, how can they be an instrumental power? Likewise, those which arrive at a certain intrinsic terminus are not the same as those which were before, and according to that terminus they follow upon the form, according to that opinion; therefore they cannot be instruments for it. And moreover, as we touched upon above in disputing on the matter of accidents, even if the same accidents remain, they cannot be instruments for the substantial form, because they have no proper preliminary action by means of which they might be elevated to the effect of the principal agent. Wherefore this instrumental efficiency is to be attributed not to the accidents which are made in the patient and dispose the matter, but to the accidents which are in the agent, from which those others proceed. From which it also follows that it cannot truly be said that the substantial form results from the accidents disposing the matter. Finally, whatever be the case about the name of resultance, and whatever be the case as to whether the accidents of the patient also have efficiency in the eduction of the form, it cannot be denied that that eduction is a new action and one most per se intended, because it is the proper action which is done in the power of the substance; for alteration is the proper action of the accident according to itself, and is as it were a means ordered to generation, which is the action per se primo intended. Just as nutrition too is properly and per se an action, and augmentation, on the testimony of Aristotle, is per se a motion, although neither takes place except with preceding alteration and by means of dispositions with which partial substance can be generated in addition.

20. Otherwise, therefore, must the proposed objection be answered, by granting that the action by which the substantial form is educed is substantial on the part of the terminus, and is nobler than any action or alteration which the accident can perform by its own power, which not Scotus alone discovered, but before him Aristotle taught, bk. II Phys., text 14, and bk. VIII, text 62; Averroes, IV Phys., comm. 129; Simplicius, V Phys., text 8. And after Scotus many of the Thomists followed the same, as may be seen in Capreolus, In I, dist. 13, a. 3, ad argum. contra 1 conclus.; Soncinas, VII Metaph., q. 22; Ferrariensis, II Cont. Gent., c. 17. And nevertheless these authors say, and rightly, that an accident proportioned to the substantial form can of its nature be an instrument accommodated to such an action; because, although in the notion of being the accidental form is of a lower order compared to the substantial, yet in the mode of being they have a proportion, if each depends on matter; and similarly they are commensurate in the notion of disposition and form, and for the same reason they can be proportioned in the notion of instrumental power and of action or terminus; for, just as it is connatural to substance to operate through accidents proportioned to it, so it is connatural to it to be made through accidental dispositions proportioned to it as through an accommodated instrument. Wherefore what was objected about the material potency with respect to spiritual intellection is not similar, because there there would be no proportion, neither in the notion of subject nor in the notion of disposition nor in another genus; and therefore it would not be an accommodated principle. Especially since the intellect is not only an instrument, but in its own way also the principal principle of the intellection connatural to it, as I shall say in the following section.

21. Whether accidents effectively attain the generation of man.—But someone may press that, at least in the generation of man, accidents are not apt instruments such that they could immediately attain the action by which man is generated, because that action is the union of the rational soul to matter, through which proximately the mode of union of the same soul is made, which mode is immaterial, since it is really the same as the soul itself; therefore that unitive action too is spiritual, for it is the same as its proximate and formal terminus; therefore a material accident cannot be the instrument for such an action. It is answered, first, by granting the whole; for in the conclusion we did not say that accidents are instruments for uniting every substantial form with matter, but for educing a form which is, namely, educible; but for uniting the rational form it is enough that the accidents of the seed concur effectively to disposing and organizing the body, while the dispositions themselves only materially cause and demand that union; which is enough for a man to be said to generate a man, although God alone, who creates the soul, also effectively unites it, as Scotus held, In IV, dist. 43, q. 3, a. 3; and Richard thinks the same probable there, a. 3, q. 2. Henry also supposes the same, Quodl. XI, q. 14, when he says that the rational soul, created by God alone in a body disposed by a natural agent, unites itself without new efficiency of an extrinsic agent, but as it were through natural resultance of the union from the soul itself; for from that opinion it also follows that the proximate agent in human generation does not immediately attain by its efficiency the union of the soul to the body, but only remotely by reason of the dispositions; which opinion the Conimbricenses also hold, bk. I Phys., q. 11, a. 3. Secondly, if anyone wishes to defend that accidents instrumentally attain this union, which Capreolus holds, In II, dist. 15, q. unic., a. 3, and more clearly In IV, dist. 43, a. 3, ad argument. Henrici et Aureoli contra 2 concl., it can be answered that that union, although in itself immaterial, yet participates certain properties of a material thing, especially that it depends on matter in becoming and in being on account of its essential and actual relation to it; whence it also has a certain extension on its part; and for this reason it can come about that material accidents are elevated as instruments to make that union, which will not seem difficult to those who believe that the material phantasm is the instrument for effecting the spiritual species.

Second assertion

22. The instrumental form is not a sufficient notion of acting unless the form which is the principal notion is joined to it.—I say secondly: it is not to be denied that the substantial form has its own proper and principal efficiency in the eduction of a like form from the potency of matter, immediately through itself, inflowing together with the accidental and instrumental principle, if in reality it is conjoined and sufficiently brought near; whence it comes about that the accident in this efficiency behaves as an instrument conjoined to the form, and not as wholly separated as to causality. This whole conclusion, and its intent and sense, have been sufficiently declared, I think, in what precedes. And they are made more manifest; for when fire, for example, is generated from tow near to it, we say that the generating fire inflows into the action which is intrinsically terminated at the eduction of the substantial form not only instrumentally through its heat, but also principally through its substantial form; not only mediately and remotely, inasmuch as it gives to its heat that being and that power through which it causes, but also because it proximately inflows in its own genus together with its heat. And we say that this very thing holds in every eduction of a substantial form, if from elsewhere there is no impediment on the part of the agent, either through lack of existence or through distance of place. The foundation of this assertion so expounded has also been intimated above, and consists in two principles. One is that the instrumental form, by itself alone and as it were destitute of the actual influx of the principal agent, cannot be sufficient in the notion of proximate cause for effecting a form nobler than itself. This principle seems to me almost known from its terms, because if that form is not then actually helped by a superior, it inflows only through what it actually has in itself; since, therefore, that is something imperfect, it cannot by itself alone effect something more perfect. Likewise, it is repugnant that heat should effect a substantial form by its own power alone; but when it operates by itself alone without the influx of the superior form, it operates only by its own power, because it has no other, except that which is connatural to its entity or which it has by virtue of its own being. That it has this being from the form of fire, or that by its nature it is its faculty, or that it is substituted in its place so as to act as it were in its name—all these things (I say), since they add to heat only certain relations or denominations, cannot be enough for heat alone, destitute (so to speak) of all superior help, to be the sufficient proximate and immediate principle of such an action. Likewise, because otherwise heat would be the power of producing substance in the same way as it is the power of producing heat, which from the very excess of substance is established to be quite absurd. The sequel is evident, because heat has both inasmuch as it is a certain power of the substance and participates its being from it. Finally, since the power of acting of heat, under whatever notion, is nothing else than its entity and perfection, and this is far less than in the substantial form, it cannot be sufficiently understood how the whole power which by itself alone would be sufficient for the eduction of the substantial form is transfused into heat; therefore heat alone cannot be substituted in place of the whole principal principle.

23. The material substantial form constitutes a supposit able to effect.—The other principle on which the assertion laid down relies is that this mode of activity, speaking per se, can belong to the material substantial form, if from elsewhere the general conditions required for acting are not lacking. This principle, however, seems sufficiently proved in the reasons made last in favour of the opinion of Scotus, which Aristotle confirms not a little, II De Gener., texts 54 and 55, where, reproving those who denied the efficiency of forms, he says: To this it is added that they attribute to bodies, in various ways, the instrumental faculties through which things are generated, and meanwhile they take away the cause which pertains to the form. Nor is it enough to say that efficiency is attributed to forms because from them flow the qualities through which alone they exercise all their actions, because, as we said above, this is not proper and per se efficiency, but only remote and radical; for the action which immediately arises from the accidental form alone also depends per se essentially on it alone as on its proximate principle, to omit the concurrence of the universal cause. A sign of which is that if God conserves heat, for example, every action which proceeds proximately from it alone can also be conserved, as even the authors of the contrary opinion confess; therefore it is a sign that the substantial form is not the principle per se of such an action; therefore, if the form can never actually inflow with the accidental faculty, it never has true and proper efficiency, which Aristotle reproved above, and which derogates not a little from the perfection of the substantial form. Moreover, no repugnance can be shown in this mode of effecting; therefore there is no reason why it should be denied; for by a similar consecution we proved above that secondary causes have the power of effecting, because it pertains to the perfection of creatures and to the efficacy of the Creator that they have the power of communicating themselves, so far as is consonant with their natures; therefore the same must be said of substantial forms, as regards this efficiency, if from elsewhere it is not repugnant to them; but no repugnance can be shown, speaking per se, either on the part of the form which is educed or on the part of the educing form. The first is evident, because that form both is finite and is made (so to speak) in a finite mode, that is, by eduction, without any admixture of creation. The second is evident, because that form is not less perfect, nor is it disproportioned, since it is of the same order; for it is an act of matter nobler or equally noble; and by its nature it is instituted for, and most inclined to, generating what is like itself.

24. The reasons of the second opinion are answered.—The first.—Finally, the reasons of the second opinion either do not militate, or do not press very hard, against this activity. For the first reason proves at most that the instrumental activity of accidents is not to be excluded, but does not prove that this influence of the form is impossible or not necessary. Thus the substantial form can be understood to be the proximate principle of some action in two ways: in one way, exclusively (so to speak), that is, without the partnership of another proximate and instrumental principle. And in this way it does not follow that the substantial form is the proximate principle of any proper action. And this at most is what the reasons made in that argument prove. In another way it can be understood that the substantial form is the proximate principle, that is, immediately inflowing through its substance into the action or effect, yet not alone, but as elevating or aiding the instrumental power, and as determined by it to such an action. And in this way we deny that it exceeds the perfection of the substantial form to be the proximate principal principle of acting of some action; which we shall show to be true not only in substantial generation, of which we are now treating, but also in some accidental operations, in the following section. Nor do the reasons touched upon in that argument proceed against this, because this mode of effecting does not exclude the accidental faculty or instrument.

25. The second.—The third.—The second reason, however, proceeds from a false foundation, as is established from what has been said, namely, that generation is not properly an action distinct from alteration. The third is of little weight, both because for efficiency in strictness contrariety or privative opposition suffices, especially where the effecting is not through proper successive motion, but through instantaneous change, such as substantial generation is; and also because, although formal contrariety is between qualities, yet radical (so to speak) contrariety is in substantial forms; and therefore the quality alone is not always the principle of action, but sometimes the form too, especially when through the action not only the contrary quality, but also the form repugnant to the other form, is to be introduced. Finally, although corruptive action is only between contraries, nevertheless the qualities themselves effect not only formally contrary qualities, but also forms, in which is the root of the contrariety and repugnance. It is a sign, therefore, that, although the action begins from proper contrariety, yet it does not stop in it, but extends as far as its root; what wonder, then, that the form itself can, in its own genus, be the principle of such efficiency, at least as it attains the substantial form and the root of the contrariety? The experiences, however, which were adduced last, do not proceed against this conclusion, which is laid down only on a hypothesis, namely, if the form is sufficiently present; what must be said of them, however, will be established from the following assertions.

26. It is shown that the first conclusion is not opposed to the second.—Only Scotus's objection can be brought against these two conclusions; for this second seems to be repugnant to the first, because if the substantial form by itself proximately inflows to effect a like form, the immediate activity of accidents is superfluous; for if heat by itself alone suffices, in the notion of proximate principle, to effect like heat, why will not the form of fire alone suffice to educe a like form, since we now suppose that it can immediately inflow into it? But if that suffices, another principle is superfluous. It is answered, first, that it was necessary for accidents to have instrumental activity because, as we shall say at once, they are given for acting not only in the presence of the form, but also in its absence; for this is often necessary for natural generations. Next, from this we elicit that the proper power of disposing and preparing the matter and the instrumental power of educing the form, when it is educible, are conjoined by the nature of the thing; and therefore, although we should grant that, on the part of the form, when it is sufficiently present, another active power is not absolutely necessary, yet because this one is otherwise per se necessary and connatural, it therefore concurs then too and helps the action much. Finally, it can perhaps be added that even then that power is necessary, because the substantial form by itself alone is never a sufficient principle of action, since of itself it is indifferent and as it were a general principle of action; and because, just as the substantial form, on the part of the matter, requires accidental dispositions, although the accidental form does not require them, so on the part of the principle it requires the partnership of an accidental instrument in order to be educed from the potency of matter.

Third assertion

27. I say thirdly: accidents are not so conjoined instruments of substance for educing the substantial form that they cannot exercise their whole activity with respect to substance, even when they are disjoined from or distant from the substantial form. This is the clear opinion of St. Thomas, which all the authors cited above follow, both in the second opinion of the first point and in the second point. And it is proved by the natural experiences adduced above, and by that which, supposing the mystery of the Eucharist, is taken from the action of the species of wine. The a priori reason, however, is that in these accidents, by whatever reason their entity is conserved distinct from their proper substantial form, there remains the whole power of acting connatural to them, because this is not distinguished in reality from their entity; therefore, if they are applied in a fitting way to some patient, they will have with respect to it the connatural action by which they dispose its matter to the form proportioned to them; but with this action, if it reaches the required terminus, there is conjoined by the nature of the thing the instrumental action by which the substantial form is educed, because this cannot naturally be separated from the ultimate disposition; therefore accidents of this kind can also have this action, even when they are distant from their proper form, provided they have the whole intrinsic perfection or intensity necessary for acting and for sufficiently disposing the matter.

Fourth assertion

28. I say fourthly: when accidents disjoined from their form so effect a substantial form that they cannot be helped by their proper form, it is necessary that the influx of the proper form, which is lacking there, be supplied by the concurrence of some superior cause, which cannot be some created intelligence, but must be some corporeal cause, such as the sun or another similar one; or, if this too is lacking or is found insufficient, that whole defect is to be supplied by the concurrence of the first cause. This conclusion, as to its former part, follows by necessary consecution from the preceding; for the accidental form alone and destitute of the help of the substantial form is not a sufficient principle in the notion of proximate cause of the substantial form, as was proved in the second assertion; therefore, when the influx of the substantial form is lacking, it cannot consummate the effect of the principal agent unless that influx is supplied from elsewhere, because an effect can never be produced without a sufficient cause. But it often happens that accidents without the influx of their proper form reach by their action as far as the substantial effect; therefore then that influx is supplied by the concurrence of some superior cause, because there is no other principle to which such action could be referred, since a lower cause does not suffice, for the same reason often repeated, and no equal one intervenes. This assertion is declared, next, from a certain common opinion of all philosophers; for all think that some substantial effects are to be attributed to some superior or heavenly cause as the proximate principal cause, on account of the defect of the particular or univocal cause; thus they say that animals which are generated from putrefaction are made by heavenly power; likewise of minerals; and many think the same of the form of the cadaver. But if accidents alone sufficed to effect the substantial form without the help of a superior cause, it would never be necessary to have recourse to a superior cause in these effects, but it would always have to be said that each thing is made by what is like it, either formally or in a power existing in its accidents, without other influx of the heaven or of another universal cause besides that which it has with the other causes. As, for example, if it were true that in red-hot iron there is no formal fire, but only intense heat sufficient to dispose the matter of the tow to the substantial form of fire, then, although such iron would generate fire, neither the heaven nor God would concur with greater concurrence than if fire generated fire, and consequently that generation of fire would be attributed to the universal cause no more than if fire generated it; therefore, by parity of reasoning, when gold is generated in the bowels of the earth, the sun does not concur there by some special influx to the substantial form of gold, but the accidents which sufficiently dispose the matter to the form of gold (for these are always necessary in the eduction of any form whatever) will induce, in the power of the form of gold, a like form; therefore gold is not generated by the heaven, but by gold, and the cadaver by a cadaver, and so of all others; but this is foreign to the sense of all philosophers, who say that in those events the universal cause supplies the defect of the particular; therefore the same must be said whenever a similar defect intervenes. And this will be declared more by running through some effects in particular.

29. Various modes in which accidents can be separated from their connatural or principal substances.—For it can happen in various ways that accidents are separated from their substantial form. In the first way, because by divine power they are conserved outside all substance, as happens in the mystery of the Eucharist. And then the separated accidents—for example, the species of wine—by their own power and the general concurrence of God dispose a drop of water, for example, mixed with them, so as to convert it into wine; when, however, they reach the instant of substantial transmutation, the same accidents apply indeed the whole instrumental efficiency which of their nature they can apply to the eduction of the form; yet because the influx of the substantial form is lacking, it is necessary that, besides the general concurrence, God apply greater efficacy, by which He supplies the influx of that form. Of which matter I have spoken in tome III of the III Part, disp. LVII, sect. 1, where I reported the authors who philosophize thus, and nevertheless call that action natural, because that whole concurrence is due, the prior miracle being supposed; in all other respects the action takes place by natural power and mode.

30. Whether red-hot iron is truly fiery in some part.—In another way it happens that an accident is separated from its proper substantial form because it is in an extraneous subject, as intense heat is in water or iron, or as light is in the air; for we call a subject extraneous not only that which is repugnant, but also that which by virtue of its form does not have such an accident, unless it receives it from an extrinsic agent. An accident, however, so existing in an extraneous subject, if it is of the same species as the dispositions required for introducing the form, is rarely able to effect a sufficient disposition for the connatural form; hence either it must have the form conjoined in the notion of active principle, or the generation will follow wholly per accidens from the disposition of the matter, and then the power of a superior cause will be more necessary. And the reason is that heat, for example, separated from fire or from an animal, speaking per se, does not suffice to dispose the matter sufficiently for the form of fire, because, existing in an extraneous subject, it never has the intensity necessary for the form of fire; nor does it suffice to generate flesh or to introduce a soul, because in an extraneous subject it is not so tempered as the disposition of the soul requires. Which reason proceeds generally of any similar accident, for in an extraneous subject either it does not reach the grade which the other form requires, or it does not have conjoined the other qualities required for the temperament of such a form; and therefore, speaking per se, it cannot sufficiently dispose to that form, and consequently cannot introduce it instrumentally into prime matter. Hence, in that common example of fiery iron, the heat which inheres in the iron does not in truth suffice to generate fire, but it has conjoined some true fire intimately entered into the pores of the iron, by which fire is generated; the heat of the iron, however, helps the speed and vehemence of the action. It sometimes also happens, from the disposition of the patient, that, although the proximate agent introduces only heat in some grade, there results per accidens a disposition to a very diverse form; as, if the matter is moist and is heated by fire, there easily results a temperament of hot and moist, and some form of a mixed body requiring that disposition. And in this way very many mixed bodies are generated, especially imperfect ones; perhaps minerals too are often made in this way. For sometimes it is probable that they are made per se, through the action of what is like them, as it were by accretion and increase, not indeed vital, but by juxtaposition. Animals likewise, which are generated from putrefaction or from rain falling on warm earth, seem to be made in this way per accidens. And in generations of this kind per accidens it is not difficult to believe that the power of a superior agent is required, by which such forms are introduced; because the proximate agent not only does not have a like or equal substantial form, but also does not have a quality or temperament per se sufficient to dispose and prepare the matter, and consequently not for a sufficient instrumental action either. The dispositions, however, which are received in the patient, as I have often said, do not concur actively, even instrumentally, to introducing their form, because either in that instant they no longer exist, but others resulting from the form, or, if they are the same, they have no proper action there, and therefore neither can they have an instrumental one; therefore in all these generations which take place as it were per accidens, some superior cause which introduces the form is rightly demanded. And the account is almost the same of the introduction of the form of the cadaver, which is made as it were per accidens, lest matter remain without form, and is made not so much according to the action of the agent killing the animal, for example, which is often only a division of the continuum, but according to the material disposition which remains or was previously in the patient. The same holds when from the vehement motion of collision or percussion of bodies fire is kindled, by means of vehement heat which that motion causes in some particle of matter well disposed to it. And finally, the account is the same of all generations which happen to take place per accidens.

31. But if the accident existing in an extraneous subject is not of the same notion, but of a superior one, with respect to the dispositions by which the lower matter is prepared for the form of the thing to be generated, it can come about that by means of that accident the generation of some lower substance takes place, not only per accidens by reason of the dispositions of the matter, but also per se from the intention of the superior agent. Which happens when the principal agent, because it is distant in place, by mediation (as they say) of supposit diffuses some power through the medium, so that through it it may be conjoined to the patient by immediacy of power; in which way the heaven acts on these lower things through light or other influences, which are qualities of a superior order and notion to the elemental qualities by which matter is proximately disposed. And of this kind of action it can be said that, although the principal agent seems to be distant in place, yet it does not cease from actual influx, because it is within the sphere of activity and touches the patient by means of the diffused power. And thus it could be understood that the action is not from the accident alone as from a wholly separated instrument, but as from one conjoined in the notion of causing to its principal agent. But this depends on a difficulty to be treated below about the proximity necessary between agent and patient, and therefore let it be deferred to that place.

32. Finally, an accident, although it is not in an extraneous subject, can be separated from the principal generator, because both the accident itself and its subject are cut off from the generator and constituted so as to take its place in acting. And this happens most of all in the generation of animals by means of seed, which is most properly a separated instrument, not only in subject, but also in place, and sometimes also in time; for it happens that seed effects generation when the generator no longer exists. From which it is also clearly established that such an instrument is separated in causality from the animal from which it was cut off, and therefore in this instrument the necessity of some influx of a superior cause appears more clearly; otherwise, since seed is a very imperfect thing, it does not appear how it could by itself alone effect a far more perfect thing as a sufficient proximate cause. For that it is a power cut off from a more perfect thing and left in its stead, although it suffices for some instrumental action, as Aristotle too thinks, II De Generat. Animal., c. 1², yet cannot be enough for it to be absolutely the total proximate agent. Nor is it enough if someone says that seed is an instrument not only by reason of the accidents, but also by reason of the substantial form, which is in the spirit enclosed in the grosser part of the seed, in which is the seminal and instrumental power. For although this is probable, yet it does not suffice, because that whole substance and its form is much less perfect than the soul which is introduced through its action; it needs, therefore, greater concurrence and help of a superior cause, especially in the generation of animals and perfect living things.

33. By what the organization of the foetus is made.—Indeed some add, especially Scotus, In II, dist. 18, that even for the accidental disposition of the organic body that power of the seed is not sufficient, because that action is so varied and manifold that it in no way appears by what reason it could be accomplished by a simple and imperfect power acting merely naturally. Hence the Commentator, whom Scotus also cites, II De Caelo, comm. 69 and following, says that the seed acts and organizes by divine power. And VII Metaph., text 31, he says that the power of the seed is divine, artful, and like an intellectual power, and therefore (he says) Galen doubts whether that power is the creator or not. Which Galen treats in the book On the Formation of the Foetus, where he ingenuously and willingly confesses that, although he had laboured much in this matter, he had found nothing that satisfied him; he concludes, however, that the wonderful operation of the seed is not without something possessed of reason and intellect. And truly that action is so wonderful that it can scarcely, or not even scarcely, be understood. If, therefore, the very action of organizing the body can scarcely be understood in the seed without some peculiar concurrence and help of a superior cause, what wonder is it that for educing the substantial form itself from the subject matter it needs greater aid and help? For without doubt there is a great difference and a wide distinction between these; for since the organization of the body is not substantial but accidental, it can rightly be understood that for the whole of it there is as it were an eminent and universal power in the seed, whether by reason of the substantial form or by reason of some accidental faculty; for either can be understood to be an instrument of the soul sufficient to effect a temperament of the primary qualities proportioned and connatural to the members of the organic body; there seems only to be required some diverse application in order that the same power of the seed may dispose the various members in so diverse a way and by its force reduce them to the wonderful order which appears in the due disposition of the members. And for this perhaps it is helped by some natural faculty of the maternal womb or by some heavenly influx; or certainly (if need be) by some motion or direction of the author of nature. Especially because the seed does not accomplish from the beginning, by its power alone, the whole organization of the body, but that of some principal part, into which the sensitive soul is introduced, which afterwards gradually accomplishes the organization of its body, as St. Thomas declares at length, I, q. 118, a. 1, ad 4. But as regards the production of the sensitive soul itself, power is lacking in the seed not only as to the mode of action, but also as to the substance of the action (so to speak), and therefore much more for this action does it need the actual help, influx and concurrence of a superior cause, as will easily be established to one who carefully weighs this matter.

34. An objection against what has been said above.—Only this can stand in the way: that it seems to be both against the due order of nature and against the perfection of these agents that in their generations a superior or the first cause should always have to supply the defect of the proximate cause. For when, from a fortuitous concurrence of causes and per accidens, it happens that some generation takes place without a sufficient proximate cause, more from the necessity of matter than from the intention of some natural agent, then it is no wonder that in the form to be introduced the universal cause should have to supply the defect of the particular. But that in the very mode of generation instituted per se by nature the proximate cause should always be so imperfect, or should apply its power in so imperfect a way, that it is never found sufficient for the effect, seems to be both a disordered institution of nature and a great imperfection of the particular causes generating in this way. And it is confirmed, for inanimate corporeal agents have, speaking per se, sufficient power to produce things like themselves; therefore animate things, since they are far more perfect than inanimate things, must have it. It is confirmed secondly, because otherwise it could with the same ease be said that a secondary cause of this kind does nothing in the eduction of the substantial form, but that the whole is done by the first cause supplying the defect of the particular cause. But if this seems a drawback because it is not consonant with the natures of things, that too ought to seem so.

35. A little question for the solution of the objection.—Before I fully satisfy this objection, it is necessary to explain what the universal cause is which supplies this defect of the particular or helps its instrument, which we proposed in the latter part of the preceding assertion. In which we said first that this efficiency cannot be attributed to created intelligences, because we think that they have no power to effect anything in bodies besides local motion, as we shall say below in treating of them ex professo. Hence the actions of natural agents do not per se depend on the concurrence of created intelligences, just as neither do they depend on them in being; and therefore, when they need greater help and concurrence, they do not expect that concurrence or help from them, but from some other cause to which they are per se subordinated. There are not lacking, however, those who say that the intelligences, although by themselves they cannot inflow into bodies in this way, can yet do so through the heavens, as through their instruments. But how difficult this is to understand and to believe I shall say at once. It remains, therefore, that such a universal cause is either the heaven or the very author of nature, God; for besides these no other superior cause can be devised. And the heaven indeed seems of itself a proportioned agent, because, since it is corporeal and from elsewhere is of a certain superior order and perfection, it has a more eminent power of altering lower bodies, as experience itself teaches us sufficiently. And therefore it is no wonder that it should also have the power of generating substances; therefore also of helping accidents towards the generation of substances.

36. Two impediments, however, and those not to be despised, intervene, which seem to render this influence of the heavens upon the substantial forms of things to be generated difficult. The first impediment is universal, with respect to all things which are generated in the earth or in the other elements, whether they be living or inanimate; namely, because either the heaven acts towards the eduction of substantial forms through its accidents alone, or also through its substantial form immediately. If the first is said, the same difficulty arises in which we are engaged: how those accidents, without the actual influx of their own or of another substantial form, suffice per se to educe a substantial form. Unless perhaps someone answers that the heavenly accidents are more perfect beings than are the material forms of generable things, especially inanimate ones. But this is absolutely false; for, as I shall show below, the substantial form is a more perfect being than any accident whatever, not only by genus, but also universally and in each case. And in some cases it is incredible per se, as of the form of gold, of silver and of gems, etc. Especially because the heavenly bodies proximately effect these effects by means of qualities which they impress on the air and on other intermediate bodies, such as light, and any other insensible qualities there may be, which are not more perfect than the very form of air, let alone all the others. If, therefore, for this reason the proper and actual efficiency of the very form of the sun or of the other stars is necessary, excessive local distance seems to stand in the way; for how can the form of the sun, immediately through itself, effect the form of gold in the bowels of the earth, so far distant and remote from it? On account of which difficulty Scotus said that some form can act immediately on a distant thing, which the other philosophers can scarcely hear or bear; for this saying of Scotus fights with an Aristotelian dogma received by all philosophers. Nor will he satisfy this difficulty who says that, just as the efficiency of the accidents of the sun penetrates to the inmost parts of the earth, so also does the efficiency of the form of the sun. For the account is not similar on both sides; for accidents diffuse their power by means of other accidents produced by them; but the substantial form cannot diffuse its power by means of substantial forms, as is easily established per se, because it neither corrupts the intermediate bodies nor can add substantial forms to forms, as accidents can. But if the form of the sun diffuses its power only by means of accidents, we fall back into the former difficulty, because now the form of the sun does not itself immediately inflow into the eduction of the other form, but through accidents only.

37. To this difficulty it can be answered in two ways. The first is that the heaven or the sun, through its substantial form together with its accidental power, inflows immediately into these lower things by immediacy of power, even if it is not immediately conjoined to them by immediacy of supposit. This way of speaking, however, both has no small difficulty, and the probable manner of defending it cannot be explained until sect. 4, in which we shall declare how the agent must be conjoined to the patient in order to be able to act upon it; and therefore let it be deferred to that place. The second way is that these substantial forms are not effected by the principal power of the heavenly influx alone, but that it is necessary for the author of nature to apply a greater concurrence, by which He supplies the effect of the proximate cause; and that these effects are attributed to the heaven either by a general reason, according to which the sun and a man are said to generate a man, which we shall declare below in treating of essentially subordinated causes, or sometimes by a more special title, namely, because the heaven takes the place of the proximate cause and applies the whole efficiency which particular causes are accustomed to apply, either for disposing the matter or for educing the form by the instrumental action of qualities, through instrumental powers, even if they cannot inflow immediately through their proper forms. And perhaps in this way the sun effects gold or other minerals.

38. Whether the heaven can effect living things.—The second impediment, less general, concerns the forms of living things; for since the heaven is not animate, even if local distance does not prevent it from being able to inflow through its form, nevertheless its more imperfect grade seems to stand in the way of its being able to inflow into these forms of living things. Some answer that, although the heaven does not live, nevertheless its form, by reason of its specific difference, is simply more perfect than those living things which are generated by the heaven. This reply can be taken from St. Thomas, I, q. 115, a. 3, ad 3, where he says that the heavenly bodies by their universal power contain in themselves whatever is generated in lower things; and q. 105, a. 1, ad 1, he says that the effect is likened to the agent either according to species or according to virtual containment: And thus (he says) animals generated from putrefaction, and plants, and mineral bodies, are likened to the sun and the stars, by whose power they are generated. But in the first place, although with respect to imperfect living things or animals what is assumed in that reply is probable, yet with respect to perfect animals it does not seem likely, because both in their operations and in their mode of operating they seem greatly to exceed the perfection of the heaven. Next, since the grade of life, as such, is more perfect than the grade of non-living things, it seems impossible that a form which is not a soul should eminently contain some soul so as to be able to be the principal principle of causing it; for a form which eminently contains a soul also contains the grade of life, not indeed according to its whole potentiality, but according to its actual and precise perfection; but it cannot be understood that a form contained under a lower grade should eminently contain the perfection of a higher grade.

39. The heaven with an intelligence cannot generate a living thing.—There is, therefore, another reply, that the heaven by its own power cannot effect the forms of living things; yet, because it does not act except as moved by an intelligence, therefore in the power of the intelligence, of which it is the instrument, it can effect such forms. So St. Thomas answers, I, q. 70, a. 5, ad 3; whence in the earlier places he seems to speak of the heaven as conjoined to an intelligence, or as including it. But this reply too is difficult for me to understand, because I do not think that the intelligence impresses anything on the heaven besides local motion, which does not serve to increase active power, but only to vary its application, as Aristotle sufficiently signified, bk. II De Gener., c. 9, text 55, saying: For the impulse produces continuous generation because it brings near and removes the sun, the author of things to be procreated. And it is evident by reason, for what is it that an angel impresses on the heaven besides motion, since it cannot impress any qualities on it? For corporeal matter obeys angels only as to local motion, as the same St. Thomas teaches, I, q. 110, aa. 2 and 3. But if the intelligence impresses nothing on the heaven besides motion, how can it increase its power to act for something beyond its proper perfection? For local motion per se is not active, nor does it give power of acting. Nor in this are physical agents, such as the heavens are, to be compared with the instruments of art, in which motion serves the form of the art, because this is nothing other than a mode resulting from the varied situation or place of some body and its parts, which are varied through motion; but physical agents induce proper and perfect forms, which do not per se result from motion, but only per accidens, inasmuch as the power of acting is applied through motion. Moreover, the heaven by its nature is not the instrument of an intelligence, because it neither has a natural relation to it, nor is any intelligence by its nature conjoined to the heaven or destined for its motion, but only by the choice and good pleasure of the author of nature. Nor does it become an instrument by reason of local motion alone; otherwise whoever applies fire or another acting cause would use it as a physical instrument, and for that reason the applied fire could do something more in the power of the one applying it, which is plainly false. The sequel is evident, because the heaven has nothing more from the intelligence than application, nor does the heaven have anything more or less because it is moved by a more or less perfect intelligence, or by anything else whatever, provided it receives an equal motion. Finally, when the heaven is said to effect living things in the power of a living intelligence, I ask whether the intelligence together with the heaven actually, through itself and immediately, inflows and effects the souls of living things, or only through the heaven, so that the action of the intelligence stops in the motion of the heaven, from which the rest of the efficiency immediately arises. The first is false, and against the doctrine of St. Thomas, as we have often said, and in great part coincides with the opinion of Avicenna. But if the second is said, the difficulty is not cleared, how an instrument not having in itself a sufficient form can effect an effect without the actual help of a superior and more principal cause. It will therefore be said more truly and better that the heaven by its own power indeed cannot effect an animal, as is supposed in the said second reply, yet effects such things in the power of God, as the author and general provider of nature, who by His greater concurrence supplies whatever power is lacking in the proximate causes.

40. Solution of the little question.—Into what effects God inflows as a particular cause.—It must be said, therefore, that whenever in these lower things the influx of the substantial form for educing a like one is lacking, it is supplied by the power of the heavenly causes in those effects which do not exceed their perfection and power; but in those which surpass them it is supplied by the efficiency of the first cause, to which it belongs to supply the general concurrence necessary to lower causes, according to their natural capacity and need. Hence not only in events or effects which happen per accidens, but also in those which as it were per se accompany the natures of certain things and follow from their natural mode of acting, it pertains to the author and provider of nature, God, to concur in this way with secondary causes for acting. Wherefore sometimes this concurrence of God is due by the general reason of universal nature, lest the order of the universe be perverted or matter remain without form or pass into nothing; just as for water to be moved upward to fill a vacuum is only from the cause of universal nature, and therefore it is believed to take place by the sole command and impulse of its author, unless perhaps this task has been committed by God to some intelligence, because local motion does not exceed its activity and ministry, of which elsewhere. Sometimes, however, such concurrence is due from the proper nature and condition of some particular agent which is not apt to communicate or propagate its nature in another way, as we believe happens in the generation of perfect animals, and in the generation of man is most certain, yet by a far higher and nobler reason. For, because the soul of man is not only more perfect, but also of a higher and superior order than all the rest, therefore for the generation of man not only a greater concurrence of the author of nature, but also a higher mode of effecting the soul is necessary, namely, through creation. Whence it comes about that human seed cannot operate even instrumentally towards effecting it, but only towards organizing the body. In the generation of other animals, however, even perfect ones, because the souls are material, they are educed from the potency of matter, and therefore the seed can concur at least instrumentally towards their effecting, yet not without the help of a superior cause which supplies the assistance (so to speak) and the actual influx of the principal form.

41. The objection set out above is satisfied.—Nor is there in this any imperfection or disorder of nature, as was objected above, but it is a natural condition or need which the mode of generation and propagation which such a species by its nature demands brings with it. Just as the fact that for the generation of man the infusion of the soul by creation is required is not an imperfection or disorder of nature, but a condition naturally consequent upon such a nature of man, and therefore that action is not extraordinary, but due by common law, the institution of such a nature being supposed; so, then, must it be said in the present case, not by wholly the same, but by a proportional reason. Wherefore, just as in man it is not from imperfection that one man can neither principally nor instrumentally effect a soul like his own, so in other animals it is not from imperfection that they cannot apply the whole principal power necessary for the eduction of their forms, but only the instrumental. For they hold as it were a certain middle place, and because in comparison with the rational soul they have less perfect souls, being material, they can therefore apply some efficiency, at least instrumental, to effecting them, which man cannot; but because, in comparison with inanimate things, the forms of living things are far more perfect, more things are required for their effecting and an exquisite and peculiar mode of generation; and thence it comes about that particular causes cannot apply the whole principal power, but only the instrumental, to effecting them. Nor, because sufficient principal power is not found in them, is instrumental action also to be denied them, because they are found sufficiently proportioned to this, and not to that; but nature has given to each corruptible species power and action to propagate its nature, so far as it could give according to its capacity and mode of operating; and therefore it gave to man that he should act at least by disposing, to others that they should act instrumentally, but to others also that they should act principally. Wherefore that way of speaking by which St. Thomas and others, as we saw above, call secondary causes instruments of the first, is verified with a certain greater propriety in living things, especially perfect ones.

42. I know that other ways of speaking can be devised; for, because in the more perfect animals the seed does not accomplish generation except as conjoined to the female, some have thought that the soul of the female herself has a peculiar principal influx in the substantial formation of the foetus. Of other imperfect living things, however, especially plants, some say that the form of the thing generated does not substantially exceed the form of the seed itself, as appears in wheat and other such things. But these and similar views have many difficulties, which it is not permitted to pursue in this place, because they depend much on the science of the soul; and therefore the most probable opinion of all seems to be the one we have expounded; and experience itself teaches that these living things are per se less sufficient and need greater aids, not only for inducing the substantial form, but also for disposing and organizing the matter, as is established in plants; indeed, even among inanimate things, simple bodies are generated more easily than mixed ones; there is no drawback, therefore, in confessing that living things need a superior concurrence for generating things like themselves, although they themselves are not lacking some power and action proportioned and connatural to them. And in this way we think the foundations of the first opinion have been abundantly satisfied; for they prove our second and fourth assertions, but press nothing against the first and third, as we sufficiently declared in their discussion. The second opinion, however, we do not think contrary to the doctrine handed down by us, nor can its foundations stand in the way at all, as has been shown.

1. What the causes of doubt are on each side.—The reason for doubting is that a substance effects an accident either by means of an accident, or by itself alone and through itself. If the first is said, a process to infinity follows; for if one accident is made by means of another, I ask of that other by what principle it is made; if by means of another accident, the same question returns about that one; but if we stop at some accident which is made proximately by the substance, this ought to have been said of the first, because there is no greater reason for one than for another. If, however, on account of this reason, the substance is said to effect the accident through itself, it follows, first, that no accident is the principle of effecting another. It follows, secondly, that the powers and faculties for operating in created substances are nothing other than their forms. Or certainly, if, to avoid these drawbacks, some accidents are said to be made immediately by the substance through itself, but others by means of accidents, it will be necessary to give some reason for this distinction and difference, and to disclose which accidents are made in the one way or the other. And again it will be necessary to expound, when one accident is the principle quo of effecting another, whether it is principal or instrumental. For hence it appears that an accident can at most act as an instrument of the substance, because it is only a being of a being (as the philosophers say), and has its whole being from the substance and for the sake of the substance as for its end. From elsewhere, however, it seems that it must be a principal principle, since the effect does not exceed its perfection.

2. To explain this matter, I suppose that accidents can be made in two ways. In one way, by proper action, as when light is made by illumination, or an Ubi by proper local motion. Secondly, by natural resultance, as a relation results from the foundation when the terminus is posited (if it is a mode distinct from the foundation), or as figure results from division, or from motion or the terminus of local motion; and the proper passions of things are also thought to be made in this way. In a third way, however, an accident could be understood to be made concomitantly with the substance without resultance from it, as quantity, for example, with prime matter; which mode we now omit, because, if it is true, it can be brought back to one or other of the preceding, as we shall explain, and because in that mode of production, whatever was the principle of effecting the substance will be the principle of effecting the accident which is made with it.

First assertion, concerning natural emanation

3. I say first, then: when an accident is made by natural emanation, the proximate principle of it according to such a mode of efficiency, whatever that may be, can be the substance, if such an accident is immediately connected with it; sometimes, however, it can result by means of an accident, if it has a nearer connection with that. This whole conclusion is commonly received, and can, first, be declared by induction; for the intellect, for example, flows proximately from the substance of the soul, and quantity from matter or from form. Hence with respect to these properties no intrinsic accidental principle can be assigned; therefore it is a substantial one. But figure, for example, or Ubi, results by means of quantity, and whiteness results from such a mixture of the primary qualities. The reason for doubting set out at the beginning also proves this conclusion, because, if an accident belongs to a substance from within, it cannot always belong to it by means of an accident as its intrinsic principle; but some accident and the substance must necessarily be immediately connected; yet it is not necessary that all intrinsic accidents be of this kind. And the reason for the diversity among them is easy, because some of them have a more immediate order to the substance than others.

4. I see that it can be answered that, although some accident is intimately and immediately connected with the substance, it is not necessary that it be connected through effective emanation of the accident from the substance, but only on account of natural aptitude and inseparability, as we said above that we can probably think concerning matter and quantity. And according to this it will not be necessary that any accident emanate immediately from the substance, but that it be received immediately in the substance from the same agent by which the substance is produced. Nevertheless the conclusion laid down supposes the contrary opinion as more probable, namely, that accidental properties, especially those which follow upon, or are due to, the thing by reason of the form, are caused by the substance not only materially and finally, but also effectively by natural resultance, either immediately, if it is a first property, or mediately, if it is a second. This St. Thomas holds, I, q. 77, a. 6, where he speaks of the powers of the soul; but the reason is the same for any form whatever and the properties following upon it, or due by reason of it. And this is very likely, because, since the substantial form is as first act, but the accidental as second, it is probable that the substantial form has some power so that the accidents proper to it may flow from it. Likewise, because in this way the natural connection between form and properties, and the per se order between them, is better understood. And this is greatly confirmed by the sensible example of water bringing itself back to its former coldness; for that reduction cannot take place except by natural resultance from the form, as was shown above; therefore by the same reasoning the same must be thought of any property naturally connected with the form, especially if from elsewhere there is no repugnance or dependence on something extrinsic. And in that example of water it is manifestly established that the conclusion laid down is true, namely, that some accident can result effectively and immediately from a substantial principle. For that intensification of cold can have no nearer principle from which it results than the substantial form of the water.

5. What natural resultance is, is declared.—The opinion of Cajetan.—But before we proceed further, it must be declared once and for all what this natural resultance is, namely, whether it is true efficiency and active causality or not. Because, if it is true efficiency, a proper accidental action will intervene there; for effective causality consists in action, as we shall see below; and thus the substantial form will be the immediate and united principle of some accidental action, and actions will be multiplied in the production of a form and its properties, and there will be an action per se towards all these things which are co-produced or co-created with others; all which seems foreign to the common doctrine of philosophers. If, however, it is not true efficiency, then neither can it be called efficiency, because what is not true gold absolutely is not gold, nor can it be called such except on account of some analogy and proportion, which in the present case appears to be none; indeed it cannot even be understood what this resultance is, if it is not efficiency. On this, Cajetan, I, q. 54, a. 3, indicates that this emanation is a natural sequel without a mediating operation; yet he does not declare what that natural sequel is, or how it takes place without mediating action or operation. And q. 77, a. 1, ad 2 and 3, he expressly says that this resultance is through efficiency without mediating action, and thinks it is the opinion of St. Thomas, there, ad 3, where, however, he does not say that the emanation of accidents from the subject is without action, but that it is not through any transmutation, but through natural resultance.

6. Wherefore, if we speak strictly, I think it more true that this resultance is not without true action, although it is not always reckoned an action distinct per se, nor a proper change. This, as I think, the reason given sufficiently proves in general, because either this is true efficiency or none at all; for there cannot be a middle. If, therefore, it is true efficiency, action intervenes. If it is not efficiency, neither is it resultance or a causal natural sequel, but only an illative one, because, one thing being posited, another is posited on account of a natural debt. As between the matter and the form of the heaven there is natural illation, yet not emanation of one from the other. Some seem to assign a middle between these, saying that this is not efficiency, but as it were efficiency, which consists only in this, that the cause effecting the substance is determined by reason of it to give it proportioned properties. But in the first place this is in truth no efficiency, but only connaturality, which intervenes also between natural passive potency and act. Next, the example of the reduction of water compels us to confess a greater and truer efficiency. Finally, even granted that, it must be said, as concerns the matter, that the efficient cause of the substance concomitantly effects a distinct property, yet not without a concomitant action, because it is repugnant that a distinct thing be made without a distinct action when the primary terminus of the other action is not itself composed of that thing; because action is only a certain mode of its formal terminus itself and per se, as I shall say below; which reason I shall declare more fully at once.

7. The twofold mode of natural emanation.—Moreover, I argue in this way: this natural resultance sometimes takes place by itself alone and separately from the production of the thing from which it results; sometimes, however, it is so conjoined with it that it is never later, but wholly simultaneous with it; as, for example, when water brings itself back to its former coldness, that is a natural emanation, as Cajetan confesses, the said q. 54, a. 3, at the end, where he also says the same of the motion of a heavy thing generated in a higher place, which, the impediment being removed, naturally results from gravity. But whenever resultance takes place in this way, it is most evident that it does not take place without efficiency and true action and change, as is manifestly evident in the said examples; and the reason is that there something begins to be in the subject which before was not. And it begins per se without new production of another thing; therefore it begins through some efficient cause and through proper action and change; whence that is a proper cooling and local motion. And the reason is the same whenever some accident newly comes to some pre-existing subject by itself alone, or without another prior accident; for if several mutually connected ones come at once, that which is first and the root of the others is thought to come per se, the rest concomitantly. You will say: then, when a relation comes to the foundation upon the positing of the terminus, a new action per se intervenes there, because only that relative accident then newly comes to such a subject. Some answer by granting the sequel; others deny it, because it is enough that it results from the positing of the terminus. Others think that no action intervenes there, because such a relation is not a thing or a mode distinct from the foundation by the nature of the thing, of which we shall see in its place.

8. From this resultance, however, which is separated in time from the production, judgment must be passed about any other, even if it is conjoined in the same instant; for simultaneity in duration does not take away distinction. Especially because, although these are naturally simultaneous, they could be separated supernaturally, which is a sufficient argument of distinction. The assumption is declared; for while God creates the substance of the soul, He could suspend the emanation of the powers from it, and after some time permit it, or give concurrence to such emanation, and then that later emanation would be proper efficiency and true action, by the same reasoning as was said of the cooling of water bringing itself back to its natural state; therefore, even when it takes place simultaneously in time, it is a proper and distinct action. Moreover, the a priori reason was touched upon above, because accidental forms or properties of this kind are things distinct from the substance; therefore, although they are made with the substance itself or result from it, it is necessary that they be made by a distinct action, although concomitant with or consequent upon another. The consequence is evident, because those two, namely, the substance and the property, are not made equally firstly as two parts of one composite terminus, but absolutely the substance is made prior in nature, and then the proper accident results or is added to it. As when the soul is created, the creative action¹ per se is terminated at the substance alone; for that alone is made from nothing and per se terminates that action; therefore, in order that some distinct thing be added to it, another efficiency is necessary, and consequently a new action, although from natural connection it necessarily accompanies the other. Add that the proximate principle of such efficiency, according to our opinion, is also distinct; for it is the intrinsic substance itself, which is the terminus of the prior action. Likewise, the material principle is often diverse; as in the said example of the creation of the soul there is no material principle, but the substance of the soul itself is the material principle of its powers. The proper terminus too is distinct in reality, as we suppose; therefore there intervenes there an action distinct in reality, although physically, and in the common way of speaking, they are counted as one, because they have intrinsic connection and emanation.

9. A difference to be noted between the aforesaid modes of natural emanation.—In which is to be noted the difference between the two modes of natural resultance which we distinguished above. For when the emanation is such that it can never take place per se and separately, but only as connected to the prior action and its terminus, then it is not reckoned a proper and per se action, and much less a change, but as it were an accidental complement of the prior action. And therefore to such accidents or properties it is said that there is no action or motion per se. But when such resultance takes place per se and separately, as in the reduction of water, then it is reckoned an action per se and a proper change tending per se to such an accidental terminus. Which difference is not so much in reality as in denomination taken from the separation or the concomitance of the actions.

Corollaries of the foregoing doctrine

10. And from the reasons given it is gathered, first, that this resultance is with true efficiency and action only when what results is distinct in reality from that from which it results. For if it is distinct only in reason, although metaphysically one is said to follow from the other, true efficiency cannot intervene there, nor physical emanation, but only metaphysical consecution. As if we say that from the fact that the form is the formal principle of being it results that it is also the principal principle of acting; and the same holds of all similar attributes, which according to our way of conceiving are attributed to a thing as its properties, although they are not actually distinguished from it in the thing itself. For in all these real efficiency cannot intervene, because this is not in concepts, but in the things themselves. Hence it necessarily requires distinction in reality between principle and terminus.

11. What accidents result from a substantial principle.—It is inferred, secondly, from the same principles, that this natural resultance from a substantial principle intervenes only among those accidents which are so connatural that they simply presuppose the very substance whose properties they are. Which I note for this reason, that, according to the probable opinion asserting that the dispositions preceding the form in time are, in the instant of generation, intrinsically terminated in such a grade as such a form requires, and remain numerically the same—according to that opinion (I say), these accidents in the instant of generation do not flow from the form, even though they are properties most connatural to it, as heat is with respect to the form of fire or cold to that of water; not because such a form would not be sufficient for that effecting by way of resultance, but because the quality is supposed to have been already produced per se by the agent through the whole change preceding in time and terminated in the instant of generation, prior in nature to the introduction of the form.

12. A little question is answered.—But you will ask, granted that this resultance does not intervene in the instant of generation, whether it intervenes immediately afterwards by way of conservation. I answer that this question is not peculiar to these qualities which precede in the order of nature; but of all properties which from the beginning result from forms it can similarly be asked whether that resultance is only by way of production in the first instant or time in which the thing is produced or co-produced, or whether it perseveres by way of conservation during the whole time in which the property itself lasts; so that, just as in illumination not only does the light persevere, but also the action of illuminating, so in the soul having intellect not only does the intellect persevere, but also the emanation of the intellect from the soul; and similarly in fire or water not only does the heat or cold persevere, but also the actual emanation from its form. In which doubt I see that nothing can be determined by certain reason, but that both can be made probable by conjectures; for after that property has once been effected by natural emanation, there is no reason why it should need continual conservation, since it already has perfect being and is in its connatural subject. From elsewhere, however, it appears probable that that actual emanation does not cease, because its principle is most present and most conjoined, and always has the same power to continue it. Likewise, it is necessary that that property be actually conserved by God; therefore, since there is there an intrinsic and proximate principle by means of which it can be conserved, it is more natural that it be conserved by means of it. Likewise, in this way the greater resistance is better explained, which, other things being equal, can exist in expelling a property from its proper subject than from an alien one. Hence this part seems more likely; and, it being supposed, it must consequently be said that, although in the first instant of the generation of water, for example, the coldness does not flow from its form, because the water already finds coldness produced by the generator, yet afterwards, the action of the generator having ceased, it is conserved by the intrinsic form through natural emanation, in the same way as if it had flowed from it from the first instant.

13. The unity and distinction of natural resultance.—It is inferred, thirdly, from what has been said, that this emanation or natural resultance is something distinct in reality both from the resulting form and from that from which it results, and also from the actual information; for all these can be present without natural resultance; therefore it is something distinct from them. The antecedent is evident; for cold is in the air, actually informing it, and is accidentally conjoined to its form; and yet it does not flow from its form; heat, however, is also conjoined and informs, and moreover flows from the form; therefore emanation adds something. You will say: although this seems so when comparing the proper accident with the extrinsic one, yet in the proper accident itself this resultance or emanation does not seem to be something distinct from it as actually informing. But against this is, first, that to inform is one thing, to emanate another; the former pertains to the notion of cause, the latter to the notion of effect. Secondly, in the example set out above of the ultimate disposition, which in the first instant does not flow from the form, a proper accident is found actually informing and conjoined to its proper form and not resulting from it, which yet in the subsequent time results or is conserved; therefore this resultance is something distinct from the proper accident as actually informing. Thirdly, it is declared in this way; for this resultance, since it is a certain kind of efficiency, does not take place without the concurrence of the first cause; God, therefore, can suspend this concurrence and prevent the intellect, for example, from flowing from the soul, and then by His efficacy alone place the intellect in the soul, because nothing is repugnant in His doing by Himself alone what can be done by means of the soul, the notion of effecting being precisely considered; there, therefore, the substance of the soul remains, and the entity and actual inherence of the intellect, without actual emanation of the intellect from the soul, but from God alone; therefore it is a sign that that emanation is something distinct; for whatever is separable in reality must also be distinct. And hence what we said above is confirmed, namely, that this natural resultance is not without some action; for what resultance adds over the entity of the inhering accidental form is only a certain mode of dependence of the intrinsic property on its form as on an active principle; but dependence on the acting principle and action are the same, as we shall see below.

14. An objection is met.—But you will object: then every action which takes place naturally and without freedom is a certain natural resultance, because, just as, the form of water being posited, such a property results through true action and dependence, and from one property another sometimes also results, as St. Thomas teaches, I, q. 77, a. 7, so, the sun, for example, being posited, light naturally results in the air by means of illumination. I answer that as to this there is some likeness; there is a difference, however, because natural resultance is wholly intrinsic and in a certain manner pertains to the consummated production of the thing, because it tends only to constitute the thing in the connatural state per se due to it by virtue of the generation; but action properly so called, and which is commonly distinguished from natural resultance, is more extrinsic, and supposes, speaking per se, the thing already constituted in its perfect and natural state. Hence it is also commonly said that natural resultance is attributed to the generator, and is not from the form or intrinsic property except inasmuch as it holds the place of the generator and is as it were its instrument. Hence that axiom: He who gives the form gives what follows upon the form, because it belongs to the generator to constitute the thing generated with its due properties; but in the remaining proper actions the thing now operates by its own power, and the action is attributed to it as to the principal agent in its genus. And hence arises another difference, which we shall touch on at once; for we think enough has been said about natural resultance.

Second assertion, concerning proper accidental efficiency

15. The conclusion is proved in the actions of bodies.—I say secondly: when an accident is made by a proper action distinct from natural resultance, the proximate principle of effecting it is always some accident. This assertion touches the common question about the distinction of active power from substance in created things, which is commonly treated both of the substance of the angel and its powers, and of the soul and its powers, and also of other forms and their active virtues. And the conclusion laid down is consonant with the doctrine of St. Thomas, who everywhere establishes in all creatures a distinction between the proximate faculty of acting and the substantial form, as may be seen in I, q. 54, a. 3, and q. 77, a. 1, in which places Cajetan defends it, and Capreolus, In I, dist. 3, q. 4; Soto, in his Logic, ch. on Property, q. 2; Giles, Quodl. III, q. 10; Hervaeus, Quodl. I, q. 9; and it is proved, first, by induction made in all the effects which we experience. For in the first place we see that the elements exercise no accidental efficiency except by means of the primary qualities, which it is manifest are true and proper accidents. Next, they do not have even natural local motion itself except by means of qualities; for although that motion pertains to natural resultance, an argument a fortiori can yet be taken from it. Moreover, the heaven, so far as we can experience, acts through qualities distinct from its substance, namely, through light or illumination; and thence we take an argument that the other, more occult influences are proximately produced through accidental qualities; for if that which seems the greatest and most perfect of all is so produced, much more the others. Again, inanimate mixed bodies, such as metals, gems, and others of this kind, if they have any actions, seem manifestly to exercise them through accidental powers; a sign of which, among other things, is that those powers can be intensified, remitted and destroyed, in which they depend on the temperament of the primary qualities. Which argument can also be made in herbs and plants, which have powers for various wonderful actions of attracting or expelling, and some have virtual heat, others cold, etc.; which powers are remitted in them through the course of time or the change of their temperament, while yet the substance remains the same; it is a sign, therefore, that these powers are accidents. The mystery of the Eucharist too has confirmed this to us; for we see that, the substance being removed, the whole power of acting which was in the accidents is conserved.

16. Also in the actions of spirits.—Ascending further from here to the actions of the soul in each of its grades, so far as we can conjecture from sense, the principles of accidental operations are also accidents, as is evident of vital or nutritive heat and of the power of attracting nourishment or expelling excrement, and similar things; for in the first place the very diversity of actions seems to be a sufficient argument of distinction between powers. And moreover the argument made, that these powers are intensified and remitted, also has place here. Next, in the operations of the senses this seems manifest; for besides the diversity of operations, the very diversity of organs sufficiently indicates that the proximate powers of those actions are per se distinct, and hence are accidental. And in man they must certainly be distinct from the soul; otherwise they would be spiritual entities, which is not likely, as is to be proved more at length in its place. As for spiritual actions themselves and their principles, we cannot have so clear an experience of them; yet, because we cannot philosophize about them except from what we experience, a proportional reason being observed, we rightly gather that the same judgment is to be passed on them.

17. Every active power is really distinct from the substance.—From this induction, then, St. Thomas gathers with sufficient probability that in every created supposit the proximate power of acting and operating is distinct from its substance, and consequently is an accident. But it must be added that every efficiency of a substance, besides substantial generation, is the efficiency of some accident, because a substance cannot effect a substance except by generation; and therefore whatever it effects besides substantial generation, all that is an accident; therefore the proximate principle of effecting an accident is always another accident. Whence it is confirmed; for the proximate principle of effecting substantial generation itself is an accident, and that in two ways. First, by preparing the way for substantial generation, by means of some preceding accidental action. Secondly, by cooperating instrumentally with the substance itself in the eduction of the substantial form, as we saw in the preceding section. Therefore much more will it be the proximate principle of effecting every accidental action, whether principal or instrumental, which we shall see at once. The consequence is evident, because substance is more disproportioned to accidental action than to substantial generation; and conversely, an accident is a more proportioned principle for accidental action than for substantial generation.

18. Reasons for the aforesaid inference.—An a priori reason, however, is difficult to give, although St. Thomas brings several probable ones in the places cited, which Scotus and others attack with many arguments. Cajetan, however, after Capreolus, defends them at sufficient length and copiously; but I think this both laborious and useless, because in truth they are not demonstrations, nor is there reason why they should be demanded by a prudent philosopher in so hidden a matter. For unless it is proved that it exceeds the perfection of a created substance to be the proximate and sole principle of accidental action, no a priori reason can be given by us why these creatures, which now exist and operate, always need an accidental principle for operations of this kind, because we do not know the proper notions of these creatures so as to take from them the peculiar causes of this need or necessity; therefore, if we proceed a priori, we must necessarily stop at the common notion of creature as such, as St. Thomas wisely observed. But if the foundation is taken from the general notion of created substance, it must consequently be said that it is impossible for God to create a substance which operates immediately through itself alone. Which, however, can scarcely be persuaded or proved, because that mode of operating does not seem to require infinite perfection in the genus of being or of substance; but every perfection which does not require this unlimitedness seems communicable to a creature; but if it is communicable, whence is it established that it has not been communicated? Or how can the said necessity be shown from the general notion of creature?

19. Induction in actions ordered to substantial generation.—Nevertheless it must be said that, although this cannot be demonstrated, it is gathered with sufficient probability from the induction made that created substance has, from its limitation, that it cannot by itself be the total and proximate principle of accidental action or form. The reason of which seems to be the disproportion and distance between such a principle and such an action, so that they cannot be conjoined except through some proportioned medium, such as a faculty or accidental potency is. And therefore only an infinite substance, which exceeds every proportion and can overcome every disproportion, is sufficient through itself for every such effect or action. And we can confirm this thus: because every operation of a substance besides substantial generation either tends to effecting substantial generation or not. An action of the former kind rightly requires an accidental proximate principle, because it is an accidental disposition to substance. For if the substance which is generated is such that it cannot be made without preceding accidental dispositions, what wonder that the substance which generates it should also require accidental dispositions, which are at the same time powers of acting and of disposing towards the generation of a like substance? You will say that this reason proceeds rightly of a univocal agent and one of the same notion, but not of an equivocal one, in which there can be a power of a higher notion. It is answered that, if the equivocal agent is finite, as we are now treating of it, judgment must be passed on it proportionally as on the univocal agent; for if it eminently contains the substantial form of the thing to be generated through its substantial form, it will also contain eminently the accidental dispositions to that form through its nobler disposition or accidental property; for since the substantial form is limited and finite in its genus, it cannot by itself alone contain eminently the perfections of diverse genera, nor be per se apt for both actions. Which the mode of acting of all bodies, both lower and heavenly, also sufficiently declares, as was expounded by the induction made above. For just as there is no substantial form, of whatever order or perfection it be, which does not have in its matter dispositions or properties proportioned to it, so there is no form which, in order to dispose other matter to some substantial form, whether equal or inferior, does not use its own accidental dispositions or properties as its own principles of acting.

20. In operations not ordered to substantial generation.—The operations, however, which are not ordered to substantial generation, so far as we can conjecture from the experience of things, are only either the operations of sensitive and intellective life, or various and diverse local motions. I omit illumination and the intentional actions of sensible species, for of these it is sufficiently established that they are produced by sensible accidents. Nor do I number the operations of vegetative life, because all of them per se tend to some substantial generation by addition. Of which the reason is the same as of the first generation; for it too takes place with preceding alteration and accidental disposition, some local motions also intervening, namely, of attraction and expulsion. The other transient actions and operations, even if they take place through eminent powers, always take place either by alteration per se primo terminated at some one of the primary qualities, of which it has already been shown that their proximate principles are some accidents, or they consist only in local motion of attracting or impelling, etc. That, therefore, for the operations of knowing and loving in the sensitive grade accidental faculties are required, a reason can be taken, first, from the very variety of operations and from the varied disposition which they require in their organs. Likewise, from the fact that such actions are immanent in the very proximate principles from which they are elicited; whence, if those powers were nothing else than the substantial forms themselves, all those operations would remain in the substantial forms alone. From which it would further follow that such operations in man would be spiritual, as is the form itself. Indeed it would follow that they would always and in all have to be spiritual; for every form having a proper operation independent of matter as of a subject must be per se subsistent and independent also in its being of matter as of a subject; for independence in operation indicates what independence in being is. And this is the chief principle from which we gather the subsistence and immateriality of the human soul, namely, because its intellectual operation does not depend on the body as on a subject, although it depends on it as on that which supplies the species. If, therefore, the sensitive operation were in the same way independent of matter, every sensitive soul too would be independent, and thus both would be immaterial and spiritual. Therefore from the mode of such material operation it is very well gathered that the substantial form is not per se apt to exercise such an operation without a mediating faculty, which also must be material and come to the matter as already informed by such a substantial form.

21. In intellectual operations.—In intellectual operation, however, this reason taken from the materiality of the action does not proceed; but the other does, about the diversity of operations; and in the rational soul there is another peculiar reason, because by its substantial entity it informs the body; but it does not inform through the intellect or the will, because these powers are therefore not organic, because they do not inform matter. This reason does not comprehend the angels, and therefore in them this matter is more doubtful, as Durandus held and as we shall see below in its place. Nevertheless that general reason, which is taken from the diversity of operations, is sufficiently efficacious in them too; for wherever intellectual operation is accidental, there is great diversity in the operations of that grade, especially in the works of intellect and affection; therefore, since created substance is of itself indifferent to eliciting and receiving such operations, it is more likely that it is determined and as it were accommodated to them through proper faculties and powers. Likewise, every intellectual substance, by the very fact that it is created, necessarily has accidental intellectual operation, as is established of man, and as we shall show below of angels in its place. It also needs other accidental principles, such as intentional species and habits; what wonder, then, that it needs an accidental power proportioned to the operation? Especially because every intellectual nature must have in itself a power per se primo ordered to the operation of understanding or loving, because, since it is instituted for the sake of this operation, it must not be instituted without a power per se primo ordered to it. But a power per se primo ordered to an accidental operation, since it takes its species from it, is also accidental. And to this the reason of St. Thomas seems to tend, that the essence of created substance as such is ordered only to its being, while power is ordered to accidental operation, and therefore they are distinguished in the way in which powers are commonly distinguished by their various acts. For although this reason seems to suppose that the created essence is distinguished from being and is compared to it as a receptive or active potency to act, nevertheless, abstracting from this question, the reason can be accommodated in the way mentioned.

22. Powers moving locally are really distinct from the substance.—And hence finally it can easily be persuaded that the powers which are in created things for effecting various local motions are accidental. First, because if the chief operations, and those more intimate and vital, require faculties of this kind, then much more local motions. Secondly, because in natural things we experience that local motion, even the most natural, takes place by means of an accidental faculty, such as gravity or levity; therefore much more, when the magnet draws iron to itself or rhubarb expels bile, they do this by accidental faculties; therefore the same will hold in all similar cases. Thirdly, because local motion, although in this respect more perfect than the others, that it transmutes the substance or subject less, yet in this seems most distant from substance, that it is neither per se ordered to it nor has almost any agreement or likeness with it; and therefore it is no wonder that the substantial form is not apt by itself to effect this motion without an accidental faculty. It is established, therefore, universally, that created agents effect accidents through accidental proximate principles.

23. What the authors of the opposite inference asserted, and their foundations.—There have not been lacking philosophers and theologians who, at least in part, have contradicted this conclusion, either in treating of the powers of the soul or of the powers of angels, as is evident from Gregory, In II, dist. 16, q. 3; Scotus, q. unica, and In IV, dist. 45, q. 3; Durandus, In I, dist. 2, q. 2, and In II, dist. 3, q. 5; Marsilius, In I, q. 7, a. 7, and In II, q. 17, a. 2; and from other philosophers, In II De Anima, with whom we must deal there; and of angels we shall say something below. I note only now that there is a difference between Scotus and Gregory and their followers, in that Gregory posits no distinction at all in reality between forms and their faculties. Whence it comes about that he grants that the soul understands, wills, sees, hears, etc., through the same proximate principle, which is quite absurd. Scotus, however, to avoid this, posited a formal distinction between the powers and the forms. But if by formal distinction Scotus understands a distinction which is not actually in reality, but at most virtually and fundamentally, and is completed by the mind, he differs from Gregory and the others only in the way of speaking; but if he understands a true actual distinction which is in reality, at least modal, first, he does not contradict the conclusion laid down, because that mode will be a certain accident, which is enough for the truth of the said assertion. Next, he undeservedly denies a most proper real distinction; for, as I shall say at once, the proximate faculty of operating is not some mode, but some proper entity and true form; and therefore, if it is distinguished in reality from the substantial form, it is not distinguished as a mode, but as a thing, and hence properly really. Especially because, if there are any reasons which prove a distinction in reality, they prove no less a real distinction than a modal one; and conversely, if the reasons which he and others make against the opinion of St. Thomas were of any weight, they would proceed equally against a modal distinction.

24. I do not, however, think it expedient now to propose those arguments one by one, both because they do not seem to me difficult, and also because they are sufficiently solved by Cajetan and others, and finally because almost all of them tend to prove that things should not be multiplied without necessity; and they prove that sufficient necessity does not intervene here, either by solving the reasons of St. Thomas, or because substance, since it is nobler, could suffice for that for the effecting of which the accident is added. And the reason taken from the former assertion can press particularly against us; for if the powers flow from the essence through true efficiency, then it contains the powers themselves eminently; therefore it will be sufficient by itself to effect whatever it can through the powers. It is answered, however, that there is sufficient necessity for created substance to have principles accommodated to accidental actions, which necessity is sufficiently proved by the inductions and reasons made above; for demonstration cannot be made about all things. Nor does it matter that the substance is more perfect, both because what is more perfect cannot always effect whatever a less perfect thing can, and also because from this it is at most had that the substance is the principal or radical principle, not also the proximate; but it is more to be a principle in both ways than in one only. In which sense we can also say that the substance with its power is something more perfect than alone. Finally, the hand too is more perfect than the pen, and yet it cannot write without the pen. To the last objection we can, first, meet with a sensible example; for water through its form is sufficient for coldness to result from it, and yet without coldness it is not sufficient to cool other things. The consequence, therefore, is to be denied; and the reason can be given, first, because the power of a form or principle can be limited, both to the perfection of its own supposit and to such a mode of action or emanation, as gravity per se moves the heavy thing itself in which it exists, not another. Secondly, because sometimes the formal power or faculty is so accommodated to the action that not every virtual one suffices; as the agent intellect, either alone or with the phantasm, virtually contains the intelligible species, and yet cannot per se concur to intellection, but through the species which they effect. Thirdly and chiefly, because I do not think that the essence contains its passions eminently, but only instrumentally; for this is why, as I said, that effect is attributed to the generator; but it can happen that something is an apt instrument for effecting another thing or another faculty, and not for immediately effecting the action of that faculty, as is manifestly seen in the instruments of art.

1. The reason for the difficulty.—Concerning the doctrine handed down in the preceding sections, some shorter doubts remain to be explained. The first is that which is proposed in the title of this section, which can be understood universally both of the activity of accidents upon substance and upon other accidents; yet, because an accident does not effect a substance except with the preceding action of some accident, as has been said, the whole question can therefore be brought back to the proper efficiency which accidents have upon other accidents. And hence arises the reason for doubting, because an accident is said to be the proximate principle of producing an accident in order that it be proportioned; therefore the accident which is the principle of the action will have to be such as is the terminus of the action; therefore quantity will be the proximate principle of effecting quantity, and one Ubi of another Ubi, etc. On the contrary, however, is the fact that, according to the common opinion of philosophers, quality alone is the proximate principle of action, and not all qualities, but some; the reason of which must also be investigated.

2. An accident can naturally emanate from an accident.—In this the distinction set out above must be premised, about activity through natural resultance or through proper action, and it must be supposed that the discourse is only of the latter; which is said once for the whole disputation, because that resultance is counted as one with the production of the thing; but if sometimes something singular must be noted about it, we shall not omit it. In the present case, then, just as we said above that an accident can result from a substance, so from any accident another can result, distinct either really or at least modally, if it is capable of such a property; for thus from quantity results figure, or the relation of equality, if it is a distinct mode; and from one relation, as many say, another can result, as likeness from paternity, etc. And the reason is that each essence, whatever it be, can be the principle of its intrinsic property through natural resultance of it.

3. Among accidents, quality alone is the principle of true effecting.—Of proper accidental efficiency, then, it must be said, first, that quality alone can be its proximate principle. This assertion can first be proved by experience; for all actions which tend to substance are commonly produced by means of qualities, either primary ones or those which eminently contain the primary ones; vital actions too are produced by means of qualities; the faculty of moving locally, too, is always some power of the predicament of quality, so much so that even for the motion of projectiles philosophers think that an impressed impetus is necessary, which is a motive quality. Secondly, it can be proved by a brief discourse through the other predicaments; for quantity is not productive of another quantity, as experience proves. And the reason is, first, because quantity follows matter, and therefore imitates its nature and is for receiving and not for acting. Secondly, because quantity is in truth not producible anew per se; indeed (according to our opinion) not even concomitantly, so that what before was not now begins to be through the actions of natural agents, because we think quantity is coeval with matter. But it only comes about that the quantity which before belonged to one thing begins, together with the matter, to belong to another; whence, if it is added to a pre-existing thing, augmentation takes place, either proper or improper, according to the diverse modes of that change. That change or addition, however, always takes place with preceding alteration and generation or generation by addition, of which the proximate principle is quality; and therefore quantity has no action of which it could be the principle; for the termini of quantity, which sometimes result when division of the continuum is made, etc., are made rather by natural resultance than by proper efficiency, of which we are treating.

4. In relation.—Again, relation, by the opinion of all, is not active; and the reason is frequently given that relation is of the least entity; and a fortiori this is confirmed from the divine relations, which as to what is proper to them are not active, as theologians teach, from that certain principle that the actions of the Trinity ad extra are undivided. But setting aside the divine relations (of which I think the proper reason is that they are only for subsisting, and subsistence as such is not the principle of acting, but only the terminus of the nature, which is the principle of operating, as is discussed more at length in the matter on the Incarnation and the Trinity), of created relations the reason can be given, according to a probable opinion, that they add no thing to their foundation; hence they are not active except by reason of it; but if it is not active, there is no source from which they could have efficiency; but it will never be found active except when it is some quality. Add that relation, as relation, cannot be the principle of effecting an absolute thing, since they are of diverse orders, and it is a preposterous order that an absolute thing should follow upon a relative one. Nor can a relation make a relation, because a proper relation is not made per se, but inasmuch as it results when the foundation and terminus are posited.

5. In action.—Whether immanent actions are principles of true efficiency.—Further, action is not truly and properly a principle of acting; for, as we shall show below, it is the very causality of the agent, and in this its notion consists; but causality is not the principle of acting, but is from the principle which it presupposes. Likewise, if action is compared to its terminus, it is not the principle of acting it, but the way to it, or its dependence on its principle; but if it is compared to other things, it cannot by itself be the principle of anything, because it cannot be the principle of another action; for, speaking naturally, action does not immediately follow from action, but at most by reason of the terminus; nor can it be the principle of another terminus, because no principle reaches a terminus except by means of action. And no action can exceed its intrinsic terminus or by itself attain another, because it is identified with it and is only a certain mode of it. But someone will press about immanent actions, which are sometimes principles of effecting something; for many say that intellection effects a really distinct word; others think that cognition effectively causes love or delight; and truer examples are that immanent acts effectively cause habits, and sometimes one act causes another of the same power, as assent to the principles the assent to the conclusion, and the intention of the end the choice of the means. Those, however, are deluded who think that in this efficiency the immanent act does not behave as a principle of producing something else, but is the very production of it; for it is repugnant that actual production be a thing distinct from the thing produced; but the habit is a thing distinct from the act by which it is produced. Likewise, because, if act is compared to act, that which proceeds from another is intrinsically an immanent action; therefore intrinsically and of itself it is a certain production; therefore the other is not its production. Others, on account of this argument, limit the assertion, so that it holds outside immanent actions. But neither is the limitation necessary, nor can any probable reason for it be brought; for why will not illumination too be active, or why will not the effects which come from light be attributed to the illumination itself as to a principle of acting? It is therefore said more truly: just as illumination has its own proper intrinsic terminus, at which it is terminated, and this is the principle of every further action, if there is any, which follows upon the illuminated thing, so immanent actions, as they are actions, have their intrinsic termini, which are qualities, and these are the proximate principles of further action, when it happens to follow; and that this is so is to be proved below, more at length, in disputing about action; but now it is sufficiently confirmed by the argument alone that has been made; for how would an immanent act be the principle of producing a habit, which is a true quality, unless it were itself a quality? Or why do we distinguish in the habit itself the notion of quality from the intrinsic production or dependence by which it is made by the act itself, and in the same act shall not distinguish the notion of quality from the intrinsic dependence or action by which it is made by its power, since habit and act are proportionally compared?

6. In passion.—Of the predicament of passion almost nothing need be added, because, as I shall show below, action and passion are not actually distinguished in reality, but only fundamentally, where action has passion conjoined; hence, if action is not a principle of acting, much less passion; and the reasons given can be equally applied. Only an objection can be made about local motion, which is a certain change and consequently a passion; for passion and change, taken broadly, are the same; but motion causes heat, whence it seems to be its principle. It is answered, however, that local motion per se effects nothing, but is only the way to an Ubi; it serves actions, however, as a necessary or useful condition, either for applying the principle of acting or for removing impediments. And in this way it sometimes causes heat per accidens, sometimes also cold, of which elsewhere.

7. In situation, duration and habit.—Whence quality draws this activity in preference to the others.—Moreover, of place, or of ubi as such, it is established that it is not a principle of acting; for if place is taken for the containing surface, it is not a principle of acting for the same reason that neither is quantity, because such place is nothing other in reality than the surface, but adds some respect or denomination to an extrinsic thing, all which have nothing to do with the notion of acting. I said, however, that the discourse is of place as such, or inasmuch as it is place, because inasmuch as it is a place, either natural or violent, it can have some action upon the thing located, but it does not have it except by reason of some qualities, as is established from philosophy. If, however, we speak of the Ubi as it is the intrinsic presence or mode of the thing located, then it is already manifest that it is not the principle of any action; it is indeed sometimes a condition of acting on account of nearness, as we shall say later; yet it is not the notion or principle of acting, as is sufficiently established by experience itself. The reason, however, seems to be none other than that it is only a certain mode of a present thing and does not per se bring a proper entity, and therefore neither does it per se confer activity. Likewise, because it cannot be understood what it per se does; for it cannot produce another Ubi in another body; for Ubi is not made per se except by local motion; but one thing does not move another locally through its Ubi, but either by impelling or by attracting or in some other similar way. From which it is established a fortiori that neither situation, nor time or duration or when, nor habit or being clothed, are principles of acting according to those precise notions according to which they constitute predicaments; because situation in reality is not distinguished from Ubi except by some denomination, relation or figure; habit only adds a certain extrinsic denomination; but time, and universally duration, either is not something distinct in reality from the thing which endures, or at most is a mode; and therefore all these, formally and as such, are not active, but the things with which they are identified can be active; as, if the thing which endures is a quality or a garment, it can be active by reason of some qualities. It remains, therefore, that among accidents quality alone is per se a principle of acting. And the reason can be given that, in the first place, quality alone, besides quantity, has a proper entity distinct in reality from the substance, and therefore is most properly an accidental form and a proper act, which is necessary for the notion of a principle of acting and in order that it have proper activity. Next, it is such an entity as follows upon the form, and therefore imitates its nature and is attributed to it to be its instrument or proximate power of acting, especially since the substantial form by itself alone is not a sufficient proximate principle of actions of this kind.

8. How many and which species of quality are active.—Not figure.—You will say: if this reason is valid, it proves that every quality is the principle of some action, because every quality follows upon the form, and consequently must imitate its nature. Especially because, just as the substantial form is a certain act, so is quality; but every act, just as it gives being, so also operating. And it can be confirmed, because each thing is for the sake of its operation; otherwise it would be in vain, as is said in II De Caelo, c. 3, and I Ethic., c. 7. Nevertheless it must be said that neither all the species of quality numbered by Aristotle, nor all the qualities contained under the single species, are active, but only the first three species as to some qualities contained under them. I declare each: for in the first place, beginning from the last, figure per se is not the principle of any action, as the common opinion affirms, which is taken from St. Thomas, II-II, q. 96, a. 2, ad 2, and bk. II Cont. Gent., c. 76, and III Cont. Gent., c. 105; and in these places Cajetan and Ferrariensis. Scotus has the same, In IV, dist. 1, q. 4; and Cajetan of Thiene, IV De Caelo, last ch.; and it is taken from Aristotle, XII Metaph., c. 3, text 14, and VI Ethic., c. 4, and II Phys., text 2, in which places he says that artefacts as such do not have a principle of motion or action. The reason of which is none other than that the form which is made by art is only figure, which is not a principle of acting. Hence also St. Augustine, bk. X De Civit., cc. 9 and 11, refutes the error of those who thought that some power of acting was in astronomical figures or images, thence demonstrating that all those things take place by pact and power of demons. The reason, however, is that figure, as is also taken from Aristotle, bk. I Phys., c. 5, text 46, adds nothing to the thing but a certain composition or order of parts, from which arises a certain mode of quantity, which is figure; and therefore it cannot be a per se principle of acting, both because it is only a certain mode, and also because it is a mode of quantity and a property following upon it. Hence, since quantity is not per se active, neither can figure be. And it is confirmed finally, because there is nothing which figure per se does, because one figure cannot effect another like it; for a statue will not make a statue, nor can it make any quality or anything similar.

9. An objection.—It is solved.—You will say: figure at least serves local motion much, the sharp for cutting, the circular for circular motion; on account of which Albert, IV De Caelo, at the end, signifies that sharp figure is a power of acting motion, or at least that it, with other conditions, namely, gravity and hardness, composes that power; and Durandus thinks the same, In I, dist. 45, q. 2, n. 8, where he also adds that the figure of a seal is per se the principle of the like figure impressed in wax. It is answered, however, that figures of this kind are only dispositions on the part of the instrument or body, so that it may more easily be moved or move in such a way, either because it resists less while it is moved by the artificer, as in the motion of a sphere, or because it is resisted less, as in the motion of cutting; for the sharper the instrument, the fewer parts it touches, and therefore it finds less resistance. And conversely, when cutting takes place without motion of the cutting body, by the motion of another, as in a river, sharp figure is a disposition to that cleaving because it serves to resist the flowing water more easily, since through fewer parts it directly meets the sharp thing, and so impresses less impetus. And so also in the figure of a seal, because some parts are sharper than others, and some prominent, others as it were concave, they therefore more easily cleave or press down some parts of the wax than others, and thence figure arises, not because one is per se the principle of the other, but because, some parts being moved locally, such a figure arises. A sign of which also is that the figure arises in the wax in a way as it were contrary to what was in the seal. For the parts which stood out in the seal are as it were concave in the thing sealed, and conversely.

10. In the first species of quality some are active, some not.—In the other three species of quality, however, active qualities are found. For the habits of the powers are principles of eliciting acts, and conversely, acts (which are also placed in the first species and are dispositions) sometimes effect habits. Power, however, is active both of acts and of habits. Passible qualities too are active, as is established of heat. In all these species, however, some qualities are found which are not principles of acting, as in the species of habit, those¹ which are proximately ordered to some being and not to operating, in which order health is commonly numbered, which is called a habit quite improperly. Hence in natural things there is perhaps no example, which some undeservedly take from intelligible species; for those are in truth principles of acting. In supernatural things, however, the common example is of grace, which is in the essence of the soul; but it is more certain of the character, of which elsewhere. In the species of disposition likewise there are many acts which do nothing, namely, when the power either does not need a habit, as in vision, or not such a one as can be effected by acts, as in supernatural acts. Many acts too are not active of other acts or habits, as is evident in all the senses, and in the fruition of God, and similar things. Power likewise is commonly distinguished into active and passive, of which the passive as such is not a principle of acting; although it is uncertain whether there is any quality which is pure passive potency, as we shall see in its place, where we shall also treat whether the power of resisting is an active or a passive power. Among passible qualities too many are not active of things like themselves, as whiteness and other colours, although they effect intentional species. Others, however, effect both, as light or heat, etc. It is difficult, however, to give the reason for this variety. The general one seems to be that substance, for its consummated perfection, needs this whole variety, and therefore received from nature diverse qualities, which according to their diversity might be ordered to diverse effects; hence some were instituted for acting, others for informing or adorning the substance and as it were finally filling its capacity. All which pertain to the office of the form, and therefore the qualities which are not active are neither idle nor lack some participation or agreement with the form. And thus the reason for doubting has been solved. To expound in particular, however, which qualities are of this or that notion does not pertain to this place.

1. The common way of speaking in this matter is that the accidental form is the proximate principle, and the substantial form the principal principle, of all the actions of the supposit, even of the accidental ones. But in what this notion of principal principle consists, or what its influx is, the Doctors either do not declare, or, if they say anything in passing, they intimate that it consists only in this, that the form is the root and principle of the accidental faculty, which was given to it by nature so as to be its proximate principle for eliciting action. In the very exercise of accidental action, however, the substantial form is not believed to have a proximate and actual influx. And the reason can be given both from that principle that created substance cannot be the proximate principle of an accident, and also because for effecting an accident another accident is a sufficient principle.

2. For vital functions not the accident alone, but the substance also, inflows proximately.—Nevertheless I think a distinction must be used; for among these actions some are vital, others not. Of the former it seems it must be said that not the accidental faculty alone, but also the soul itself through its substance, inflows proximately into them in its own order. Experience seems to persuade this conclusion; for these vital actions take place in so intimate a manner that they seem to proceed actually from the very first principle of life, which is the soul; whence it comes about that, although the eye has the image present and receives the species from it, if the soul does not attend, it does not see. Nor does it matter if someone says that this comes from the distraction of the imagination or the common sense, both because I shall make the same argument about the common sense and the imagination. But if it be said that then the sensible species does not pass beyond the external sense, we shall take from that an argument against the former evasion. For if the species of a present sensible object, changing the external sense, does not reach the internal sense when the soul does not attend, this is because the species of the exterior sense is not communicated to the interior sense except by means of the act of the exterior sense. From which it follows that the exterior sense senses prior in nature to the interior's cooperation; for this cooperation seems to follow upon the operation of the exterior sense; therefore the reason why, in the aforesaid case, the exterior sense does not sense does not come from the interior sense, but rather the interior sense is not touched by the species of that object because the exterior sense does not perceive it. Another cause, therefore, must be sought why the exterior sense then does not effect its act, which seems to be none other than that the soul then does not inflow into it or cooperate with it. You will say that the reason is that it does not cooperate, not indeed through its substance, but through the animal spirits, which are necessary for sense and motion. But although it is true that these spirits are necessary, yet this very thing confirms the argument and the experience adduced. For for these vital acts there is required not only the proximate faculty, but also the concurrence of the spirits, which do not flow there by chance, but by the power of some faculty supplying those spirits for that act; therefore there must be some common principle actually using those two faculties, and from natural inclination or sympathy ordering the action of the one to the act of the other.

3. Moreover, another experience confirms this, by which we proved above that there is in man only one soul, namely, because from excessive attention to the work of one faculty it is impeded in the work of another; as, if a man looks at something very attentively, he will not hear one speaking; and lest this be attributed to a defect of the spirits, the attention of the intellect too impedes the operation of sense, and the higher and more perfect it is, the more it also diminishes the motion or representation of the phantasy, and (what is more) also impedes or suspends the works of the nutritive part. But if each faculty had its operation by itself alone, there would be no reason why the operation of one should impede the operation of another; for when powers are multiplied, if one does not depend on another, nor both on one third whose power, while it is applied to both, is diminished in each, there is no reason why their operations could not be multiplied and exercised together equally perfectly. Moreover, an excellent argument is taken from the contrary, from the connection of operations; for while the intellect understands, the will is aroused to love, etc.; but this is because the same soul actually operates through both powers; for a merely habitual rooting, as it were, or remote emanation from the same soul would not suffice for this actual causality or motion and arousing, if each operation proceeded actually from its own power alone without connection in some common principle. And thence also arises the dependence between the appetite of life and cognition, so that nothing can be loved unless it is foreknown. The a priori reason, however, can be taken from the proper mode of vital operation, which requires this intimate connection with its principal formal principle so that it may take place in a manner consonant with its nature, and that its principle or supposit may effect it in a vital mode; for, so far as we can reach by experience, in this consists actual life and the primary difference of living things from non-living ones. And it is confirmed, for on this account all think that sight separated cannot see or elicit vision, nor the intellect understand. Against this opinion, however, some things can be objected, which I prudently omit, because they either are not difficult or necessarily touch on many things which belong to the science of the soul. As for what someone may ask, namely, for what the accidental and vital faculties are necessary if this form also actually inflows, he has a sufficient answer from what was said in the preceding section. For the form is as it were a universal principle, while the power is necessary as a particular, and more accommodated and proper, one, as was declared more at length there. We shall also at once dissolve other lighter objections.

4. A non-vital accident is not necessarily made proximately by the substance.—Of accidental actions, however, which are not vital, it must be said that they can be produced by accidents alone. This is evident in heat, which, existing in water and in any other subject, heats without the form of fire. Similarly whiteness, in order to effect its intentional species, does not need a superior concurrence. Likewise, hence it arises that if a thing has two active qualities, it can exercise the action of both together just as well as of one only; as water at once cools and moistens as much as it can, etc. Finally, the reason for doubting proposed above proves this, because, if the perfection of the effect is considered, the power and perfection of a like or more eminent accidental form suffices to communicate it; but from the mode of action that so intrinsic a dependence is not required, and therefore there is no reason why it should be necessary. Hence, by the way, that reason is solved inasmuch as it can be made against the former assertion. For although it can be doubted whether an operation of life is more perfect in its entity than the faculty from which it proceeds, now, however, supposing that the power is more perfect, we say that on account of the special mode of such an operation the actual immediate influx of the principal principle is necessary. Nor is it repugnant that the substantial form should inflow into the action in this way, if it has an accidental principle by which it is proximately determined to that action; for the accidental form is not always called the proximate principle because it alone inflows immediately, but because it is the principle determining the substantial form to such an action. Just as the particular cause is called proximate with respect to the first, not because the first does not inflow immediately, but because the particular cause is, in its genus, the one determining the action.

5. The substance concurs immediately to the production of no non-vital accident.—Whether organization is a vital action.—But someone will ask concerning the latter part: granted that the influx of the form is not necessary for these actions, whether it is possible and useful; that is, whether heat existing in fire is helped by the form in heating, and consequently whether, other things being equal, it heats more vehemently than when existing in another subject. Against the former part too it can be objected that sometimes a vital action seems to be exercised by some power separated from the soul, as in seed. To the former part I answer that no sufficient sign of that influx is found, and therefore it is not to be asserted lightly and without foundation. Which the mystery of the Eucharist also confirms, where the accidents of wine act equally without the influx of their form. I see that it can be said that God supplies that efficiency on account of faith in the mystery; yet where no necessity compels, there is no need to have recourse to divine causality. To the latter part: it is probable that the seed, as to the spirit planted in it, lives with vegetative life, to which pertains that vital mode which seems to be in the generation of a living thing¹; and so Aristotle seems to think of seed, II De Gener. Anim., c. 1, because it has the power of organizing the body and of generating, which seems the work of the vegetative soul. Nor does St. Thomas seem to dissent from that opinion, I, q. 118, a. 1, ad 1. Secondly, whatever be the case about this, it is answered that the actions of the vegetative soul, as to their substance, are of the same notion as those which are produced by an extrinsic principle; for all are either local motions, or alterations, or the eduction of a substantial form; hence they have the notion of vital action only from a peculiar relation to the soul as to a principle conjoined in the same self-moving supposit. Just as the speech of a man is a vital action, but the speech of an angel in an assumed body is not vital, although they are alike in exterior species. Thus, then, the action of the seed, as it is from it, is not vital, but a merely natural action; that, however, it observes the mode of life in its artistry (so to speak), or in its manner of acting, is to be referred to another, superior principle, as was touched upon above.

1. Some contend that an accident is to be called only an instrumental principle. And this opinion is commonly attributed to St. Thomas, who intimates it In I, dist. 3, q. 4, a. 3, ad 2; and therefore his followers more frequently follow it, and confirm it with these reasons. First, because the accident is essentially subordinated to the substance in being, and consequently also in action. Secondly, because the accident receives its whole power of acting from the substance. Nor does it stand in the way that the proximate principal cause also receives its power of acting from the first; for the second and the first cause are of diverse orders, and it is not repugnant that an inferior principal cause should receive power from a cause of a superior order; but the accident in acting is of the same order as its substance, and with it constitutes one integral proximate agent, and receives its power of acting from it; but to receive power in this way from another of the same order, constituting with it one proximate agent, is proper to an instrumental cause. Thirdly, because such as being is, such is acting; but the being of the accident belongs to the substance, for an accident is a being of a being; therefore the acting of the accident principally belongs to the substance; therefore it belongs to the accident only instrumentally. And the way of speaking of all philosophers confirms this, who attribute all these actions to substances as to first agents.

2. The contrary opinion is held more frequently by other Doctors, as may be seen in Scotus, In IV, dist. 13, q. 3; Paludanus, q. 4, concl. 1; Major, q. 1; Giles, Quodl. III, q. 1, and theor. 43. To declare the foundation of this opinion, however, it must be supposed that there is no question here of the principal cause ut quod, or that which operates, but of the principal principle quo. For it is established that in the former way it is the supposit that operates; but if it is taken formally, as it is the per se cause of accidental action, it must be taken as it underlies the accidental form which is the principle of such action; for thus Aristotle said that Polyclitus makes the statue per accidens, but the artificer per se. In this way, then, the accident is called the principal cause as principle quo, but the supposit, as underlying the accident, as principle quod. And so this opinion is proved: because the accidental form effects another accident by its own power; but the principal cause is that which operates by its own power; therefore. The major is evident when heat effects heat, and universally one accident another like it, or when a nobler accident effects a less noble one, as light heat; for then the perfection of the effect does not exceed the perfection of the accident which is the principle of acting; therefore neither does it exceed its power; therefore then the accident by its own power is the principle of such action. According to which reason this opinion is to be understood of the accident when it operates in this way; for if a lower accident is elevated to effect another of a higher notion, it will not be denied to be an instrument. Let the second reason be that that is the principal principle of acting to which the effect is likened; but through heating as such the effect becomes like the cause in heat; therefore heat is the principal principle of that action. The third, because heat separated per se from the substance exercises its action with the same force and efficacy, so that it needs neither the influx of the substance nor of another cause supplying it, as all confess of the accidents of the Eucharist as regards accidental actions. The fourth, because whiteness, for example, does not effect intentional species as an instrument of the substance, since to that action the substance seems to be related wholly per accidens.

3. This controversy, supposing what has been said in the second doubt, seems able to be only about the way of speaking; for as regards the thing it concerns only what influx the accident requires from the substance in order to accomplish its proper action. But this being established and declared, there can be controversy only about the signification of a name, when it is asked whether it is to be called an instrument or a principal principle. Thus the powers of the soul, for vital actions, can deservedly be called instruments conjoined to the soul, inasmuch as they are subordinated to it as to the principal form, so that they cannot effect their operations without its actual influx and as it were motion; although on another ground they can be called principal principles, at least partial ones, namely, because the power which they have in themselves, and by which they cooperate to the effect, is of itself proportioned and commensurate to such an effect, because it does not exceed the perfection of the faculty itself; for I speak of connatural actions. Hence too the power and the form can be compared as the universal and the proximate principle, but each principal and sufficient and total in its order; yet, because between those two the form is more principal, to which the power is subordinated, this subordination and dependence can be signified by the name of instrument.

4. But in other accidents, which do not so depend in their action on the substantial form, much less of the notion of instrument is found with respect to such actions. Hence, as regards the thing, they are most truly reckoned principal principles of such actions, as the arguments made in the latter place convince, because by virtue of that perfection alone which they have from their species or entity they elicit such actions. Likewise, because such a form alone suffices per se to give the supposit the being per se and formally required for such an action; as in hot water the being per se required for heating is only being hot. Just as, then, heat is a form per se and from its proper notion giving being hot, so in reality it is the principal principle of heating. Nor does it matter or stand in the way that the accident is in the substance and for the sake of the substance and from the substance, because we are not treating of whence, or from what causes, the accident has the power of acting; for we confess that it has it materially from the substance and finally for its sake, and perhaps also efficiently, mediately or immediately, through natural emanation; but we are treating of whether formally it has in itself the whole power sufficient and necessary for that action. And thus we say it has it, and this alone we contend is signified when it is called the principal cause, not ut quod, but ut quo. To which principle it stands in no way opposed that the accident is a being of a being, that is, of the substance, and that its whole being belongs to another; rather that particle ut quo seems to hint and signify all these things. Hence even the substantial form itself, inasmuch as it is the principle quo with respect to its supposit, is in its own way a being of a being. Lest, however, there be contention about a name, we shall also grant this to the former opinion: that if by the name of instrument or instrumental cause there is signified only (as indeed it sometimes is signified) that relation which the accident has to the substance, inasmuch as it was given in order that the substance might operate through it as through its instrument, and for this receives its power from the substance itself and is sustained by and depends on the same in its being, then in this way it can be called an instrument; yet it is more properly called the power or potency of the substance.

1. What conditions are required between agent and patient for action.—We have explained the per se principles of acting of created causes; it remains that we speak of the conditions required for acting, which, although they are commonly numbered as various, yet three seem weightier and more difficult, and to them all the others are reduced. It must be supposed, however, that every created agent needs a patient for action, because, as was said above and will also be shown below, it does not act by creating, but from presupposed matter. The conditions required for acting, therefore, are not to be demanded between cause and effect; for thus they will not be required for acting, but consequent upon action. They are, therefore, prerequisites between agent and patient, or between the efficient and the material cause. The first condition, then, is the necessary distinction between agent and patient. The second, the necessary nearness, the distinction being supposed. The third, unlikeness and proportion; although this third seems in a certain manner to pertain to the notion of acting, as we shall see later.

2. I omit the condition of existing, because, as I have often said, I do not reckon this a condition distinct in reality from the agent or the principle of acting; hence Aristotle rightly said, IV Metaph., c. 4, text 16: Things which are not, how will they either speak or walk? Moreover, because this condition is included in all the others; for if it is necessary that agent and patient be near, much more will it be necessary that they exist; for how will things be near in place which are not in the nature of things? Likewise, we showed above that for acting, even by resultance, it is not enough to have existed immediately before; much more evident, therefore, is it that for proper efficiency existence is necessary. Which in natural efficiency no one will deny; and that suffices for the present purpose; but it is to be understood with proportion, namely, that what acts through itself exists in itself, but what acts only through a separated instrument exists only virtually in the instrument, because it is said to act only by extrinsic denomination from it; but that virtual existence is nothing other than that the instrument itself exists. Which existence we have shown elsewhere to be necessary even in divine instruments.

3. I omit moreover another condition which is commonly required in a material agent, namely, that it be extended and existing in a quantitative mode. For this condition is necessary for these things for acting inasmuch as it intrinsically pertains to their natural mode of being; but whether, that mode of existing being divinely separated, they can act naturally, is not so much a metaphysical question as a theological one, which we touched upon sufficiently in tome III of the III Part, disp. XLIX,¹ sect. 1.

The difficulty of the present question, and various opinions are proposed

4. These things being supposed, the first condition is to be treated in this section. In which a difficulty arises, first, from many examples in which it seems to be shown that a distinction in reality between agent and patient is not necessary: first, on account of natural emanations, for the intellect flows from the same soul and is received in it. Secondly, in the immanent actions of knowing, and especially of loving, for the same soul through the same will elicits love and receives it. Thirdly, in physical motions, for heavy and light things move themselves, and living things more properly, and water cools itself, etc. Finally, reason stands in the way, because, although that condition often intervenes in those things which act by transient action, because it is natural to them to act on other things, yet there is no reason which necessarily demands that condition. For if there were any, it would chiefly be that common one, that the same thing cannot at once be in potency to receive and in act to act; but this does not seem pressing, because, as Scotus argues, it can be in virtual or eminent act and in formal potency, that is, it can have an eminent power for effecting such a form and a capacity for receiving it formally; for in this no repugnance is involved. On the contrary, however, is that axiom handed down by Aristotle, VII and VIII Physic.: Everything that is moved is moved by another, which is so received that it is held as the foundation and principle of the demonstration by which it is shown that God exists.

5. The opinion of some.—In this matter some think that this condition is not necessary in all agents, although it intervenes in many. So thinks Scotus, In I, dist. 3, q. 7, and In II, dist. 2, q. 10, and IX Metaph., q. 14; and there Antonius Andreas, q. 1; Gregory, In II, dist. 6, q. 1, a. 3; John of Jandun, VIII Phys., q. 12, who rely on the arguments made. The Commentator favours them, III De Caelo, com. 28, saying that the same thing can suffer from itself by equivocal action. Others more frequently accept Aristotle's axiom without distinction and require this condition as altogether necessary in every agent, not only as to transient but also as to immanent actions. Which Capreolus expressly declared, In I, dist. 3, q. 3; and Giles, Quodl. III, q. 16, and Quodl. V, q. 15; Ferrariensis, I Cont. Gent., c. 23, where, however, he excepts efficiency by natural resultance, which perhaps (if he spoke consistently) would not be necessary. Others, however, use various distinctions, as we shall explain as we proceed.

Some suppositions for the resolution of the question

6. The agent is not necessarily distinct in supposit from the patient.—First, then, it must be established that it is not necessary that the agent be distinguished in supposit from the receiving patient. This is sufficiently evident from the induction made; and Aristotle expressly teaches it, VII Phys., at the beginning, and VIII Phys., c. 4. Whence he infers that the same thing can move itself, if it is distinguished into a part moving per se and a part moved per se, in which way he says animals move themselves with local motion; and in almost the same way living things move themselves with the motion of augmentation; for they act directly on nourishment, which they convert into themselves and unite to themselves, and so they are increased. Thus too it is not unfitting that the same thing should move itself per accidens, as the soul is moved when the body is moved.

7. In the same supposit the agent is variously distinguished from the patient.—Secondly, it must be supposed that in the same supposit acting on itself the agent can be distinguished from the patient in various ways. First, according to diverse integral parts; secondly, according to diverse substantial and essential parts, as if it acts through the form and receives through the matter; which two modes can have place in bodies, yet not universally in all agents, as we now speak; for spiritual things too act on themselves. Thirdly, they can be distinguished so that at least the faculty of acting is one thing and that of receiving another. Which distinction can be either total and real, or at least as of the including from the included; of all which we shall bring examples later.

8. Various actions about which the question is.—Thirdly, it is necessary to distinguish various actions and to run through them one by one, so that from all we may gather some general rule. Among actions, then, natural emanation or resultance can be numbered first; next, physical and material motions, which of their genus are accomplished by transient action, which, for the sake of clarity, can be distinguished into their species: of alteration, of augmentation and of local motion; I omit substantial generation, for it is known per se that the same thing cannot generate itself. To these can be added the local motion of spiritual things moving themselves; for it is partly like the motions of bodies, because it behaves as a transient action, and partly unlike, because it is not a physical motion, that is, extended on the part of the subject. Finally, besides all these, there is efficiency through the immanent actions of sense or appetite, of intellect or will.

First assertion, concerning natural resultance

9. I say first, then: in natural resultance, although it happens that the proximate efficient is not distinct from the recipient, yet simply that effect is reduced to an efficient cause distinct from the patient. The former part is evident from the argument made above about the powers of the soul flowing from the same; for although in the soul the notion of acting and of receiving those powers can be distinguished, as Ferrariensis noted above, yet, since that distinction is only of reason, it is nothing to the present purpose, especially as regards the first property, which results immediately from the substance alone; for the second perhaps emanates by means of the first, although it is received proximately in the substance alone, as St. Thomas thinks, I, q. 77, a. 8. And the same holds of the substance and powers of angels. In material things, however, the efficient principle (at least as quo) of this emanation can almost always be distinguished in reality from the notion of receiving the emanating property; for it flows from the form, yet is not received in it, since it is not a subsistent form, but is received in the matter or in the composite by reason of matter. Only an instance can be brought about quantity, if perhaps it flows from the entity of matter and is received in it, which is uncertain.

10. The latter part of the conclusion is established from the preceding section; for we said that the property does not flow from the substance or essence as from the principal agent, but as from an instrument of the generator; therefore that effect is to be attributed to the generator as to the more principal cause. But the generator is distinct from the thing generated and from its powers. You will say that the reduction of this effect to the generator is only as to a remote cause and per accidens, which gave the form from which the other faculties flow; but here, as I said above, we are not inquiring into reduction per accidens, but per se and to the proximate cause; otherwise we should easily say that everything that is made is made by another, even distinct in supposit—by another (I say), either one that acts proximately, or one that remotely gave the power of operating. It is answered that this reduction is not to a cause per accidens, but to a principal cause per se; first, indeed, from the intention and ordination of nature, for that power was given in order to operate as the instrument of another whose place it in a certain way takes. As projectiles are said to be moved not per accidens but per se by the thrower who impressed the impetus, not only because he gave the power of acting, but because he gave it with this relation, that it should be an instrument operating in his stead. Next, when the essence does not contain these faculties eminently, but only instrumentally, it is probable that a greater influx of the generator, or of the author of nature, is required than if that cause were the proper and principal one, to which the effect would be wholly attributed; because, by the very fact that the proximate principle contains the effect neither formally nor eminently, it cannot be the proper and adequate cause of it, even in the notion of proximate and principal cause. Wherefore, if in some whole species that eminent power is not found with respect to the properties naturally following upon it, it is necessary that the property which is in the thing generated be made by a like property which is in the generator, or flow from the form with some reduction to the author of the whole species as principally effecting it.

Second assertion, concerning physical motion and action

11. I say secondly: every cause effecting through physical motion and transient action is distinguished in reality in some way from the material cause receiving the effect. This conclusion is consonant with the mind of Aristotle, who perhaps intended nothing else in the place cited; for he treats of the physical motion of corporeal things, makes his induction only in physical motions, and always supposes in his reasons that such motion has parts on the part of the mobile. And since in the motion of alteration and augmentation there is less difficulty, the conclusion is first briefly explained in them. For when the induction is made, no proper alteration is found which takes place per se primo from some agent upon itself, that is, according to the same part; it happens indeed that the same thing through one part alters itself in another, if they are unlike affected; but according to the same part it does not happen, as is established by induction in all. There is only the common instance of the reduction of water to its former coldness, and the same holds of any similar reduction; for we showed above that that action is not produced by an extrinsic agent, but by an intrinsic one. It is answered, however, that that action pertains to natural resultance, of which we spoke in the first conclusion, and therefore that action is commonly attributed to the generator, as Capreolus noted, In II, dist. 6, q. 1, a. 3; Giles, Quodl. II, q. 16; Henry, Quodl. XI, q. 6.

12. And hence it is easily established that in the motion of augmentation too the same thing does not act on itself per se; for that motion does not take place except with preceding alteration; but alteration is not produced by the same thing upon itself according to the same part; therefore neither augmentation. The a priori reason for this part, however, seems to be none other than that which Aristotle touched upon, namely, that the same thing cannot be at once in act and in potency according to the same. To which reason the objection made above is very opposed, because this reason proceeds at most of univocal alteration, that is, proceeding from a quality of the same notion, but not of equivocal alteration, which proceeds from a virtual quality, or one of a superior notion; for then there would be no contradiction in the same part having the virtual quality and lacking the formal one, and therefore acting on itself. On account of which Scotus and the others cited above think that Aristotle's reason is not universal, which is in truth to say that it is not efficacious. Especially because, as we shall see below, he uses that reason also in local motion, in which the action is always equivocal; for the motive power is always of another notion than the form or terminus of local motion.

13. By the part moving per se and the part moved per se Aristotle does not understand form and matter.—Others use this reason: material alteration which is produced by a material substance proceeds actively from the form, for matter is not a principle of acting; but it is received in the composite by reason of matter, which is the principle of suffering; and thus, even if it happens that the same thing acts on itself according to the same integral part, nevertheless the agent is distinguished from the patient as to the principles of acting and suffering. But this reason is plainly against the mind of Aristotle, who does not treat of the formal principle quo—for it was sufficiently established that matter and form have diverse offices in corporeal things—but treats of the principle quod, either integral or at least partial, as St. Thomas rightly noted, q. 22 De Veritate, a. 3, and as is established from VIII Phys., c. 4. Otherwise, when he treats of the motion of heavy and light things, he would not have needed to have recourse to the generator, but to the form effecting and the matter receiving the motion. Nor in animals would he have needed to distinguish the part moving per se from the part moved per se, which Aristotle openly understands of integral parts, ibid., text 28. Nor finally, ascending to the motion of the heaven, would he need to assign a separated mover of it, but an intrinsic form which would be the active principle of the motion, and matter which would be the receptive one.

14. The mind of Aristotle on this is explained.—According to the mind of Aristotle, therefore, it must be said that the same material composite cannot alter itself per se, or according to the same integral part. The reason for this can be given thus, as it were declaring or consummating Aristotle's first reason: because if a substance has in some part a formal and not a virtual quality, or has neither, it cannot move itself to that same quality, as the reason given excellently proves. If, however, it has in that part a virtual quality, either the formal quality too is connatural to the same part, or it is violent or neutral. If it is natural, it will always have it, because a connatural property always belongs to it from within. But if perhaps it is such that it can be violently taken away or diminished, then, the impediment being removed, that thing will bring itself back to its connatural state; yet that will be by way of natural resultance, and the action will principally be reduced to an extrinsic principle, which is the generator. If, however, that quality is violent, it is impossible that the same thing, through a virtual quality of heat, should formally heat itself with a violent and preternatural heating. An example can be pepper, which has the power of heating the tongue or the stomach, and yet cannot heat itself, because such heating would be violent to it. The reason of this, however, is not easily given. For what some say, that it has been provided by the law of nature that nothing should prepare for itself destruction or harm, does not seem to satisfy; for the same living thing, while it is corrupted from within, prepares destruction for itself; it seems to matter, however, that this be according to diverse parts, altering one through another, or through the same according to diverse qualities. And it is evident by reason, for that virtual quality is sufficient to effect the formal one in a capable subject, and acts naturally and necessarily; therefore, if the subject in which the virtual quality is is capable of the formal one and lacks it, it will by necessity of nature effect it in itself, nor can it restrain its action on account of that law of nature, unless it is impeded from elsewhere, because it is not a free agent.

15. Add that some think that natural heat in living things dries itself and consumes the natural moisture, not only according to diverse parts, but also according to the same, as may be seen in Giles, Quodl. II, q. 17, where, however, he says that that consumption of moisture takes place by natural resultance of excessive dryness from the native heat. But I think this impossible; for since that action is violent, it cannot result naturally from within, because it is a contradiction in terms, since the violent is that which is from without, the patient contributing no force. Hence I think what Giles supposes is false and impossible, namely, that the same homogeneous part of an animal, that is, disposed in the same way according to its whole self, in a manner connatural to it, through heat native to it, whether formal or virtual, should diminish the moisture connatural to it, violently drying itself; because it is impossible that the same form in the same part of matter should require dispositions repugnant either formally or eminently; otherwise it would involve repugnance in itself and in its inclination.

16. The reason why a virtual quality does not alter its subject.—If, therefore, some substance, either wholly or in some part, has heat, for example, virtual heat, in so great an intensity, say as four, either it will necessarily at the same time have as much formal heat connatural to it, or certainly it will have such a temperament and such a natural disposition as to resist and prevent that virtual quality from exercising its formal action in the same part; and for this reason nothing can alter itself from within according to the same part by violent alteration. Which is especially declared in those mixed bodies which have virtual qualities active of the primary ones; for those suppose a temperament accommodated of the primary qualities and of the other dispositions which follow upon them; therefore it cannot happen that in the same part such a temperament be dissolved by the intrinsic action of that virtual faculty. And that example of pepper confirms this; for it is so disposed and affected by other qualities and dispositions that its virtual heat does not have the power of heating it beyond the connatural grade of heat which it requires inasmuch as it is such a mixed body. Others think that no other reason need be given except that a quality is not active in the subject in which it is, even if no other condition is lacking. But this does not satisfy me, because it is a manifest begging of the question; for it is the cause and reason of this that we are investigating.

17. Another reason for proving the same.—Another reason can be given, however, why pepper does not heat itself, namely, because perhaps it does not have the total or integral power of heating unless it is helped from elsewhere. For it is established by experience that, applied to the hand, it does not heat, but needs some excitation or alteration and some commixture with the intrinsic heat of the animal; and the same can be said of wine and similar things. Hence, although none of these things can by itself alone alter itself by its virtual quality, yet after it begins to be altered from without and to be conjoined with the extrinsic agent, there is no drawback in its consequently helping towards its own alteration or corruption; for now the integral alterant is sufficiently distinct from the patient. Thus, then, violent alteration can never be of the same thing upon itself through a virtual quality.

18. Indifferent alteration is always from without.—Indifferent alteration, however, that is, neither violent nor natural, cannot be in one which has a virtual quality for making such an alteration, because that quality acts naturally and necessarily as much as it can; therefore either it finds in its subject a natural disposition repugnant to its action, and thus its action would be violent, or it finds no repugnant disposition, and thus the emanation will be natural, because it is from an internal and native quality and from the intrinsic necessity of nature. Hence, if there is any alteration or action towards an indifferent quality, such as illumination in the air, it is always and necessarily from an extrinsic agent. And the reason is clear, because, if it were from the intrinsic form, either immediately or by means of some quality connatural to the same form, that quality would no longer be indifferent, but connatural.

19. The adequate reason for the conclusion.—How it is true that the same thing cannot be in potency and in act, even virtual.—From all these, then, the reason is concluded thus: every quality is either violent, or natural, or indifferent. If it is violent or indifferent, it is evidently from an extrinsic agent. If, however, it is natural, it is from the generator, or, if it is said to be from within, it is by natural emanation, of which there is no discourse in this conclusion. Accommodating this discourse, however, to Aristotle's reason, it must be said that that principle, the same thing cannot be at once in potency and in act, is true even of virtual act, with a twofold limitation applied. One is that the discourse be of the act which is the principle of a physical and merely natural motion, so that we exclude immaterial and vital actions, of which there is now no discourse. The other is that it be understood of a thing existing in its natural state; for in a preternatural state it does happen to be in virtual act and formal potency, as in hot water, which is virtually cold; yet the action of that power is only natural resultance and is attributed to an extrinsic agent, as has been said. Hence, if someone does not wish to call this containment virtual, but instrumental, the first restriction will be enough.

20. From these it is easy to prove the conclusion in local motion, applying the discourse made and the induction, which can be made from Aristotle, in the place cited, in this way. A body is moved either naturally, or violently, or with indifferent motion. In the second and third ways the motion always comes from an extrinsic cause; for under these two members we comprehend all the motions which Aristotle called beside nature, whether they are contrary to nature, which we call violent, or wholly outside what is due or outside the intrinsic principle of the proper nature, as is the circular motion of fire in its proper sphere, and if there is any other similar one. Natural motion, however, is either of animals moving themselves or of inanimate things tending to their proper places. In both, however, the efficient is distinguished from the patient; for inanimate bodies are moved to their natural places by the generator; but in animals the part moving per se is distinguished from the part moved per se, and so the whole does not move itself except as it were per accidens.

The difficulty concerning the motion of heavy and light things

21. About this induction three chief difficulties occur. The first is that common one about the motion of heavy and light things; but since that is purely physical, and, although it is treated with great contention among those of diverse opinions, there can scarcely be disagreement in it except in the way of speaking, therefore, omitting arguments, I shall briefly note the point of difficulty and how I judge one must think and speak in it. Many, then, say absolutely that heavy and light things are moved by themselves to their places: Scotus, In II, dist. 2, q. 10; Gregory, dist. 6, q. 1, a. 3; Mayronis, dist. 14, q. 6; Abulensis, on Matt. XXII, q. 224; Buridan, Jandun, Nifo, Saxonia, VIII Phys. Others think that these bodies behave merely passively towards these motions, but are moved either by the heaven, or drawn by their natural places, or by the medium or the contrary place expelling them. These and other views Richard reports, In II, dist. 14, a. 2, q. 4; Zimara, II De Anima, text 54; Gregory above; which I omit as improbable. The common opinion, therefore, is that they are moved principally by the generator. It is taken from Aristotle in the place cited, especially VIII Phys., from text 29, and IV De Caelo, c. 3; and the Commentator thinks the same in these places, although at times he seems to vary. St. Thomas holds the same in the same places, and I, q. 18, a. 1, and I Cont. Gent., c. 97; Cajetan and Ferrariensis in these places; and Capreolus, In II, dist. 6, a. 3; Giles, Quodl. V, q. 16; Albert, VIII Phys., tract. II, c. 4. And more frequently the expositors of VIII Phys. And this opinion, rightly explained, is true; many, however, even Thomists, err greatly in explaining it.

22. Various ways of explaining the common and true opinion.—For some think that this motion is from the generator in such a way that in the mobile itself there is no intrinsic active power of the motion, but only a natural passive potency, by reason of which such motion is due to them. Against which opinion there are evident reasons of Scotus and others², because it is evident that the generator cannot immediately impress this motion through the form or qualities which it has in itself without a quality placed in the mobile itself, from which that motion effectively flows, because it happens that the generator does not exist, or is so distant that it cannot move immediately. Others, however, use a distinction; for when a heavy thing (they say) begins to be moved downward immediately after it has been generated, then it is moved immediately by the generator, itself behaving only passively, because then the generator could impress the motion per se. But when the heavy thing is moved some time after the generation, then they say it is not moved by the generator, but by itself actively. So Soncinas, IX Metaph., q. 8, who attributes it to the Commentator; and Cajetan of Thiene follows the same, VIII Phys.; and Paul of Venice, in the Summa on the Heavens, c. 24. But to me the distinction is improbable, both because this motion is always of the same notion and is produced by the same natural principle, and also because, even if the heavy thing begins to be moved immediately after the instant of its generation, it is not yet moved intrinsically by the generator, because there is not yet motion; but immediately after that instant it can come about that the generator no longer exists, or at least a little afterwards, while the motion still lasts; and although it exists, yet immediately after the instant of generation it is already distant from the thing generated; for I suppose the generator remains in its place; therefore it cannot per se immediately effect motion in the thing generated. Therefore it is said to move only because in the instant of generation it impressed the impetus by which immediately afterwards it is moved; but that impetus is nothing but gravity; for whatever else is imagined is vain. Because the generator per se impresses only what per se follows upon generation; but upon the generation of a heavy thing per se there follows only gravity, so far as concerns the present matter; therefore that motion is then produced by the intrinsic gravity of the heavy thing itself, in the same way in which it is produced after any length of time. And this is most consonant with reason, since gravity is always the same and has the same power, and distance of time is irrelevant.

23. The difficulty is resolved.—Aristotle attributes the motion of heavy and light things to levity or gravity as to the proximate principle.—It must be said, therefore, that whenever an inanimate thing tends to its natural place, its intrinsic gravity or levity is the proximate efficient principle, not however the principal one, of that motion. This is almost evident by experience and by the reasons given against the earlier ways of explaining the common opinion. Likewise, because, since motions belong per se and necessarily to these bodies, it is necessary to assign some active principle of that motion which also belongs to them per se and necessarily; but there is none other besides the intrinsic form and gravity; for the generator, as we said, happens not to exist at all, or to be very distant, and all the remaining causes either are none or at least are merely contingent. And this is without doubt the opinion of Aristotle; for in bk. VIII Phys., c. 4, text 32, having distinguished a twofold potency, namely, remote and proximate, he adds: The cold is potentially hot; but when it has been changed, it is fire; and it burns, unless something prevents and hinders; and he adds: It is no otherwise with the heavy and the light, for from heavy comes light, as from water air; for this was first in potency and is now light, and will at once act, unless something impedes. And below: But if what impedes has been removed, it will act. And IV De Caelo, c. 1, text 2, he says that heavy and light things have in themselves the kindlings or incitements of motion; and more clearly, c. 3, text 25, he compares the heavy and the light to a body capable of being healed, saying that, as this proceeds to health, so do those to their places. He adds, however, a difference, saying: This, however, is excepted; for these, the heavy (he says) and the light, seem to have the principle of change in themselves, but those not in themselves but outside, as the healable and the increasable; where he must be speaking of the active principle, for the passive is also in the healable subject. Hence of that and of the increasable he adds: Although these too sometimes change of themselves, and with little motion made in external things, the one comes to health, the other to increase. Likewise, IV Phys., c. 9, text 85, he says that the dense and the rare, inasmuch as they are endowed with gravity and levity, are productive of locomotion; but inasmuch as they are hard and soft, they do not have a principle of moving, but either of resisting or of suffering alteration.

24. Testimonies of Aristotle to the contrary are brought in and explained.—Nor does it stand in the way that the same Aristotle, II De Gener., c. 2, text 8, says that gravity and levity are not principles of acting; for there he also says that they are not principles of suffering; for he is speaking of the principle of acting upon or transmuting another, or of suffering from another, by action or passion which tends to generation or corruption, of which he was speaking there. Likewise, we can say that he speaks of the proper and principal principle, to which the action is simply attributed, and consequently of proper efficiency and action. For this, which belongs to gravity or levity, is rather a certain natural resultance; in the way in which it is efficiency, there is no doubt that gravity is its principle. Which is also the opinion of St. Thomas, I-II, q. 36, a. 2, and III Cont. Gent., c. 23, reason 4, and in other places which Capreolus notes above, and Bergomensis, in the Concordances, dub. 690 and 691. Who also reconcile those places with others in which St. Thomas seems to deny that these bodies have in themselves an active principle of motion, namely, that there he understands it of the principal principle, here of the instrumental; or there of the principle quod, here of the principle quo.

25. Whether the form of the heavy or light thing inflows into its natural motion.—But you will ask whether this internal principle is gravity alone or also the substantial form; for authors speak variously. It is answered that, if we speak of the principle per se proximately and actually inflowing, it is gravity alone, because in it there is sufficient power to effect that motion and its terminus, no less than there is in heat for heating. Which is declared from the mystery of the Eucharist, for the species of bread have equal gravity and will be moved downward with equal motion without the form as if the substance of bread were present there. But if the discourse is of the remote intrinsic principle, then the substantial form is the principle, because from it gravity flows and naturally results, as do other natural properties.

26. Such motion is to be attributed principally to the generator.—Nevertheless it must be added finally that this natural motion is principally to be attributed to the generator, who placed the form and, by means of it, the gravity from which the motion results; just as the motion which flows from the impetus is attributed to the thrower who impressed it. Because, just as the impressed impetus, although it is a true motive power and has in itself sufficient force for that motion, nevertheless does not move except as the instrument of the thrower and in his stead, so gravity does not move except as the instrument of the generator and in his stead. This is the mind of St. Thomas and of the other authors whom I cited in the last opinion; and of Aristotle in the places cited, who in this sense often says elsewhere that inanimate things do not have in themselves the principle whence motion is, and always assigns this difference between them and animate things, as may be seen in II De Caelo, c. 2, text 9, and I De Anima, c. 2, text 19, and bk. II, c. 2, text 13. And this difference of living from non-living things has been received by the common consent of all, as St. Thomas notes, I Cont. Gent., c. 97. The reason for this attribution, however, is that the perfection of these inanimate things does not consist in motion to their places, but in being or remaining in their places; which state or perfection, speaking per se, can belong to these things in the same moment in which they begin to be by virtue of their generation; and therefore, just as other properties and natural dispositions which belong per se to the thing generated by virtue of the generation are reckoned to be given by the generator, so also the natural place. And hence it further comes about that, for whatever reason the natural place is impeded or taken away, the way or return to it is always attributed to the same generator, because it always takes place from the same principle and by the same natural denomination, and because it belongs to the same to confer the terminus and the way or motion to it. And in this way St. Thomas explained this matter, III Cont. Gent., c. 23, saying: The form is the principle of local motion inasmuch as to some body, according to its form, some place is due, into which it is moved by virtue of its form tending to that place; and because the generator gives this, he is said to be the mover. Thus too we said above that the reduction of water is attributed to the generator, because natural and perfect coldness, speaking per se, is due to water by virtue of its generation and form. There is only this difference, that that motion of the reduction of water to coldness is immediately from the substantial form; but here the reduction to the natural place is by means of a motive power. The reason for this, however, is only that coldness is a first passion; but to be in such a place is not a first or immediate passion, but one belonging mediately by reason of another, namely, gravity or levity; this, however, in no way prevents both from being a natural emanation by virtue of the generation.

27. Which actions of inanimate things are attributed to the generator, which not.—And from this reason is gathered the difference on account of which the actions of inanimate things upon external matter are not attributed to the generator, as when fire heats, etc., although they follow naturally upon the form and the faculty given by the generator. Likewise, why the motion of augmentation, through which the thing generated tends to perfect quantity, is attributed not to the generator, but to the thing generated itself. For the reason is that these are not natural properties or perfections due to the thing generated in the instant in which it is generated, by virtue of its generation. You will say: when hot water heats, not fire alone is said to heat, but also the water itself; and a stone, if in descending it impels something else, is truly said to move it; therefore it will also truly be said to effect its own motion, and hence to move itself as the supposit sustaining in itself the proper principle of that action. For it is for this reason alone that the action of heating is attributed to hot water. It is answered that in some sense there is no drawback in admitting that way of speaking, as Ferrariensis noted, I Cont. Gent., c. 97, and Capreolus signified above, namely, inasmuch as it denominates as it were materially the supposit having in itself the proximate principle of such motion. Since, however, that principle takes the place of another, whose instrument it is, therefore, speaking simply and absolutely, the action is referred back to that other, as is clearly established in the example of projectiles.

28. An objection is satisfied.—You will say finally: although this congruity given sufficiently declares that that way of speaking is philosophical and has some foundation in reality, yet what does it matter for declaring real efficiency and the conditions necessary for it? For from what has been said it is sufficiently concluded that a truly active power, in order to effect something in a subject, need not necessarily be in a distinct subject, nor in a distinct part of that subject. It is answered that this was deservedly and wisely considered and declared by the philosophers in order to signify that things lacking life have not received from nature a power of perfecting themselves, speaking per se, but that the nature of these things only demands that they be generated in their natural perfection. And hence they established the difference between living and non-living things, which Plato too attained in the Phaedo, and in dial. 10 of the Laws, that living things have been so instituted by nature that they can perfect or actuate themselves (we speak properly of created things), while non-living things per se have nothing but rest in that perfection which they receive from the generator, unless they are impeded from elsewhere. Since, however, they have been excellently instituted, they receive that perfection with the due connection of their essence and properties among themselves, all of which is deservedly attributed to the author of such things, or to the generator. And therefore, whenever things of this kind are by accident impeded from their natural state, and afterwards, the impediment being removed, return to it, such return is not reckoned to be through proper action, but through natural resultance, and therefore is attributed not so much to them as to the generator.

The difficulty concerning animals moving themselves locally

29. The second difficulty about the same induction of Aristotle concerns the motion of animals moving themselves; for in them the agent does not seem to be distinguished from the patient. Aristotle dissolves this difficulty by saying that an animal does not move itself per se primo, that is, so that each part moves itself, but by one part, namely an integral and organic one, it moves another, as experience itself seems to show; and so the agent is there distinguished from the patient, at least according to parts. But the difficulty presses; for this process between moving part and moved part does not proceed to infinity; for it is not between proportional parts, but equal ones, or of some certain magnitude; nor does that process have place in causes per se ordered; one must therefore stop at some first moving part; but that cannot move unless moved; for this Aristotle himself teaches of all corporeal movers, VII Phys., c. 1, text 3, and it holds most truly in a body moving another as it were by impelling, in which way one part of an animal seems to move another. I take, therefore, the first moving part in an animal and ask by what it is moved. Not by another, since it is the first mover in that order; therefore by itself. For there is no other principle to which it may be reduced; for that motion cannot be attributed to the generator, since it is vital and is not by natural emanation, but from the appetite of the animal. Nor will he satisfy who answers that the motion of that part is from the soul as informing that part, but is received in the same part by reason of matter, because, as I objected above, in this way any body could be said to move itself by reason of form and to be moved by reason of matter.

30. The same difficulty arises about the motion of the heart, which is perpetual while the life of the animal lasts, and is between two termini, and is composed of beat and draw. Hence, although it always lasts in that way, it is yet not perfectly continuous; for between dilation and contraction some rest necessarily intervenes. Of this motion, then, there is no other efficient cause besides the heart itself, which, since it is homogeneous, cannot be distinguished into a part moving per se and a part moved per se, but the whole moves itself per se primo. Nor can that motion be attributed to the generator, for the same reasons just touched upon, namely, because it is a vital motion and in it the perfection of the living thing consists; otherwise the motion of augmentation too would have to be attributed to the generator.

31. What the locomotive power of the animal is.—To the former difficulty: if it were true, as some think, that the active power of the animal's motion is none other than the appetite, which by its act immediately excites the nerve, which is the first part that moves the others, then the answer would be easy; for the appetite, if it is sensitive, is in the heart; if rational, in the soul itself; and by its act, formally immanent and virtually transient, it moves the first part of the animal; and so the agent is there distinguished from the patient, because either the appetite is in a distinct part of the animal, or certainly it behaves as a kind of separated mover. Nevertheless this reply supposes a false opinion; for in truth the motive power of the animal, as it is active, is distinct from the appetite, as is proved more at length in the science of the soul. There are indeed those³ who think that this motive power is either the soul itself according to its substance, or certainly is in it alone; who consequently say that the soul alone, as informing the nerve, moves it through itself or through a power which is in itself, and through the nerve, as through an instrument, moves the next part, etc. And to the objection made above it could be answered, according to this opinion, by granting that in that first part of the animal's motion, or in the nerve, a part moving per se and one moved per se is not distinguished as integral, but only as essential. And that this is not unfitting, because there the soul, since it has in itself the whole power of moving, behaves as if it were a mover both quod and separated. And thus this is not repugnant to the intention of Aristotle. Indeed, it could be said that it suffices that no corporeal mobile, integral and total, moves itself per se primo, although according to some part beginning the motion it moves that part without another instrument, but only by reason of its form, as we shall say below about the motion of the heart. In which sense this reply could probably be defended, even if the motive power which is in the nerve is not in the soul alone, but in the part itself as composed of body and soul, which seems more probable, especially in brute animals.

32. Further, however, we can add that the first instrument of animal motion is the muscles, which are compacted of nerves and certain ligaments and flesh, as Galen explains more at length, XII De Usu Partium, c. 3. But this instrument is not so moved by itself but that other things concur to its motion, by reason of which it can be said to be moved by another. For in the first place it cannot begin motion unless another part of the animal remains unmoved, on which it rests; in every motion of an animal it is established by experience itself that the motion of one part cannot take place unless another is at rest; that resting part, therefore, also pertains to the instrument of motion and is called a mover per se unmoved, and so by reason of it the mover is distinguished from the first part of the animal which is at once moved and moving; which Albert noted, bk. III De Anima, tract. IV, c. 8. We can likewise add, from St. Thomas, the Commentator and others, III De Anima, c. 10, that the heart too is in some way the foundation of this motion, both because the nerves come from it, and especially because it concurs by means of the animal spirits to moving the muscle; for it is also established by experience that this motive power cannot be exercised without the spirits, which the heart or the brain (according to the various opinions of philosophers) sends to that part by which the motion is to be begun; therefore it is likely that those spirits also serve in some way as instruments of the motion; but the spirits themselves are moved, impelled or agitated by the efficacy of some power existing in the heart or brain, which, itself remaining unmoved, impels the spirits, the appetite intervening. Just as the expulsive power of excrements naturally expels while remaining unmoved. Nor is it necessary that every body move actually moved, but it is enough that it be otherwise mobile, or certainly that it be moved per accidens with the motion of the whole; but of that axiom more will be said again below.

33. The nature of the motion of the heart is explained.—To the latter part of the difficulty: because the motion of the heart, since it is natural, seems to be composed of contraries (for it consists in continual approach and withdrawal between the same termini, not by way of circulation, but through dilation and constriction), therefore that motion has seemed wonderful to all philosophers. Hence some⁴ have said that it is not from the particular and intrinsic nature, but from universal nature and an extrinsic mover. Which opinion St. Thomas calls ridiculous, Opusc. 15, and deservedly, because the end of that motion is not something pertaining to universal nature, but to the particular nature of the animal itself, namely, the cooling and moderation of the vital heat of the heart itself, by means of air drawn in by respiration; and therefore it is absolutely necessary for the conservation of life; it is not, therefore, from universal nature, but from the particular nature of the animal itself; therefore there must be in the very nature of the animal a proper principle of that motion, because those things which are necessary and perpetual from within must have an internal principle in the nature itself.

34. St. Thomas says, therefore, in the opusculum cited, that that motion comes effectively from the soul itself, inasmuch as it is the natural form of the body. But because the objection touched upon above at once occurred, that this is not enough for there to be a distinction into moving part and moved in Aristotle's sense, from which it follows that the whole heart moves itself per se primo, St. Thomas adds that that motion is to be attributed to the generator, because it results naturally from the form itself after the manner of a proper passion; which opinion Capreolus and Ferrariensis follow above. Which certainly has no small difficulty, first in explaining how so varied a motion can result from one and the same faculty acting naturally; because a power acting naturally is determined to one thing; but dilation and contraction, or approach and withdrawal from the same terminus, are contrary motions. For it is not similar to the motions of animals, which can also be called natural inasmuch as they take place by a certain necessity of nature; for those proceed from appetite, which follows cognition and can be varied according to various apprehensions, which also vary according to various applications of objects; but the motion of the heart does not proceed from appetite, but from a mere natural property. Nor does what St. Thomas adduces about the circular motion of the heaven seem similar, in which approach and withdrawal according to diverse parts to some partial terminus is included: both because in circular motion that is found without any contrariety of motions and with true continuity of the parts of the motion, whereas here there seems to be true contrariety between the parts of this motion, whence true rest intervenes between them; and also because that circular motion is not from an internal active principle, but from an extrinsic mover. This difficulty, however, proceeds equally whether we say that that motion is produced by the generator through natural resultance or by the animal itself through proper action; for it is always produced by a faculty acting naturally. And therefore nothing else occurs to be said except that the sensitive soul, because it is a nobler form, can have natural faculties which in their mode of operating surpass lower forms; and of this kind is this motive faculty which is in the heart; and therefore it is not wholly determined to one thing, except within its sphere, as it were, that is, within those termini to which it approaches by dilation and from which it withdraws by contraction. Of which parts the integral motion is composed, which is physically one, although it is not mathematically continuous.

35. This, however, being supposed, it is difficult to attribute that motion to the generator. First, because it is a vital act; but an act of life is from an intrinsic principle, whence it ought not to be reduced to an extrinsic one. Perhaps there may be someone who denies that that motion is vital, because it does not take place through appetite and cognition. This, however, is improbable and against all philosophers; for although they doubt whether that motion is from the soul as vegetative or as sensitive, as Zimara at length, Theor. 12, yet all agree that it is from the soul as it is soul, since it is as it were the foundation of life. Secondly, it seems absurd to attribute my respiration to the generator and to say that I do not breathe; yet respiration too is a natural action, which takes place without the intervention of appetite, indeed it takes place from the very motion of the heart and lungs. Thirdly, scarcely can a reason be given why nutrition too is not attributed to the generator; for it too is merely natural, begins only extrinsically from the instant of generation, lasts perpetually of itself, and, as nutrition (not as augmentation), does not tend to any perfection due by virtue of the generation, but to conserving life by repairing what is lost. Thus, then, that motion of the heart begins extrinsically from the instant of generation, always lasts of itself, and does not tend to any place due to the animal or the heart by virtue of the generation, but is produced by the living thing itself for the conservation of life, which that motion serves, at least as a cause per accidens, either for removing and expelling some corrupting things or for drawing in something cooling. And therefore I do not think it unfitting to attribute this motion to the animal itself and to assert that it moves and is moved according to the same integral part, and that it is enough that the notions of acting and receiving are diverse; for Aristotle said only of the motion of the whole animal that it takes place through the motion of one part upon another. According to which reply it must consequently be confessed that the agent and patient ut quod need not be distinguished in this physical motion, because it is vital and only partial, which is no drawback, as will be more evident below from the third assertion, and seems quite consonant with the mind of Aristotle, in the book On the Common Motion of Animals, at the end.

The difficulty concerning the mover of the heaven

36. The third difficulty is that Aristotle makes his induction only in sublunary bodies; he omits, however, the heavenly ones, or rather argues from them to these; but it does not seem efficacious, at least for inferring that the heaven is moved by another mover ut quod, but at most by another ut quo, that is, by its proper form. For what if someone says that the form of the heaven is a certain special kind of soul, upon which such motion follows by natural necessity, not through one integral part upon another, but in each part through itself, by means of the form and natural faculty alone, as we said a little before about the motion of the heart? It is answered that it is true that Aristotle did not take the heavenly bodies into his induction, but argues from the lower ones, which are known to us, to the higher, which are less known. It will, however, be a most efficacious argument if we suppose that that motion is not so natural to those bodies according to their proper and particular natures as is the motion of the heart or of heavy and light things, because that motion is neither ordered to any conservation or perfection of those bodies, nor to any place naturally due to them. Which discourse St. Thomas uses, III Cont. Gent., c. 23, reason 4, to prove that the motion of the heaven is not from the intrinsic form. For motion flows naturally from the form when the place acquired through such motion is due to the mobile by reason of its form, as is evident in all natural bodies; but the place which the heaven acquires through circular motion is not due to it by reason of its form, because it matters nothing to the perfection or inclination of its form to have this Ubi rather than another, namely, in order to its diverse parts—for example, to have the sun in this hemisphere rather than in the other. Add that the form of the heaven cannot be called a soul on account of local motion alone, as was touched upon above and will be said below in treating of the intelligences. Hence, even if someone contends that that motion is as natural to the heaven as are the other motions of natural bodies, nevertheless he must reduce that motion to the author of the heaven as to one who impressed the impetus for that motion, as heavy and light things are said to be moved by the generator. But if someone were to deny that the heaven has an author, but say that it is of itself and has a natural inclination and faculty for that motion, such an error would have to be refuted by other principles of metaphysics; for this cannot be done from physical motion alone, as we shall say more at length below; although it is incredible per se that a thing which needs motion, either for its perfection or also for its action, should have being of itself without the communication or production of another.

37. From the preceding difficulties the conclusion is elicited and proved by reason.—From these, then, it seems sufficiently established by induction that every corporeal and physical local motion requires a mover or efficient cause distinct from the thing moved. The reason for this necessity, however, can first be given in that principle of Aristotle, that nothing can be at once in potency and in act. Which, however, is to be limited and accommodated in the way in which we spoke of the motion of alteration. Although in truth it may have still less force in local motion, because local motion or its terminus is not, speaking per se, the principle or power or act from which a like motion proceeds, but some motive faculty of a superior notion to the motion itself. That principle would, however, be efficacious in bodies if another axiom were true, quite received and attributed to Aristotle, that a body does not move locally unless itself moved locally; for whether that motion is required as the notion of moving or as a condition, it is already supposed that the body must be actually moved in order to be able to move. And thence it is excellently inferred that it cannot be mobile by itself, because it cannot be at once in act and in potency. Nevertheless that axiom is not received by all⁵ and seems to suffer some instances; for the magnet, remaining unmoved, draws iron, etc. But it must be said that one body can move another in two ways. First, per se and immediately, impressing nothing besides motion; and then in truth it never moves unless moved locally. Secondly, it happens that it is moved locally with preceding alteration, and in this way the magnet draws iron; and then indeed it happens that one body, remaining unmoved, moves another. Then, however, at least for the reason that that motion takes place by means of alteration, it will be necessary for the mover to be distinguished from the mobile; and so the reason given will be efficacious in local motion, either immediately by reason of itself (so to speak), or mediately by reason of the alteration, if it takes place by means of that.

38. Another reason of Aristotle is examined.—Aristotle, however, adduced another reason, VII Phys., text 2, to prove that a body cannot move itself locally per se primo, which in sum is this: Everything that is moved is divisible into parts; therefore it cannot move itself per se primo. The consequence is proved, because what moves itself per se primo does not rest because another rests or ceases to move; for since it moves itself, it does not depend on another in its motion. But when the mobile has parts, when a part of it rests, either the whole rests, and thus it is not moved per se primo, but by that part by whose resting it ceases to be moved; or it is still moved, and thus too it follows that it does not move itself per se primo, but by that part by which it is said to be moved while the other rests. About this reason much has been written by the expositors, and many think it a demonstration, such as Alexander, Simplicius, Averroes, St. Thomas, who differ, however. For Averroes thinks it is a demonstration only a posteriori, while St. Thomas holds that it is a priori, signifying that the divisibility of the mobile is the cause why it cannot be moved per se primo. To others, however, the reason seems sophistical and inefficacious.

39. And certainly there seems to be an equivocation in that term per se primo. For something can be understood to be moved per se primo in two ways. One is that the motion of the whole mobile belongs to the whole in such a way that it depends on nothing else, even on its parts. And in this sense the reason rightly proves that a body cannot move itself per se primo. But this does nothing towards concluding that a distinction between mover and mobile is necessary, because that dependence of the whole on its parts can be only material and not effective, except perhaps respectively, that is, inasmuch as each part moves itself, as will be declared at once. In another way, then, something can be said to move itself per se primo because according to every part of itself it moves and is moved, so that no part moves another, nor the whole as such, but each moves itself, and thus partially concurs to the motion of the whole, which arises from the motions and movings of all the parts. And indeed, if something moves itself in this way, it will most properly be said so to move itself per se primo that in it the mover is not distinguished from the mobile. That no body can so move itself, however, cannot be efficaciously concluded by the aforesaid reason, even if each member of it is granted. For, first, it can happen that, when a part rests, the whole rests wholly according to every part of it, not because the whole was moved by that one part alone, but because, while one part ceases to move itself and rests, it resists another and prevents it from moving itself; which may be seen not only in diverse parts, but also in diverse mobiles; for if two stones are moved downward one after the other, if the former is held back it will also prevent the other from descending, not because it moved it before, but because it resists the motion by which that one moved itself. Next, it can happen that, when a part rests, the whole does not rest according to every part of it, but only according to that which is said to rest, while according to the others it is still moved; as when, the root of a tree resting, the remaining parts are shaken. And from this too it does not follow that the whole was before moved by that part alone which still moves itself, but only that it concurred to the integral motion of the whole together with the other parts.

40. The Aristotelian axiom is explained.—Hence that axiom, What moves itself per se primo does not rest at the rest of another, must be limited by a twofold distinction. For per se it is true that one mobile does not rest when another by which it was not moved rests; but per accidens, and because an impediment is posited, it can happen that it rests. Again, if that other which rests is not wholly extrinsic, but a part of the mover and mobile, it can rightly happen that, when it rests, the whole ceases to be moved per se primo, that is,⁶ according to every part of itself, not because the whole did not move itself per se primo, but because it was moved partially by that part; for these two do not conflict with each other, as is per se manifest. That the whole as a whole depends on its parts, therefore, does not prevent the motion of the whole per se primo from coming from the same whole. And it is openly declared; for otherwise it would in the same way be proved that a body cannot be moved per se primo by another, which is openly false; for the heaven is moved per se primo by an intelligence, and the earth is moved per se primo when it is borne downward, although by the generator. And the sequel is evident; for in these too it holds true that, if part of the heaven rested, the whole would rest, or at least would not be moved per se primo as before, because the motion per se primo of the whole depends on the motion of the part materially, as on an integral part. Just as, conversely, the whole earth rests per se primo at the centre, and yet if a part ceased to rest, the whole would no longer rest per se primo, not because the whole rested effectively from the part, but because the rest of the whole arose as it were materially from the rest of the part. And while the whole water is cold, the whole can be said to be cold per se primo; and yet if a part begins to be heated, the whole is no longer cold per se primo as before, not because the whole was actively cold from the part, but because the coldness, as belonging per se primo to the whole, arose as it were materially from the coldness of the parts. From the dependence, therefore, of the motion of the whole, as moved or moving per se primo, on the motion or moving of the single parts, it cannot be concluded that the whole is moved by a part except partially and (so to speak) respectively, that is, inasmuch as each part moves itself; which dependence does not prevent the same thing from moving itself. Hence I do not see how the said axiom is demonstrated by that discourse. The other proofs adduced, therefore, are more probable.

Third assertion, concerning the motion of spiritual things

41. A spirit can move itself locally.—I say thirdly: the cause effecting through motion or action in some way transient, in a spiritual thing, is not always distinguished in reality from the material cause or that receiving the motion, except at most as to the notion of acting and receiving. This conclusion is laid down chiefly on account of the local motion of angels, which I call in some way transient, because, so far as concerns the notion of such motion, it can be produced by one agent in another supposit, and because in truth it is not per se an immanent act in the power through which it is proximately effected. By this motion, then, it is certain that an angel, an intelligence or a separated soul can move itself, effecting motion in itself; for, as we shall touch upon below in its place, the motion by which a spiritual substance is moved is not in another distinct thing, but in the very substance which is moved. And it is almost evident from the terms, because a thing is not said to be moved by extrinsic denomination, but by true real change, which must necessarily have some efficient cause, and none other than the very spiritual substance moved, when it moves itself. Then, therefore, the efficient cause cannot be distinguished in supposit from the recipient, because we suppose the same supposit moves itself; nor can it be distinguished into a part moving per se and one moved, because it has no parts; therefore at most the notion of effecting can be distinguished from the notion of receiving the motion or its terminus. In which too there are various opinions; I suppose, however, as more probable, that that motion is received immediately in the substance of the angel; for, just as a body is present to place through quantity, so an angel immediately through its substance; for it does not have quantity, nor can any other accident be imagined in it by means of which it is capable of local presence. I speak, however, of the proximate and immediate subject of that presence, whatever be the case as to whether for that action some action or contact of power with respect to a body is required; for that is nothing to the present purpose, for what is made in the angel through local motion is not an action upon a body, but is its real presence; but this immediately affects the substance of the angel; the same substance, therefore, is the notion of receiving such motion, because the motion and its formal terminus are in the same proximate subject.

42. What the proximate principle of local motion in spirits is.—Concerning the notion of effecting that motion, however, there are various opinions; for some posit that it is produced immediately by the will; whence, supposing, as we suppose, that the will is a thing distinct from the substance, it follows that the proximate notion of effecting that motion is distinct in reality from the notion of receiving. But those who deny that the power of the will is distinguished in reality from the substance would perhaps say that the actual volition of moving oneself is the proximate notion of effecting that motion, and that it is distinct from the substance. Others, however, do not think that the will or volition is the proximate and per se principle of effecting that motion, but that it is a peculiar motive power, and that volition is the application or command of that motive power, which, just as in us and in other animals it is distinguished from appetite, so in angels from the will. That power, however, some think is not distinct in reality from the substance. According to whose opinion the notions of acting and receiving this motion too are not distinguished in reality, but only in reason. We, however, think it more probable that that motive power, even if it is believed distinct in reality from the will, is also distinct in reality from the substance of the angel, from the general principle laid down above, that the proximate faculty for accidental action in a creature is an accident distinct from the substance; and thus we conclude that the proximate principle quo of effecting that motion is distinct in reality from the subject in which it is received. And the reason is that this principle is a merely active power, which does not act except in a presupposed subject; therefore it requires in it a passive potency distinct from itself. And that definition of Aristotle confirms this, IX Metaph., saying that active power is the principle of transmuting another inasmuch as it is another, of which we shall say more a little below.

43. Nor does that principle of Aristotle stand in the way of this conclusion, Everything that is moved is moved by another, nor the reasons by which he confirms it; for, as I noted above, Aristotle spoke of physical and material motion; but this motion of the intelligences is not of this kind, and it is quite doubtful whether Aristotle knew of that motion, or rather thought the intelligences wholly immobile. Hence his induction does not comprehend the intelligences, as is established per se. Nor does that reason which supposes that the mobile is divisible into parts. The other reason, however, that a thing cannot be at once in potency and in act, is excellently dissolved here by the distinction of virtual act and formal potency; and at most it proves the distinction of the principle quo of acting from the receiving subject. For an angel existing in heaven is in formal potency to be on earth; yet actually it has the power by which it can move itself and make itself present to the earth. Nor do the limitations laid down above have place here, with which we said that that principle is true also of virtual act; for one limitation was that it be understood with respect to physical motion; but this motion of which we are treating is not physical. The other, namely, that the thing must be in a preternatural state, is not necessary here, because in this living things surpass those which do not live, that they can move themselves even when they exist in their natural state; and therefore in the same thing they can have virtual act together with formal potency to some motion.

44. Three orders of things moving themselves locally from within.—Hence from the discourse so far made we may gather three orders of things moving themselves locally in some way from an intrinsic principle. The first is of those which are so moved only when they are in a preternatural state; and in these, although the principle of motion is in them, yet not as proper to them, but as the instrument or power of another; and of this kind are inanimate things. Others, however, are things which properly move themselves from an intrinsic principle as proper to them, yet not perfectly and per se primo, but by moving one part through another, and so moving the whole as it were per accidens; and at most they can move one part of themselves per se primo, namely, that which is as it were the foundation of the motion of the others. And of this kind are corporeal living things. In the third and higher order, however, are things which not only move themselves through an intrinsic principle as proper, but also move themselves per se primo according to their whole selves, because they have no parts; and therefore in them the principles of acting and receiving ut quod cannot be distinguished, but at most the principles quibus. And this is consonant with the perfection of these things, because among living creatures they possess the most perfect grade.

Fourth assertion, concerning immanent actions

45. I say fourthly: in the cause effecting an immanent act not only are the principles ut quod of acting and receiving not always distinguished, but rather it is not always necessary that the principles ut quo be distinguished in reality, although it often happens so. The first part of this assertion is manifest and follows from the very notion of immanent action; for it is received in the operator itself, and therefore it is not necessary that the acting supposit be distinct from the receiving one, nor that it act and receive according to diverse parts. Both because it often has no parts, and also because this action is received in the same power from which it is elicited; and therefore also in a supposit having parts it is made and received in the same part. And hence the reason in general for the second part of the conclusion can be given; for since immanent action remains, as effecting, not only in the same supposit but also in the same power, nothing forbids that also in the proximate principle quo acting and receiving it no distinction in reality should be found.

46. In order, however, that this part and the whole conclusion may be declared and proved more fully, it will be necessary to distinguish these immanent actions more in particular and to declare how the assertion has place in each. All these actions, then, pertain either to cognition or to appetite; and they can be either in the rational part or in the sensitive. Again, in all of them one can consider either the principal or substantial principle quo, or the proximate or accidental one. In these actions, then, inasmuch as they are in the sensitive part, the principal principle quo of acting and of receiving can easily be distinguished; for the former is the soul, as is manifest from the definition of the soul; the latter is the body. For, according to the true doctrine, these sensitive operations, since they are material, are received in the body or in the whole composite by reason of matter. As these operations are found in the intellectual part, however, the principal principle of acting and of receiving is not distinguished in them except only in reason; for the same simple substance of the angel or of the soul exercises both offices. For what some say, that these two are distinguished in the very substance, because it acts through being as through act and receives through essence as through potency, both falsely supposes a distinction in reality between being and actual essence, and, even that admitted, is not said consistently; for, that opinion being supposed, being is not the notion of acting, but is the condition without which the essence would not act; and similarly it is the condition without which the essence would not receive the operation; but the existing essence itself, or the essence having such a condition, is the principle of acting and of receiving such an operation. Hence in the soul of Christ, even if, according to that opinion, it does not have created being of existence, nevertheless the principal principle of eliciting created intellection is not the uncreated being itself, but the substance of the soul itself according to its proper being of essence.

47. Whether in cognitive operations the notion of acting is distinct from that of receiving.—Not the species alone, but the intellect too, effects intellection.—But in the proximate and accidental principle there seems to be a different account of the actions of knowing from that of the actions of appetite, both in the rational part and in the sensitive. For in the actions of knowing the proximate principle of acting is always or almost always distinguished from the proximate principle of receiving. The reason is that for effecting this action, besides the vital faculty, there is required a species supplying the place of the object and concurring to the act in its stead. And so the principle of acting is the power as informed by the species, but the principle of receiving is the power alone, because the object or its species does not help towards receiving, but only towards acting; wherefore the proximate principle of acting and of receiving is in some way distinguished. I say in some way, however, because they are not distinguished except as including and included; for the opinion of those is improbable who think that the whole notion of acting is the species and that the power is only the notion of receiving, which Scotus deservedly attacks, In II, dist. 3, q. 8; he undeservedly attributes it, however, to St. Thomas, who nowhere intimated it; and it is very improbable, because an act of life must necessarily be actively from an intrinsic vital faculty. It is certain, therefore, that the same cognitive power in which the act of knowing is proximately received is at the same time the proximate principle of effecting the same act; it differs, however, because it is the adequate proximate principle of receiving, but not of acting, but together with the species, according to the more probable doctrine, on which Capreolus may be seen, In II, dist. 3, q. 2; and Scotus, In I, dist. 3, q. 7; Giles and Ferrariensis, in the places to be cited at once.

48. In the intellection by which the angel understands itself, what distinct notion of acting and receiving there is.—An instance can only be brought about that act by which the angel sees itself without the help of a species, through its substance, according to the truer opinion, although others think otherwise, as we shall see below in treating of the intelligences; that intellection, therefore, has the same adequate principle of acting and of receiving, namely, the substance and intellect of the angel. Perhaps someone will answer that that act is attributed to the generator, or to the author of nature, because it is merely natural and necessary from within for the fitting state of nature from the first instant of creation. But this attribution does not seem to be so extended in proper vital acts, especially speaking in physical strictness; for morally it can more easily be used, as I shall say a little later. Therefore I do not think it unfitting to admit that in these acts, if it is necessary, as I signified in the assertion and as will be declared more at once. In that act, however, there is not so absolute a necessity, but some distinction in reality can be understood between the proximate principle of effecting and of receiving that act; for since the substance of the angel concurs to other intellections in one way only, namely, as principal principle, to that one it concurs in a twofold way or title, namely, as principal principle and as the object and as it were the ultimate form of its intellect in intelligible being. And thus the proximate principle of that act is not the intellective power alone, but as constituted in its way in first act by its substance conjoined to it in the notion of an actually intelligible object. But the proximately receptive power and the whole notion of receiving that act is the intellect alone; nor under this notion does the substance have a greater concurrence in that act than in the others. Thus, therefore, it comes about that even in that act the adequate proximate principle of acting and of receiving are distinguished as including and included.

49. Whether the cognition of the object inflows effectively into volition.—Concerning the actions of appetite and will, however, there is a special difficulty, because these powers do not need species, and so they seem to be through their entities alone the principles of acting and of receiving their acts. Therefore some say that the cognition of the object concurs effectively to the acts of appetite. So Soncinas, IX Metaph., qq. 10, 11 and 13, which many theologians also hold, as is handed down more at length in the I-II. This opinion, however, does not satisfy me; for I think that the knowledge of the object concurs to the act of appetition only as a necessary condition by way of applying the object, because the will is not moved except by the goodness of the object. Wherefore, if that motion, as it is from the object, is not effective, as in truth it is not, but final and metaphorical, which Soncinas too confesses above, q. 12, and others, then as it is from the cognition there is no reason why it should be effective, because, a good object being presented, the appetite does not need an extrinsic agent in order to be borne towards it, but can be borne by natural inclination—or rather the soul, as⁷ living through it.

50. Whether the appetite of the end is to be attributed to the generator.—Others say that the appetition of the end, although it is produced by the will alone, is yet to be attributed to the generator or the author of nature, but that the appetition of the means is not produced by the will alone, but by means of the appetition of the end, while it is received in the will alone; and for this reason the principle of acting and of receiving is distinguished in this act. For either the internal principles themselves are distinct in reality in some way, or certainly, if they are not distinguished in the proximate agent itself, the action is attributed to an extrinsic agent. So think the Thomists of the intention of the end: Cajetan, I-II, q. 9, a. 4; Ferrariensis, III Cont. Gent., c. 89, where St. Thomas signifies it; and Capreolus, In II, dist. 25; and in the same place Giles, q. 5. But although this attribution can be sustained according to a certain moral consideration, because man does not move himself morally in the intention of the end as such as he does in the deliberation and choice of means, of which elsewhere, yet as to real efficiency it does not seem to be approved, nor is it to be denied that it is man himself who by his own power, and not as the instrument of another, effects the intention of the end; especially in acts contained within the order of nature, which the will elicits by its own power with the general concurrence alone; this action, therefore, cannot be attributed to God more than the heating of fire. Especially because it is not only a vital action, but also often free; whence it in no way takes place by natural resultance, nor is it due according to that connatural state which the thing demands in the instant of its generation.

51. Wherefore Scotus, In II, dist. 25, and Henry, Quodl. IX, q. 5, and others, rightly deny that that act is to be attributed to the generator. And the same must be said of many other simple acts which the will elicits of itself without another prior act, such as desire or complacency, or simple love of some known good. Add that that discourse has no place in the sensitive appetite, which does not operate for an end formally; whence in it there is not properly choice, which proceeds from the intention of the end as from the proximate notion of acting, but all acts of appetition proceed proximately from the very natural inclination of such an appetite; therefore either it must be said that all the acts of this appetite are attributed to the generator, which is ridiculous, or certainly it must be confessed that wholly the same power through itself is the proximate principle of acting and of receiving such an act. And so Scotus, Henry and others cited above concede, and at length Antonius Andreas, IX Metaph., q. 1. Nor do I see what drawback follows from this, such that, in order to avoid it, Soncinas, Javellus and others should so scrupulously seek in every power acting and receiving some co-principle of acting and not of receiving, and therefore take refuge in the efficiency of knowledge with respect to love; which, if it is not shown to be necessary by other reasons, is undeservedly asserted for this cause. For they bring no other drawback except that the same thing according to the same would be agent and patient, and consequently according to the same would be in potency and in act, which is an implication of contradiction. But this drawback, if what was said above is considered and the terms are understood, is none; for there is no repugnance in the same faculty being in first act and in potency to an immanent second act, because first act does not formally include second act, but the power to elicit it, which the same faculty can have which is the receptive potency of the same act; and this is consonant with the nature of such an act, since it is immanent; and this is what others say, namely, that the same faculty can be at once in virtual act and in formal potency. Hence, just as by the same act in reality the thing is constituted actually acting and receiving, and just as the same thing is action and passion according to diverse relations, so by the same faculty in reality the supposit can be constituted in the notion of agent and patient in potency; wherefore in this sense it is not unfitting that the same thing according to the same be constituted agent and patient, if it is taken with proportion, that is, both in potency or both in act, and that according to the same reduplicates or designates only the same thing, not the same relation or the same formal notion conceived and prescinded by an operation of the mind.

Corollaries of the foregoing doctrine, and formal resolution of the question

52. From what we have said so far, in order to answer the proposed question formally and universally, it follows, first, that it is not of the notion or necessity of an acting cause as such that it be distinguished in supposit from the patient. This was supposed and proved at the beginning, and is established more evidently from the whole discourse made. Hence, if in some cases such a distinction is necessary, this does not come from the general notion of efficient cause, but from the special notion of such a cause. As, for example, in efficiency through substantial generation a suppositive distinction (so to speak) between agent and patient is necessary, because it is necessary that they differ in being simply and in substantial forms; and the same distinction is necessary between any generator and the thing generated, because the same supposit cannot generate itself, since for generating it is necessarily presupposed. But for nutrition, or substantial generation by addition, if the patient is considered at the beginning of the action or alteration, it too must be a distinct supposit, because it must be a dissimilar substance; but in the very instant of the generation by addition it is no longer a distinct supposit, but a new part of the same supposit, because through that action it is converted and united to the pre-existing supposit. The cause effecting through accidental action or motion, however, in inanimate things is commonly distinct in supposit, especially when the patient is moved per se primo, that is, according to every part of itself; yet this does not come from the necessity of the efficient cause as such, but from the imperfection and proper condition of inanimate things, as has been declared. Similarly it is necessary to observe that this is to be understood of the particular and per se cause; for if the discourse is of the first and universal cause, it is clear that it must be distinct in supposit from the effect and from the patient subject, if it acts through change, because it cannot act on itself, since it is pure act. And similarly, if the cause is per accidens and remote, that is, one which produced the proximate cause and gave it the power of acting, then too it will be a distinct supposit, because it is supposed to have produced the proximate cause substantially. Hence that axiom of Aristotle, Everything that is moved is moved by another, although, understood of the proximate and per se mover, it is not always verified of another supposit, yet, understood indifferently of some mover, whether proximate or remote, particular or universal, every mobile will always be found to be moved by some distinct supposit, or (to use metaphysical terms) every patient to suffer from some efficient distinct in supposit. This, however, cannot be demonstrated by a purely physical middle term, but by a metaphysical one, namely, because no particular acting cause has the power of acting from itself, but from another supposit, nor can it act per se without the concurrence of a superior cause, as will be established below from what we shall say about God and the first cause.

53. An inference from what has been said.—It follows, secondly, from what has been said, that it is not of the notion or necessity of the efficient cause as such that it be distinguished from the patient according to diverse substantial parts, whether essential or integral; but in agents in which this necessity is found, it comes from some peculiar reason, not by virtue of efficiency as such. All these things are established from what has been said; for the first part was demonstrated in the third and fourth conclusions, the rest in the earlier ones. For that in material living things a distinction of integral parts is required for moving themselves by the first vital action, which is through nutrition, comes, first, from the notion of material alteration which intervenes there, according to which the same thing cannot act on itself, nor like on like, as is said in I De Generat., text 48, and its reason was declared in the first and second assertions; it comes, secondly, from substantial generation by addition; for the same part cannot substantially form itself, as is established per se. Thirdly, it comes from the fact that for true augmentation it is necessary that new quantity be added to the pre-existing, because the same part cannot by its own quantity alone increase itself. Hence, in the way in which imperfect augmentation by juxtaposition can be found in inanimate things, it is necessary that the action take place according to diverse parts. And the same holds of alteration, if it happens that an inanimate thing alters itself such that the action is attributed to it; for it can only happen according to diverse parts, if they happen to be unequally affected, which is per accidens in things of this kind. Again, that in animals moving themselves locally this takes place through the distinction of an integral part moving and one moved does not come from the notion of efficient or mover as such, but from the fact that such an efficient and such a living thing is imperfect, and therefore does not participate an intrinsic and natural power of moving its whole self per se primo; which perhaps also comes from the materiality of the body itself, which cannot be so moved by the soul, but through parts and diverse organs or instruments. Hence, however, it becomes probable that it is not repugnant to this living thing that it can move some integral part of its body per se primo, that is, not through another prior integral part, but through itself. Yet in that very part, and universally in every material agent, the essential principles of acting and of suffering will be distinguished; which does not come from the precise notion of particular efficient cause as such, but from the particular imperfection of material substance, which is not active according to its whole self, but only by reason of form.

54. It follows, thirdly, from what has been said, that it is not of the notion of efficient cause as such that the notions of acting and of suffering be distinct in reality, either in subject or in entity, whole or partial; but whenever this is found (which is frequent), it comes from some particular reason. This too is wholly evident from what has been said; for this condition is sometimes lacking; therefore it is not per se and universally necessary by virtue of efficiency. Therefore, that the notions of acting and of suffering be distinguished in subject is necessary only where the action is to be exercised either by a distinct supposit or through really distinct parts, and thence that necessity comes. Which necessity indeed is universal in univocal action, from that principle that the same thing cannot be at once in act and in potency. In equivocal action, however, that principle does not press so universally, nor any other which is universal, and therefore in diverse causes it arises from diverse principles, as has been explained. Again, that those principles of acting and of suffering must be distinct in reality in their whole entity, even if they happen to be in the same subject and in the same integral part of it, comes either from the fact that those principles are substantial and proper to material things, namely, matter and form; or certainly, if they are accidental principles, especially that which is the notion of acting, it comes from the fact that the action is not immanent, but of its genus transient, as is evident in the motion of a heavy thing, inasmuch as gravity is considered as its active principle. And the same holds a fortiori in the motion of the heart, and more clearly in the motion of an angel moving itself. Moreover, that the proximate principle of acting and of suffering, when they are distinguished neither in subject nor in whole entity, should at least differ in some reality which the principle of acting includes and the principle of suffering as such does not, is found in some agents with immanent action; yet it does not come from the common notion of agent as such, as is established from what has been said, nor from the common notion of immanent action as such, because there is no reason why immanent action as such should demand that distinction; indeed in a certain manner it will be more immanent if it remains in wholly the same principle from which it is proximately elicited. It comes, therefore, from the fact that such action takes place through a certain assimilation, and therefore requires, beyond the intrinsic faculty, a proper principle of such assimilation. And so it remains that in immanent action which does not require that assimilation, nor from another particular condition of its own demands some principle cooperating by way of efficient, but only concurring in the genus of end or of extrinsic form—with respect (I say) to such action—it is not necessary that the principle of acting be distinct even in partial entity from the principle of receiving. And this mode of acting is quite consonant with the will, both on account of its freedom and on account of the common notion of appetite, to which it belongs to be able to be borne by its sole inclination and efficacy towards the subject proposed to it. Some diversity could, however, be considered here in the principle of acting and of receiving the act of appetite; for, as I said above, to the act of life there concur effectively and immediately in their order not only the power but also the substantial form; but to receiving the act the power alone seems to concur proximately and immediately. But this difference is both uncertain—for perhaps an accident, and especially a vital act, by inhering attains not only the accidental power but also the substance itself—and whatever be asserted on this for other reasons, it is not necessary for the present cause, because in truth there is no drawback in the same faculty which is the proximate principle of receiving an immanent act being through itself sufficiently constituted in first act as the sufficient proximate effective principle of the same act.

55. First objection against what has been said. Second.—There are not lacking, however, some objections against the last part of this resolution. The first and chief is taken from Aristotle, IX Metaph., text 2, where he says that active power is the principle of transmutation in another as it is another; therefore it is repugnant that an active power be adequately the principle of transmuting itself. Hence he at once adds that the power of suffering is the principle of passive change from another inasmuch as it is another. And V Metaph., c. 11, text 17, he defines the acting and the suffering power in the same way; therefore from the precise notion of agent and patient a distinction between them is required, at least as to the principles of acting and suffering. Hence Aristotle, De Gener., c. 7, reckons it a great absurdity that the same thing should suffer from itself. And I Metaph., c. 3, he lays down this principle: Nor does that which underlies effect its own change; and he says this was the beginning of discovering the efficient cause distinct from the material. The second objection, and a common one, is that the same thing cannot be really related to itself; but the efficient cause is really related to the effect; therefore the same thing according to reality cannot act on itself. And it is confirmed, for if according to the same reality it is at once in active and receptive potency, why does it not always change itself? It is confirmed secondly, because the agent must be brought near to the patient; but the same thing according to the same cannot be brought near to itself.

56. The definitions of active and passive power handed down by Aristotle are explained.—The relation founded in action intervenes between effect and cause.—Why active powers sometimes cease from actual operation.—To the places of Aristotle it can be answered, first, that in those definitions he speaks of merely active and merely passive power; but besides these there are certain powers at once active and passive, of which the doctrine given proceeds when they are completely active of their acts. Hence, secondly, it is said that Aristotle, in bk. V Metaph., declared the same more fully when he said that active power is the principle of change in another, or inasmuch as it is another. And in this way the will, inasmuch as it affects its act, can be said to be a principle of acting in itself, not inasmuch as it is active, but inasmuch as it is in potency. I think it more true, however, that Aristotle spoke of physical transmutations, which take place by transient action, as I shall show more at length below in treating of power as it is a species of quality. And Aristotle speaks of the same change in I De Gener.; for there he disputes of that change which tends to generation and corruption. Similarly he speaks in I Metaph., where he speaks in general of how it is evident that matter and the efficient, in generations and physical changes, do not concur into the same cause. To the first reason it is answered that the real relation is not between agent and patient, but between agent and effect; and in this way, even if some power acts on itself, it yet acts an effect distinct from itself, between which and itself there can be a real relation. To the first confirmation it is answered that, if the power acts naturally, it therefore does not always act because it does not always have the object applied, which it needs not as co-effecting, but in another genus, of final or extrinsic formal cause; as fire cannot act without the combustible, not because it needs it as co-effecting, but as matter. But if the cause is free, even if all the rest are applied, it can not act solely from its natural perfection. To the second confirmation it is answered that identity is the highest or most eminent nearness, if otherwise neither power for acting nor capacity for receiving is lacking.

1. This question is treated ex professo by Aristotle, concerning physical motions, in VII Phys., c. 2; yet the question is more universal and properly metaphysical, for it embraces every efficient cause. Hence it is commonly treated by theologians both of God, I, q. 8, and In I, dist. 37, and of angels, I, q. 52, and In I, dist. 37, and In II, dist. 2; we, however, are dealing here with finite causes, for of God we shall speak later. The question, however, is treated of transient action by which one thing acts on another; for in immanent action, and whenever a thing acts on itself per se primo, that is, according to the same part, it is clear that the agent cannot be distant from the patient; but when one supposit acts on another, or the same supposit through one part on another, they can either be immediately near, or some body, or part of a body, or some space can be interposed between them. And there is no doubt among philosophers that an efficient cause can act on a distant thing through a near one; but the difficulty is, when the cause acts proximately and immediately through the power which it has in itself, and not through another which it diffuses, whether it must immediately touch by its quantity or presence that thing on which it acts, or whether it can act immediately on it even though it is distant in space. With which difficulty another is conjoined, namely, when the cause acts through a near, undistant thing, how through the near it attains the distant.

The first opinion is reported and founded

2. There are, then, two celebrated opinions on this matter. The first is that the efficient cause can act on a distant patient, and so immediate nearness is not required, but only that it be within a certain sphere of activity; for there is no doubt that a finite power has a certain terminus in space or distance which it can attain, because, as is established by experience, a thing acts more strongly on what is near than on what is distant. Greater power, therefore, is required for acting on a distant thing; since, therefore, the power is finite, it also has in this a limited sphere, in which all agree; yet within it, this opinion says, the agent can immediately effect in a distant patient. Avicenna holds the same, in his book On the Soul, sect. 4, c. 4, citing Hippocrates for the same opinion. Likewise Alexander of Aphrodisias, I Metaph., comm. 18; Scotus, In I, dist. 37, and there Ockham, and Gabriel, Bassolis, Mayronis, and other Scotists. Although Scotus confesses of physical causes that they never act on a distant thing through one form or quality without acting on what is near through another, although it is not necessary that they attain the near and the remote through the same one; whether this is said consistently we shall see later.

3. The preceding opinion is founded on various experiences.—This opinion is proved, however, by an induction made through all the genera of actions. First, in substantial generation: the sun generates in the earth various mixed bodies, such as minerals, or also animals which are generated from putrefaction; but that action must flow immediately from the substantial form of the sun, for the accidents diffused through the medium either do not attain substantial generation or do not suffice for it.

4. Secondly, in the motion of alteration there seem to be certain things which alter a distant thing without altering the near one. The first example commonly adduced is of the imagination, which is said to have efficacy to induce a new quality by altering a distant member or another thing, as Avicenna hands down above from Hippocrates. The second example is of the fascination of the eye; for the eye sometimes harms by altering a distant thing, as experience bears witness of the eyes of some women, as Aristotle too notes, sect. 20, Problem 34; Alexander, bk. II of the Problems, at 50; Albert, bk. XXII De Animal., c. 5; Marsilio Ficino, bk. XIII On the Immortality of the Soul, c. 4; and of the basilisk Isidore affirms, bk. XII of the Etymologies, c. 4, that it kills serpents by its smell, slays a man by its look, and harms flying birds although they are far distant. Pliny reports almost similar things, bk. VIII of the History, c. 31, where he attributes the same power to the catoblepas, that it kills a man who sees its eyes; and in c. 22 he similarly says that the sight of wolves is harmful and for the moment takes away a man's voice. The third example can be of the torpedo fish, which numbs the hands of fishermen from afar; and Aristotle, bk. IX of the History, c. 37, says: The torpedo fish affects those it seeks with the faculty of numbing which it has in itself, and so it catches them and feeds on them, and for this it hides itself in sand and mud. Which is a sign that it does not act through the medium; and in the same place he reports other similar experiences. Pliny reports the same, bk. XXXII, c. 1, where he expressly says that the torpedo does this from a distance and from afar, even if it is not touched by a spear or rod. Let the fourth example be of a certain herb named aproxis, whose root catches fire from afar, as Pliny reports, bk. XXIV, c. 17, where he reports the same of naphtha, a certain kind of bitumen, of which the same Pliny speaks, bk. II, c. 108. Fifthly, it often happens that a distant thing is more vehemently altered than a near one; therefore it is a sign that the agent by its own force acts immediately on the distant thing; for through a quality which is remiss in the medium it could not effect a more intense quality in the extreme. The antecedent is evident from many experiences; for fire heats the water existing in a cauldron more vehemently than the bottom of the cauldron, and makes oil placed on paper boil much more vehemently than the paper, and heats tow at some little distance so much more intensely than the intermediate air that sometimes it inflames it; and the sun heats a mirror or the earth more vehemently than the intermediate air. Nor is it to be wondered that an agent sometimes acts more on a distant thing than on a near one, if the disposition of the patient is unequal. And this very thing is confirmed by other examples; for the sun illuminates more clearly those parts of the air which it reaches or regards through a window by a straight line than those which are to the side or at an oblique line; therefore it is a sign that it does not illuminate those which are directly opposite only through the parts of the intermediate air, but immediately through itself. The consequence is evident, because with respect to the parts of the intermediate air the other parts of the air, whether they are directly opposite the sun or only to the side, are equally near and equally applied; if, therefore, the illumination of the remote parts takes place only by means of the near part, the remote parts which are equally neighbouring to the nearer will be equally illuminated, even if they have a diverse aspect with respect to the sun; for that part, so far as concerns itself, acts equally towards every part near to it. A similar experience is of the hand or another thing exposed to fire or the sun through the window of a furnace, for example, which feels a more vehement heat when directly exposed to the fire than when placed to the side, even if with respect to the intermediate air it is equally near; therefore it is a sign that the fire immediately attains the distant hand if it is directly opposed through an unimpeded medium. A sign of which also is that if something is interposed or the window of the furnace is closed, the vehement sensation of heat which came from the action of the fire suddenly ceases, and yet the medium still retains all the heat which it had conceived; therefore it is a sign that the action came immediately from the fire, and not only from the medium.

5. Thirdly, experiences are principally brought concerning local motion, which takes place in various ways from a corporeal mover (for of the incorporeal I shall speak below), namely, by pushing, pulling, carrying and rolling. And concerning pushing, the experiences of projectiles are commonly brought, and of heavy and light things, whose motions are reduced to pushing, as St. Thomas notes, VII Phys., c. 2. But they are of no weight; for the proximate instrumental principle of that motion is not only near, but even existing in the mobile; but that impulse is either communicated by generation—whether this requires nearness has already been proposed—or is impressed by some quantitative contact; for a corporeal mover cannot of itself immediately push a mobile except by touching it; but what is impressed through that contact, or what impulse is, is not to be declared in this place; it is treated, however, by Aristotle, bk. IV Phys., c. 8, and VIII Phys., last ch., and III De Caelo, c. 2. And hence too it is established that rolling, since it includes pushing, requires the same nearness that pushing requires. Of carrying, however, it is known per se that it requires contact, since what is carried is moved as it were per accidens with the motion of the carrier. Only in pulling, therefore, are examples brought in favour of the said opinion. The first is of the magnet drawing distant iron to itself. The second can be of amber lifting straws. The third, almost of the same notion, is what is commonly brought about the fish remora, otherwise echeneis, which holds back a passing ship, as Aristotle reports, bk. II of the History, c. 14; Pliny, bk. IX of the History, c. 25.

6. Fourthly, an induction is made in the actions of the powers of the soul; for the phantasy existing in the brain immediately moves the appetite which is in the heart, and the appetite immediately moves the hands or feet. Similarly the external sense seems by its act to impress a species on the imagination. For it is not likely that something should act through the whole medium, so that, for example, if the foot is heated, the species of heat should continuously ascend as far as the head, where the phantasy or the common sense is.

7. Fifthly, the same induction is made in the action of the intelligences, which can only be twofold, namely, either local motion, whether of a body or of another spirit, or speech, which is only to another intellectual thing. This latter action, then, by the opinion of all, can take place to a distant thing, as is established from St. Thomas, I, q. 89, aa. 7 and 8, and q. 108, a. 4, and q. De Anima, a. 18, ad 13; and it does not take place without some efficiency, because through it the angel to whom another speaks receives the faculty of understanding what before he could not, namely, the free thought of the other; but it does not seem that he can receive a new faculty without something new being made in him. Especially because he not only receives the faculty, but is also aroused to hear; but he cannot be aroused unless something is impressed on him. Hence St. Thomas, I, q. 107, a. 1, ad 3, says thus: As sense is moved by the sensible, so is the intellect by the intelligible; as, therefore, sense is aroused by a sensible sign, so the mind of an angel can be aroused to attend by some intelligible power. As, therefore, a sensible sign does not arouse sense except by impressing something on it, so angelic speech does not arouse the hearer except by impressing something on him, for example, some intelligible species. Hence the same St. Thomas, q. De Anima, a. 20, ad 11, treating of a similar action by which intelligences effect species in the separated soul, says: Since such action is not situational, one need not seek here a medium carrying situationally, but the order of nature operates the same here, indicating that this action does not require nearness, but subordination. For with similar words and similar reasoning he said, in the I, that the speech of an angel is not impeded on account of distance. Of the other action of the intelligence, however, which is local motion, that it too can take place to a distant thing is taught by Durandus, Gabriel, Ockham, Scotus and Hervaeus, In I, dist. 37. And it seems likely from the same foundation, that the angel of itself has no situation nor acts in the manner of a corporeal thing, but through intellect and will; therefore its efficacy does not require situational nearness, but the power of the will. For since it moves only by willing, what need is there that it be substantially present where it wishes to move?

8. A reason for the preceding opinion.—Sixthly, a reason can be formed in this way: because the active power of a creature has some quantity (so to speak) of perfection; therefore it is not likely that it is so limited that it cannot through itself act immediately except on a point or indivisible surface; therefore it can act immediately within some quantified or quantifiable distance; therefore it can also immediately attain the distant parts of that sphere or space. This reason is declared and confirmed, first: for when fire heats water by means of air, it has immediately near to it only the last surface of the air neighbouring it; therefore, according to the opposite opinion, it will act immediately through itself on that alone; indeed it will act on that immediately only through the heat which it has in its last surface; and through the surface it will act on the immediate part, and through the nearer part on the more remote, as it were dividing the action through all the near and remote proportional parts; but this mode of acting seems incredible per se and to have no small drawbacks. First, on account of the reason given, because it seems irrational to confine every power of acting, however great, to the very space in which the agent is, or at most to the last surface contiguous to it; for the power of acting can be greater and less, and its efficacy consists not only in the effect, but also in the mode of acting and in a greater sphere of activity. Likewise, I take the surface of the air nearest the fire and ask on what it acts immediately. It will be said that it acts immediately on the part near it; whence, since none is adequately near according to its whole self, it must consequently be confessed that it has no immediate subject, either indivisible or of definite magnitude, on which it acts immediately as a whole, but that it acts immediately only on the near taken as it were confusedly; but this seems unfitting, namely, that a determinate action, which takes place in an instant, for example, from the heat or light which is in this surface, should not have a determinate subject in which it takes place per se and immediately. Likewise, that mode of acting, as it were enumerating all the proportional parts, acting through these on those, since they are infinite, scarcely appears intelligible, especially in an action which is not extended successively through the subject, but takes place as a whole at once and in an instant, by way of one.

9. Finally it is confirmed, secondly, because from that principle it follows, speaking per se, that natural agents have no sphere of activity nor a terminus in it. The sequel is evident, for if one considers that on which they can act immediately and per se, they have no sphere, but only the surface nearest them. But if one considers that whole on which they can act mediately, attaining the remote through the near, there is no certain sphere nor any terminus of that action; for whatever terminus is designated to which the action intrinsically reaches, through it it will be able to proceed further, because in that terminus there is some power of acting; therefore that power will do something on what is near it. I say, however, speaking per se; for from the resistance of the patient it can happen that the power reaches that terminus so weak that it cannot overcome the resistance of the next part, either per se or in the power of the most distant agent; but this is accidental, on account of resistance. Although that too is most difficult to explain, namely, how a quality received in the medium can, in the power of the remote agent, overcome the resistance of the part nearest it, which it could not overcome per se and by its own power, if the remote agent does nothing per se immediately on the remote resisting part, but only through the power received in the nearer part. But of this later; now, however, the argument presses, speaking per se, and with resistance removed from the medium. And thus it comes about that the sun could in an instant illuminate the air to infinity, which is plainly false, because now it illuminates the near part of the air more than the remote, as is evident in a lamp; therefore, if the action is extended too far, it will at last be finished. Add that the reason for this effect too could not be given; for why does a lamp illuminate a remote part less than a near one, if it does not illuminate the former, like the latter, per se immediately? But from this head the reason is excellently given; for since the power is finite, it does not equally overcome a thing neighbouring it and a distant one, and therefore greater nearness contributes to greater perfection of action; but if it acts on the remote only through the near, it will communicate to the remote part all the intensity of quality which it communicates to the near, because that quality is active of what is like itself, and the remote part is capable of it and is immediately near to the nearest part; it is a sign, therefore, that the action does not take place in that way, but that the agent through itself immediately attains the whole sphere.

The second opinion is reported and declared

10. The second principal opinion is that in every efficient cause it is a condition necessary for acting that it be near and undistant from that thing on which it first and immediately acts; so that, if both, namely the agent and the patient, are quantified, they are contiguous, and the action begins from the last surface in which they touch each other, and so contact of power always presupposes quantitative contact; but if the agent is spiritual, it is near in a proportional way according to substantial presence. This is the opinion of Aristotle, VII Phys., c. 2, and I De Generat., c. 6, which St. Thomas defends everywhere, especially I, q. 8, a. 1, and III Cont. Gent., c. 68, in which places Cajetan, Ferrariensis and other Thomists; Capreolus, In I, dist. 37; and there Durandus, q. 1. And Richard signifies the same, a. 2, q. 1; Albert and others suppose the same when they infer His presence from the operation of God. The same Albert, VII Phys., tract. I, c. 4, where the Commentator, Aphrodisias and others commonly. The holy Fathers too favour this opinion, indeed even sacred Scripture, when they signify that even in God Himself immediate presence is rightly gathered from immediate operation. Of which argument we shall speak at length later, treating of the immensity of God. This opinion, however, is not proved by Aristotle by any reason, but by induction and experience alone, which is sufficiently known to the senses, so far as it can be from frequent sensible effects. The induction, however, will be perfect if we show that it never happens that natural action takes place otherwise, or at least that it cannot be persuaded by any experiment; but this will be established by the solution of the objections. And thus the argument is concluded; for the mode of acting common to all natural agents is founded on some intrinsic and natural necessity; but this mode is through immediate contact and nearness; therefore it is a sign that this is a necessary condition for every natural agent in order that it be able to act.

11. Various reasons for the necessity of the presence of the agent to the patient.—The reason for this necessity, however, is given by some as follows: just as a thing cannot pass from place to place except through the medium, so the action of the agent cannot be transmitted immediately to a distant thing unless it first attains the medium, and through it as it were continuously reaches the distant thing. But this reason in my view is inefficacious, because the action does not pass numerically the same to the distant thing through the medium as the numerically same body passes to the extreme place through the medium; hence it is not rightly said that the action passes to the extreme, but that it is educed by the power of the agent from the potency of the distant subject; in which, by virtue of that reason or likeness, no repugnance appears.

12. Others take the reason from the limitation of the finite agent, which on account of the defect of its power needs the presence of the patient in order to act. And this reason can be confirmed, because if the agent could act on a distant thing, by the same reason it could act at any distance whatever; for if it does not need action on the medium, what does it matter whether the patient is more or less distant? But in the first place the authors of this opinion, and especially St. Thomas, do not limit it to finite agents, but require this condition also in God; therefore it does not arise from the limitation of power. Next, from the limitation of power there seems at most to arise a limited sphere. But why should so great a limitation, to the proximate and immediate patient, be inferred from any limitation of power whatever, if the notion of efficient as such does not require that condition? Especially because not every power is equally limited, as we argued above. And for the same reason the inference made in the confirmation does not appear efficacious; for those who deny that that supreme nearness is simply necessary for action do not deny that it is useful in order that the agent act in the best way; indeed they even assert that it is necessary in order that it act with its whole power and as much as it can; and hence they think it arises that, other things being equal, natural agents act uniformly-difformly through spaces; and so nothing follows of what is inferred in that confirmation. For without doubt it is established from the very terms that it belongs to greater power to overcome a distant thing than a near one; and in the same proportion it will belong to greater power to overcome a thing more distant than less, just as it belongs to greater power to throw a stone to a more distant place. Hence Capreolus above, to the eighth argument, says that the reason for this is not to be taken from some imperfection or order of the acting and receiving power, but from the fact that the agent is in a certain way the act of the patient itself and the patient is in a certain way in potency to the agent; but act and potency of their notion demand to be undistant, so that, namely, they may exercise between themselves the notion of act and potency. Which reason, although it does not suffice to convince a perverse intellect, yet, sufficient experience of the thing being supposed, seems to me to touch more nearly and indicate more the proper cause of this necessity. In order, however, that we may declare this matter more fully and defend the opinion of Aristotle, it is necessary to explain the modes of nearness and distance and the various modes of acting through the near on the distant.

Resolution of the question

13. Various modes of distance and undistance of the agent from the patient.—It must be noted, then, that the patient can be distant from the agent because between them there lies a wholly empty space, which, although it does not happen naturally, yet they could be so understood, and it is necessary to say how they would then behave in action, because it will contribute not a little to explaining the matter. Secondly, the patient can be distant from the agent with some intermediate space interposed, not empty, but full of such a body that the agent could do nothing on it. Thirdly, it can be understood that the agent does something on the medium, yet not through the same power, as if it acts on the air through light, but on the earth through the substantial form. Fourthly and finally, it can be understood that the distant patient is conjoined to the agent through a medium on which the agent also operates, and through the same power. But this itself can be understood to happen in various ways. First, that the remote agent immediately brings action only on the patient near it, and through the quality impressed on that the action takes place on the remote patient, so that the relation per se and immediate of that action, as it is in the remote patient, is only to the power or quality impressed in the nearest part, but to the agent itself only remotely and inasmuch as it gives or conserves that power. Secondly, it can be understood that the agent acts on the remote by means of the power conferred on the nearest part, at the same time and actually inflowing with it into the remote part, so that it can neither attain the remote without it and through it, nor does that power alone, although conserved there, suffice for the action which takes place in the remote part without the actual influx of the agent itself. Thirdly, it can be understood that the action of the agent is diffused of necessity to the remote through the near, not by necessity of the causality of the near part of the patient upon the remote part, but only by necessity of order (so to speak); which necessity can arise either on the part of the agent, which by its nature determines for itself this mode of acting as it were through an uninterrupted line, or on the part of the patient, which, applied to a natural agent, necessarily suffers in the near part before the remote.

First assertion

14. With a vacuum lying between, there is no action on a distant thing.—Why all bodies abhor a vacuum.—First, then, it must be said that the efficient cause can do nothing on a distant patient if an empty space is interposed. This assertion is commonly received, so that not even the authors of the first opinion seem to deny it; for Scotus, even if he admits some generative action from distant matter, says nevertheless that some other action must be diffused through the medium, although he confesses this only of natural agents. This assertion cannot, however, be proved by positive experience (so to speak), because such a vacuum has never been given between bodies; it can, however, be proved by negative experience (so to speak) and by the providence of universal nature, or rather of its author, who so founded things and placed in them such a propensity or motion that they wholly avoid a vacuum, even if it is necessary to desert their proper places. Of which the chief reason seems to have been that some bodies might be able to exercise their actions through others, and distant bodies through intermediate ones participate in the influx of others, and especially of the heavenly bodies. Which Aristotle not obscurely signified, text 1 of the Meteorology, saying: It is necessary that it (that is, the lower world) be in a certain manner (that is, through the intermediate elements) nearest to the highest revolutions of the heaven, so that its whole faculty may be constituted and ruled from there. Nor will he satisfy who says that nature did not abhor a vacuum and so solicitously procure the contiguity of bodies on account of simple necessity, but only on account of greater convenience and utility. Both because so great a solicitude of nature indicates a greater necessity, and also because, if it were true that natural agents could attain a distant thing without a medium, it would often be more useful for action to have no real medium interposed, because the sphere would be more free and the power of the agent less occupied about it, according to what will be said at once.

15. Secondly, it can be proved by another experience which, although it is taken from a wholly opposite thing, yet seems to have the same root, namely, that if the space interposed between agent and patient is filled with some body which interrupts the action of the agent, the action on the distant patient is wholly impeded, even if otherwise it is constituted within the sphere of activity of the agent; therefore by the same reason, if the medium were wholly empty, the action of the agent could not pass to the distant patient, because the action would be interrupted no less by the vacuum than by that plenum. It can be answered that that interposed body impedes the action on further bodies not because it interrupts the action of the agent, but because the whole power of the agent is occupied (so to speak) about that body, whence it comes about that its sphere is terminated there. For they say that the sphere is not always the same, or of the same magnitude or distance, but according to the capacity or resistance of the medium. For it can happen that a body a foot long, on account of its density, resists more than a large rare body, and therefore finishes and terminates in itself the sphere of the agent. But although this reply can have some appearance of truth when the interposed body truly has the notion of a patient, in overcoming and (so to speak) penetrating which the power of the agent is occupied, yet, when the interposed body is wholly incapable of such action, so that the power of the agent is in no way applied to it according to that action, how can it detain it or resist the agent so that it does not effect on further bodies? An example is in the sun illuminating, whose action is impeded by an opaque body interposed in a window, which is incapable of light and does not resist illumination of itself positively, but negatively through incapacity; in which way also a vacuum can be said to resist, although from diverse principles; therefore the illuminative power of the sun is not occupied as it were in striving and acting about that body, but only does not act on it, as neither does it act on a vacuum; therefore that body impedes the passage (so to speak) of that action in no other way than by interrupting its continuation and as it were its line or ray; therefore an equal impediment will arise from an interposed vacuum. And this experience seems to me very efficacious for proving the conclusion laid down; of its reason, however, we shall speak below.

Second assertion

16. What it cannot effect on a full medium, it will not effect on a distant patient.—Hence it is said secondly: when the patient is distant from the agent through an interposed real medium, the agent can effect nothing on the distant patient if it cannot also act on the whole medium. It is manifestly evident from what has been said. First, because, if the interposed medium were not necessary to sustain and as it were carry the action of the agent, that medium would be related wholly per accidens to the action; it would therefore be irrelevant whether that medium were real or empty. Secondly, the experience of the interposed dense body proves this, which impedes the further passage of the action only because it is incapable of the action of the agent. Thirdly, because the reason which we gathered from the vacuum was only that in it the action of the agent is interrupted, and this was a sufficient impediment to action; but this same interruption intervenes when the medium nearest the agent is not capable of its action or influence; therefore. And thus we see that the sun does not illuminate the earth except by illuminating all the intermediate bodies; but if sometimes the moon is interposed, which the sun cannot penetrate with its light, the action of illuminating does not attain the earth.

Third assertion

17. By the power by which something acts on a distant thing, it must also act on the medium.—I say thirdly: in order that the agent may effect on a distant patient, it is not enough that it act on the medium through another, wholly distinct power or action; but it is necessary that, through the same or a subordinated power by which it acts on the distant thing, it begin to act on the medium near it and diffuse the action or influence through the whole of it as far as the distant patient. This assertion is directly against Scotus and others; it is proved, however, from what has been said, because in order that the agent act on a distant thing, it is necessary that prior in time or nature it act on the near and continuously on the whole medium; therefore it is necessary that that continued action flow in some way from one and the same power of the agent. The consequence is evident, because if there are two powers and two actions flow from them, there are formally two agents there, although materially it is one by reason of one supposit or subject; therefore it is not enough that it act on the proximate through one power in order that through another it may act on the distant. The consequence is proved, because those actions are related only concomitantly, and one cannot be said to be continued through the other and to take place without interruption. As, for example, although fire can act through heat and dryness, in order that it may act through heat on a distant patient it is not enough that it act through dryness on the near medium, because this is per accidens to the action of heat as such; it is necessary, therefore, that it act through heat on the near, because that is per se necessary for the continuation of the action. Indeed, although it can happen that the action of one power is necessary on the part of the patient in order that the action of another power may reach it—as, for example, if the action and disposition of dryness were necessary for the action of heat—it would not be enough that one power act beforehand, disposing, in order that the other might act immediately on the distant doing nothing on the near; because that disposition is merely material, and it is irrelevant that it comes from another concomitant power in the same subject, because through this the action of the other power does not take place continuously through the whole medium; which, however, has been shown by the two preceding conclusions to be necessary for the action.

18. A note.—Two things, however, are to be observed. One is that, when we say the action must be from one power, the sense is not that that power must be one form or one entity, but that it must be the adequate principle of one action, even if it coalesces from several forms, whether acting equally or subordinated. The other thing to be observed is that, when we say that the action on the near and the remote must be as it were one by continuation, it is not to be understood of rigorous and physical continuation, such as there is in illumination if the medium is continuous; but it is enough if there is continuation according to a certain subordination and causality. For it is not necessary, when the agent operates as far as some distance, that in the whole of it it produce a quality of the same notion; for in a body near it it can effect a certain quality, and in a more remote one a diverse one; as the sun, for example, produces only light in the heavenly bodies which it has below it; but in the air down to the earth it produces heat together with light; but in the earth, according to its depth, it does not produce light, but heat only, and by means of heat it effects other forms. The same may be considered in the other stars, which have proper influences, which they diffuse as far as the recesses of the earth, yet they do not do the same in all intermediate bodies, but in each they operate, according to its capacity, what is proportioned to its disposition. Then, therefore, since the qualities or termini produced in diverse bodies are distinct, the efficiency cannot be diffused by way of one continuous action; it is necessary, however, that through the quality produced in the neighbouring body it produce another in the remote, and through that similarly in the more remote, and in this way the action is said to be continued through subordination and causality. For since it is necessary that the action take place continuously by way of one, as was shown in the assertions, and continuation in the same species of action or quality is not necessary, it is necessary that it be through the emanation of one from another; otherwise the action which takes place on the distant will have no connection with the action which takes place on the near, but both these actions will be related wholly per accidens; which the reason given in the third assertion proves cannot happen.

Fourth assertion

19. Some agent can act immediately on an extended space and all its parts.—I say fourthly: although it is necessary that the efficient cause be near and undistant from the patient on which it first acts, yet it is not certain that it always acts through the near on the distant as through an instrument or power of acting; but it is probable that it sometimes acts on some whole patient immediately through its own proper power; and similarly, when it acts through the near as through an instrument on the distant, it is not necessary that it act through it as through an instrument separated in causing, but as through a conjoined one, so that together with the power diffused through the medium the agent itself inflows immediately by one and the same action. The first part is the very conclusion of Aristotle and the common opinion which we defend, and besides his induction it is manifestly proved from the preceding assertions and their proofs, by which it was shown that the agent cannot diffuse its action as far as a distant thing except by way of one uninterrupted action; therefore it is necessary that the action begin from a wholly neighbouring and undistant patient; otherwise it would from the beginning be begun interrupted. And this is not a little confirmed by some experiences in which we see that the agent per se intends action only on the remote, and nevertheless does not exercise it except through the medium, although that action, as it takes place in the medium, is altogether useless, except that it at least serves for this, that through it the action may be carried to the distant patient in which the agent has the effect per se intended; for example, the visible object does not diffuse species to the eye except through the medium. Of which there are some evident signs. One is of the mirror in which reflection of species takes place, which also takes place in water; but it could not take place unless species were multiplied as far as those bodies. Another is that according to the disposition of the medium the species are either disturbed or conveniently carried. Likewise, there is that touched upon above, that, for whatever reason some part of the medium is incapable of species, the action is impeded from reaching the eye. But this action of the species per se and from the intention of nature is wholly ordered to the eye, because in that alone can the species have the effect for which they were instituted; such action of the species in the medium would therefore be useless unless it were necessary in order that through it the action might reach the distant eye; therefore it is a sign that such action takes place on account of this necessity. And the same judgment is to be passed on every similar action, even if it is not known by such certain experiments.

20. An inference from all that has been said.—From all these, then, I gather that the natural mode of acting of the efficient cause is as it were through a continued line of its action from the near to the distant. And this ought to be a sufficient reason for the conclusion, the experiences adduced being supposed, even if another reason were lacking, namely, that this cause determines for itself from its nature such a mode of acting. For we often judge so of the natures of things from what we experience, even if we are not able to give a further reason for that natural condition. As, for example, the object of sight multiplies species only in a straight line, but the object of hearing also in an oblique one, and enters through any pores whatever, as is established by experience, from which we rightly gather that this is the natural mode of acting of such objects; of which the sufficient reason is that such a property follows the nature of each sense. We try, however, to investigate some reason for this nature when we say that sound is a certain quality following motion and imitating its nature, and therefore can enter by any ways whatever, while colour acts in a more quiet and subtle way, and therefore diffuses species only by a straight way. Thus, then, in the present case, if we wish to investigate some reason or conjecture of that natural condition of agents, certainly that which was touched upon by Capreolus is not to be despised; for every act requires conjunction with the potency in order to exercise its causality upon it; as, therefore, in a formal act intimate union is required, so an efficient act requires at least undistance, not on account of imperfection, but rather on account of the perfection which the notion of act or actuation includes. Or if this is to be referred to some imperfection, it is to be taken on the part of the effect, which, since it is dependent on its cause, demands conjunction and undistance from it in order to be able to flow from it, as a stream requires conjunction with its source in order to flow from it. In which too a certain latitude can be considered according to the various perfections of causes; for corporeal causes and effects cannot according to their whole selves be immediately present or undistant to one another, and therefore they are brought near at least according to their extremes. Created spiritual things, however, are conjoined or present according to their whole selves to the effect or patient, although it is not always necessary that they be intimately present to the whole patient and to all its parts; for they can be present to one part and through it act on the whole, in which way the intelligence moving the heaven is thought to be in the East. But God, wherever He acts, is present whole and in the whole, not only from immensity, but also from the perfection of acting, as we shall see below in its place. I said, however, that this mode of acting, beginning the action from an undistant patient, is connatural to the efficient, because we are not now disputing whether God can supernaturally change this mode of acting. We believe, however, that this is not repugnant to divine instruments, even if it cannot be connatural to any created agent; of which matter I have spoken in tome I of the III Part, disp. 31, sect. 7.

21. And hence it can further be understood that from the necessary nearness between patient and agent it is not at once inferred that it is also necessary that the agent act through the near part of the medium on the remote as through an instrument; for it will be enough if it acts through it as through a medium necessary for the continuation of the action, or in order that the action take place without interruption, because neither the experiences nor the reasons so far adduced prove more. Wherefore, when the action through the medium varies in the proximate and the remote patient according to various qualities and termini of action, then certainly it seems necessary that the power diffused in the near medium be the instrument for acting on the remote, as we said just now, because otherwise there would be no continuation or per se subordination between those actions. But when the action is wholly of the same notion in the near and the remote part of the medium, it does not seem per se necessary, at least by virtue of the nearness necessary between patient and agent, that the near part be the instrument for acting on the remote; because that action per se has its continuity and integrity, which is necessary from the natural mode of operating of such a cause, as we have shown. I said, so far as concerns the force of the necessary nearness; for if the quality diffused through the medium is active of what is like itself, it follows from the nature of the thing that, existing in the near part, it can help to act on the remote, either by way of instrument or by way of partial agent; this, however, can be as it were per accidens and only concomitant to the action of the first agent.

22. Wherefore, if it happened that the quality diffused through the medium were not active of what is like itself, then it would not be necessary that the nearest part be an instrument, but only a medium for the action. Whether this ever so happens is not certain to me; yet I do not see a repugnance by virtue of that condition necessary for acting which we are now treating, namely, nearness. And an example could be in the object of sight, for it seems so to multiply species through the medium as far as the sense that the species received in the diaphanous medium is not effective of what is like itself; which seems to be proved from the fact that beyond a certain distance the object cannot effect a species of itself, which would not happen if the species received in the medium effected what is like itself. Which argument was touched upon among the foundations of the first opinion, and in the replies we shall see how efficacious it is. Another example can be of the impetus which is impressed on a thrown stone; for the contact of the thrower is only in one part of the stone, and yet the impetus is not received in that part alone, but in the whole thrown body; nor does the part of the impetus impressed on one part effect another like it in the neighbouring part, both because impulse is not effective of another impulse, but of local motion only, just as gravity is not effective of gravity, but of local motion; and also because impulse is not impressed except by strong contact; but one part cannot in this way touch another continuous with it; it seems likely, therefore, that impetus is impressed on the whole mobile and all its parts immediately by the thrower, by means of contact in only one part of it. Whatever be the case, however, about special examples, yet, speaking in general, in order to save that axiom about the necessary nearness between the agent and the first patient, we are not compelled to say that the efficiency of one part of the patient on another is necessary. Whether, however, some experiences or reasons sufficiently show that that efficiency does not always intervene, or is not per se necessary, we shall see in treating the arguments of the first opinion.

23. The parts of the medium nearer the agent do not act on the remote ones without its help.—Finally, on this too depends in part the last part of the assertion; for even if the nearest parts of the medium act on the remote ones, it seems to be proved by experiment that they do not act by the power received in themselves alone, nor are they wholly destitute of the actual influx of the first agent; otherwise the action of the same medium would not be so vehement in some parts and so remiss in others equally near to it, but unequally applied with respect to the first agent; which is to be examined more closely in the solutions of the arguments. Now, however, we say only that from this nearness and condition necessary for acting which we are now treating it does not follow that the agent acts on the distant part only through the power received in the nearest part as through an instrument as it were separated in causing, that is, acting per se alone without the actual influx of the principal agent: both because neither is this necessary in order that the patient be absolutely near to the agent, from which the action may flow continuously and without interruption; and also because then from the agent itself and the power received in the medium there is as it were composed one integral agent which touches the other part, and therefore can act on it through its whole power. Which I declare by this likeness: for when fire heats the air near it, it does not act on it through the heat alone which it has in the last surface by which it touches the air, nor through some neighbouring part alone, even if it be imagined of any quantity whatever, which can only be determined merely gratuitously; it acts, therefore, immediately through the whole heat which it has in itself and in all its parts (for I suppose all are within the sphere of activity), and yet not all the parts of the acting fire are immediately near to the air suffering; but because from all of them there coalesces one agent which through its terminus is contiguous to the air suffering, that is enough for all those parts to inflow immediately into the patient by way of one integral agent. And it would be the same if two fires, discontinuous between themselves, were applied to the same part of the patient, so that from both together one action would flow by way of one integral agent; therefore similarly it can be understood that the agent conjoined to the first part of the patient, already affected with its quality, acts by way of one and inflows into the further patient, whether they concur as two partial agents or as principal and instrumental agent. But all these things will be more elucidated in the replies to the first opinion.

Solutions of the arguments

24. What agent is present to substantial generation.—To the first experience, then, concerning substantial generation, the common reply is that the accidents which are proximately present effect substantial generation in the power of the substantial form, although that is distant. Which reply has the difficulty touched upon in sect. 3, because, although accidents can be instruments for effecting substance, they cannot be sufficient principles if they are separated as to causality. And therefore, if the substantial form, far distant, can in no way actually inflow with the accidental power into substantial generation, it cannot through accidents alone be a sufficient principle of such generation. Wherefore it can probably be said that that instrumental power diffused from the heaven as far as the place of the earth in which substantial generation takes place does not act as a separated power, but as conjoined in causality, and that the form of the heaven actually inflows with it, if otherwise the effect does not exceed in perfection the very form of the heaven. Nor does it follow from this that the heaven acts immediately on a distant thing, because it does not act except as conjoined to its power diffused through the medium as far as the distant patient. You will say: the form of the heaven and the accidental power of the same heaven are diverse powers of acting; but the whole preceding alteration was produced by the heaven by means of the accidental power only; therefore that does not suffice for the form of the heaven to be able afterwards to inflow by means of its substantial form into the substantial generation of another. I answer that the form and the accidental power of the heaven itself are not two powers only concomitantly and as it were per accidens conjoined, but are subordinated as principal and instrumental principle; and therefore, although the substantial form attains the generation which takes place in a distant place, it does not act formally and properly on a distant thing, because it is conjoined by means of its power. And this will be easier and clearer if one holds that the substantial form of the heaven concurs per se as principal principle not only to the eduction of the substantial form, but also to the preceding alteration, which we said above is probable. But if perhaps this does not please someone, it must necessarily be said that the heaven concurs to these generations only instrumentally through the accidental power diffused through the medium, but is helped to accomplish these generations by some superior agent.

On the alteration of the body by the imagination

25. To the second, about alteration, the assumption is denied, namely, that some cause alters a distant thing without altering the near. And to the first example, about the imagination, it is answered that the discourse is either of the body of the animal itself whose phantasy it is, or of another's. Speaking of another's body, I deny that the phantasy of another has the power of altering it; nor has any probable experiment been brought so far which shows it; nor is it likely by force of reason, because the act of imagination is immanent, and there is no source from which it should have the power of naturally altering another's body. But if the discourse is of the proper body of the animal itself which operates by imagination, it must be said that the imagination does not move the body except by means of the sensitive appetite, at whose motion the humours and vital spirits are aroused, by means of which the body is altered; but the motion of the appetite by the imagination is not an alteration, but a certain vital affection, of which I shall speak below. The appetite, however, since it is in the heart, which is the principle of the animal's motion and of the vital spirits, can easily arouse such motion or alteration, doing nothing immediately on a distant thing, but by means of near parts; although in that motion too a special reason intervenes, because it takes place through the natural sympathy of powers rooted in the same soul, as will be said below and more at length.

On fascination

26. To the second example, there are those who deny that power of fascination. But there is no reason why we should deny an experience confirmed by philosophers and physicians and received almost by common sense. We confess, therefore, that fascination happens naturally; its mode, however, St. Thomas declares, I, q. 117, a. 3, ad 2, and III Cont. Gent., c. 103. And in the first place it must be said that fascination does not take place by the very act of seeing as the principle by which alteration takes place in another, because an immanent act, as we said above of the act of imagination, is not per se active upon anything. Next, it must be said that that alteration takes place from some poisonous quality existing in the eye, or in the internal disposition, complexion or humours of the body, which is communicated to the vital spirits, which are stirred by the imagination and attention of the mind and reach the eyes. Again, hence it comes about that by means of those spirits the nearest air is infected and the alteration reaches to a certain distance, and so harms another although he is some little distance away. And perhaps sometimes it happens that the infected spirits themselves are sent forth as far as that person on whom the gaze is directly fixed, and so harm more easily and more vehemently; and Aristotle signifies above that fascination sometimes takes place by the corrupted breath itself transmitted as far as another person. In these ways, then, fascination can take place naturally without immediate action on a distant thing. I omit (what St. Thomas noted above) that sometimes harm of this kind happens from the malice of demons, who by a hidden pact cooperate to inflict harm of this kind. St. Thomas also notes there that this alteration happens more easily in infants and children, because on account of their tender body they more easily suffer any external impression. More about action of this kind can be read in Pliny, bk. VII, c. 2, and bk. XXXIII, c. 10; Abulensis, paradox 4, c. 16; Richard, Quodl. III, q. 12. The same, due proportion being kept, must be said of any harm whatever which is inflicted by venomous animals, either by sight or by smell. And the same holds of the third example, of the torpedo, of which Pliny expressly says that it affects the limbs by the odour and a certain breath of its body; it does not, therefore, act immediately on a distant thing, but either by altering the medium or also by breathing out some noxious vapour. Nor does it matter that it is said to hide under sand or mud, because it is not necessary that we understand it to lie wholly hidden under the earth, so as not to leave either its head or mouth open for harming.

Whether an agent can act more intensely on the distant than on the near

27. Why the bottom of a cauldron is colder than the boiling water placed over it.—In the fourth and fifth examples it must be declared whether, and for what reason, it happens that the agent acts more vehemently on a distant thing than on the near medium, and whether then that more vehement alteration takes place immediately on the distant thing without the cooperation of the medium. And indeed Aristotle, sect. 24 of the Problems, qq. 5 and 8, notes that when water is heated in a vessel, at the beginning of the heating, while the water is still cold, the bottom of the vessel is felt hotter; but afterwards, when the water is boiling so that it burns the hand, the bottom of the vessel is more temperate, so that it can be held by the hand. He assigns the reason, however, that at the beginning of the action, while the water is cold, the whole heat is shut up in the bottom of the vessel and not permitted to ascend; but when the water is now hotter, the heat is as it were permitted to breathe and ascend, and thence it comes about that the bottom of the cauldron is tempered. For which cause he says in the same place that baths are hotter in winter than in summer. And thence it consequently comes about that, as the action proceeds and the water is excessively heated and rarefied by heating, the hotter parts ascend upward and the thicker and colder descend downward and cling to the bottom of the vessel and temper it, and therefore it is reckoned less hot. Here, however, by the name of heat is not to be understood the quality or accident of heat alone; for this can neither ascend nor descend, nor be detained so as not to ascend, except by reason of its subject; but the hot exhalations or vapours which are aroused by the action of the fire are to be understood. For that ascent or descent cannot be declared only metaphorically, that is, that heat is said to be impeded from ascending only because the patient resists the heating's proceeding further towards the upper part. For in this sense the reason would be of no weight, namely, that the bottom of the cauldron is hotter at the beginning because then the heat is impeded from ascending further; for that the action proceeds further per se in no way prevents that lower part from remaining equally hot, as is known per se. It must therefore be understood properly of some hot exhalations, which, while they are detained by reason of the nearest body, namely cold and dense, make the heat of that part both greater and more vehemently felt; but when, the nearest body being heated and consequently rarefied, they are permitted to ascend, less heat is felt in that lowest part; especially since in the pores where those exhalations were, colder parts of the water succeed in their place, which, as they are heavier, so they naturally descend more, and from that head too that heat is tempered more.

28. From this reason of the Philosopher so expounded, however, it is easily understood that from this experience it is not had that the agent acts more intensely on the distant than on the near except by transmitting some proportioned agent which proximately effects that intensity. For in the said example, when at the beginning of the action the bottom of the vessel grows excessively hot, this comes from the neighbouring fire and from the fiery or hot exhalations enclosed in the very pores of the bottom; but when, as the action proceeds, the upper parts of the water seem hotter, this comes not only from the remote fire, although its action helps much, but also from the hotter vapours ascending and penetrating the water itself, and for this cause it heats it more vehemently. Add that the water itself, while it begins to be heated more near the bottom of the vessel, at once ascends, having become lighter; while that which was above, heavier and colder, descends; and so it comes about that the more distant part of the water is hotter, not because, being so distant, it has been more heated, but because it was before near and there more heated. But never is that part of the water which sits nearest the bottom of the vessel more vehemently heated than the vessel itself or its bottom, through which the action is transmitted, except perhaps at the end of the action, when the water is now wholly overcome, so that it happens that it is all exhaled and corrupted. Which comes from the fact that by reason of its moisture it is more easily changed into air or into some imperfect mixed body. Likewise, because, since it is less dense than the vessel, the hot ascending vapours or exhalations more easily penetrate it. It also helps if there is any surrounding air. And thus the whole action and its intensity always takes place through some medium.

29. Why paper is less hot than oil placed on it.—Why tow is inflamed while the air lying between it and the fire is not inflamed.—In the same way it must be said of the similar experiences adduced above, namely, of the oil which seems to grow hot more vehemently than the paper by means of which it is heated. For the oil, as soon as it begins to be heated, is also easily rarefied and penetrated by the ascending vapours, and itself too, made subtler and lighter, at once ascends; while the thicker and moister parts descend; and so the same happens in this example as in the former. Of the tow, however, that it is inflamed through the interposed air while the air itself is not inflamed, is not so manifest by experience; for perhaps the air is inflamed first, although it is not so perceived by sense as in the tow, on account of the latter's density. And the same can be said to the example of the root of the herb aproxis and of the bitumen naphtha.

30. An objection is answered.—It could, however, be answered otherwise, admitting what is assumed in the argument, that remote matter is sometimes inflamed while the near is not, and saying that this comes from the disposition of the matter without a more intense action of the fire on the remote than on the near. Which will easily be declared if we suppose that it is not necessary that in some matter supreme heat precede in order that it be inflamed, but that it suffices that intense heat precede in that grade with which the form of the tow, for example, cannot be conserved, and, if sufficient dryness is joined to it, it sufficiently disposes for the introduction of the form of fire. Thus, then, it can happen that the intermediate air is hot as seven and is not inflamed for defect of dryness, while the tow, as soon as it reaches that grade, is inflamed; and so the action of the heating fire was never more intense in the remote matter than in the near, but had another effect on account of another disposition of the patient. You will say: in that instant in which that matter is inflamed, it is already hot as eight. I answer: if it is so (for it is not certain of the first instant), yet this does not come from the action of the distant fire alone, but is by natural resultance from the form already conceived. Which resultance, if no resistance remains in the matter, takes place in a moment; and so it must be said to take place if we suppose that all accidents perish in corruption. If, however, some grade of the contrary quality can remain, some succession will intervene, yet most brief and imperceptible, because the resistance is least and the activity great. But what of the action of the substantial form itself, which takes place in the distant matter, not in the medium? It is commonly said to take place by natural resultance, sufficient disposition being supposed, or to be produced by the accidental dispositions existing there, in the power of the substance. We, however, must answer, according to the first assertion, either that the form of fire together with its power can reach there and at the same time inflow into the eduction of that form, or certainly, if the substantial form does not have this power, that it is necessary that that concurrence be supplied by some superior cause; just as, when it happens that some thing is so heated by motion that it is inflamed, the introduction of that form is attributed to some universal cause.

31. Another way of explaining the experiments adduced.—Another way of answering these experiences can be by admitting that the agent can make some quality more intense in a distant patient than in a near one, yet not by acting immediately on the distant thing, but through the medium. This mode of action, however, can be conceived in two ways. First, so that the medium does not serve as an instrumental or partial co-efficient for acting on the remote, at least as to that grade of greater intensity which is made in the remote part. This way of speaking, however, is not sufficiently consistent with the opinion we defend; for it plainly follows that that action, inasmuch as it is intensification in such a grade, is produced by the remote agent immediately on the distant patient without any action about the medium or through the medium; because the remiss action which takes place in the near medium per se does not contribute to, nor is continued with, the action on the distant thing, except at most up to a like grade; therefore that greater intensity which is produced in the distant thing is an immediate action on it without a medium. Just as, if the whole medium and the distant patient were first hot as four without the action of fire, and afterwards the applied fire immediately intensified that heat in the distant patient and not in the medium, without doubt that action would be immediate on the distant thing; therefore the same will hold even if the heat as four was produced by the same fire. In another way, therefore, it can be understood that the agent, through the power impressed in the medium, effects a more intense quality in the remote patient than in the medium itself, on account of greater capacity or disposition and less resistance. This power, however, can sometimes be a quality of a diverse notion from the other which is intensified, and then the matter is not difficult; as in the example given above of the mirror and the air heated by the sun, because that heating takes place by means of light, it can happen that, by means of the light of the air as power of acting, the sun heats more vehemently the distant mirror or another similar thing than the near air, on account of the greater capacity and disposition of the patient; and in this I see no repugnance. For as an acting cause through diffused power can have some effect on the remote which it does not have on the near, as all concede, and notably St. Thomas, In II, dist. 15, q. 1, a. 2, ad 6, and the Commentator, IX Phys., and bk. II De Caelo, com. 34, so with greater reason it can alter the remote part more intensely than the near. In another way, finally, it can be understood that this takes place through a quality of the same notion; as, for example, that the sun, through air remissly illuminated, illuminates a distant mirror more intensely, so that the light of the intermediate air, even if it is in itself more remiss, concurs as conjoined to the first agent, either instrumentally or partially, to effecting the light in the mirror, even as to the greater grade of intensity. And this mode is harder to believe, because it supposes that a remiss quality, at least as conjoined to the prior agent, can concur to the intensification of a quality of the same species in that grade in which it is unlike it and exceeded by it; whether this can happen we shall examine in the following section, where we shall say more about that example of the mirror and its reflected action.

Why the agent operates more efficaciously in a straight line

32. To the other experiences which are brought in confirmation of that second argument, I answer that they quite probably persuade the second part of the last assertion. Nor does any other probable reply or evasion occur to me; for I do not see why the presence of the sun in a straight line with respect to this part of the remote air conduces to its greater illumination, except because the sun itself inflows into it together with the air nearer to it; but into another part of the air, not so directly opposite, but to the side, for example, of the window, it cannot so inflow, even if with respect to the medium itself that part is equally near. Someone will perhaps say that the light received in the medium acts in the power of the sun on that part of the air which lies in a straight line opposite the sun, but on another falling to the side acts only by its own power, and therefore illuminates that part more than this. But this is both said merely gratuitously and voluntarily, and it cannot be understood what thing underlies those words, nor in what that difference consists, if the sun itself actually inflows through itself into neither of those parts. For, this being supposed, what is to act in the power of another except to act as a power diffused from it and taking its place? But that power received in the medium is one and the same; therefore with respect to any part of the medium whatever it acts as a power diffused from the sun and in its stead; therefore it acts equally in the power of the sun. Nor can it be explained what that situational position (so to speak), or presence of the sun, contributes such that for that cause it is said to act in the power of the sun on one part and not on another, if by reason of that application the sun itself does not inflow more per se.

33. Which finally I confirm and declare thus: for when an accident acts in the power of another without its actual influx, if such an accident is conserved without that other in whose power it is said to act, it can have the same action. This is evident in gravity or impetus moving in the power of the generator or the impressor, and the same holds of the heat of water, if heat is said to heat in the power of fire; indeed, those too who say that supreme heat effects in the said way the form of fire in the power of fire without another actual influx of it consequently say that heat separated, equally as conjoined to fire, can in the power of fire effect the form of another fire. Thus in the present case, if the light received in the part of the air nearer the sun effects light in another part in the said way in the power of the sun, then if that light were conserved in one part, the sun being taken out of the way, it would illuminate in the same way the same part which it now illuminates. But the consequent is plainly false, both because otherwise even now it would equally illuminate the part of the air neighbouring it which is not opposite the sun, because the sun is not more, nor so, absent now from that part as it would be absent from the other if it were wholly removed; and also because in fire and heat the opposite is established by experiment, as was proposed in the same confirmation we are treating. Therefore it seems necessarily to be said that the sun actually inflows with the nearest part of the medium to illuminate another directly opposite it, but cannot equally inflow into another part existing at the side, even if it is equally near to the intermediate air itself, and that thence it comes about that those parts are not equally illuminated or heated.

On the action of the magnet and similar things

34. In the third argument, concerning local motion, the first and chief experience is of the magnet; of which, as of many other experiments which we treat here, the Conimbricenses learnedly gather much, bk. VII Phys., c. 2, q. 1. Briefly, however, so far as concerns the present matter, we admit that that attraction is effectively produced by the magnet. For Alexander, bk. II of the Natural Questions, c. 3, thought that iron is not drawn by the magnet except as by an end, and that it moves itself to the magnet by an internal and innate power, as it were by natural weight. This, however, Albert rejects, II Metaph., tract. III, c. 6; St. Thomas, VII Phys., lect. 3, text 10; and Galen, bk. III On the Natural Faculties, last ch. First, because natural motion from an intrinsic power takes place from any distance whatever, as is evident in earth and fire; but iron does not tend to the magnet from any distance whatever, but from a certain and definite one; therefore it does not tend to it, but is drawn. Secondly, because iron is not moved to the magnet unless they exist in due proportion of quantity; for a mass of iron will not be drawn by a small magnet; therefore this is on account of action, which does not follow from a proportion of lesser inequality. Thirdly, because it is said to be established by experience that if a magnet is anointed with goat's blood or the juice of garlic or onion, it cannot draw iron; therefore this is because its attractive power is thereby weakened.

35. It must be added, next, that the magnet impresses on the iron some motive quality by which it draws it to itself. So all authors teach; for just as projection takes place through an impressed quality, so also does drawing; there is, however, a difference, because impulse is impressed by immediate quantitative contact, but not this attractive quality; and the reason is that they were instituted by nature for contrary effects. For by impulse the mobile is separated from the mover which touches it; but by drawing the mobile is drawn towards the mover, or even until it touches it. Moreover, this attraction of the magnet is such that it not only draws iron per se to itself, but also communicates to the iron itself a participation of its power; for the iron attracted draws other iron to itself, and that draws another, so that as it were a chain is made of them, as Augustine reports, XXI De Civit., c. 4, and as we too have sometimes experienced; this, therefore, is an open sign that the magnet impresses on the iron a quality which has both the power of moving the iron itself and of effecting another like one by which the iron draws to itself.

36. Finally it must be added, in order that we may answer the argument proposed, that the magnet does not impress that quality on the iron except through the medium, namely, by altering it as far as the iron; for although this alteration of the medium is not perceived by sensible experiment, yet, since it can easily take place, we gather from other experiments and reasons that in that alteration too the natural mode of acting of the efficient cause is observed. Nor does it stand in the way that the medium itself is not drawn to the magnet; because it is not necessary that the quality diffused through the medium have the same effect in the medium which it has in the distant patient; as was said above, on account of the diverse disposition of the patient it happens that the power diffused through the medium effects in a distant body a new quality, or an intensification of quality, which it does not make in the medium itself. Thus, then, it can happen in the present case, either that the quality diffused through the medium is not of the same notion as that which is impressed on the iron itself, or certainly that, although it is in itself of the same species, it does not have the same effect of drawing in the medium which it has in the iron, on account of the peculiar proportion or disposition of the iron.

37. Only another experience can stand in the way, by which it is established that the magnet changes iron even with a dense medium interposed, as is also perceived by experiment and as Augustine reports above, saying that, iron being placed on silver and a magnet beneath, the iron is moved with the motion of the magnet, with a most rapid course and recourse, as the magnet is moved by someone, the silver (he says) in between suffering nothing. For it does not seem likely that the magnet could alter and penetrate the whole of so dense a medium. But nevertheless, when Augustine says the silver suffers nothing, he plainly understands it of that sensible passion, such as was the motion and agitation of the iron; of invisible alteration, however, Augustine disputes nothing there. Nor is it so difficult to believe that the magnet penetrates the intermediate body by its alteration, either because it is porous, as wood is, or because it has little depth, as perhaps was that silver of which Augustine makes mention; just as the heavenly influences too penetrate even the densest bodies and at a great distance, on account of their great power of acting. For this power of the magnet is thought to be a certain participation of a heavenly property, as St. Thomas says, q. 5 De Verit., a. 10, ad 5; q. unica De Anima, a. 1. Perhaps it can also happen that that action, although it does not penetrate the whole dense body, by the intervention of the surrounding air reaches continuously as far as the iron. And in the same way judgment is to be passed of amber lifting straws, and the same holds of quicksilver drawing particles of gold, and of any other similar thing, or a medicinal root or herb, which has the power of drawing something or also of expelling.

38. How the remora holds back a ship.—As regards the holding back of the echeneis, however, although otherwise it is a wonderful effect of nature, it is most difficult to explain by what power so small an animal can retard so vehement a mass; yet in the present case it brings in no difficulty, for Pliny expressly says that it does this with no labour of its own, not by holding back or in any other way than by adhering; it does nothing, therefore, on a distant thing. What it impresses on the ship in order to detain it Scaliger treats at length against Cardano, exercit. 218, and against him the Conimbricenses above, a. 5. I, however, think the matter most hidden, and one which must necessarily be reduced to some power of a superior notion, which has such and so great a force for resisting the impulse of the ship that it cannot be weakened by it. Whether this is done by this animal impressing on the ship some quality weakening the force of that impetus, or only by adhering by a power innate to it, as a man holds a proportioned stone so that it does not fall, or finally whether this fish has such power of stopping itself and as it were adhering to its place that it cannot be snatched away or dislodged even by what impels the ship, is uncertain to me. In whichever of these ways it happens, however, there is no doubt that it comes from a wonderful and hidden power, helped perhaps by some special and connatural heavenly influence. Indeed Ambrose adds, bk. V Hexaem., c. 10, at the end, imitating Basil, hom. VII Hexaem., that by the gift and power of the Creator so small an animal received so great a power.

On the action of the phantasy and similar things

39. In solving the fourth difficulty those labour who think that the knowledge existing in the phantasy concurs effectively by its own physical influx to the act of the appetite. Hence some place both powers either in the brain or in the heart, so that they may be neighbours and able to act on each other, although the truer doctrine holds that the phantasy is in the brain and the appetite in the heart, as is to be shown more at length elsewhere. Others say that I know not what qualities are diffused from the brain, by means of the act of the phantasy, as far as the heart in order to change the appetite. But this is like a fiction, because those qualities are neither species of the object nor of the very act of the phantasy—for they would be useless, since the appetite cannot use species—nor can they be some qualities as it were carrying to the appetitive power the knowledge of the object which is in the phantasy; because the appetitive power itself never perceives that knowledge; nor can the knowledge of one power be manifested to another, either formally or objectively, except by means of another species or knowledge of itself. Others finally, convinced by the argument, confess that the knowledge existing in the brain inflows by immediate action, through its own efficiency, into the appetite. Nor do they think this unfitting, because those two faculties are conjoined in the same soul, which is the principal principle of that action; for just as a principal power can cooperate with its instrumental power, even if this is diffused as far as a distant place, so conversely some instrumental power will be able to cooperate with the principal power, even in a distant place, if the principal power itself is diffused as far as that, provided that in that part too, where the action takes place, there is another instrument more proper and proportioned to such action. Which reply, that first foundation being supposed, is among the rest less improbable, and is commonly applied to divine instruments, that they can attain immediately to distant things because the principal power is present there. Absolutely, however (whatever be the case about miraculous actions), it does not satisfy, because efficiency is now admitted from some form or quality or act which leaps across to a distant thing as it were by a jump, without continuous action through the medium.

40. And therefore we shall more easily escape these straits by denying that knowledge concurs actively to the act of the appetite, but only as a condition representing the object, which being posited, the appetite effects its act through the natural sympathy of these powers. And to this the rooting of those faculties in the same soul contributes excellently; for it, or the supposit through it, is what principally operates and uses these faculties; and therefore, while through one it perceives an object fitting to itself, through another it desires it; not indeed because through one it effects in the other, but because from the object apprehended through one it is aroused to operate through the other; which arousing is not by real and effective change, but by metaphorical or final change, and therefore does not require local nearness, but animal nearness, so to speak. And the same must be said proportionally of the appetite and the motive power; for although it could be said that every motion begins from the heart and proceeds by means of the spirits and nerves as far as the part in which the motion is exercised or appears, yet, as concerns the present matter, the application of the motive power by the appetite is not through the proper and physical action of one power on another, but through the subordination of the powers in the same soul; in which way also the intellect and senses are applied to operating by the will and appetite; of which more at length the philosophers in the books On the Soul, and the theologians in the I-II. Of the efficiency of the sensible species in the internal senses, by means of the external, however, there is another and far diverse reason; for here proper efficiency truly intervenes, which must take place through the medium, as the visible species are said to tend from the eye as far as the common sense through the optic nerve; for this action of such species is not properly vital or immanent, but is proceeding from an extrinsic thing by means of those instruments, and therefore it is properly diffused through the medium, like other natural actions.

On the action of a spiritual thing on a body

41. So far we have spoken of corporeal agents and patients among themselves; in the fifth argument, however, the action of spiritual things on bodies and among themselves is treated. And as to the first part, concerning the action of spirits on bodies, speaking consistently, it must be said that the immediate nearness of the intelligence to the body is necessary in order that it can move it locally; for I suppose that a created spirit can exercise no other action on a body, which I shall show below in disputing about the intelligences. Hence, if an angel, in order to move a body, can impress impetus by means of another body which it does not move locally, then indeed for moving some body locally it will suffice for it to be present by immediacy of power; yet it will be necessary that by immediacy of supposit it be present to the body in which it first began to impress that power. If, however (which I think more probable), the angel cannot impress that power through intermediate bodies not moved, it will be necessary that the moving angel be proximately present by immediacy of supposit to that body which it immediately moves. And in this way the philosophers say that each intelligence moving the heaven is present to that orb which it moves. Thus too theologians say that angels are present by supposit to those bodies which they assume and in which they appear. And whenever Scripture says that an angel moves or carries some man, it signifies there that the angel is substantially present, or is moved with the thing which it moves. Which would not be necessary unless the angel had to be present where it moves. And St. Thomas plainly supposes this, I, qq. 52 and 53, and 55, a. 2, ad 3, and q. 113, a. 6, ad 3, and more clearly in the places to be cited below.

42. Nor does it stand in the way that a spiritual thing does not have situation; for it has a substantial and real defined presence, according to which it must be conjoined to the patient when it acts on it. Nor do I now dispute whether operation is the reason of that presence, which some theologians seem to assert, or, conversely, whether that presence according to itself is prior or even independent of operation, which more affirm and which seems to me more probable; but I assert that substantial presence is necessary for operation, which St. Thomas perhaps called spiritual touch upon a body, q. 6 De Potentia, a. 7, ad 12; and more openly, q. 16 De Malo, a. 1, ad 15, he says that an angel does not act immediately on any body distant from it, and brings Damascene saying: Where an angel is, there it operates. Who is to be seen in bk. I De Fide, cc. 16 and 17, and bk. III, c. 2.

43. Nor does it stand in the way that the angel moves through intellect and will, because, as I shall say below in its place, it does not move through these powers as proximately eliciting the motion, but by directing and applying the executive power, which must be conjoined to the patient. Which reply St. Thomas intimates in the place just cited from De Potentia; for when he had objected in argument 12 that mover and moved must be together, but that the angel is not together with the body from the fact that it wills it to be moved, he answers: The command of an angel requires the execution of power; whence there must be a certain spiritual touch upon the body which it moves; and Quodl. VI, a. 2, ad 2, which was similar, The command of an angel requires the execution of power. And it is declared further, because, if the efficacy in moving were to be weighed from the mode in which the will attains its object, just as the will of an angel can indifferently will the near and the distant however far, so with the same efficacy it could move a near body and a distant one at any distance whatever; but the consequent is plainly absurd, because, since it has a finite power, it is not likely that it can operate equally on a thing however distant, but that it has a terminus in the sphere of its activity. As, therefore, the motive power is compared otherwise to its subject than the will to its object, so also in the absolute condition of nearness and distance; for the moving power acts really and transiently on the subject which it moves, and therefore it must be really undistant from it; but it is otherwise with the will as it is concerned with an object on which it does not really act nor which it changes.

On the action of spirits among themselves

44. The other part of that argument concerned the action of one angel on another or on a separated soul, which action too can be either speech or local motion. Of the latter the reason is the same as of the motion of a body; nor do I see a reason for a difference which could be assigned. Hence St. Thomas, in the place just cited, says generally that the substance of an angel must be conjoined to the things which it moves; for he did not say bodies, but things, in order to indicate that the doctrine is general. I suppose, however, that the discourse is of when one angel moves another truly and physically, effecting motion in it; for if it moves only morally by command, it requires only that presence which suffices for command, of which the reason is the same as of speech, for command takes place by speech.

45. How angels speak with one another.—Of the speech of one angel to another, however, we cannot speak here ex professo, for it is a theological matter and difficult to explain; speaking generally, however, one may proceed in it in one of two ways. One is that the speaking angel does nothing on the one to whom it speaks; and thus the reply in the present case is easy, because the angel to whom another speaks is not compared to it as subject or patient to agent, but only as object to immanent act; and therefore it is no wonder that speech can be immediately to an angel however distant. According to this way of speaking, however, it must be answered to the argument made that the speech of one and the arousing of the other do not take place by transient action from one to the other, but as it were by a certain natural sympathy; because, while one angel wills that the other perceive its act or concept, at once the other uses the species which it had of that act or concept in order to attend to the speaker. Nor do I see in what other way that opinion could be explained; but at once there appears from this how great a difficulty there is in it, namely, that faculties rooted in diverse essences or substances should have among themselves a natural sympathy and connection and concomitance in acting, not causal,¹ but infallible and per se, without action of one on the other. To which difficulty another is added: if the angel has innate species of the other's acts, why can it not behold them as soon as they exist, if it wishes, even if the other does not arouse it and as it were apply it by its ordination or will? Again there is added the difficulty about the illumination by which one angel not only speaks to, but also teaches another; for which, even if that sympathy is admitted, it does not seem to suffice. Finally, whatever be the case about speech taken strictly, the difficulty can be extended to every action of an intelligible species; for it is probable that one angel, inasmuch as it is an actually intelligible object, can, so far as concerns itself, impress a species of itself or of its acts on another angel, if this one lacks such a species. And whatever be the case about angels among themselves, with respect to the soul which is separated from the body this is more received; such action being posited, therefore, the difficulty remains intact, if it is not impeded by distance.

46. Another way of speaking, therefore, can be by admitting some intellectual action of one spirit on another through the real affection of some intelligible species, or of some intensification or modification of it. Which being supposed, the touched difficulty can still be answered in two ways. First, by excepting this action from the general rule handed down. Which way St. Thomas intimates in the cited question De Anima, and in Quodl. VI, a. 10. And he signifies the reason in both places, because the same thing is order in angels as situation in bodies, and therefore purely intellectual action does not depend on situation or medium, but on the order of nature. And in I, q. 107, a. 4, he adds that the operation of the intellect abstracts from place and time, and therefore the speech which takes place through it is not impeded on account of distance. And this can be confirmed, for it seems incredible that one angel cannot speak to another unless they are undistant in supposit and substance, for that action cannot be carried through the medium. This opinion, however, in truth seems less consistent with all that has been said, because it greatly weakens the principle laid down and its whole reason. Likewise, although in angels there is no situation, there is yet substantial presence; therefore the difference assigned is none for excluding the necessity of this presence for the said action; otherwise neither would undistance between angels be necessary in order that one might locally move or detain another. Likewise, according to that reason, God by virtue of the action by which He creates or illuminates an angel would not be intimately present in it through essence, but only by reason of immensity; which is against St. Thomas and the truer doctrine, as we shall see below. The sequel is evident, because God too acts on an angel as spirit on spirit; therefore the reason is the same of Him. On account of these things, therefore, the last way of speaking will be probable, that for this action too, and for angelic speech, if it requires that action, undistance is necessary. Between which opinions I leave the judgment to others as to which is simply more probable; I assert only that this third is more consistent with the matter we are now treating, unless the first is chosen, whose difficulties it is most difficult to satisfy.

On the sphere of activity

47. The last difficulty proposed in the sixth argument is most easily solved from the second and third parts of the last assertion, which it probably persuades, while against the earlier assertions it proves nothing. For although we grant that each agent has a natural sphere of activity of a certain magnitude, on which it can act per se and by its own power and action, it does not follow that it can act immediately on the remote part of that sphere without acting on the near, because it cannot act except by continued action, beginning it from a patient near and undistant to it, and continuously diffusing it through the whole sphere; for every efficient cause determines this mode of acting for itself. Nor is it unfitting that all causes, even if they are unequal in power, equally determine for themselves this nearness of the patient, because this does not come only from the limitation or imperfection of the power, but from the nature of this causality; but the limitation of the sphere comes from the limitation of the power, and so according to the inequality of power the sphere too will be unequal, if other things are equal. That argument does, however, seem rightly to prove that natural agents are not limited to acting per se and through their own proper power on the last surface alone of the body contiguous to them, but within some certain space, which they can attain by their power, even if, by a possible or impossible supposition, one part of the medium does not act on another; which we asserted in the last conclusion.

48. That argument does not prove, however (although it seems also to tend to this), that that mode of acting through the near part on the remote through the whole space is impossible, so that, however we divide the remote part from the near by proportional parts, and indeed the nearest surface from the rest of the magnitude, the effect can always proceed actively to the remote through the near; because in this mode of acting no repugnance is involved, since the quality received in the medium, or in any part of the medium, or in the surface, can be active, and the patient is also apt to receive such a quality, and the remote part is in due proportion with respect to the nearer so that it can suffer from it; because the action proceeds uniformly-difformly from the beginning of the sphere to the end; therefore all things necessary can concur for the action always to take place through the near on the remote. For the infinity of proportional parts cannot stand in the way, because a similar infinity is in the succession of action. We do not, therefore, assert that this mode is impossible; but we assert, first, that it is not necessary in order that every agent require nearness and undistance of the patient on which it first acts. Nor yet that it suffices for defining the sphere of activity of the agent per se by virtue of the quantity and limitation of its power. We assert, next, that even when the action proceeds in that way through the near part on the remote, it does not take place from one part on another in such a way that the agent does not at the same time and actually act with all within the sphere of its activity, and therefore the action on the remote part through the near is more efficacious than if the near part alone acted on the remote through the power received in itself. And both of these were asserted in the last conclusion, and seem to be sufficiently proved from all that has been said and what is contained in that last difficulty.

1. Difficult reasons for doubting.—The first.—The reason for the difficulty can be taken, first, from what was said in section 4, where it was shown that the agent sometimes acts on itself even according to the same part; but the same thing cannot be unlike itself according to the same part; therefore it is not necessary that the patient always be unlike the agent. It will perhaps be said that, when something acts on itself, it always operates through a power of another notion than the form which it makes in itself, and so at the beginning of the action it is unlike itself, inasmuch as it does not have that form formally, but only virtually.

2. The second.—But against this I argue, secondly, that something sometimes acts on itself even through the same quality formally; for the heat or cold of some body, when it is surrounded by a contrary agent, is commonly wont to intensify and as it were fortify itself in order to resist or overcome the other, as is evident in the heat of the stomach, which for this reason is stronger in winter time, as experience shows and as Hippocrates testifies, aphorism 15. The same is evident in air existing in caverns or very low places, which is warmer in winter time. Nor can this be attributed to an extrinsic agent, since that is contrary and cannot intensify a quality opposed to itself. Nor can it be attributed to natural emanation from the intrinsic form, both because this of itself is always the greatest that can be, since it is merely natural, nor is there any reason why it should be increased on account of a surrounding contrary—indeed it ought rather to be impeded by it—and also because that mode of action is found not only in a natural subject but also in a preternatural one, for water too in wells becomes warmer in winter time.

3. The third.—Thirdly, there is a similar argument: one thing sometimes acts on another like itself in quality and intensity, even though the action takes place through the same quality. The assumption is evident from the common example of iron, which, although it does not have in itself supreme heat, but as six, for example, intensifies like heat in straw or tow so that it burns it. And in the same way the heat and light of the medium are commonly intensified by reflection from the heat or light of the extremely distant body, even if that is not in itself hotter or brighter intensively; as when the sun directly heats the air and the earth, the heat of the air is intensified by the reflection of the earth, and similarly the light of the air is intensified by the reflection of a mirror, etc., although neither the heat in the earth nor the light in the mirror could be more intense than in the air from the action of the sun, since they are more distant from the sun than the air.

4. The fourth.—Fourthly, if this unlikeness were necessary for any cause, it would chiefly be in order that the agent might surpass the patient in power of acting; but it is not necessary for this cause, both because it can happen that that superior power comes from elsewhere, namely from greater density or from other conditions of the subject, and especially because that excess on the part of the agent does not always seem necessary; otherwise the patient could never react upon its agent. For either it is surpassed by it in power or not; if it is not surpassed, and nevertheless suffers from it, then excess of power is not required in the agent; but if it is surpassed, and nevertheless reacts upon it, then excess of power is not required for reacting; but reaction is true and proper action and effective causality; therefore for this excess of power is not always necessary; therefore neither is unlikeness in form or in the notion of acting. Finally, it can happen that an action is coeval with the agent, as illumination with the sun; but then there never intervenes unlikeness between agent and patient, because they were always alike.

Notes for the resolution of the question

5. Unlikeness between agent and patient is to be considered for the beginning of the action.—It must be noted that, when we ask whether the efficient requires a patient unlike itself, the discourse is not of the end of the action, but of the beginning, or of the disposition and proportion which must precede between agent and patient for the action; because here we are inquiring into the conditions required for acting, not those which follow upon action. And moreover, because at the end of the action the patient will not so much be compared to the agent as the effect to the cause. Whence it comes about that unlikeness in the terminus of the action cannot be of the notion of efficient cause, since rather the intention of the agent is to render the patient like itself. But if sometimes it does not perfectly attain this, it comes from the imperfection of the effect; and this sometimes arises from the weak power of the agent, which cannot overcome the resistance of the patient; sometimes from the incapacity of the patient and the nobler power of the agent, which is universal, or an equivocal cause acting through a form of a superior order, which the effect cannot receive according to the same notion, and therefore it becomes like according to some analogy or common notion, but not perfectly.

6. The action can be coeval with the thing which acts.—Again, it must be observed that, when we inquire into the unlikeness which must precede between patient and agent, the discourse is not of antecedence in time or duration, but in the order of nature and causality; for the former, although it often intervenes, is not per se necessary, as the last argument made at the beginning rightly convinces. For there is no doubt that an action can be coeval with the agent when it does not require succession and takes place without resistance. Hence, if it is a natural action and of its species such that it can render the patient perfectly like the agent, it will accomplish that likeness from the beginning; for a natural agent, as soon as it exists, acts as much as it can; and therefore, if it acts without resistance, it produces a perfect effect from the beginning; therefore according to real duration in that action the patient is never unlike the agent. Nevertheless in the order of nature it can be understood as unlike, because such a patient of itself, the action of the agent set aside, would not have likeness with it. And so that action does not take place about the patient as already like, but rather renders it like; and thus it takes place formally from the unlike.

Resolution of the question

7. Each thing acts on what is unlike in form and like in matter.—The sense of the question being thus explained, its resolution is easy; for it must be said that an acting cause cannot effect in a patient except inasmuch as it is unlike itself in form or in the terminus of the action. This is as it were a first principle in philosophy; Aristotle hands it down, I De Generat., c. 7, text 46, where he says that the greatest part of the ancients affirmed with the utmost agreement of mind that nothing like suffers anything from what is like, because the one is in no way more active or passible than the other. And in text 48 he confirms the same, because otherwise by the same reason the same thing would be affected by itself. Which he declares in what follows, saying that this unlikeness is necessary according to form or species, for in the matter or subject-genus likeness rather is required between agent and patient, which we shall declare a little below. Aristotle supposes the same principle in the same bk. I De Gener., c. 9, when he says that the agent acts inasmuch as it is in act, and the patient suffers as it is in potency. Which he also teaches throughout bk. I Phys., and bk. III at the beginning, and bk. VII from text 35, and bk. VIII from the beginning. And the expositors in these places generally think so, although some in certain particular actions do not declare it rightly, as we shall see in answering the difficulties.

8. The reason for the conclusion.—Absurdities from the opposite of the conclusion.—The reason, however, has been touched upon: because the agent acts inasmuch as it is in act, and for acting requires a patient which is in potency; but that which is in potency, as such, is unlike that which is in act, as such; therefore. The major as to its first part is established, because to act is to communicate or give being, and therefore it is necessary that such being be supposed actually in the cause, either formally or eminently, according to the mode and dignity of the agent; for no one can give what he does not in some way have in himself. And by almost the same reason the other part of the same proposition is proved, because, while the agent communicates its being to the patient, it brings it from potency to act; therefore the patient, as it underlies such action, is supposed in potency. And therefore in I Phys. privation is placed among the principles necessary for generation on the part of matter, which principles are proportionally necessary in every change or action which takes place from a subject. Aristotle also excellently confirmed the conclusion from the drawbacks: because otherwise there would be no reason why of two like things one should act on the other rather than conversely. Likewise, because the same thing could intensify itself. Likewise, there would be no end of actions, but after a perfect fight between contraries, victory gained and the patient assimilated, the action would then be begun anew. And finally, as Aristotle says, in this way nothing could be preserved either from perishing or from motion.

Corollaries from the preceding resolution

9. And from these reasons it follows, first, that the unlikeness per se necessary between acting and suffering cause is only that which is between habit and privation, or between a thing constituted in act and one existing in potency; for if in the patient there is supposed capacity to receive the form, and the agent has the power to produce it, it requires no other unlikeness on the part of the patient except that it lack such a form; because neither from the notion of motion or action nor from any other general principle can another be universally required. Hence, that in generable and corruptible things there is found not only this unlikeness but also positive opposition and contrariety is not from the notion of efficient cause as such, but from the fact that such things have been so instituted that they can have mutual fight and action among themselves, and be generated and corrupted from one another according to species. It must be noted, however, that among efficient causes some are univocal, others equivocal, which words we have already explained above; we are treating, however, of principal causes, for from them it is easy to accommodate the doctrine to instrumental ones. In univocal causes, then, the said condition intervenes most properly and formally; for since the agent introduces into the patient a form of the same notion as that through which it acts, it supposes in the patient the lack of it, and consequently supposes formal unlikeness with it.

10. But the equivocal cause does not introduce into the patient a form of the same notion, and hence formally like its form through which it acts; and therefore it does not properly suppose in the patient formal unlikeness, that is, lack of that form according to the species which it has in itself; but it supposes unlikeness between the patient as it underlies the action and as it is perfected by the action, and consequently it also supposes in the patient the lack of that likeness which can intervene between some form formally taken and another which eminently contains it. And the reason is clear. First, the equivocal cause does not make formal likeness, but only eminential (so to speak); therefore it prerequires only proportional unlikeness; for only the privation of the form which terminates the action of the agent is necessarily supposed for the action. For it is not required for action that the patient lack the form which is formally in the agent, if it is not going to receive it formally or of the same notion; but it is only necessary that it lack that form which is to be introduced into it and is going to be the terminus of the action, even if in the agent it is only virtually or eminently; because the privation required for action is not formally opposed to the form which is the principle of the action, but to that which is going to be the terminus ad quem of the action, since such privation has the notion of terminus a quo. Thus, then, the unlikeness necessary between an agent of this kind and the patient need not be formal, but eminential suffices, as has been declared. And for this reason one heavy thing can move another downward, even if they are alike in gravity, or even if they are moved downward together and in this too are alike, because the formal terminus of that motion is not gravity but a lower Ubi, which is in a certain manner contained virtually in gravity; and therefore the privation of that, not the privation of gravity, is necessary for that motion. And the same holds of all similar cases, especially in immanent acts, in which the action of the power is always equivocal, of which it is commonly said that it does not so much tend to producing what is like as to producing what is proportional, that is, a second act consonant with the first and which is its perfection, in which it is contained not formally but virtually and eminently. And therefore in that action too, between the active and the passive principle, as such, only the said eminential unlikeness is supposed, namely, that in the one is eminently contained the act which the other does not have formally until it receives it from the active principle; which unlikeness is always found, whether those principles are distinguished in reality or only in reason, as will be more evident in the solution to the first.

11. From what heads there is no action between two things.—The first.—The second.—It follows, secondly, from what has been said, that for efficiency per se it is required that the acting cause have power over the patient and about its capacity, because otherwise it would be impossible for action to follow. This follows from what has been said; for on this account the aforesaid unlikeness between agent and patient is necessary, in order that in the agent, inasmuch as it is in act, there may be power to subject to itself the patient, which is only in potency. And it is confirmed, for just as it is impossible for a form to inform matter unless it has an informative power proportioned to the matter, so neither can an agent in its genus actuate a subject unless it has power over it, because universally second act requires proportioned first act. In order, however, that this may be declared more fully, it must be noted that it can arise from four heads that action does not follow between some two things—I speak of natural agents. First, if there is no active power in them. Secondly, if in the one there is power, but in the other there is not capacity for that form which the other can make; for which cause fire cannot heat the heaven; and therefore Aristotle did not posit negation as a principle of generation or change, but privation, because it must be in a capable subject. Therefore too he said, in I De Gener., that between agent and patient there is required unlikeness in form and likeness in matter, by reason of which the patient is capable of the form of the agent. Which, however, is not true in the same way in all agents; for the heaven acts on these lower things although it does not agree with them in matter, and an intelligence moves a body with which it does not agree in matter. In agents, then, which act by univocal and corruptive action that proposition is simply true, and of them Aristotle properly spoke; for in the same place he said that the agent which agrees with the patient in matter also suffers from it, but that it is otherwise of a superior agent, which does not communicate in matter. In agents, then, acting by equivocal action, only that agreement according to some common notion is required; for we are speaking of created agents, among which none can alter or generate another unless they agree in some way in matter, at least in general, because both must be material. In local motion too this is found, that mover and moved always agree in some way in the capacity of receiving motion proportioned to them; for nothing created can move locally unless it is itself also mobile, as is established of bodies, and of the intelligences too we shall say below. But this is in a certain manner extrinsic to the notion of agent; what is intrinsic, however, is that there be in the patient capacity for that form of which the active power is in the agent.

12. The third.—Thirdly, action will be impeded if that capacity has already been reduced to act, because then too the power of the agent over the patient ceases, since whatever could be done by it has already been done; which coincides with what we have said so far, namely, that nothing can act on what is like itself inasmuch as it is such; which is as true in univocal agents as in equivocal ones, speaking of the proportioned likeness which can be between them and their effects, as is established from the foregoing. For the proportional reason arises from this same root, namely, because the whole power of such a cause has already been fulfilled in such a patient, and therefore nothing remains for it to do. You will say: even if the patient is in act through one form or quality, there can still remain in the agent power to introduce another like it; otherwise this whole question will be reduced to that one, namely, whether two accidents differing in number alone can be in the same subject. I answer that it cannot, because after the capacity of the subject has been completed by one act, it no longer remains in potency to another like act; and as to this it is true that this question is very closely conjoined with that about several accidents differing in number alone in the same subject. For if in the same matter there could be several substantial forms, differing either in species or in number, a natural agent could introduce another form into matter which had only one; therefore similarly, if a subject could have two wholly like accidents, although it had one, it could receive another from a like agent, or even from itself; and therefore we said above, disp. V, sect. 9, that accidents diverse in number alone and wholly alike cannot be received together in the same subject.

13. The fourth.—Fourthly and finally, power on the part of the agent and capacity in the patient being supposed, with unlikeness and privation, action can still be impeded on account of the resistance of the patient. In which it must be observed that for action as such resistance in the patient is not per se required, just as we also said that contrariety or positive opposition is not necessary; for privation as such does not resist, but rather prepares the way for action; whatever, therefore, resists is reduced to positive contrariety or repugnance, and therefore it is not per se required for action, but rather of itself impedes or retards action. Hence, that an action is successive and not instantaneous comes from the resistance of the patient, unless local motion intervenes, to which such succession is intrinsic, as is established from philosophy and as we shall touch upon below in the treatise on action and passion. Hence, then, it comes about that, when beyond the unlikeness of the patient resistance also intervenes, if it is so great that it either surpasses or equals the power of the agent, the action is impeded; and therefore it is a common axiom of philosophers, and as it were a first principle, that for effecting a proportion of greater inequality is necessary, that is, one in which the power in the agent is greater than the resistance in the patient. Which is taken from Aristotle in the places cited, and is easily evident, because the agent as agent overcomes the patient, at least as to that which it does; therefore it is necessary that according to that notion it surpass it in strength; otherwise how could it overcome? And this will be declared more fully in the solution of the fourth argument.

Solutions of the arguments

14. It remains, then, that we satisfy the arguments; and to the first it was rightly answered there, and from all that we have said the answer has been declared, and can be declared further. For the same thing can at once and according to the same part be in first act and in potency to second act, which others call being in virtual act and formal potency; and so according to those two notions, whether they are distinguished in reality or only in reason and relation, it has to itself a certain unlikeness, not proper and formal, but eminential and virtual, which is enough for action, as we have said.

On antiperistasis

15. The opinion of some.—In the second argument the common difficulty about antiperistasis is raised, which is purely physical and is commonly treated ex professo in I De Generat., c. 7; and therefore I shall touch on few things necessary in this place. Some, then, say to that reason that, although the same quality cannot intensify itself by direct action, it can by reflected action, which they say intervenes in that case in this way: that the hot thing, for example, besieged by its contrary, sends certain species into it, which are as it were instruments for acting on it; but since the contrary itself resists those species, they are reflected onto their agent, and so intensify it. So teach Marsilius, I De Gener., qq. 17 and 18; Albert of Saxony, q. 15; Paul of Venice, in the Summa on Generation, c. 23, and in the Summa of the Meteorology, c. 3; and others. But this opinion says incredible things and does not solve the difficulty. For, first, it imagines intentional species without foundation. Next, it makes them the instrument of material alteration, which is unheard of. Again, it makes them go and return, although they are accidents, unless perhaps it says they are some little bodies, which is more incredible; or unless it says that that return is metaphorical, by reaction, which will at once appear cannot be true in proving the other member, namely, that the difficulty is not solved. Which is evident, first, because those species, whatever they may be, are instruments of the agent from which they flow; they act, therefore, in its power; therefore they cannot exceed its power in acting; how, then, can they intensify it, even if they return to it? Secondly, this action often takes place without any diffusion or action through the medium, as when contrary agents are immediately neighbouring and the power of one is strengthened in itself; for then there are no species which could return to it, because they are neither received in the contrary, as is supposed—for on account of its resistance they are said to return to their principle—nor in the medium, because there is none. Finally, sometimes this action takes place about a subject to which such quality is repugnant, as in well-water; therefore it cannot be through its reflected action.

16. The opinion of others.—It is attacked.—Others, therefore, say¹ that one contrary, surrounded by a stronger one, from the natural appetite of its conservation gathers and unites itself and turns its action into itself in order to protect itself. And Nifo adds, I De Gener., his text 195, in the recognitio, dub. 2, that one contrary per se has the power of acting through some sphere, and, because it is impeded by the opposing contrary from diffusing it outside itself, it turns it into itself and so intensifies itself. But this opinion too is both false and does not solve the difficulty. It is proved, because it already admits not only that like acts on like, but also that the same thing acts on itself according to the same formal quality. Nor does it matter if it be said that this happens on account of the surrounding contrary and as it were from fear of it; for either there is in the quality itself an intrinsic natural power for that action or not; if there is, then from the beginning and always it will effect that action and intensification in itself without the occasion of the contrary, because a natural power naturally executes its whole force without another occasion, provided it is not impeded. But if there is not in the thing a power sufficient for that action, it will not effect it, even if the contrary presses it. A similar argument will be made by inquiring whether that greater intensity is natural to such a thing and quality or not. For if it is natural, it will always have it flowing from its intrinsic nature, nor will it wait for the necessity of protecting itself from the contrary in order to make it. But if it is preternatural, it cannot come from within from the quality itself.

17. And again I shall ask whether that greater intensity, acquired from within on the occasion of the pressing contrary, perseveres in the thing when the contrary is removed before it diminishes it,² or not. For if it perseveres, it is a sign that it is natural, and would from the beginning and per se always have been going to be without the occasion of the contrary agent, if there had been no impediment. But if it does not persevere, then it never could be produced from within; for a perfection which flows from within is not taken away without an extrinsic agent. Finally, it can scarcely be understood what those words signify, that the agent gathers itself and unites itself more, or that it turns its action to itself. For either they signify that it condenses itself and reduces all its parts into a smaller place, and this is easily disproved by the arguments made, applying them proportionally, because either that motion or condensation is natural or not; if it is natural, it will always be present, speaking per se; if it is not natural, it will not take place from within on account of the pressing contrary. Which experience also confirms, for we do not experience in all things which suffer from their contraries motions of this kind; but it would have to take place in all, if it came naturally by virtue of the appetite of protecting itself from the contrary. As for what was added, namely, that the agent turns its action into itself because it is impeded from diffusing it, it has no likelihood, because from the fact that the agent ceases from action on another it does not become capable of action on itself, nor of greater intensity. Otherwise a thing existing in a vacuum would by that very fact intensify itself, because it cannot act on another. Likewise, because that effecting of greater intensity exceeds its proper power; therefore, although the agent is impeded from going forth into action proportioned to it, it cannot for that reason effect in itself an action which surpasses its proper power.

18. Others, therefore, not finding a way to declare this action, deny that there is such action in things, and to the experiences answer that they are apparent, not true; and various causes of such appearances are devised which are fictitious and repugnant to sense; although Galen, bk. III On the Faculties of Simple Medicines, c. 3, is inclined to this opinion.

19. A twofold way of declaring action through antiperistasis.—Why baths and the stomach of an animal are warmer in winter.—The same of well-water.—It must be said, therefore, that a quality is intensified on the occasion of a surrounding contrary in only two ways, namely, either by an extrinsic agent which on that occasion is enclosed and detained there, or, conversely, because on that occasion the extrinsic corrupting agent withdraws, and at once the thing brings itself back from within to its natural state, which demands that greater intensity; and so it comes about that a quality never intensifies itself. The first mode we touched upon in the preceding section, where we said from Aristotle that baths are warmer in winter because the heat in them is enclosed by the colder medium and prevented from breaking out, which we declared of the hot exhalations. Thus too the belly of an animal is warmer in winter, because the animal spirits are retained within, since the coldness of the air constricts the skin and pores, as Galen noted in declaring the cited aphorism of Hippocrates, and Aristotle elegantly, sect. 2 of the Problems, q. 29, where he adduces other examples. And from the same cause (I think) it comes about that in winter the water of a well is warmer, because, namely, some hot exhalations generated in the caverns of the earth are prevented from ascending, the medium being denser and thicker on account of greater coldness.

20. In which experience, however, two things are difficult. One, whence such exhalations are there. The other, how, since they are most subtle, they can act on the water, which is most cold. To the first it must be said that by the power of the sun and of the other heavenly influences such exhalations are generated from the earth, which on account of its density and dryness, which, speaking per se, it has greater in the lower parts, is apt matter for such exhalations to be aroused from it. And perhaps very many of these, generated there in summer time, are afterwards detained there longer for the cause stated above. Those, however, since they are subtler than water, are easily mixed with it while they try to ascend, and so they will easily be able to temper its coldness, at least by continually reacting on it. Perhaps too the air enclosed in the caverns or pores of the earth, since by its nature it is hot, is for the same cause hotter and helps towards that action. The other mode of this action is declared by other examples. The first is of well-water, which in summer time is colder; for the hot exhalations by which it could be heated do not remain there, but ascend more quickly, both because the medium, since it is hotter and rarer, does not impede, and also because at that time those exhalations are subtler on account of the more vehement influence of the sun. And so, the contrary agent being removed, the water becomes colder from within—not colder than its nature demands, but than it was before while it suffered more from its contraries. In this way too it happens that cold water exposed a little to the sun in summer becomes colder; for the extrinsic heat effects in the medium, or in the external surface of the water, or in the vessel which contains it, some rarity; and then, if any hot vapour surrounded the water or was mixed with it, it evaporates more easily, and thence it comes about that the water brings itself back more to its natural state; and perhaps too it is condensed further, not only for the said cause, but also on the occasion of avoiding a vacuum; and from this head too the cold increases. Aristotle may be read, sect. 24 of the Problems, q. 13, and I Meteor., c. 12. In one or other of these two ways, then, all similar experiences can be declared, so that it is never necessary to admit that the same thing intensifies itself according to the same quality; for when that intensification is from within by natural emanation, it is attributed to the generator.

Whether a multitude of agents, or the density of the matter of one, contributes to the intensity of the action

21. The affirmative opinion of some.—In the third argument two difficulties are raised: one is whether a quality existing in a denser subject can intensify in another, rarer one a quality like itself beyond its own grade; or, what is the same, whether several partial agents, or several parts of the same agent, on account of greater application to the same patient like it in quality and equal in grade, can intensify its quality. For many affirm so, as Marsilius, I De Gener., q. 19; and Soto, II Phys., q. 2; and Nifo, I De Generat., his text 195, dub. 2, q. 2. Their reason is that the power of the agent grows not only from the intensity of the form but also from its multitude, Aristotle saying, VIII Phys., text 80, that in greater magnitude there exists greater power; therefore, if that whole power is applied more to the same patient, as happens when the agent is denser, it will also make a greater effect. And it is confirmed by the common example given above of red-hot iron, and of two equal luminous bodies equally applied to the same part of the air. Likewise of equal acts multiplied, which intensify a habit, and of equal drops falling equally, which at length hollow a stone. And it is confirmed secondly, for the air in winter freezes water, because, namely, it intensifies its coldness beyond that grade of coldness which it has in itself; for if it were itself so cold, it too would be condensed and become water.

22. Nor do these authors think this opinion of theirs contrary to the doctrine handed down about the unlikeness required between efficient cause and patient; but they say that, just as like acts on like according to form if it is unlike in grade, so also that which is like in form and grade can act on another like thing if it is unlike in power and potency; and that so it happens in the present case; for something hot as four and very dense, although it does not exceed the air in grade, nor a hand equally hot, exceeds it in power and potency. Because this is not commensurate with intensity alone, as has been said. And it is declared further, because that dense hot thing has the power of producing in another the whole form which it has in itself; since, therefore, in the rarer patient it cannot multiply it on account of the latter's incapacity, it increases it intensively.

23. The reported opinion is rejected.—Resolution of the question.—This opinion I judge false and contrary to the principle laid down, which is to be taken in this sense, namely, that nothing can act on another thing like itself according to that form in which they are alike, nor add to it perfection or intensity, if they are supposed to be perfectly alike, that is, not only in species but also in the grade of intensity; which Aristotle in the cited place of De Generat. says, if they are wholly alike. Wherefore to the argument made it must be said that a multitude of form with equal intensity, whether in one very dense agent or in many however applied, does not suffice to intensify in another a like form beyond that grade which such a form has in the agent. This is the more common opinion, which Paul of Venice holds, in the Summa on Generation, c. 23; Albert of Saxony, I De Generat., q. 15; and Astudillo, q. 21; and excellently Victoria, in the relectio On the Increase of Charity.

24. The a priori reason has already been touched upon, because the agent by its action intends to assimilate the patient to itself, and this end being attained, its action ceases; but if the patient has been made like in form and grade, it is already perfectly like; therefore the action does not proceed further. Nor can it be said that perfect likeness has not yet been made because the patient has not attained so great a multitude of form as is in the agent: both because the multitude or fewness of form does not pertain to the notion of the form or quality itself, but comes from the subject or quantity, and therefore it is not unlikeness in form but inequality in quantity—for one white thing will not be called unlike two white things because it is not many as they are, but will be called unequal; but through action such equality is not intended, but likeness in form; and also because such likeness, or rather equality, is impossible, the capacity of the rare or dense subject being supposed, or, what is the same, it being supposed that the patient is one and the agents many. Nor is it true that that inequality can be compensated by greater intensity, both because they are quantities or perfections of diverse notions, and also because rather through that greater intensity a new unlikeness in grade would be made, the same inequality in the multitude of form remaining.

25. The second reason is that in a remiss form, however multiplied in many and differing subjects, or in many parts of the same subject, there is not sufficient power to effect greater intensity in a like form; therefore. The antecedent is evident, because, in the first place, such power is not there formally, since such intensity is not formally in that form. For I suppose that intensity is not an aggregation of several like grades in the same part of the subject, but a proper and per se increase of the same quality in the same part of the subject; which increase, for example as eight, would not exist even if two heats as four were placed in the same part of the subject, of which I shall speak below in its place; this perfection, therefore, can much less be formally in a multitude of remiss form existing in many subjects or parts of a subject. Nor is it there eminently, since that form according to species is of the same notion, and according to grade is of an inferior notion in the single parts of the subject, and consequently in all taken together. For in many things of the same notion there is not a more eminent power than in the single ones, since eminence of power demands a form or nature of a superior notion. Nor can it be said that that intensity is virtually in that form on account of its multitude, because virtual containment, as it is distinguished from eminential, is attributed only to instrumental power; but in this way that intensity cannot be attributed to a multitude of form of inferior intensity and of the same notion, both because such a form, while it acts what is like itself, behaves not so much as an instrument as a proper principle of acting, as was said above, and also because no principal agent can be assigned in whose power it may be said to effect that effect; indeed that multitude of form per se was not instituted to be the instrument of any action, but is as it were a certain aggregation of instruments of the same notion.

26. Absurdities from the opposite opinion.—Thirdly, I argue from the drawbacks, because from the opposite opinion it follows, first, that three things hot as four could make one another supremely hot, if two joined together intensified the heat of the third up to the fifth grade, and that again rendered the others like itself, and so they proceeded up to the highest. Secondly, it similarly follows that water hot as four according to every part could render itself hotter in any grade whatever; for two extreme parts, for example, will effect in the intermediate one and intensify its heat, and that again will effect in the extreme parts, and so the action will proceed up to the highest. These and similar things, however, are plainly false and against experience. Thirdly, it follows that a habit is intensified by remiss acts, so as to incline to a more intense act, which too is false, as I suppose.

27. In order to answer the foundation of the contrary opinion, it must be noted, first, that it is one thing for the power of acting to grow from the multitude of form, another for it to grow as to the power of producing an effect more perfect intensively; for the former is more general, and from it the authors of that opinion do not rightly gather the latter. The power of acting, then, is increased in that way not intensively but extensively, and therefore it is not increased so as to be able to produce a more intense effect than is the form itself which is the notion of acting, but so that it can effect its adequate effect more easily, more quickly, more strongly and at a greater distance, other things being equal. Hence it can be said to be increased as to the mode of making, not as to the thing which it can make. And similarly, when density of the parts of the subject is joined to the multitude of form, it helps much towards this mode of action, because that whole multitude of form is better applied to the patient, and therefore it conduces to more prompt action; yet by itself alone it cannot conduce to a better effect than is contained in the power of the form, because that application is only a condition which per se does not conduce to acting, except power being supposed.

28. Secondly, it must be observed that the discourse is of a multitude of form which is wholly equal in essence and grade to the form of the patient; for if it happens that the quality of the agent is as to essence and species of another notion from that which is made in the patient, and contains it eminently, although in its own order it were remiss, it can be the principle of effecting the inferior quality intense in its grades, as was touched upon above; for that superior quality in any grade whatever, by reason of its essence, could eminently contain the whole latitude of the inferior quality. Nor then would like act on like, even if a quality, for example as one, intensified a quality as one, because they would be of diverse notions, and that would rather be a certain proportion than proper likeness. Next, it can also happen that a multitude of form conduces to a more intense effect when the effect does not equal the intensity of the form of the agent; as, for example, when one lamp illuminates the air, it does not produce in it so intense a light as it has in itself, and therefore it can rightly happen that two lamps taken together, and of equal intensity between themselves, produce a more intense light in the air than either could by itself; for then the reasons given cease, because the patient has never been made perfectly like the agent; since, therefore, in the agent there is not only a greater multitude of form but also a more intense form, there can be in it power to intensify the effect. Hence in any one of those agents by itself there will be a form productive of that whole intensity; that one agent by itself alone did not produce all of it could come either from the indisposition of the patient, or from distance, or from another similar cause. And then a multitude of intense form can excellently contribute to producing a more intense effect, which yet does not exceed the intensity of the cause.

29. Whether two like or unequal agents help each other in action.—The greater difficulty is, if two unequally intense agents concurred together, whether they could help each other to produce a more intense effect, which, although it does not absolutely exceed the whole intensity of the cause, yet exceeds the intensity of the other partial agent having a less intense form; so that, although a remiss quality, however great in multitude, cannot per se intensify a quality like it in grade, yet in partnership with a more intense quality it can help and cooperate towards intensification. For then too the reasons given seem to cease; for in such a total agent there is absolutely a more intense form and power sufficient for that effect, and the lower grades of quality conjoined to the higher can concur to any grades whatever of another like quality; as, for example, when something hot as eight intensifies heat as four, it does not concur to the fifth grade, for example, only through the fifth of its heat or through the higher ones, but through its whole heat; just as conversely, when it makes the first grade, it does not effect it through the first, but through its whole heat. A sign of which is that for effecting the first or the fifth grade what is hot as eight has greater power than what is hot as five or as one, other things being equal; for it will both overcome greater resistance and act more quickly; therefore it is a sign that it does not act only through the like grade, with the others related concomitantly and as it were per accidens to that action, but that they truly concur to it. And the reason is that, in order that all help and concur, it is enough that in all and each there be the essence of heat, although there is not in the single grades that peculiar likeness which is between grades of wholly the same notion; for it is enough that that likeness be in the whole form, which is the principle of acting. Thus, then, several remiss forms too, conjoined to a more intense one, will be able to concur with it to producing a more intense effect. This, then, is probable, nor do the reasons given so militate against it, as is easily evident from what has been said; and it can contribute to saving some experiences, as was touched upon above and as we shall see at once.

30. It is not, however, free from all difficulty; for if a remiss form, conjoined to a more intense one, acts towards the intensification of a form like itself, why will it not rather act towards the intensification of itself? Likewise, because otherwise something hot as eight, equally neighbouring two things hot as four, would act with one and through it towards the intensification of the other, and conversely. It could be answered, however, that it comes from a peculiar disposition of the patient or of the partial agent that one remiss partial agent cooperates more with the more intense agent to intensify a like form in another subject than in itself, or than another like thing, as will more easily be established from what is to be said. This, then, is probable, of which more below.

31. How red-hot iron generates fire.—From these, then, the foundation of the contrary opinion is sufficiently disposed of. To the first experience brought by us, however, of the red-hot iron, the common consent and reply of all philosophers is that there is some fire enclosed in its pores, although it is hidden from us; from which fire enclosed in the pores of the red-hot iron comes that greater intensity which we easily experience by the senses, although the vehemence and quickness of the action comes from the partnership of the iron and its density. A sign, however, that there is some fire there enclosed and contained (as we said just now) in the pores of the iron can be taken from the brightness which always comes from fire, as Plato said in the Timaeus. Likewise this very thing can be shown by a reason by no means to be despised, because iron is not without pores, in which there is commonly air; therefore, since vehement heating has intervened, it will be turned into fire by the force and efficacy of so intense and vehement a heating. And finally, never does so vehement a heating take place in any matter or subject capable of such heating without some exhalations being separated from it and inflamed or turned into fire. Others answer for a far different reason, namely, that there is in the iron the supreme heat that can be, and this without the form of fire on account of other dispositions repugnant to fire and conserving there the form of iron. But it is hard to believe that those dispositions which connaturally exist in iron as in a subject proportioned and connatural to them do not also impede so great an intensity of heat, since they are repugnant from the nature of the thing. I intimated another reply above, that in dry and disposed matter fire can be generated without preceding supreme heating, which can easily be defended, and this being posited, it does not follow that there is supreme heat in the iron. The first reply, however, is sufficient.

32. Whether remiss acts increase a habit.—To the experience adduced about remiss acts, it is answered that it rather proves the opposite, because according to the common opinion they do not intensify or increase a habit; although this requires a longer exposition, which we shall give more ex professo in its place. To the other, about falling drops, it is answered that each does something, because they gradually dispose the subject, which they render somewhat softer; otherwise, if the subject remained equally indisposed, the second could do nothing more than the first, nor the hundredth than the third; yet each acts on an unlike patient; for of itself, for example, it was dry, and at the beginning it begins to be moistened according to the proportion and power of the falling drop; but because the later ones find the patient more disposed, they do more; none, however, acts beyond its proper intensity and power. To the third, about frost, it is first denied that the air cools the water more than it is itself cold; but at most it can wholly prevent it from being heated by an extrinsic agent, and then the water itself brings itself back to the supreme coldness which by its nature it can have. But if that coldness suffices for congelation, then it does not come from the air; but if it does not suffice (as indeed it seems not to suffice, otherwise water existing in its natural state would always be frozen), then too another cause of that congelation besides the air will have to be sought, because the air was said only to cool. I think, however, that congelation comes from the diminution of the moisture of the water, and hence from some heavenly drying influence; for that dryness, so affected and tempered with such density and coldness of the matter, accomplishes congelation; no quality, therefore, intervenes there which is intensified by a more remiss quality of the same notion.

On reflected action

33. The other doubt raised in the same argument concerned reflected action, in which some confess that a remiss form can intensify itself, let alone one like itself. Which opinion, taken so absolutely and universally, we rejected above, and we shall at once add something against it again. Others say that through reflection the solar rays, for example, are multiplied about the same part of the medium; for because of themselves (they say) they could pass further, obtaining a greater sphere, therefore, when they meet a body which impedes their diffusion, they return to the same patient from which they are reverberated, and so reflection takes place. But unless these things are said by metaphor, they are plainly false and openly contrary to reason; for rays are imagined to be certain little bodies which arise from the sun, which was the view of Democritus about every agent, rejected by Aristotle and all philosophers, as St. Thomas generally noted, I, q. 115, a. 1, and specially of light, q. 67, a. 2.

34. The first way of explaining the question is disproved.—It can be understood in two ways, then, that action on the medium is more intense on account of reflection. First, because, while the principal agent operates in a smaller sphere, it acts more intensely in its parts than if its action were diffused to a greater sphere; which principle per se indeed appears probable, for finite power applied to more things is less in each; therefore, conversely, gathered to fewer, it will act more strongly in each; therefore it will also act more intensely, yet within the latitude of its power and intensity. Thus, then, fire heating this hall, although it could heat at once a much greater sphere, yet because its action is held within the bounds of the hall, makes a more intense heat in this air than it would otherwise make; and the same holds proportionally of the sun illuminating. Although, however, the intensity is then said to be greater on account of reflection, yet in truth that reflection, so expounded, on the part of the body in which it takes place, is only an impediment to the action's proceeding further; but on the part of the principal agent there is more efficacious action and greater application of its power.

35. But this way of explaining reflection, and action through it, although it is probable in what it affirms, does not seem, however, to suffice by itself to save all that experience shows in reflection of this kind. First, indeed, because, if the body in which the reflection takes place served only as an impediment of diffusion, by reason of which the power of the first agent, as it were united to a smaller sphere, acts more strongly on it, any body placed at the same point and equally impeding the extension of the sphere would make equal reflection, for it would give wholly equal occasion to the first agent to intensify its action more strongly and (so to speak) double its strength; but the consequent is openly against experience; for a black thing, for example, other things being equal, does not make equal reflection of light as a white thing; nor a white thing equal to a mirror. Secondly, because, if reflection took place only in that way, it ought to take place in equal proportion through the whole sphere; for that stronger action or application of power takes place in equal proportion to that whole. But the consequent is against manifest experience, for stronger reflection takes place in the parts nearer to the body from which the reflection takes place, as is sufficiently established per se.

36. The body which reflects the action truly acts on that against which it reflects.—Wherefore it seems necessarily to be said that in this said reflection there intervenes proper efficiency of that body in which the reflection takes place; for it receives from the first agent an active form or quality, and, affected with that, acts again on the patient nearest to it, which is the very medium through which the first action of the agent came as far as that body. And therefore that first action of the agent is called direct, but the other is called reflected. This mode, however, is not proved otherwise than from a sufficient enumeration, and because per se it is probable and involves no repugnance, since it often happens that one thing through a form received from without acts again, as hot water through heat. It is not, however, without its difficulties; for in the first place it can be asked, since the medium receives the same quality from the first agent, why it does not rather itself act on the other, from which the reflection is said to take place, than suffer from it. It is answered that this comes from a peculiar disposition or condition of such a body and quality; for light, for example, does not seem per se active unless it is received in a dense and polished body; or at least it is not equally active, as experience teaches; for this is why the moon illuminated by the sun illuminates more than other parts of the heaven, because it is so lucid as to be also dense. Since, therefore, the reflection of light always takes place in a dense body towards a rare medium, therefore that action is rather from such a body than from another. Something similar is found in the reflection of heat; for it commonly takes place from a denser body, which acts more strongly, as was said above, on account of the multitude of matter.

37. A doubt is satisfied.—But then a second difficulty arises, because hence it follows either that the first agent heats or illuminates the distant thing more intensely than the near, on account of its disposition, or that that distant thing in which the reflection takes place intensifies a like quality in the medium only on account of the greater multitude of matter, although in it the quality is either less intense or at most equal; but both are repugnant to what was said above. This is the argument by which those are chiefly moved who say that in reflected action what is like in grade is intensified by what is like, or the same by itself. But this was partly attacked above, and moreover it can easily be refuted, because reflected action is true action and cannot take place without sufficient power, and has nothing special except the denomination, because it is bent towards the agent from which the form is directly received from which the reflected action is. And therefore someone could answer that this reflection never takes place except either through a quality of a diverse notion or with some like quality helping; as, for example, when a mirror heats through light by reflected action, then the reflection is said to take place through a quality of a diverse notion, and the touched difficulty easily ceases, as was said above; because, although the light is not more intense in the mirror than in the air, it can heat more intensely, because it is a quality of a superior notion, and from elsewhere it is helped by the density of the subject and the multitude of form more applied. But when reflection takes place between lights themselves, the said reply has no place; and therefore there will not then be lacking one who denies that there is in reality such reflected action by which the light of the medium is made greater, but that it so appears because that polished or white body moves the sight more vehemently. But this does not appear credible, because we experience that the air itself shines more clearly when reflection takes place, and objects placed in it are better seen. It could also be said that the light in the medium is not intensified, but a new one is made by the body through reflection; and that it is not unfitting that two lights be together in the same part of the air. Just as, when reflection takes place in a mirror, it is probable that a new visible species of the same object is caused in the medium by reflection. But this multiplication of lights, although it pleases the perspectivists, has not been received by the philosophers, nor is it consonant with what was said above about the individuation of accidents. And therefore it could otherwise be said that the light received in a dense body is of a diverse notion from that which is received in the air, which is hard to believe. Or it could also be said that it is helped by some quality of the subject; but all these and other things which can easily be devised would be affirmed without foundation, rather to flee the difficulty than to resolve it.

38. Wherefore it seems necessarily to be admitted one of the consequences stated, provided it is not understood that a remiss quality by itself alone intensifies what is like itself, but in the power and with the partnership of the principal agent; for this was declared above to be probable. If, then, we say that the sun, for example, on account of the greater capacity of the subject, illuminates a distant mirror more intensely than the intermediate air, the medium itself helping as instrument or partial agent, then it is easy to understand that the mirror so illuminated acts again on the air neighbouring it and intensifies the light; for it is not unfitting that in the same quality some grades be made by one agent and others by another, when they act by diverse actions and not equally firstly, but with some order, as happens here. But if we say that in direct action the remote mirror is not more intensely illuminated than the intermediate air, then it must be said that, because the mirror is more apt for acting through received light than the air, as soon as it is illuminated it is virtually conjoined to the first agent and helps it and is helped by it to intensify the light of the air. And so these two ways of speaking can be probably defended, although, all things weighed, between these two the first seems easier and to declare reflected action better and to avoid the difficulties.

On reaction

39. In the fourth argument the difficulty about reaction is raised, and how in it the greater proportion necessary for effective causality is saved. But this difficulty is treated most broadly in bk. I De Gener., and depends chiefly on understanding the difference which is between the power of acting and of resisting, which we shall hand down below in treating of power. Now, therefore, it is briefly said that formally to resist something is not to act on it; for a thing can sometimes resist even if it does nothing on another. From which it comes about that for acting it is not necessary that the power of acting of one be greater than the power of acting of the other, but per se it is only required that the action of the one overcome the resistance of the other. Hence, then, it comes about that the patient reacts on its agent even if it suffers from it more vehemently, because, although it is surpassed in activity, it can nevertheless by its activity somewhat overcome the resistance of the other; and so it does not act on it inasmuch as it is greater than or equal to it, but inasmuch as it is in some way inferior. But these things will be better understood when the notions of active and resistive power, and their proportions, have been explained, which we shall carry out below. The last argument was solved above.

1. We have declared the principles and conditions necessary for the efficient cause in order that it be proximately apt to cause; it remains that we explain what that is by which it is formally constituted actually causing; for this we call the proximate notion of causing, or the causality, of each cause. And, as I have often said, the discourse is not of the relation of the cause which is said to result when the effect has already been produced; for it is manifest that that is not causality, since it rather supposes causality as the notion on which it is founded. The discourse, then, is of causality as, according to our way of understanding, it signifies the proximate notion of founding the relation; for that notion is what constitutes and denominates the cause in act, as it is said to be prior in nature to its effect.

The opinions of some

2. The difficulty, however, is whether this causality is the very action by which the agent acts, or something else besides the action; for some Thomists deny that the causality of the agent is the action itself, as Soncinas, V Metaph., q. 4, and Javellus, also q. 4, who reports Hervaeus, Quodl. II, q. 1, and Quodl. IV, q. 8. The foundation can be that the causality of the agent must be something other than the effect of the agent; for causality is not caused, but through it the effect is caused; but action is the effect of the agent; therefore it is not its causality. The minor is proved, both because action in reality is nothing else than the effect as it flows from the agent, and also because the action itself, even taken formally, arises from the agent and from its power; therefore it too is an effect of the agent and needs causality by which it may be caused. Secondly, because, the action being past, there still remains a true efficient cause; for the sun, after it has produced gold, is its efficient cause, and it is true to say that gold depends on the sun as on its efficient, and yet the action does not last.

3. But if you ask these authors what the notion of causing of this cause is, they answer nothing else than that the causality of the efficient is to give being to the effect. Because, however, these words are also common to the other causes, especially to the form, they add an explanation, namely, that it is to give by effecting, or that it is to effect or produce. In which they seem to fail in two ways: first, because they say the same through the same; secondly, because they unwillingly fall back into the opinion which they reprove; for what is it to effect but to act? And from what is a thing denominated as acting except from action? It is the same, therefore, to say that the causality of the efficient cause consists in acting itself as to say that it consists in action, except that by these latter words it is declared more formally, not only through the concrete itself or through the denomination of agent, which is the same as the denomination of the efficient cause in act, but through the abstract and through the denominating form.

4. The second.—Others, therefore, in order to depart wholly from the aforesaid opinion, say that the causality of the agent cannot be something outside the agent, but must be a mode intrinsic to the agent itself; for in the other causes the causality of each is its mode intrinsically affecting it; therefore it will be the same in the efficient cause; but action properly so called, as such, is not a mode of the agent, but something outside the agent itself. And it is confirmed, for action of this kind, which is in the effect, does not intervene in every effective causality, as is evident in creation, and yet there is a true efficient cause there; therefore the causality of the efficient as such does not consist in action, but in something intrinsic to the agent itself, whatever that may be. It is confirmed secondly, because one efficient cause with respect to one adequate effect has one causality, and yet often it has not one but several actions; as fire by one causality generates fire like itself, and yet there intervenes there the action by which it transmutes the matter, and another by which it makes the form, and another by which it unites it, and another by which it produces the whole composite; for all these actions can be distinguished in the generation of man, and the reason seems to be the same of the rest; for the very distinction of relations and respects indicates a distinction of actions.

Resolution of the question

5. The causality of the efficient is the action itself.—It must be said nevertheless that the causality of the efficient cause can consist in nothing else than in action. This opinion is taught in these times by most learned modern writers, and it is signified by St. Thomas, V Metaph., c. 2, in these words: The efficient is the cause of the end as to being, because by moving it brings it about that the end exists; and below: The efficient is a cause inasmuch as it acts. Albert thinks the same, II Phys., tract. 2, c. 6. And it is proved, for that is the causality of the acting cause which constitutes or rather denominates it actually acting; but this is action, nor can anything else be; therefore. The major is established from the very exposition of the question given above, and from the terms themselves, because a cause in the notion of cause is constituted by causality; but to be an efficient cause in act is the same as to be acting. The minor too seems clear from the terms, because the cause is constituted actually acting by that which is immediately understood to be added beyond the power of acting; for while a cause is understood to have only the power of acting, it is not understood as actually acting; therefore there must be something beyond this power per se and necessarily required within the latitude of this cause; but this is nothing but the action itself, which being removed the power cannot be understood as actually acting, and which being posited it is necessarily actually acting; on account of which Aristotle said that the relation of the agent is proximately founded on action, V Metaph., c. 14; therefore that is the proper causality of the agent.

6. Secondly, because the causality of each cause is that by which it proximately, per se and intrinsically attains the effect, and by which, conversely, the effect depends on such a cause; for causality is as it were the way or tendency to the effect. Hence it lies between cause and effect as between two termini, because through causality the cause inflows into the effect and the effect proceeds from the cause. But action is that by which the efficient cause actually attains its effect and by which the effect depends on its cause; for it is the very dependence of the effect made on the making cause, as we shall at once signify and treat more at length below in disputing about action; therefore.

7. Thirdly, from a sufficient enumeration, because action is necessary for this causality, and besides it nothing else is necessary, nor can anything even probably be devised; therefore. The major I suppose as certain, especially in the present matter, where we are treating of created causes; for only of creation could there be doubt, but now we are not treating of it, although even in it this holds true, as we shall show below. The minor will be clearly established from the solutions of the arguments of the opposite opinion; now it is briefly declared in this way: because, if something else mediates between the power of acting and the action which is the causality of the agent, either it is preliminary to the action and in some way its root, or subsequent to the action and resulting from it, or something behaving concomitantly; none of these can probably be said. The first member is proved, for whatever is preliminary to action does not pertain to the actual causality of the efficient, but either to the notion of causing by way of principle quo or quod, or to a condition required for acting; a sign of which is that, if one stops at all that preliminary and action does not follow upon it, the cause is not yet understood to be actually causing, whether this takes place through the prescinding of the intellect, or because in reality the action is suspended, all other prerequisites being posited, whether this takes place supernaturally or from the freedom of the cause; but as soon as action is understood to be posited in reality, it is impossible that the cause should not actually cause. The second member is easily persuaded in the contrary way; for whatever follows upon action is either its terminus or something posterior to the terminus; therefore it can much less pertain to the causality of the first cause than the action itself; for that is properly the effect, either primary or secondary, of such a cause. The third member likewise is easily proved, because, if it behaves only concomitantly, it is per accidens to the action; therefore, it being set aside, the action can remain; therefore, it being set aside, the causality of the agent will also remain; therefore this causality cannot consist in it. Especially because it cannot be understood or declared what that is, distinct from the action and from its principles and from all conditions preliminary to it, which is nevertheless necessary to it. Nor can any probable reason of this necessity be given. It remains, therefore, that action alone can be the causality of the agent.

The arguments objected to the contrary are solved

8. Whether action can be called the effect of the agent.—Action is not made through another action.—The agent in act is constituted by action in act.—To the foundation of the first opinion, then, it is answered that action properly and formally is not the very effect produced by the agent, but is a mode of such an effect distinct from it by the nature of the thing; a sufficient argument of which is that the effect can remain without such a mode, or with its dependence varied, which is the same. For that mode is the emanation or dependence of the effect on the acting cause; but the effect can now depend on this cause and afterwards on another, and so the dependence about the same effect can be varied, and then nothing else is varied but the causality of the agent; of which distinction of action from terminus we have touched on some things above, and shall say more in what follows, partly in treating of creation, partly below in treating of action and passion. But if under the name of effect we comprehend not only the thing produced but whatever flows from the power of the agent, in this way we grant that action is in some way the effect of the agent, since it is dependent, or rather is the very dependence, on it; but to be an effect in this broad way is not repugnant to causality; rather, in all the causes which we have treated so far, causality is an effect of the cause; for union is an effect of the form and also of the matter in its genus, and is the causality of both according to diverse relations. And the general reason is that causality always comes from the cause; and therefore, although it is not caused for its own sake, it is yet concaused, and therefore, broadly speaking, it is comprehended under effect. Nor is it therefore necessary that causality be caused by another causality, or that action be made by another action, because it is of the notion of causality that it have an immediate relation to the cause and be as it were the medium or bond between cause and effect. And thus action is compared to its terminus and to the principle or efficient cause from which it flows; but action itself does not flow by means of another action—otherwise there would be a process to infinity—but action is the very emanation; just as the terminus of motion is made through motion, but motion itself is not made through another motion, because it is the very way to the terminus. From which it comes about (to answer the second argument) that it is impossible that, the action ceasing or being past, the cause should last in act; the thing which was the cause in act can indeed last, yet it will not last in the notion of actually causing, since it does not actually inflow into the effect; hence neither can such an effect truly be said to depend actually on such a cause now, but to have depended at some time in its becoming; which dependence it had only by reason of the action, which also existed then when it flowed from its cause.

9. The causality of the agent is not a mode intrinsic to the agent.—To the arguments placed in the latter position, we deny that the causality of the agent must or can be an intrinsic mode of the agent itself, distinct from the action which flows from the agent and is in the terminus itself or in the patient. Which in natural agents which act by transient action alone seems manifest, because they are not changed nor do they acquire anything from the fact that they act. Nor is there any necessity of imagining such a mode, since action suffices for the effect to flow from its agent. In those, however, which act by immanent action, if they do nothing else than the immanent act itself, it is also manifest that there is not in the acting faculty another intrinsic mode, distinct from the act itself or the immanent action, which is the causality of such an act; for the immanent action itself flows immediately from its principle, and whatever else is added as a medium between the power sufficiently constituted in first act and the action will be gratuitously imagined and without necessity, and beyond all common doctrine, which in these powers recognizes nothing but either the acts themselves or actions and their principles, which are either species or habits. And in the will there is nothing actual in which the freedom of the will is first exercised except the action elicited by the will itself; that, therefore, is the effective causality of such a power. Because, however, the thing which is made by such action remains in the power itself, such action is therefore a mode affecting the acting cause—not because this is of the notion of the causality of the agent as such. In those, finally, which through an immanent act do something outside themselves, it may seem that the causality by which such a cause acts outside itself is an act or motion remaining in it; yet in truth it is not, because that act which remains in such a cause is not the formal causality which constitutes the thing actually causing outside itself, but is either the proximate principle of acting or the application of the proximate principle from which the causality arises. Which may be seen in God Himself, who most of all acts ad extra through an act remaining in Himself; for since this act in God is eternal and immutable, yet His actual causality is placed in time, because God does not actually cause until the effect is made; and therefore such causality cannot be something in God Himself, who cannot be changed, but in the creature, which is made or changed. Never, therefore, is the causality of the agent a mode intrinsically affecting the agent itself as such.

10. Nor indeed is it necessary that in this there be complete likeness among all causes, because the reason is not the same for all; for material and formal causes are intrinsic, while the efficient cause of its genus is extrinsic. And comparing matter and form with each other, the latter is in a certain way more intrinsic, inasmuch as it is more proper and determining matter by affecting it. And therefore among the causalities of these causes there is a certain proportional unlikeness. For the causality of the form is an intrinsic mode and in reality the same as the form; the causality of matter, however, can be called intrinsic inasmuch as it is intimately in the matter itself, but it is not a mode so identified as that of the form; but the causality of the agent per se is extrinsic and as distinct from the agent as the effect itself; but if sometimes it remains in the agent or is distinguished from it not really but only modally, that is accidental to the notion of agent as such, and comes either from the fact that the agent is at the same time the patient, or from the fact that the thing which is made is not wholly distinct from the agent, but a mode of it.

11. To the first confirmation the assumption is denied; for in creation too the causality consists in action, as the argument made a little before shows; for since that causality is temporal, it cannot consist in a mode intrinsic to the agent; therefore it must consist in extrinsic action; but what that action is, and in what subject, we shall say later.

12. To the second confirmation it is answered that that argument can be turned to the contrary; for wherever there is formally one cause, that is, one causation, there is one action, and conversely, where actions are multiplied, causalities too are multiplied; it is a sign, therefore, that this causality consists in action. Wherefore, if the generation of fire is taken as it includes the preceding alteration and substantial generation, we grant indeed that those are two actions; but in the same way they are two causalities; but if the discourse is of the causality of the substance alone, we deny that there are several actions there, but it is one and the same by which both the whole composite is made and the form is educed from the potency of the matter and united to it; for in all these only several relations are denoted which the same action has to its subject or to its formal or total terminus. In the generation of man, however, by a peculiar reason the action productive of the form is distinguished from the unitive action (whatever some may say), because that form does not depend on matter as on the proper cause of its production, but does depend on it in union; but the action by which the form is united and the composite is made is not distinct, because the composite cannot be made otherwise than by uniting the form to the matter¹.

1. If the very name of efficient cause is attentively considered, it does not seem to signify a cause which takes away being, but which gives being; and therefore in all that we have said so far about this cause we have explained only the causality of this cause inasmuch as it gives or inflows being; because, however, philosophers commonly speak of the efficient cause in such a way that they think it effects not only the generations of things but also their corruptions—which is not to give being but rather to take it away—therefore, for the completion of this disputation, it is necessary that we say a few things about this matter too, and explain whether this too is true efficiency, and by what causality and power it takes place.

2. Various modes of destroying a thing.—It must be noted, then, that a thing can be corrupted or cease to be in two ways: first, because the non-being of one thing follows from the being of another. Secondly, because a thing is absolutely deprived of its being as it were immediately and without consecution from another being. In the first way wood is corrupted when fire is generated from it, because the being of wood cannot be together in the same thing with the being of fire. In the latter way, however, light in the air is corrupted by the absence of the sun; for no being is introduced into the air repugnant to the being of the luminous, but that form simply perishes, the conserving cause withdrawing. Although the very being of the sun in the other hemisphere can also be said to be naturally incompossible with the being of light in the air of this hemisphere; but that is very remotely, extrinsically and per accidens, on account of the defect of a condition necessary for acting, and not on account of a repugnance which is intrinsically and per se between light and Ubi.

Resolution of the question

3. By positive action nothing is ever directly destroyed.—This being supposed, two principles seem certain: the first is that the corruption and ceasing of a thing never takes place through positive and proper efficiency, except inasmuch as the lack of some being follows upon the effecting or positing of another being. It is proved, because positive efficiency takes place only through positive action; but positive action does not immediately and per se tend to non-being; therefore through it the corruption or destruction of something cannot be positively effected, except inasmuch as through it is made the being of some thing with which the non-being of another is necessarily conjoined. The major was proved in the preceding section, and the same is established from the terms themselves; for efficiency and action are the same, as are efficient and agent. The minor is proved, both because real or positive action (for they are the same) necessarily tends to a real terminus, as will be shown below in its place, and in transient actions it is denied by no one; but a real terminus receives some real being through the action; for this is why it is its terminus. Hence even those who deny a real terminus in immanent actions cannot deny that the action itself, inasmuch as it is positively made, receives some real being from its efficient cause. But if through that action something is immediately corrupted (that is, without the production of another terminus or thing), it is only inasmuch as the being of that action, whatever it may be, is incompossible with the other being which is destroyed. It is, then, universally true that through positive efficiency nothing is immediately destroyed, but only consequently upon another being which is made through the action; which consecution is always founded on some repugnance of such things. And it is confirmed from that common axiom that no agent operates intending evil; but non-being as such has the notion of evil; positive efficiency, therefore, never per se tends to non-being, but to some being from which another's non-being follows.

4. An objection is dissolved.—You will say: although this is true in natural agents, it is not so in voluntary ones; for God can will something not to be, not in order that another may be, but only in order that it may not be; and one man often in this way intends the death of another; hence in artificial things action often per se primo tends to destruction. It is answered that, although a voluntary agent can per se intend the destruction of a thing, it cannot execute and effect it through an action which of itself primarily tends to non-being, for the reason touched upon above. Hence God Himself too, when He wills to destroy some thing, will either obtain this through the mere suspension of His influx without positive action, or, if He wills to use positive action, He will necessarily make something from which such corruption follows. But man, who cannot destroy a thing through the mere suspension of influx, because things do not depend on him in their being, always uses actions which commonly are nothing but the local changes of bodies, which directly and per se tend to their proper termini; and from them per accidens follows corruption or destruction, which, although it is intended per se as to the extrinsic intention of the agent, yet takes place per accidens or consequently through such action.

5. The destruction of a thing directly intended takes place through lack of efficiency.—The Aristotelian axiom is explained.—The second principle is: when the ceasing of some thing does not follow upon the positive effecting of another, but takes place by itself alone, it does not take place through proper efficiency, but through lack of efficiency. This principle follows from the preceding, because positive action is only towards some positive being; therefore, while no being is communicated, positive action cannot intervene; but in this kind of ceasing and corruption no being is communicated, but is only taken away; therefore it cannot take place through true action; therefore it must necessarily take place through lack of action, because no other mode of causality can intervene which pertains to the efficient cause. You will say that this kind of cause seems to be only per accidens, such as that which removes the cause per se; but a cause of corruption of this kind is not only per accidens, but per se; therefore it is not only through the absence of the cause, but through proper efficiency. The minor is evident, both from Aristotle saying that, just as the presence of the sailor is the cause of the conservation of the ship, so his absence is the cause of its sinking; and also because that effect cannot be referred back to a more proper and per se cause. And on this seems to be founded that common axiom: If affirmation is the cause of affirmation, negation will be the cause of negation, which is most known in proper, per se and adequate causes. It is answered that from this very axiom it is gathered that the per se cause of corruption (if indeed it can have any) is not to be sought positively acting, but rather not acting, since the cause must be proportioned to the effect. Hence in that example of Aristotle too the absence of the sailor is not an acting cause, but rather a non-acting one. Wherefore, if it is compared to the sinking of the ship inasmuch as this is a certain positive effect, it is only its cause per accidens, considering the thing truly and physically, although morally and imputatively it is reckoned per se, if he was bound to be present; but if it is compared only to the lack of help or defence of the ship, the one negation can be called the per se cause of the other negation; for they have between them proportion and intrinsic and immediate consecution. In this way, then, if a cause per se inflowed being and takes away the influx, it will be called the per se cause of the ceasing of such being, not because by positive action it effects the ceasing, but because in a proportioned mode it is the proper principle and origin of such ceasing. Hence, just as privation is said to exist not through positive being but through lack of being, so it is said to be made not through positive action but through lack of action. And in the same proportion its efficient cause per se is not called such because it positively effects it, but because it takes away the influx by which it per se caused that being which is destroyed by such corruption. Indeed, every cause which by positively effecting destroys another, as such, or inasmuch as it is efficient, is not a cause per se, but per accidens, of the destruction of the other.

Corollaries of the foregoing doctrine

6. In every destruction of a thing change is found, not in every action.—From these principles we can infer some things worthy of note concerning the changes or corruptions of things. For it follows, first, that in every corruption or loss of some real being there intervenes some change, but not always necessarily some action. It is evident from the second principle laid down, the definition of change being added. For, on the testimony of Aristotle, a thing is changed when it is otherwise than before; when, therefore, the air from illuminated becomes dark, it is changed; there takes place in it, therefore, some change; and yet that does not take place through action, as is established from the second principle laid down; there is, therefore, change there without action, and the same holds in all similar cases. The reason, however, is that that change is purely privative, not positive. Whence it comes about that this happens only in accidental changes, if we speak properly and according to the common course of nature about change, because the subject of an accident can sometimes lose it even if it does not acquire another; but the subject of a substantial form cannot be substantially changed by losing one form without acquiring another. And therefore I said speaking properly and according to the common course of nature about change. For God could suspend the influx of the substantial form while conserving the matter; or, if the name of change is extended to annihilation, He could wholly change a thing from being to non-being without any action. In which there is also to be noted the difference between free and natural causes, that free causes can suspend their influx from intrinsic dominion and power without any prior action or change in themselves or in another; and so they can also cause this privative change, either in themselves, if they themselves are changeable, as created causes, or in others, as God; but naturally acting causes cannot suspend their influx unless something else is first changed which was necessary for acting; and therefore, although sometimes they change some subject in the aforesaid way without action about it, yet some other action always intervenes, either about the same subject or about another; as the sun does not destroy light in the air by withdrawal of influx unless there precedes an action by which either the sun itself is moved, or the window is closed, etc.

7. Action tending secondarily to destruction is always dependent on a subject.—Annihilation cannot be from a subject.—It follows, secondly, from what has been said, that whenever the corruption or ceasing of a thing takes place through positive action which of itself has consequently to cause such corruption, it is necessary that such action take place from a presupposed subject. The reason is that corruption or ceasing does not take place by virtue of physical action (for so we are speaking), except because that being which is made through such action has natural repugnance with the being which is destroyed; but this natural repugnance can only be in order to the same common subject, which remains under both termini, because between things subsisting per se and having no order to a subject there cannot be natural repugnance on account of which they could not exist together in the nature of things; therefore it is necessary that such action be from something presupposed. And hence it is that proper annihilation cannot be done by God through positive action, because annihilation leaves nothing of the thing which could be the subject of the action. Likewise, because either the action takes place in a subject, and so does not destroy it, and consequently does not effect annihilation, or it takes place without a subject, and so nothing can be made through it which is repugnant to the whole being of another thing; nothing, therefore, can be annihilated through such action. But if someone objects that the action by which the rational soul is made is not from a subject, and yet upon it follows the corruption of another, namely of the embryo, it is answered by denying the minor; but properly that corruption follows either from the action by which the matter is sufficiently disposed for the introduction of the rational soul, or from the action by which the soul itself is united to the body, or from both in their genus, as will be explained below; but each of these actions is from a presupposed subject; creation, however, is only in the order of nature presupposed to the unitive action, but naturally consequent upon the dispositive action. Someone could more difficultly press about that action by which bread is converted into the body of Christ, which is not an action from a presupposed subject, and yet by virtue of it the substance of bread ceases to be. But this difficulty is higher than can be treated in this place; and therefore, to exclude it, I said that the discourse is of natural action and ceasing; but that mystery is wholly supernatural. In it, nevertheless, I think it true either that the ceasing of the bread does not follow there by virtue of physical action alone¹ and the natural connection of things, or, if some such action intervenes there, that it is concerned in some way with a subject, and that the quantity of the bread, conserved without the substance, takes the place of such a subject, as I have disputed more at length in the proper place.

8. The third inference.—Thirdly, I infer that whenever corruption or ceasing takes place through positive action, there intervenes there one simple action, but two partial changes, one positive, the other privative. For a thing happens to be changed in three ways, as Aristotle proposes in V Phys. First, from some form into its lack; and then change takes place, but no action intervenes, speaking per se, as has been said, but lack of conservative action. Secondly, change takes place from pure privation into form, as from dark into bright; then, just as one action intervenes, so also one simple positive change. Thirdly, it happens that a thing is changed from one form into another, as when from hot it becomes cold, and from wood fire. And then one simple action intervenes by which is educed or united the form which is newly introduced into such a subject; for to expel the other no other action is necessary, as we have said; but the change is twofold; for that subject is otherwise by a twofold title, namely, both by lacking the form which it previously had and by having that which it previously did not have. Which two changes are so distinct that in reality they are sometimes separated, as was declared in the first two members. Likewise, one is generation, the other substantial or accidental corruption, or sometimes one is intensification and the other remission. Finally, one is positive, the other privative. Hence, as much as the information of one form and the privation of another differ from each other, so much do those changes differ from each other. Those changes, however, can be called partial because in a physical way they compose one integral transit from one positive terminus into another, which in philosophy is called the conversion of one thing into another. You will say: just as there intervenes there positive and privative change, so there intervenes positive action and the lack of the action by which the opposite form was conserved, either by natural causes or at least by God; for one of these is always necessary; therefore the reason is the same of action and of change. It is answered that the only difference is that the notion of change is saved in a new privation inasmuch as it is in becoming, but the notion of action by no means, but it requires positive influx; which is established from their definitions and essential notions.

9. It is inferred, fourthly, that corruption which takes place through some efficiency takes place through the same principles, whether principal or instrumental, and with the same conditions, as the generation or production upon which such corruption follows. It is proved from what has been said, because there is no other efficiency nor other action towards corruption than towards production; therefore through the same principles by which one being is made another is taken away. Nor can any principle positively concur to taking away being except inasmuch as it concurs to giving another being. From which we said above, against some moderns, that the form introduced into the patient by the agent does not concur effectively to expelling the opposite form—as heat to expelling coldness, and so of the rest—because the form introduced into the patient is not the efficient principle of its own generation; therefore neither of the corruption of the opposite form. Likewise, because, if that efficiency is positive, something positive is made through it; but the form introduced into the patient positively effects nothing by which it expels the other form, but the expulsion of the other form immediately follows; therefore.

10. How one body drives another from its place.—Hence the example commonly adduced of one body expelling another from the same place, which seems to expel it effectively, is not similar; for although Scotus, In IV, dist. 12, q. 3, seems to deny this too, yet in truth the case is not similar. For the two bodies touch each other and one drives the other; and that which is expelled does not lose its place by mere ceasing, but by real change and tendency to another place, to which it is effectively moved by the expelling body; and therefore there intervenes there not only the formal incompossibility of those bodies in the same space, but also a special positive action by which the body, driven from one place, is transferred into another, which is distinct from that by which the other body is introduced into the place of the other. But it is otherwise when a form introduced into one subject expels another, for that which is expelled is not changed positively, but merely privatively ceases to be; and therefore no special efficiency can intervene there. There is, therefore, only formal expulsion there; and universally any cause in its genus so concurs to the non-being of one terminus as it concurs to the being of the other; since, therefore, heat introduced into a subject does not heat it actively but only formally, therefore it does not expel cold actively but only formally. But it is otherwise of the heat which is in the generator; for that is the efficient principle of another heat, and consequently expels the opposite cold. And in the same proportion the heat produced in wood (and the same holds of every similar disposition), although it excludes the directly opposite accidental form only formally, yet corrupts the substance itself dispositively, because in this way it causes the introduction of the opposite form; and, as has been said, in that genus of cause one form concurs to the non-being of the one terminus in which it concurs to the being of the opposite terminus. Hence, because an accident from its proper notion and power has to dispose to the substantial form connatural to it and formally to expel the contrary disposition, it can therefore be said in this genus to corrupt the substance by its own power. But if those accidents and dispositions of the patient also concur effectively to the eduction of their form, by the same genus of efficiency they concur to the corruption of the other; or if they have no efficiency towards the former, neither towards the latter. And so it is universally true that only those are the efficient principles of corruption which effect generation, when corruption takes place through efficiency; for when it happens through mere lack of efficiency, it does not need a proper principle of acting, but it is only necessary that that which was the principle of acting or of conserving the thing cease from acting.