Disputationes metaphysicae

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.