Disputationes metaphysicae

1. There are causes acting necessarily, if the requisites for acting are present.—What these requisites are.—This question is easy, and therefore it must be said briefly, first, that among created causes there are many which operate necessarily, if all the things which they need in order to operate are applied. This is established by experience and easy induction; for the sun necessarily illuminates, fire heats, and so of others. The reason, however, is to be taken from the intrinsic condition and determination of the nature, as we shall declare in the following assertion. That condition, however, if all necessary things are present, is added because a sufficient cause, proximately apt and with all the conditions required for acting, must be supposed. For if any of these is lacking, action will not follow, not indeed from the indifference or indetermination of the cause, but from the defect of some concause, or from the defect of power or of a condition necessary for operating. Among these things necessary for acting, however, the action itself must not be numbered, as is known per se, because otherwise nothing special would be said of these agents, but what is common to all, not only agents but also things, namely, that if they have the form by which they are constituted in such being or notion, it necessarily follows that they are such. For just as, if someone has whiteness, he is necessarily white, so if he exercises action, he necessarily effects; which is only necessity of the consequence (as they say), or conditional, not of the consequent or absolute; which is irrelevant to the purpose, because in it causes cannot be distinguished. In order, then, that the discourse be of true and proper necessity, the action itself must not be included when it is said that a cause acts necessarily, if all requisites are applied. From which it follows a fortiori that whatever is posterior to the action and consequent upon it must not be numbered among these either, as is clear per se. Indeed, properly speaking, what is of this kind cannot be said to be necessary for action, but rather necessary from action.

2. The first and second requisite for acting.—The third.—The fourth.—The fifth.—Under that condition, therefore, must be included all and only those things which are preliminary to action. These, however, are numbered as many by authors, as may be seen in Scotus, In IX Metaph., q. 14, ad 2; Antonius Andreas, q. 1, ad 2; Zimara, theorem 112, who posit six conditions. The first is that the cause have integral and sufficient power of acting, which is known per se, because action must presuppose sufficient power; and, in order that it act necessarily, it must be supposed simply and absolutely able; but it is not absolutely able without sufficient power. The second, that it have a capable patient sufficiently brought near, because created agents can do nothing except from a presupposed subject; and because they are finite, they require it within a proportioned sphere, outside which they have no power of acting. The third, which follows from this,¹ is that the medium, if any lies between agent and patient, be unimpeded and capable of the action of the agent; for we suppose that agents can effect nothing on a distant thing except through the medium. The fourth, that there be nothing impeding the action of equal power for resisting; because nothing can overcome by acting unless it exceeds in active power, and therefore it was shown above that for action a proportion of greater inequality is necessary. The fifth, that the patient not be already in the terminus, or have the whole form which the agent can effect. For on account of this cause alone gravity does not move earth existing at the centre; and this condition is contained in the second, for the patient is required for action in that state in which it is capable of action; but after it is in the terminus, it is no longer capable of action. Finally, this condition coincides with that treated above, that agent and patient must at the beginning be in some way unlike.

3. The sixth.—A sixth condition is applied: that, if some action is naturally prerequired, it be already presupposed; as the appetite of a brute, although it operates naturally, does not always act, because it necessarily prerequires a condition which is not always present. And similarly sight does not act unless the action of the object upon it precedes. And this condition is virtually contained in the preceding ones; for when one action is prerequired for another, either this is because through it the power of acting is completed, as in the example of sight, which must first suffer from the object, because without the species it does not have the power of acting complete. And many think the same of the knowledge of the object necessary for appetite, namely, that it completes its power of acting. But it is more rightly said that it applies the object in a sufficient and proportioned mode. For what we said in the second condition, that a sufficiently near patient is necessary, is to be extended, as regards immanent acts, to the object, which behaves as the matter about which such acts are concerned. And universally, whenever some efficient cause needs other concauses, even of diverse genera, in order to effect, it cannot begin the action unless all the necessary concauses are so disposed that they can concur in their genus; for this is why the patient is necessary, because the action of a created agent cannot take place without a material cause. Thus, then, because the known object or the knowledge of the object is a necessary concause for vital appetition—whether it concurs by way of efficient, or by way of end, or by way of extrinsic form, or by way of matter about which (for about all these there can be opinions which are irrelevant to the present matter)—the knowledge of the object is an action preliminary of necessity to the efficiency of the appetite.

4. The seventh.—The eighth.—A seventh condition is added, that the cause not be free; but this condition is not necessary for us, because this is what we assert in the assertion, namely, that some causes are not free in operating, but, the requisites being posited, act of necessity. An eighth condition can likewise be added, that the cause have the necessary concurrence of the first cause. But of this concurrence we must treat ex professo below. As regards the present matter, however, this condition either is not among the prerequisites, or is contained in the preceding ones as explained by us. For if the discourse is of actual concurrence, this is not distinguished from the action itself; and therefore, just as action is not comprehended among the conditions prerequired for acting, so neither is actual concurrence. But if the discourse is of aptitudinal concurrence (so to speak), or of the sufficient application and conjunction of the first cause for concurring, in this way that condition is indeed necessary; it is contained, however, in what we said, that a cause having integral power and every concause is necessary; for the power of a secondary cause without the power of the first is either not integral, or, if it is called integral and total in its genus, it needs the conjunction of every other necessary cause in whatever genus or notion of causing. Wherefore under that condition is comprehended every concurrence of a superior cause to which the inferior is essentially subordinated, whether this subordination among efficients be only between created causes and the uncreated, or also among created causes themselves; which we shall see below.

5. Whether there are some natural agents indifferent to several effects.—A ninth condition can be added, that the natural cause not be equally indifferent among several effects; for then, by the very fact that the cause is not free but natural, it will not of necessity make either, and consequently will make neither, because there is no greater reason for the one than for the other; and because it is not free, it cannot be determined to one more than to the other, unless the indifference is taken away from elsewhere. Many examples are commonly applied; we shall, however, bring those which suffice to explain the root of this indifference. The first is of fire existing at the centre of the earth in a circular figure, which according to every part of itself is equally distant from the highest place; for it would not be moved to one part rather than to another, because there is no determining reason or cause. Nor would it be moved towards every part, because otherwise it would be divided according to every part of itself. The second is of perfectly flat glass placed on a perfectly flat stone, upon which another perfectly flat rock falls; for it will not break it, because either it will divide it according to every part, which is impossible, or there is no greater reason why it should divide some parts rather than others. The third, a common one, is of a brute having at once two equally lovable objects, which would be moved to neither. The fourth is of superior causes able to effect contraries, which of themselves cannot be determined to either, if they are applied for acting with that indifference. The fifth, and more difficult, is of every natural cause which, although it is determined to effecting a form in one species, is yet indifferent to the various individuals of that species.

6. Where a spherical fire existing at the centre of the earth would tend.—But nevertheless it seems it must be said that this condition is rather to be reduced to some one of those posited above, or to the defect of some one. For this condition of indifference, considered per se, is in a certain way repugnant to the proper determination of natural agents, for it is proper to them to be determined to one thing; how, then, can they have indifference of themselves? Nor is it enough if it be said that they are determined to one according to some common notion; for in this way the free agent too is determined to one, namely to good in general. But if it be said that the natural agent is determined to one in species, but not in the individual, first, from this at most there is found in these agents the indifference indicated in the last example, not that which is signified in the others. And still it can be objected against that, because this very thing seems to be beyond the fitting institution of nature, namely, that these agents should be founded with some indifference and that they themselves cannot determine themselves; for in this way they would be of themselves most inept for acting. Moreover, in the first four examples, so far as they contain some truth, the lack of action does not seem to arise from indifference, but from some impediment or the defect of some necessary condition from those posited above. For example, in the first example it is very probable to me that the fire in that case would not be moved from within. The reason, however, arises from the equal activity and resistance of all the parts; but among the conditions required for acting of necessity, one was that equal power not resist the action; but in that case all the parts of the fire equally incline to motion upward in a straight line with respect to each, and so they have among themselves equal activity and resistance, and thence it comes about that none is moved. Nor indeed are they wholly divided among themselves by those as it were contrary propensities. First, because they are more inclined to their conservation than to their place. Secondly, because the division itself would have to take place through local motion; hence, by the very fact that they cannot be moved, neither can they be divided.

7. Why perfectly flat glass, struck by a flat rock, is to be broken.—The second example, in the first place, cannot happen naturally, because a perfectly flat thing cannot naturally fall equally firstly upon a flat thing, just as a flat thing cannot be equally separated from a flat thing, because it would be necessary either that there be a vacuum or that air fill that whole place in an instant. For thus, conversely, it follows that, if a flat thing falls equally upon a flat thing, either some part of the air goes out together in an instant, so that it passes through a remote space as quickly as a near one, or remains there penetratively, or certainly, if the air remains in between, those two flat things do not touch each other. It is necessary, therefore, that the falling flat thing touch according to one part before another; although about this very thing the same difficulty can arise, namely, why it falls and touches according to one part before another, if the flat thing is equal and of equal weight according to every part. On account of which either some extrinsic cause of this inequality must be sought, such bodies and such motion being posited—namely, that the medium is not equally divisible according to every part, or something of this kind. Or certainly, if none of these intervenes, it must be said that that flat thing which falls equally cannot exclude all the intermediate air, and for this cause does not touch the glass nor break it. The reason is that even the least particle of air, while it cannot be penetrated nor pass through some space all at once, resists any heavy thing falling, lest it be expelled from there; just as, conversely, no force however great can separate two flat things all at once according to every part, because air cannot enter all at once to fill the vacuum. And so in that case the effect does not follow, because there is a sufficient medium for impeding.

8. But if, pressing the difficulty, we grant either that the air goes out all at once or that that fall takes place through a vacuum, two likely things can be said. The first is that the rock would act naturally as much as it could, and so would not divide the glass, but would so compress it that it would corrupt it and change it into another nature, as we see happen in wheat ground by a mill; but that body which would arise from it could be continuous; for if it were divided into particles, as flour is, scarcely could a natural reason be given why some parts rather than others should be divided, except by reducing that variety or inequality in the effect to some inequality in the contact and in the alteration arising from it on account of the pores of the bodies themselves or on account of some other causes concurring there. Or certainly, if that contact were not enough for there to result from it an alteration sufficient to corrupt the glass, it is not unfitting, but necessary, to say that it would not be broken. The reason is that, while one body falls upon another, it does not break it except on account of some local motion unequally made in the parts of the broken body; for while one part of it is pressed down before another, which can neither resist on account of defect of power nor yield or bend on account of hardness, breaking takes place; but in the said case the glass could not be moved locally, because it is both equally touched and impelled according to every part, and is also resisted together and equally by the body placed beneath according to every part. Hence, if that were not equally flat or equally solid and yielded more easily according to some part, the glass would be broken according to that part. And so in that example the action never ceases on account of indifference, but on account of an impediment equally resisting.

9. Towards which of two equal and equally proposed objects a brute would be moved.—In the third example too it can easily be denied that that equality can naturally happen in all respects, because those objects cannot be equally considered and presented at once; or even if we grant that they are represented at once as equally lovable, we shall say that they are also loved at once, but that it is moved to attaining the one before the other, because motion towards that part is apprehended as easier on account of some circumstance. Finally, if we admit equal apprehension in all circumstances, both with respect to appetition and to execution, it seems it must be conceded that there is not in the appetite of the brute the faculty of determining itself to one rather than to the other, on account of the lack of freedom. Hence that indetermination does not come from indifference, but rather from natural necessity and determination in the mode of operating, and from the defect of a condition necessary for operating in that way; which defect comes from causes equal in their genus and mutually resisting each other. For, as we said, the sensitive appetite cannot operate except with sufficient proposal and motion of the object; but this is lacking in that case, because neither of those objects is apprehended absolutely as to be loved and pursued, as is necessary in order that the effect of the appetite follow necessarily. The reason, however, why that apprehension or judgement is not had in that case is that those objects mutually impede each other while in their mode of causing they move and resist equally. And so in that case too the conditions enumerated above are lacking.

10. Why an equivocal natural agent effects this rather than that effect.—In the fourth example we can deny, in the first place, that there is any natural cause which per se is equally indifferent to effecting contrary effects; rather Aristotle, as we shall see below, places the difference between free and natural powers in this, that the former are powers for opposites or contraries, but the latter by no means, but for one only of the opposites. Which is to be understood per se, and all other things being the same; for per accidens it happens that contrary effects follow from the effect of the same natural agent, as we declared above concerning antiperistasis. Likewise, from the diverse disposition of matter it happens that the same sun renders wax softer and hardens mud; and from the various concurrence of causes it also happens that the sun concurs to various or repugnant effects; yet it always acts with natural necessity and determination, all the causes concurring together being supposed. Indeed, so far as concerns itself, it always begins the action in the same way, by illuminating and heating; and then, according to the disposition of the patient or the concurrence of other causes, a proportioned effect follows with the same necessity. And in this sense Aristotle said, II De Gener., text 18, that a natural agent, the same and in the same way disposed (namely, in itself and with respect to others), is apt by nature always to do the same. Therefore on account of the power of acting contraries there is no indifference in natural causes either, because they can never by themselves alone effect contraries, but with others added, which being posited they of necessity make one or the other effect.

11. Whence any efficient effects this singular effect rather than that in the same species.—In the fifth example there is somewhat greater ambiguity about the indifference or determination of any natural cause to individual or singular effects. In which there is a not improbable opinion that, although the power of a natural cause, considered absolutely, is indifferent to many individuals by way of a superior cause sufficient for all of them, yet, applied in particular to this patient with these circumstances, it is naturally determined to effecting such a form in the individual; but when we say that a cause acts necessarily, all requisites being applied, the discourse is of all things in particular which are required for action. It is more probable, however, as I touched upon above, that this determination to the individual effect comes from the concurrence and definition of the first cause; which being posited, it must be said that this condition too is contained among the prerequisites for acting, according to what was explained by us. For the secondary cause needs the concurrence of the first determined to a particular effect; which concurrence being shown in first act, and all other requisites being added, such a cause is necessarily determined to such an effect in particular. And so in this way too no indifference intervenes here which is repugnant to the natural necessity of acting. Nor is this last indifference, as was objected, against the due institution of nature, that natural agents cannot determine themselves to individual effects unless the determination begins from the first cause. But this is a natural imperfection and need of such agents, and a certain subordination which they have to the first cause, on account of which they are reckoned as it were certain instruments of it; and therefore, just as they depend on it in operating, so also in the determination to operating this individual rather than another. Indeed, from this effect we rightly understand that the work of nature is the work of an intelligence; and that the effect, however necessary with respect to the particular cause, is free with respect to the universal. It is established, therefore, from all these that in natural causes there is no proper indifference which is repugnant to the necessity of acting, so as to prevent such a cause, all other concauses and the conditions required for operating being posited, from operating of necessity without any indifference whatever.

What causes act necessarily

12. Secondly, it must be said that all causes which operate without the use of reason, as such, operate with the aforesaid necessity. This is taken from Aristotle, bk. IX Metaph., c. 2, where he places this distinction between rational and irrational powers, that irrational powers are determined to one, while rational ones are indifferent to opposites. But what he understands by rational powers, and whether that mode of operating belongs to all of them, we shall see below; now we assert only that all faculties which wholly lack the use of reason exercise their operations with natural necessity. Which can also be confirmed by induction; for so it is established by experiment in all grades of things down to brute animals.

13. Whether the sensitive appetite of man acts freely or necessarily.—Only about the sensitive appetite of man could there be doubt, to which some attribute I know not what trace of freedom. Indeed there are those who extend this to the appetite of brutes, as we shall touch upon again below. But in that matter, which is disputed more at length in theology, the truth is that, if there is any participation of freedom in the sensitive appetite of man, it is there in so far as there is a participation of reason in the cogitative power of man. But if in the latter there is not true reasoning, as in truth there is not, neither in the former, taken per se, is there true freedom which excludes the necessity of operating, all requisites being posited. And so by this example the induction made is rather confirmed and as it were completed. Its reason, however, is that the adequate root of freedom is the use of reason, as we shall see below; and therefore the lack of the use of reason is also the adequate cause of the lack of freedom, and consequently of necessity in operating. But if we inquire into the intrinsic and as it were positive root of this mode of operating, there is none other than the very nature of such things or faculties, which from their nature have this determination in the mode of operating, because they are not so perfect that they could participate dominion over their operations. Likewise, because indifference in operating arises intrinsically and adequately from the amplitude of the rational faculty, as we shall declare below; but just as affirmation is the cause of affirmation, so negation of negation.

14. From which, finally, it may be inferred that necessity of this kind is so great that it cannot be taken away, or impeded from going forth into act, not only by the intrinsic power of the faculty itself, but also by any other natural causes whatever. Natural causes can indeed, as we said, impede one another by resistance or contrary action; and so they can also take away all the requisites for operating; yet, these being posited, they cannot restrain the action of a necessary agent, because they cannot change the natures of things nor wholly take away intrinsic properties. God alone seems to have this power; for through it He brought it about that fire did not burn the three children, and similar things; yet, if the matter is attentively weighed, even God Himself does not seem able to make a cause which by its nature acts necessarily cease from acting in the composite sense (as they call it), all the requisites for action being posited; but He can only take away some one of the requisites, and so simply, or in the divided sense, can make such a cause not operate; as in the said example God impeded the action of the fire by denying His concurrence to the fire, that is, by not applying His power to operate with the fire; but this is one of the prerequisites in order that fire may act. God, therefore, did not bring it about that fire did not act, all the requisites being posited, but He took away one of them. For if God had determined to give concurrence so far as concerns Himself and to leave the other required conditions intact, He could not impede that action, because it implies a contradiction to take away what is natural without any contrary efficiency, or at least without the denial of help or of efficiency necessary on the part of God. For how can a natural action be impeded with no impediment posited? Or what other impediment can be understood, if none of the aforesaid intervenes? Thus, the said supposition being made, as it has been declared, the action arises with so great a necessity that it cannot be impeded except by taking away some part of the supposition. The difference, however, between God and other created agents is in this, that, all things being posited which are required outside God for the actions of natural agents, He can by His will alone impede the action by denying what is necessary on His part; but other created things cannot do this, but only by opposite action or resistance, or certainly because by some local motion they can place some impediment or take away the matter or another necessary condition. And so it is sufficiently established what and how great this necessity is.