Disputationes metaphysicae

1. The order of sequence between this and the preceding disputation.—We have compared several causes to one effect; now conversely we compare one cause to several effects. And because in contrary effects there is a peculiar difficulty, we shall speak chiefly of them, and most of all because Aristotle, treating of causes, made peculiar mention of this matter, saying that the same thing can be the cause of contraries. But the question can be treated of several effects either at once or successively. And because in the material, formal and final cause the matter is easy, we shall speak of them first, afterwards of the efficient. Although, as regards contrary effects, we can take of all without disputation that one cause cannot cause contrary effects at once, because they include repugnance, if they are taken with respect to the same, as they ought to be taken; for if they are taken with respect to diverse things, they are no longer taken as contraries. For although the sun at the same time dries mud and melts wax, it will not properly make contrary effects.

The question is dispatched in the formal cause

2. These things being supposed, of the formal cause it must be said that one cause cannot cause except one effect; hence a fortiori it comes about that it can never confer contrary effects. It is proved, because in the first place this cause does not cause except by offering itself to the effect; but it itself is only one entity; therefore from this side that which it causes and which it offers to the effect is always one and the same. Again, the formal cause causes the effect by giving complement in its being; therefore from this side too one formal cause always causes only one effect. And it can be confirmed by induction, both in any individual cause one in number, and in that which is one in genus or species; for the former always constitutes the same effect in number, the latter the same in species or genus.

3. But an instance can be made of the rational soul; for in the others, which depend on a subject and therefore are not changed from subject to subject, there is no difficulty; but the rational soul, the same in number, is united gradually to diverse matter; therefore it already has various effects, either inasmuch as it conserves various matters or inasmuch as with them it composes diverse composites. Another instance can be that one form according to species gives to the effect specific and generic unity, while it does not participate that genus, as is evident in the same rational soul, which gives to man to be animal, while it itself is not sensitive. Thirdly an instance can be made, for Aristotle said of the efficient cause that the same thing can be the cause of contraries, because, just as presence is the cause of conservation, so the absence of the same cause is the cause of corruption; therefore by parity of reasoning it must be said that light is the formal cause of contraries or opposites, because, just as the presence of light formally causes the luminous, so absence causes the dark.

4. To the first it must be answered, from what was said about the principle of individuation, that man, physically speaking, is always the same, nor can it happen consonantly with the natures of things that the same soul inform, even successively, wholly diverse matters. But if it informed them supernaturally, the effect would still be the same, although not wholly, yet it would be more the same than diverse in number. But we speak physically; nor are we treating of matter itself, which is improperly called the effect of the form, but of the composite itself, inasmuch as it is constituted through the form; of which matter many things are wont to be said by the theologians treating of the resurrection. Of the second argument too the philosophers say many things in the books On the Soul. Briefly, however, I say that the physical effect of one real form is one really and essentially. But if in the effect specific or generic grades are metaphysically distinguished, the same can be proportionally distinguished in the form, so that the form never constitutes an effect one in genus with the effects of other forms unless it too has proportional generic unity with those forms. Which is true also in the rational soul; for it does not constitute animal except inasmuch as it is the principle of sensing, in which genus it agrees with the souls of brutes, and under that notion it is truly a sensing soul. For it is not of the notion of the sensitive soul that it be material; or if that word is taken in this sense, that is not the form adequately constituting animal as such. To the third it is answered that the privation of the form is not the form itself, but rather the opposite, and therefore that it is no instance. But of that example of the efficient cause it will be said below.

Resolution of the question in the material cause

5. Of the material cause it must be said that one and the same can be in some way the cause of several and contrary effects, not at once, but successively. It is proved, for the same prime matter is the cause of the several forms which in succession of time succeed in it and of the composites which result from them. In which matter partly agrees with form, partly differs; it agrees indeed, because it too causes by giving itself to the composite. Hence from this side it always confers the same being on the effect, namely its own proper potential being, which is always the same, under whatever forms it exists; and therefore the effect is not diverse in the matter itself, but in the form. But matter differs from form, because it only begins and as it were offers the foundation of the effect to be consummated through the form, on account of which, even if prime matter in various effects is of the same species, nevertheless the effects are simply different by reason of the forms; and the forms themselves too, either according to their being, if they are material, or at least according to information, are properly effects of matter. And moreover matter, because it is a common subject, can underlie various forms successively, while yet the form cannot change matter, or successively inform several as such. And therefore the same matter in number can simply be the cause of several effects, successively indeed, but not at once, because it cannot receive several forms at once, at least total and adequate ones. But we are speaking of substantial matter and form, for if the discourse is extended to the material cause of accidents, the same thing can indeed at once be the material cause of several effects, because, as was said above, the same matter sustains quantity and the substantial form, and the same subject can at once sustain several accidents, as is per se known. But of which accidents this is to be understood, namely whether distinct in species, or genus, or number, was said above, disp. V.

6. And hence it is easily established how the same matter can successively be the cause of contrary effects; for we do not take contraries in all propriety, but as opposed termini in motion or generation are called contraries. So, then, matter successively is the cause both of the form and also of the opposed privation, in the way in which privation can have a cause; for the same matter is the cause of the generation and corruption of the thing. Hence it is also the cause of the forms succeeding one another in the same matter, which, inasmuch as they are formally repugnant among themselves, can in some way be called contrary. But the same subject of accidents will with greater propriety be called the material cause of contrary effects, because proper contraries are concerned with the same thing. Indeed a material cause of this kind can in a certain way be at once the cause of contrary effects, at least in remiss grades, although those as such are not truly contraries.

Reply to the question as to the final cause

7. Of the end it must be said that the same end can truly and properly be the cause in its genus both of several and of contrary effects; of several indeed both at once and successively; but of contrary ones only successively. All these are easily established from what was said above about the final cause, where we showed that there are several acts or actions of the agent which can be caused by the same end, namely the election of means, execution, and also the intention and love of the end itself. Which actions, either all or some of them, it is not repugnant to be made at once for the sake of the same end, since they are in some way subordinated among themselves. It is true that, compared to the end, they have in a certain way the notion of one adequate effect. Hence not only in voluntary but also in natural things it happens that several actions are made for the sake of the same end; for since the end of generation is the substantial form, for its sake is made not only the generation itself, but also the preceding alteration. Yet this is always true of an end in some way extrinsic, or which is not made through the action itself, for an end so intrinsic is naturally made only through one action.

8. And in a proportional way it is easily evident how the same end, namely an extrinsic one, can be the cause of contrary actions, not indeed at once, for that is repugnant, unless they are made in diverse subjects, by which reason they are not contrary. But in this it must be considered that it is one thing to speak of internal acts which are caused by the end in the will itself, another of external actions, which are means to attaining the end; for in the former the same end, if it is properly and formally the same, cannot be the cause of contrary effects which are truly contrary; for effects of this kind are contrary, love or hatred, joy and sadness, and similar; but the same end cannot move to love and hatred of itself, either at once or at the same time, and consequently neither to other contrary acts which follow upon these. But I said if the end is properly and formally the same, because, if it is taken only materially, the same thing which under one notion of good moves to love of itself can under some notion of evil move to hatred. I said also which are truly contrary, for the same end which moves to joy at its attainment moves to sadness at its loss, and so of others; yet that joy and sadness are not properly contrary, as sadness for sin and joy in a good work are not formally contrary; indeed rather one effect follows from the other, if the object is supposed. But about external actions themselves the same end formally and according to the same notion of good can move to contrary actions at diverse times, as from the affection for health we are aroused now to motion, now to rest; yet always those contraries fall under the causality of the end as they are in some way one, that is, inasmuch as they agree in the notion of useful good for attaining the end.

The question is treated in the efficient cause

9. Of the efficient cause the same general answer cannot be given, but a distinction is needed. First between free and natural cause, next between per se and per accidens cause, universal and particular; and judgement must be passed otherwise of the plurality of effects, otherwise of contrariety.

10. First, then, it must be said that every efficient cause, if it effects through proper causality, can successively effect several effects, yet not in the same way, for the particular and univocal cause can only effect several effects distinct in number, but the equivocal cause also effects diverse in species. The whole assertion can easily be shown by induction. But I said if it effects through proper causality, because, when there is efficiency through natural resultance alone, sometimes the cause is determined to only one effect in number, as this rational soul to this intellect or will in number; for no other powers distinct in number can naturally emanate from this soul. But it can be said that this comes from the fact that these powers can never naturally be separated from the soul; yet if in fact they were separated by divine power and no other impediment were posited, at once other powers would flow from the same soul; and so that active power is not of itself wholly defined to one effect in number. Which is probable, although it could be called into controversy, which does not matter to the present; for it is enough that a principle properly effecting is not of itself limited to one effect in number. And the reason is that in the first place it is not an intrinsic principle, nor does it confer its own proper real being, but another like itself, which it effects by its power; but after it has conferred such being on one effect, its power remains as whole as before, per se, as we speak; therefore, if matter capable of another form distinct in number is applied, it will equally be able to effect another effect. But if it is a cause which does not need matter for acting, much more will it be able to do this by its sole power and will.

11. And this reason is common to all causes, both univocal and equivocal. But univocal causes, inasmuch as they are such, are determined to one effect in species, because the notion of univocal cause consists in this, that it effect an effect like itself in the same species; for if it could also effect in another species, it would already be an equivocal cause. But the equivocal cause, since it is of a superior notion to the effect, can of itself be universal in causing several species of effects, and the more eminent and superior it is in power, the more it will be able to extend to several. But I say that the equivocal cause can have this universality, and does not necessarily have it, because I do not see why it is repugnant that there be given also an equivocal cause determined to one effect in species, so that on account of some eminence of its own, as, for example, because by its nature it is ingenerable and incorruptible, or on account of another similar cause, it cannot produce a univocal effect and wholly like itself in the lowest species, yet can effect some effect of an inferior order, yet only of one species, because in that order its power is too limited and among the lowest. For I find no repugnance in some equivocal cause being of this kind; but whether in fact one is given, or all extend to effects distinct in species, is uncertain to me.

12. Nor in this assertion does a difficulty of any moment occur, except that which was touched upon in the foregoing about the determination of the natural cause to one effect, if it is itself indifferent to several. For, since in natural causes that philosophical principle holds most true, The same, remaining the same, always does the same, which is taken from Aristotle, II De Generat., c. 10, it does not appear how the same natural agent, remaining the same, can be determined to various effects, even at diverse times, or certainly to one out of many at the same time. But to this it has already been answered in the foregoing that an agent of this kind is determined from the concurrence of other causes or circumstances, and cannot otherwise be determined by itself. But when it is said that the same remaining the same does the same, remaining the same is to be understood not only in itself, but also in concurrence and in the concauses and circumstances required for acting; which happens otherwise in the free agent, as was declared at length in the foregoing.

13. I say secondly: no efficient cause can at once effect several effects adequate to its power; yet it can effect several inadequate ones. The prior part is proved, because it is repugnant that an adequate effect be multiplied, for if it is adequate, it is equal (so to speak) to the power of the agent; therefore it is a clear repugnance that effects be adequate and be several; otherwise the thing would act beyond its power, and the power beyond its adequate object. Hence not even God Himself can at once effect several effects adequate to His power; yet He can effect several in any number whatever, even if one proceeds to infinity, because no effect or multitude of effects is adequate to His power. And by the same proportional reason a finite power can be so superior with respect to one effect only that it is not equalled as to the efficacy which it can exercise at once and at the same time; then, therefore, it will be able at once to effect several effects inadequate to its power up to that multitude which is adequate to the efficacy of the power; for a finite power will always have in this some terminus, because it is finite. And from this principle philosophers and theologians teach that a man, or even an angel, cannot understand at once several things as several, but can as one; which briefly has this sense, namely, by way of one adequate effect, of which elsewhere. But a difference can be noted as to this plurality of effects between free and natural agents; for the free agent per se and from its intention and freedom can be determined to several effects, if they can fall under its power; but the natural agent within the sphere of its activity acts naturally and in the same way; but because it happens that within that sphere there are distinct subjects, therefore from them it also effects several effects; in which way one fire can effect several heats in diverse subjects, if they are contained within the sphere of its activity.

14. Thirdly it must be said that only the free agent can per se and properly effect contrary effects, either successively in the same, or at once and disjunctively even in the same, or at once and conjunctively in diverse. This is taken from the Philosopher, IX Metaph., text 3, where in this sense he says that it is proper to rational powers to be able for opposites. And it is also established from what we said above about causes acting freely or naturally. And it is declared briefly, for these opposites can be taken either privatively or contrarily; which correspond to the two modes or parts of freedom, namely as to exercise or as to specification. In the former way, then, it is clear that only the free agent as such can be for opposites, per se speaking, that is, all the requisites for acting being posited; for it can both love and not love and in general operate and not operate. But the natural agent can only operate, if the requisites are present; but if they are not present, it can only not operate; and therefore it is only per accidens said to be able for opposites of this kind, namely from the defect of some thing necessary for operating. Which difference Aristotle taught, IX Metaph., c. 9, in these very brief words: All the powers which are according to reason are powers of contradiction, namely per se and by their own power; hence he adds: But the irrational ones, by the very fact that they are present and absent, will be of contradiction the same, that is, because either they themselves can be applied and not applied, or the matter necessary or other things required for acting. Which place of Aristotle is worthy of note, for from it is plainly gathered the definition of the free faculty expounded above by us. Hence the free agent is said to be the cause not only of its operation, but also of the lack of operation, when it has it freely, because namely not from defect, but from its power, which it has for suspending its action, it is the cause of such lack of action. Nor is it necessary that this causality be through positive and real influx, but through the suspension of influx from the power of the cause itself, for causality must be proportioned to the effect; since, therefore, the effect is privative, it ought not to be caused through positive influx, but through suspension of influx, which is in the power of the cause itself; but the natural cause cannot so properly be said to cause the privation of its operation, because in truth that privation does not come from its power, but rather from impotence or from another defect.

15. And in this way I think is to be understood what Aristotle says of the pilot of a ship, that the same is the cause of contraries; because, just as his presence is the cause of conservation, so his absence is the cause of the sinking of the ship itself. For it is not to be understood of the sole absence and presence of the pilot of the ship, for in this way the same would not be assigned as cause of contraries, but contrary causes of contrary effects; because absence and presence are contrary among themselves, as are the conservation and sinking of the ship; it is to be understood, then, of the pilot himself, who both through presence is the cause of conservation and through absence is said to be the cause of the sinking of the ship. Which can be true in so far as the pilot himself is the cause of his absence, as also of his presence, for if he were not the cause of his absence, he would not be reckoned the cause of the loss or sinking which followed thence. But it is to be noted that that causality which is said to be through absence, if it is considered with respect to the privation or lack of action, such as is not to defend or not to govern the ship, can be per se causality, even physical, in the way in which it can intervene between privations, because there is a per se order of one to the other. But with respect to the positive effect which followed thence, such as is the sinking of the ship, that is only a cause per accidens, physically speaking, for the per se causes are the winds, etc. But morally the pilot will be called a per se cause, if he could and was bound to be present and govern the ship, as is treated more at length in moral science. Wherefore that mode of attributing contrary effects to the same cause present or absent, properly and per se speaking, has place only in moral causes; for the sun will not so properly be said to cause darkness by its absence, because it is not the cause of its own absence; hence, although darkness follows from absence, yet not from the causality of the sun, but of him who was the cause of that absence.

16. In the latter way contrariety is properly between positive effects or repugnant forms; and in this way too the free agent per se and by its own power and all the requisites for acting being posited can effect contrary effects, either by eliciting them through the free power, in which way it can either love or hate, or by commanding them, in which way a man can either assent or dissent to the same thing proposed, and the physician (which is the example of Aristotle) can by the same art of medicine heal the sick man or kill him. And so it can effect contraries in those three ways posited above, namely, either successively about the same, for it can now love, afterwards hate the same thing; or for the same instant and about the same, yet not conjointly, but dividedly, because it can in the same instant exercise either love or hatred; but both at once is repugnant; hence conjointly and for the same instant it can do this only about diverse things, as the physician can at once apply to one a salutary remedy, to another a harmful one. So, then, the free cause per se and by its own power can operate contrary acts or effects. But it is otherwise in the cause acting naturally, because it is by its nature determined to one, and therefore per se cannot effect contraries. And although sometimes contrary effects seem to proceed from the same natural cause on account of its eminent power, yet either they are not made about the same and disposed in the same way, but about diverse things diversely affected, and so they are not made properly as they are contrary, in which way the sun dries mud and melts wax; or one is made per se and the other per accidens, as we said in the foregoing of the effect through antiperistasis; or certainly such cause does not by itself alone effect each of the contraries, but with other causes and dispositions concurring; for so the sun concurs to various and repugnant forms in these lower things; of almost all which we spoke in the foregoing, and of the special difficulty which seems to be in the motion of the heart it was said in disputation XVIII.

17. Only against the prior part it can be objected that Aristotle, IX Metaph., text 3, signifies that even rational powers cannot per se be for each of contraries, but for one per se, and for the other per accidens. But, as we noted there, that per se and per accidens are not there taken in that signification in which they distinguish the cause beside intention and beside the proper influx and operating power from the per se cause, but as they distinguish the primary and secondary inclination of the operating power; and the will will be said in this way to love per se, but to hate per accidens, not because it does not per se and by proper influx elicit the act of hatred, but because pursuit belongs per se primo to the appetitive power, but flight consequently and as it were per accidens, that is, by reason of another.