Disputationes metaphysicae

1. The reason for doubting for the negative part.—The reason for doubting is that the cause, as was said above, is prior to the effect, and consequently the effect posterior to the cause; therefore that which is the effect cannot be the cause of its cause; otherwise either it would be at once prior and posterior, or not every cause would be prior to its effect. Nor will it satisfy if someone answers that it is not repugnant that the same thing be prior and posterior to another only in nature and according to diverse notions, for the priority of nature which is required in the cause with respect to the effect is not only priority according to one or another consideration, but is absolute priority, which can be called priority of presupposition, inasmuch as, absolutely speaking, being must be presupposed in the cause in order that it can cause. Hence it can be concluded thus: in the cause being is absolutely supposed to the being of the effect, for the effect does not have being except by means of causality, and to causality being in the cause is simply supposed; therefore to the being of the effect being in the cause is simply supposed; therefore the cause simply and in every notion must be prior in nature to the effect, for priority of nature seems to be nothing else than a certain priority of presupposition; therefore it cannot happen that the cause be the effect of its cause.

2. Reasons for the affirmative part.—On the contrary, however, is that Aristotle, treating of causes, taught that axiom, which has been received by the other philosophers. Wherefore we do not so much investigate whether this is true as in what sense it is to be understood; which we shall perform better by comparing the single causes among themselves, for, speaking in general, it is neither necessary nor possible that all causes be causes of each other, whether they are compared according to diverse genera or within the same genus, because in the first place not all causes have a cause, as is established of the first efficient cause and the ultimate end. Next, although some cause, an efficient for example, has a cause, yet it does not have a cause caused by itself, nor yet does it always have a material or formal cause. That axiom, then, ought not to be understood universally, but indefinitely or non-repugnantly, namely, because it is not repugnant that some causes be causes of each other, or certainly that in some it is even necessary, and therefore it remains to be seen in which it is not repugnant or is necessary.

The sense of the question is expounded

3. But it is to be noted that causes can be understood to be causes of each other in two ways: first, only formally (so to speak), or according to the general notions of the causes; secondly, in particular and according to the same things causing and caused. The former sense is easy and without difficulty, but is not chiefly intended at present, because in it it is only asserted that the efficient cause, for example, can have a material cause, and conversely that the material cause can have an efficient cause, and so of the others, which is manifest in all genera, for both matter is effected and many efficient causes are things caused by matter, and inasmuch as they are actually causes, their causality too is caused by matter. Nor in this sense does the difficulty touched upon above proceed, because the same thing is not compared in the notion of cause and of caused, but one thing is compared to another as to its effect in some genus of cause, but to another as to its cause in another genus, which genus of cause is participated by the effect of the other; but in this way there is no drawback that some material cause be posterior to some efficient cause by which it is made and prior to another which it causes materially. The causes, then, must be compared in the individual and in the same things. Again, among these very things the comparison can be understood either according to the same or according to diverse things; according to the same, as if one is the cause of the being of the other and in turn is caused by it as to its being, for, since each cause causes through its being, if according to that it is also caused by its effect, such things, both the same and according to the same, will be causes of each other; but according to diverse things they will be, if one is the cause of the other according to its being, but the other is the cause of the other only according to causality towards some other superadded perfection, all which will be more clearly evident by examples from what follows.

How matter and form are causes of each other

4. I say, then, first: matter and form are causes of each other and in some way according to the same, yet not wholly. This assertion is declared first in prime matter and material substantial forms, of which it is certain that they are caused by matter both as to their being, because they are made from it and are sustained in it, and as to their causality, because their information depends in the same way on matter. But conversely the form too is the cause of matter in its genus, because it informs and actuates it and because without that information matter cannot naturally be. In which it is to be considered that two things are contained in this causality of the form about matter: one is that the form perfects matter itself by informing it; the other is that, by means of this information, matter retains its being. As to the former, they are causes of each other, yet not according to the same, because that perfection which the form formally offers to matter is something distinct from the very being of matter, because it is not other than the form itself or its information, hence under this notion the form is not so much the cause of matter absolutely and simply as of informed matter. And so matter is the cause of the form simply and according to its being, but the form is the cause of matter only inasmuch as it is formed, and according to this notion we say that matter and form are not causes of each other according to the same.

5. But according to the other thing which matter has through the form, they can be said to be caused and to cause each other according to the same, for matter through its being causes the form, and in the same it can be said to be caused by it inasmuch as it cannot have it without it, for this is the sign of dependence and causality of something. Yet, if what we said above about these causes is true, in this quasi-circle there is not wholly the same propriety and likeness, for matter through its being directly and per se causes the very being of the form, so that in no notion should or can the being of the form be understood as something presupposed to the influx of matter, but as caused by it. But conversely the being of matter is simply to be conceived as presupposed to the being of such form, because it is the principle of the material influx itself, without which such form is not made; so much so that its natural effecting, if conceived according to its proper notion, cannot be so prescinded as not to presuppose matter, because it is essentially eduction from the potency of matter. The being of matter, then, depends on the form only as on a condition and superadded actuality, without which it cannot naturally be, which is called by many (as I noted above) dependence a posteriori and not a priori. For this cause, then, I said that, although this mutual causality is in some way according to the same, yet not wholly, because namely directly and immediately it is according to diverse things, but consequently it is terminated in some way at the same, inasmuch as the very being of matter depends in some way on the form.

6. The assertion is explained in prime matter and the rational soul.—And according to these the conclusion is easily explained in matter and the subsisting substantial form; for that form is not caused by matter according to its being, but only according to information; but it is the cause of matter in the same way as the other substantial forms, and so in that mutual causality there is in a certain way less difficulty. Between subject and accident likewise that mutual causality intervenes in a proportional way, for the subject is the material cause of the accident and most properly causes its becoming and being, because it sustains it; but the accident is not properly the cause of the subject according to its being, yet it is in some way a cause actuating and perfecting it, which is rather to be the formal cause of that being which it confers on the subject than of the subject itself. But sometimes this causality redounds in some way to the subject itself, namely when there is such connection between subject and accident that the subject cannot naturally remain without such accident or disposition, and then in some way such causality can be called mutual according to the same being of the subject; but that is not so much causality properly and dependence a priori as a certain condition necessary according to the natural order, as has often been said.

How the end and the efficient are causes of each other

7. I say secondly: the end and the efficient are causes of each other not only according to diverse things, but also according to the same. This assertion as to the first part is Aristotle's, V Metaph., c. 2, and bk. II Phys., c. 3, where he does not apply examples of this mutual causality except between end and efficient. But it is commonly expounded according to diverse things, namely, that the end is the cause of the efficient as to its causality, but the efficient the cause of the end as to its being. So almost St. Thomas on Aristotle; and Alexander of Hales, on the Metaphysics; and Albert, II Phys., tract. II, c. 6; but I do not think it wholly to be excluded that in some way these two causes are causes of each other also according to the same, as will be established from what we shall say. Now the common opinion is easily declared as to what it affirms. For the end which the agent has in acting is not the cause of its being, for it supposes being in it in order that it can both act and be metaphorically moved by the end to act, if it is capable of such motion. But that the end is the cause of the efficient as to causality is evident, because it arouses and moves the efficient cause to act. But that conversely the end is the effect of the agent according to its being is evident, because the same form which moves the agent to act is the terminus of its action. Finally, the a priori reason is that the end, in order to cause, does not require actual existence, but only being in apprehension, and therefore, before it is in reality, it can move the agent in its genus to act and in turn can receive existence from it through true efficiency.

8. Some objections against the resolution about the efficient and the end.—But it is objected, first, against each part. First, because the end in no way confers on the efficient that it be that whence motion first proceeds, but it has this from itself or from other prior causes; therefore the end is not the cause of the efficient as to causality. Secondly, for otherwise it follows that God, inasmuch as He is efficient, is caused by the end, which can in no way be said. Thirdly, conversely, the end seems to be the cause of the efficient not only as to causality, but also as to being, as is evident in the example of Aristotle; for to labour or to walk is the effective cause of health; but it is caused by health in the genus of end; and it is caused not only as to causality, but also as to being; for the very being of walking or its becoming (which in it is the same) is for the sake of health. Fourthly, it also seems false that the end is from the efficient as to its being, for the end of the operator is the agent itself, which cannot be from itself effectively.

9. On account of the first objection some deny universally that the end is the cause of the efficient as to causality; indeed in all causes they deny that they are causes of each other as to causality, because neither does matter have from the form that it sustains the form, nor the form from matter that it informs. But I fear there is an equivocation in these terms; for we can speak either of causality in first act or in second act. When, then, it is said that one cause is the cause of another as to its causality, the discourse properly and per se is of causality in second act; but the arguments proceed of first act. For so it is true that matter does not have from the form to sustain, that is, that power which it has for sustaining the form, and conversely that the form does not have from matter the power which it has for informing. Although this latter is not universally true, but only in the rational soul, for the other forms, as they have their being dependently on matter, so also all their power and substantial aptitude, as is sufficiently established per se. Hence, if conversely matter too is said to have its being from the form, it must be confessed that it also has from it the power of sustaining the form; but we do not so speak, because we do not think that, properly speaking, matter properly has its peculiar being from the form, but has it dependently on the form as on a posterior condition, as has often been declared. But as to actual causality it is false that matter and form are not causes of each other, for both matter is in its genus the cause of the actual information of the form, because the form cannot inform unless matter materially causes the very information of the form; and conversely matter similarly cannot actually sustain the form unless the same form causes in its genus the very sustaining of matter, whatever that may be. Hence, the thing itself being regarded, this mutual causality in causing is nothing else than the mutual concurrence of each cause to their proper causalities.

10. So, then, it is easily established how the end is the cause of the efficient cause as to its causality, whatever be the case about the power of causing, of which I shall speak below. The end, then, is a cause alluring the power of the agent to cause, and consequently in its genus inflowing into its actual causality. From which I further gather that the efficient cause too can be called in its genus the cause of the end as to actual causality. For, although the power of causing of the end, as it precedes in intention, is not from the efficient itself, yet the actual causality of the end cannot be without the efficiency of the agent, as was demonstrated above; and therefore, just as the efficient cause is constituted in second act with the end concurring, for the sake of which it causes, and for this reason is said to be caused by the end as to its causality, so conversely the final cause is not constituted in second act unless the efficient cause concurs in its genus to its causality; therefore they have in this mutual causality among themselves in their genera, as matter and form among themselves. And as to this part, first of all, what I said in the conclusion holds true, that the end and the efficient are mutually causes to each other not only according to diverse things, but also according to the same.

11. The second.—To the second it can be answered, first, that the conclusion posited need not be understood universally of every end and of every efficient. For what we noted at the beginning, that the proposition of Aristotle is not universal of all causes, can be applied also to the present conclusion, because, as we shall at once say, not every efficient gives being to the end for the sake of which it operates, and in a similar way not every agent is moved by the end to operate through the proper causality of the end. But secondly it is said, speaking of God as of the efficient, not as to the power of effecting nor as to the internal will of causing, but as to His actual and transient causality, that it is true that this causality by which God is denominated actually efficient is caused by God Himself as end, for this causality of God is nothing else than His action passing from Him and received in the creature, which is also truly caused by God Himself as end, as was seen in the foregoing. And so in God too it is true that He is not constituted actually acting except with Himself concurring as end to His causality, and conversely that He is not constituted actually end except with Himself concurring actively to His final causality.

12. To the third, the whole which it intends must be granted; for there is some efficient cause which has its whole being from the end in the genus of final cause, which it causes and for the sake of which it causes. Which can be shown not only by the example of Aristotle, but also by others; for the end of the intellect, for example, is to understand; indeed universally a created power or agent is said to be for the sake of operation; therefore in the genus of end the intellect is caused by understanding, not only as to causality but also as to being, for it is made and is for the sake of intellection. And hence it is also understood that sometimes the end is the cause of the agent, not only as to actual causality in second act, but also as to the power of causing in first act, as, for example, health is the final cause of rhubarb, not only as actually expelling or applied to expelling choler, but also as to the very innate power which it has for that effect, for for the sake of this end it received it from the author of nature, that it might cause health. And this second is gathered a fortiori from the first, as I said above in a similar case; for if the very being of the thing which is the efficient cause is caused finally by its own effect, much more the effective power for causing, which follows upon the being itself, can be caused by the same end. And in this too is verified what we said in the conclusion, that the end and the efficient can be causes of each other according to the same, for both the end in its genus causes the efficient as to its being, and the efficient in its own causes the end as to its real being. And the reason is the same which was touched upon above, because the end, in order to cause, is not supposed to be according to real being, and therefore, if it is supposed apprehended in an efficient cause, another efficient cause of the end itself, it can finally move it or concur finally with it to giving being to the thing from which afterwards the same end according to real existence proceeds, and so the house in the mind of the artificer is the final cause of fabricating the saw, for example, by which saw the house itself is afterwards efficiently made.

13. Wherefore, when grave authors say that the end and the efficient are mutually causes to each other according to diverse things, they are to be expounded as having explained that which more per se belongs to these causes and more formally as actually causing, not as having excluded every other mode of mutual causality which can be had between these causes. Thus it is specially attributed to the end that it is the cause of the agent as to actual causality or action, because this is always and per se necessary, because every action is in some way for the sake of an end; but that it is the cause of the very being of the agent is not so per se or necessary, although it often so happens. And although the agent too concurs to the causality of the end, as we have declared, yet this is attributed more to the end, because it is first in moving and inflowing to the causality of the agent, as was also declared above. But conversely the efficient is said to cause the end according to its being, because this belongs to it per se and always, because it cannot operate for the sake of the end unless it in some way effects the end itself.

14. But this (that we may now answer the fourth objection) is to be understood of the end of which, or also of the end by which or formal end, which is the attainment of the objective end. For the end to which is not made by the efficient, as that fourth objection rightly proves; nor yet is the objective end made, but obtained; but the end of which is the intrinsic terminus to which the action of the agent tends and at which it is terminated, and therefore per se and according to its being it is the effect of the agent. And similarly, when a good is loved or desired not in order to be made, but in order to be possessed, the very attainment or possession of the end is made by the agent itself, because the whole intention and application of means tends to it; and then in that series it is a certain end for the sake of which and on account of which the operation is made.

How matter and the end are causes of each other

15. Thirdly it must be said that the end and matter can mutually be causes to each other. It is proved, because Aristotle says that form and end coincide in the same in number; but the form is not only the end of generation but also of matter itself, because matter by its nature is for the sake of form as for the sake of the end, and at the same time also is for the sake of the composite, because these two are not repugnant, but subordinated. Matter, then, is the effect of form and of the composite in the genus of final cause; but the same matter is the material cause of the form and of the composite; therefore there is reciprocity between these two causes in the notion of cause and caused. Which indeed is general on the part of matter, but not on the part of the end, but then only when the end is such that it consists of matter or depends on it; for all matter is ordered to some form or composite as to an end, and therefore in any matter whatever with respect to such the said mutual causality always intervenes; but not every end consists of matter or depends on it, as is known per se; and therefore on its part that reciprocity cannot be universal. And this assertion being so explained, no difficulty remains in it, and its foundation is the same which was touched upon above, because the end, in order to cause, does not suppose to pre-exist really, and therefore it can be the cause of its matter, although it is really caused by it in its genus.

Mutual causality between form and end is excluded

16. I say fourthly: form and end, properly and per se speaking, can never be causes of each other. I speak of the form as it exercises the genus of formal cause, and therefore I said properly and per se speaking; for sometimes it happens that one form, which is the effect of another in the genus of final cause, is the cause of the same form which is the end; yet it is never its formal cause, but either efficient or material. As the light of glory is the effect of the beatific vision in the genus of final cause, and is also its cause, not formal, but efficient; and the intellect too is the effect of the same vision in the genus of end, because it is made for its sake, and is its cause both material and efficient, but formal it cannot be. And the reason of the conclusion is that either the form is considered as it is the end of generation, or as it is ordered to another form or operation as to an end. In the former way form and end fall into the same in number, and therefore that form cannot be the formal cause of that end, because it cannot be the formal cause of itself; which is otherwise in final causality; for the same form, as preceding in intention, is the cause of itself in execution according to final causality, which does not require pre-existence in reality. But in the genus of formal cause the form cannot cause itself, but the composite, because its causality consists in composition and union with matter.

17. But in order that the conclusion as to this part be free of all difficulty, it is to be understood of the form compared to its proper effect, which is the composite, which I say because, if it is compared to the union itself or actual information, in truth in the genus of end it is its effect, for the form is in order to inform, and for the sake of this end it is made, and yet the information itself is from the form in the genus of formal cause; yet it is not so properly its effect as its causality; but if the union itself or information too is called the effect of the form in the genus of formal cause, as to such effect the posited conclusion is to be limited on account of the special connection which it has with the form itself, as it exercises the notion of form. For, just as the efficient is for the sake of operation, and therefore between them there is mutual causality, for, just as¹ operation is the final cause of the active power and the power is the efficient cause of operation, so the form, for the sake of information and in its genus, is its cause. But comparing the form as it is the end of generation to the same proper form as informing, the said mutual causality cannot intervene, because it is one and wholly the same form.

18. But if we compare two forms of which one is ordered to the other as to an end, the mutual causality cannot intervene either, because one form cannot be the formal cause of another inasmuch as it too is a form; for if it happens that one form is informed by another accidental one, it is necessary that that which is informed exercise under that notion material causality, not formal. I know that some so speak as to say that immanent acts depend on the soul or on the vital power in the genus of formal cause, while yet the immanent acts themselves are accidental formal causes; and similarly it is wont to be said that the passions or powers of the soul depend on it in the genus of formal cause, while yet they inform it. But these expressions are improper, for neither acts nor powers depend on the form except either materially or effectively; but because that efficiency is very intrinsic or through natural resultance, it is wont to be called a secondary effect of the form, yet properly and in rigour it does not pertain to the formal effect.

Mutual causality of the efficient cause with respect to the material and formal is excluded

19. I say fifthly: the efficient cause cannot have mutual causality with matter or form, but only with the final cause, as we have already explained. The sense of the conclusion is that, if some cause truly and properly effects some form, it cannot be caused by it in the genus of formal cause; and conversely, if some form formally constitutes some thing, it cannot be made by it effectively. And as to these two parts there is no difficulty in the conclusion posited. And the reason is, first, because the efficient cause is supposed absolutely existing for effecting; therefore it cannot be formally constituted through the form which it effects. The consequence is evident, because, if that thing is to be constituted in its being through the form, the form is already supposed constituted, because it is already supposed having being; therefore it cannot be formally constituted through a form made by itself. Secondly, because the form is the principle of acting; therefore the form which is the terminus of the action cannot be the formal cause of the agent itself; for by this reason Aristotle said, II Phys., c. 7, text 70, that the form which is made does not coincide in the same in number with the efficient, but in the same in species. But from these reasons it is easily gathered that the conclusion is to be understood of formal causality as to the proper being of the efficient cause itself, for if we speak of formal causality as to some other being superadded to the efficient itself, it can often happen that the form made by the efficient cause informs its cause, as love informs the will by which it is made, but does not inform it as to giving it that being through which it is caused by it; hence neither does it inform it as it is efficient, but as it can be subject and material cause.

20. In a similar way is the conclusion to be understood comparing the efficient cause to the material. For if some thing effects some matter, it cannot be caused materially by it; and conversely, if one thing causes another materially, it cannot be made by it effectively. And indeed, if the discourse is only of prime matter, the matter is most evident, because prime matter cannot be made except through creation, and therefore its cause is most remote from all dependence on matter; therefore it is impossible that whatever is caused from such matter be the efficient cause of matter, not only of the same in number, but of none at all; yet, extending the conclusion (as in truth it is to be understood) to every material or subjective cause, the general reason is that the efficient cause is supposed simply and absolutely existing for acting, and therefore, if it needs some cause or material causality in order to be, such cause is supposed before all its efficiency, and accordingly such a thing cannot be the efficient cause of its matter. And it is confirmed, for the material cause is intrinsic, if it is compared to the composite, or is intimately conjoined, if it is compared to the form; therefore, whether the thing which is called the efficient cause is the composite or the form, it cannot effect the matter or subject on which it depends. The consequence is evident, because the intrinsic constitution or union of a thing is simply prior to its efficiency; likewise also because the intrinsic constitution cannot be effectively from the very thing which is constituted; nor can the intrinsic material union be effectively from the very form which is united, otherwise the very eduction of the form too could be effectively from the same form which is educed.

21. The ultimate disposition is not effectively from the form.—But against this part some instances are wont to be brought: one is about the form and the ultimate disposition; but of this many things were said in disp. XIII, on the material cause, where we showed it more probable that the ultimate disposition which truly prepares matter is not effectively from the form; but that which is effectively from the form does not prepare matter, nor participate material causality, but is a disposition adorning and as it were fostering and contributing to the union of the form with matter.

22. Whether the expulsion of one form is the material cause of the introduction of another.—Another instance is about the introduction of one form and the expulsion of another, for this expulsion is as it were the material cause of that. But this pertains more to mutual causality between matter and form than to the present; for the introduced form does not expel the other effectively, but formally, as was seen above; but if the discourse is of the form actively introducing another, with respect to it the expulsion of the form has no causality, but is only a secondary effect of that action. I add also that the expulsion of a form is improperly called the material cause of the introduction of another form; for it is rather the removal of a certain impediment, not so much antecedent as subsequent or concomitant, or, if there is some order or priority, it is more according to our consideration than according to true causality.

23. Whether the opening of a window has causality with respect to the entrance of light.—Another instance is wont to be about the opening of a window and the introduction of light, which seems more popular than philosophical, for the opening of the window is the removal of a certain impediment simply antecedent in the order of nature, because it is in no way the effect of the introduction of light. But if we feign that the window is opened by external wind pushing and entering, so the opening indeed is effectively from the pushing air, yet that air, as pushing and effecting, is in no way the effect of the opening itself in the genus of material cause, because the pushing air does not effect that motion of the window as already introduced into its place, but as touching it and impressing impetus on it, which it does prior in time or instant to its being introduced into its place and to the window itself being moved from its place; and so with respect to that efficiency there is no material causality in its effect. But if the air is considered as already occupying the place of the window which is opened, so it is not the effective cause of the opening, but formal, namely through the formal incompossibility of those two bodies in the same space. And according to this notion, if there is mutual causality between the opening of the window and the introduction of the air, it pertains to the material and formal, not to the efficient; and the same judgement is of it as of the introduction of one form and the expulsion of another. And so it is universally true that the efficient cause does not have mutual causality with its effect except in the genus of end; nor did Aristotle ever teach another. But at once here a difficulty occurs to the theologians about the ultimate disposition to grace, which we refer to them; but we think that according to these principles true judgement is to be passed about it.

How among causes of the same genus there can be reciprocal causality

24. In the same genus of cause none are simply causes of each other.—Finally it must be said that within the same genus of cause two things cannot be causes of each other simply and according to the same; but in a qualified sense and according to diverse, as it were specific, notions within the same genus of cause it is not repugnant. The prior part is the opinion of Aristotle, in the places cited, which all his interpreters too absolutely teach, and it can be proved by induction, for the thing which effects another cannot in turn be made by it, and so of the rest. But a proper reason can be given in each, for matter either does not have a material cause, as prime matter, or, if it has one, as second matter, the same thing which it composes or receives cannot be its matter. Because matter is compared as part or receptive potency to its effect and is supposed to it; but if it itself has a material cause, it is compared to it as whole to part, and in the order of generation or existing supposes it, and therefore there cannot be such a circle among material causes. Nor yet among formal ones, because the form does not have a formal cause, as we said above. In the final cause too the matter is manifest, because the final cause as such does not have a final cause; but if it has one inasmuch as it puts on some notion of means, it cannot be ordered to the same thing which is a means to it as to an end; otherwise in the same order of intention it would be prior and posterior, which is repugnant. In efficients too the reason is manifest, because the thing which effects another is supposed to be, and consequently made, if it needs effecting, and therefore it is impossible that it be made effectively by its effect. Which is always to be understood (which is also to be observed in ends) speaking of actual mutual causality which is at once; for, speaking only of the power of causing and dividedly, it is not repugnant that the thing which is now the end of another cease from that causality, and afterwards be ordered to the other as to an end from the freedom of the agent. And similarly it would not be repugnant that the thing which now effects another should be made by it, if the order of causing had been changed from the beginning, and the thing which is now made by one cause were not made by it, but by another; for then without drawback it could effect the same thing by which it is now made, as I treated above. But now we speak not dividedly, but conjointly, and so it is impossible that a thing be made by the effect which it makes.

25. Another general reason is wont to be handed down here, because otherwise the same thing would be the cause of itself, for what is the cause of the cause is the cause of the caused, which axiom holds in causes of the same genus, as all say, and Scotus specially noted, In IV, dist. 49, q. 2, and in the Theorems, 22nd universal conclusion. But not without reason someone can ask why that consecution holds in causes of the same genus, but not of diverse ones. Next someone can doubt, because it does not follow that something is the cause of itself per se, but only per accidens, as the grandfather is the cause of the grandson, which does not seem a great drawback. To the prior part I answer that the reason is that in diverse genera, by the very fact that the mode of causing is changed, the notion of being too is changed, which in the cause is supposed to the effect. And consequently that which is the cause of its cause is not its cause according to that which it has from its cause, but according to another; as, although the end is the cause of its efficient, it is not its cause according to the exercised being of existence, which it has from it, but as apprehended. But if in the same genus two things mutually effected each other, both according to the same order one would be supposed to the other and conversely, which is repugnant, and one would cause the other according to that very being which it has from it, and conversely, and therefore by power it would cause itself. Hence to the other part it is answered that that cause is called per accidens because it does not immediately inflow into the mediate effect; yet it is the per se cause of its immediate effect, in which the other effect is contained virtually, and per se flows from it, and therefore it is equally repugnant that something be in this way the cause of itself as if per se and immediately it effected itself.

26. Lighter objections against the aforesaid are solved.—Other lighter objections are wont to be made against this conclusion, because in all genera of causes it seems to suffer cavil; in the efficient, because two hands, if they are warm and touch each other at the same time, mutually foster and conserve each other; but if they are cold, by rubbing they mutually warm each other. In dispositions which pertain to the material cause, heat truly disposes to rarity and rarity to heat. In ends, the power is for the sake of operation, and operation for the sake of the power. In formal ones, finally, although physically that vicissitude is not found, yet it is found metaphysically, while one difference contracts another and in turn can be contracted by it, for mortal contracts rational or intellectual broadly taken, as if man is called a living, intellectual, mortal thing; and conversely rational contracts mortal.

27. How hands rubbing each other mutually warm each other.—It is answered, however, to the first that two hands, if they are equally warm, do not conserve each other by mutually acting, but by more strongly resisting or overcoming the contrary. But if they are cold, they do not warm each other per se, but per accidens by means of motion, and then one does not act on the other inasmuch as it receives heat by means of the rubbing of the other, but by the force of moving and touching which it has, and in this way it is no drawback that two things mutually act upon themselves, if they act per se through their proper powers and not through that which they receive from each other, as the stomach warms the wine by formal and innate heat, and the wine warms the stomach by virtual heat which it has of itself, and in this way it is not repugnant that two things mutually effect in each other; yet that is not according to the proper being through which they cause, and so, formally speaking, the cause is not made by its effect, which we say is repugnant.

28. Whether two forms are mutual dispositions to each other.—To the second instance it is answered, first of all, that the dispositive cause is not properly a material cause, but in a qualified sense and reductively, hence that is not so much mutual material causality as a certain mutual concord or proportion between two forms existing in the same subject; in which there is no repugnance. Next it is said that these dispositions are always in some way of diverse notions; as in the example posited of heat and rarity, heat seems to be not only a disposition, but also in some way efficient, and then rarity is not so much a preparing disposition as a consequent one, which does not have the proper notion of cause. And we said many similar things of these causes above, disp. XIII, sect. 3.

29. Two partial ends are final causes of each other.—Finally, of this connection of dispositions the latter part of the conclusion can be understood. But it was posited chiefly on account of the third instance, to which we grant that according to diverse notions of ends it is not repugnant that two be ends of each other, as the argument proves; yet that is only in a qualified sense, for those are as it were partial ends, from which one integral end coalesces, which wholly falls under one adequate intention; yet for that sort of mutual relation it is necessary that those ends be in their genus in some way of diverse notions. To the fourth it is answered that here we treat of proper and real causes; but differences are not of this kind, but only according to reason, and even in that way differences do not contract each other per se, but at most inasmuch as they are conjoined in one common genus.

The reason for doubting posited at the beginning is satisfied

30. Finally, from what has been said the reason for doubting posited at the beginning remains dispatched. For if anyone attentively considers what we have said, two causes are never so mutually compared that one simply supposes the other in existing, and conversely, even in the order of nature, for the end, as it is the cause of the agent, is not necessarily supposed existing; but as it is the effect, it supposes the efficient cause as existing; the form likewise supposes matter, yet matter does not simply suppose the form, but only requires it as concomitant or consequent in the order of nature. And so the circle of prior and posterior in existing is easily avoided, even according to the order of nature. But in causing, according to diverse genera of causes, it has no drawback, because either one causality is such that it does not suppose existence, as happens in the end, or, if it requires existence, they are not mutually causes to each other according to being simply, and so, if in one cause being is supposed, according to that it is not properly the effect of the other, but according to something which is adjoined to it; as we declared in the form with respect to matter and in accidents with respect to the subject; and so all drawbacks in this mutual connection and causality of causes are easily avoided. And so far let these things be said about the causes of being and about the first principal part of this work.