Commentaria in Primam Partem Summae Theologiae

In the title, a doubt immediately arises from I Poster.¹ No science proves its own subject: and, as Averroes says in II Physic., comment. XXVI, neither from prior nor from posterior grounds; rather it supposes that being to be either per se known to sense or intellect, or it takes it from elsewhere. But in this science the subject is God, as was said in the first question². Therefore God's existence ought not be proved here. Against the art, then, this article is raised.

To this it is said that no science, speaking per se, proves that its subject exists: per accidens, however, it is not unfitting for some science to prove that its subject exists. And so it is in the case at hand: for a twofold accident occurs here, on account of which this science proves that God exists. The first is our imperfect participation in it. For if we participated fully in the divine light, it would at once be evident that God exists. The second is the condition of the medium, namely, that it is as it were foreign. For although no science proves its subject from what are simply its own proper principles, nevertheless from foreign but appropriated ones it can prove it, if those foreign things are better known to us than the esse of that subject. And so it happens in the case at hand: since theology, not from what is simply proper to it, but from what is proper to it ministerially—that is, from things known by natural light, which are absolutely foreign, as we have said³—proves that God exists; as is clear in the course of this question.

II. In the body there is one conclusion, answering the question in the affirmative, namely: God is. – And it is proposed for proof by five ways, which need not be set out here, since they are found both here, and in Book I of the Contra Gentiles, and in Question de Potentia, and in Question de Veritate, and in Book I of the Sentences⁴.

III. Concerning these arguments in general, it must be carefully noted that they can be brought forward for two purposes. First, to conclude to that incorporeal, immaterial, eternal, supreme, immutable, first, most perfect being, etc., which is what and of what kind we hold God to be. And in this way these arguments are highly disputable: because the first way, as is said in I Contra Gent., chapter XIII, does not lead to a mover more immobile than the intellectual soul; but the second, as Averroes says⁵, leads only to the heavenly body and its mover; nor does any of the rest seem to lead further upward. And it is not for this purpose that these arguments are adduced here, as will now now be evident. – In another way they can be brought forward to conclude that certain predicates are found in the nature of things which in truth are proper to God: without concerning themselves how or in what manner they exist, etc. And it is for this purpose that they are adduced here: and according to philosophy they have scarcely any difficulty.

And so that what we say may be better understood, it is explained point by point: of the first way, from the side of motion, it is enough that there be inferred therefore there is a first unmoved mover, without concerning ourselves whether that be the soul of the heavens or of the world; for this will be inquired into in the following question. Of the second way likewise, from the side of the efficient cause, it is enough that it lead to a first efficient cause, without concerning ourselves whether that be corporeal or incorporeal; for this will be inquired into in the following question. Of the third way indeed, from the side of the necessary being, it is enough that it lead to a first necessary being not from another, without concerning ourselves whether it be one or many; for this will be inquired into in question XI. Of the fourth way likewise, from the degrees of things, it is enough to lead to that which is being in the highest degree, true, good, noble, from which are all participations. And similarly of the fifth way, from governance, it is enough to lead to a first governor acting through intellect, whoever he may be. For all these predicates—namely, unmoved mover, first efficient cause, necessary being not from another, being in the highest degree, and first governor through understanding—are, according to truth, proper to God; and therefore, in concluding that these are found in the nature of things, it is concluded directly, as it were per accidens, that God exists, that is, God, not qua God, but as possessing such a condition, exists; and consequently the very subject itself, namely God qua God, exists.

From these considerations, however, it is clear that neither the arguments of Averroes⁶ against Avicenna, nor those of Aureol⁷ against these arguments, are directed against the intent of this article—except for the objection against the last one, and against the propositions assumed.

IV. Hence it must be known, secondly, that in the first argument, which is taken from Book VII⁸ and Book VIII of the Physics⁹, two propositions are attacked. One of them is that nothing moves itself in the first instance. Against this Scotus indeed argues, in the matter of heavy and light bodies, and of the will, etc.¹⁰ And since this would be to go beyond our limits, there will be a special question on this matter.

The second is, the first is the cause of the middle: for this is assumed both in the first and in the second and third argument, in order to prove that there is no infinite regress. And against it, although it is expressly Aristotle's in Book II of the Metaphysics¹¹ and Book VIII of the Physics¹², the argument runs thus, in substance. The middle cause, or mover, if it necessarily depends on the first cause, or mover, has this either because it is a middle, or because it is a cause, or because it is a middle cause: but it is none of these: therefore the middle cause need not depend on the first. – The assumption is evident from a sufficient distinction. The refutation of each member is proved. And first, that it is not from the notion of a middle. For a middle is said with respect to two things, namely on this side and on that, of which it is the middle: and not necessarily with respect to a first and a last, as is clear in the middle proportional parts of a circle. Second, that it is not from the notion of a cause. For a cause, as cause, is directed to its effect; and not to dependence on a prior or a first, as is clear. Third, that it is not from the composite notion, namely of a middle cause. For a middle cause, as such, requires nothing else than that it mediate in causing: but this, namely to mediate in causing, is sufficiently secured if between some prior cause and the effect there be some mediating causality: therefore the middle cause, from the notion by which it is a middle cause, does not require dependence on the first cause, but on a prior. And it is confirmed: because according to you, that conditional is true, that if causes proceeded to infinity, all causes would be middle causes. Therefore to the notion of a middle cause there is not required dependence on a first, but on a prior, with respect to which and to a posterior it is called a middle.

V. To this it is briefly answered that a mediate cause, precisely because it is a mediate cause, necessarily depends on the first cause. For the clarification of this point, one must recall that efficacy belongs to the very notion of a cause: unless a cause actually produces something, it cannot be called a cause in act, of which we are here speaking. For the efficacy of a cause consists in its actual causality; and therefore, unless that causality is completed, neither is there any cause in act, nor is any efficacy or efficiency preserved. It follows that, for the notion of cause to be preserved, its causality must be completed; and hence whatever is repugnant to the completion of some cause's causality is repugnant to that cause itself. Since, therefore, the mediate cause is truly a cause, it must possess its own complete causality.

Then thus. The complement of the causality of a mediate cause can in no way be without dependence on the first cause: therefore the mediate cause, insofar as it is a mediate cause, depends on the first. Therefore Aristotle says excellently, and it is found in the text, that the first is the cause of the mean. – The consequence is evident. And the antecedent is proved. If the first cause were removed, such that before every cause there were another cause, the causality of these causes essentially dependent would never be completed: therefore the complement of the mediates depends on the first. The conditional is clear: because an infinity of descent or ascent is repugnant to the complement. But the consequence is evident: because it is established that the complement of the mediate cause depends on some antecedent; and not on a prior merely, as is clear from the conditional; therefore on the first.

VI. To the objection on the contrary side, when it is said a mediate cause requires nothing except what it mediates in causing, this is granted; but when it is subjoined that this is preserved with respect to the prior cause, it is denied. For it is impossible that mediate causality be brought to completion unless it is sustained in the first cause: for if it depends upon infinitely many prior causes, it will never be able to be brought to completion.

For confirmation, it is denied that that conditional, namely if essentially ordered causes were infinite, all would be intermediate causes, is Aristotle's or ours simply speaking: rather, it is ad hominem, against those who posit infinity in causes of this kind. For among these it follows very well that, since all are posited as causes, and none is first, therefore they are intermediate. But according to the truth, from that antecedent, one proceeds to infinity in causes, there follows therefore no cause exists, as Aristotle and St. Thomas deduce: because it follows, therefore there is no first; therefore neither an intermediate; for the first is the cause of the intermediate, as has been proven ¹³.

VII. Concerning that proposition assumed in the fourth way, namely that which is most such in any genus is the cause of all the others which are of that genus, since it is attacked by Aureol¹⁴, note three terms. First, that it is one thing to be most such in some genus and another to be the first or most perfect species of a genus. Hence what is assumed here is not that the most perfect species is the cause of the rest: but that which is most such, etc. Second, that being a cause can be taken in the proposition in two ways: namely as properly an efficient cause, or as an exemplary cause. Here being a cause is assumed indeterminately: for it does not matter to the purpose by what causality the greatest being, good, and true is the cause of the esse, goodness, and truth of the others; for to be their cause, whether exemplar or efficient, belongs properly to God. Third, that the other things of that genus can be taken in two ways: namely absolutely, that is, according to the whole of what they are; and they can be taken according to the ratio of that genus. In the proposition they are not taken absolutely, but insofar as they possess that ratio: for we do not say that what is hottest is the cause of the remaining hot things according to their substance and the whole of what they are, but only insofar as they are hot. – So that the sense of the proposition assumed is: That which in the highest degree possesses some formal ratio is the cause, whether exemplary or efficient, of the rest possessing the same formal ratio, as such.

From this it is clear that Aureol's objection concerning whiteness in relation to the colors has no force. First, because whiteness is not color in the highest degree. Second, because even if it were color in the highest degree, it would not on that account be necessary for it to cause the other species of color absolutely, but only with respect to the formal character of color. Third, because to say that whiteness is the exemplary cause of the other colors insofar as they are colors involves no difficulty: since more perfect things are naturally the exemplars of imperfections as such; and all colors, the more they approach whiteness, the more they possess of light, and consequently of perfection according to the character of color.

VIII. Concerning the fifth way, there is also the objection of Aureol¹⁵, which however St. Thomas had already excluded beforehand, in III Contra Gentiles, chapter 64: namely, that the quiddities of natural things are sufficient causes of the effects that appear naturally, in an ordered manner, etc., throughout the universe. See there, and also in the Quaestiones de Veritate, question 5, article 2, and you will find the reason for their insufficiency to be the unity of order, mutual utilities, the connections of contraries, etc.: besides the one given here in the reply to the second objection, namely because nature acts for an end, from II Physics¹⁶; therefore it either has the end conceived by itself, or is directed by another intending it, etc.

IX. Concerning the solution to the first argument, note that the response of the text consists in denying the consequence. Yet since no cause is assigned in general, but only in the particular matter under discussion, therefore, speaking generally, know first that one of two opposites excluding the other can be understood in two ways: namely, formally and effectively. Formally indeed, one of two opposites does not exclude the other except from its own recipient, as is evident. And thus in our case, because the divine good is infinite, it formally excludes every evil from God: but not from a creature, because it is not received in a creature, but in God alone. Effectively, however, one of two opposites excludes the other insofar as it produces something like itself: just as the solar power excludes cold from the air, insofar as it assimilates the air to itself in hot being esse. And according to this opposition the argument proceeds, that if one of two opposites is infinite, the other is excluded by it not only formally but also effectively, wherever it may be found: and this on account of the infinity of its efficacy, which nothing can resist unless the other opposite were also infinite. – Know secondly that Scotus, in I Sent., dist. II, qu. I, ad 1, examining this conditional, says it is true not only formally but also effectively, in opposites acting naturally: but not in agents acting voluntarily. And he solves the argument as applied to our case, because the infinite good acts voluntarily. – In the text, however, the consequence is simply denied: and the reason is assigned, namely that from the infinite goodness of the agent there follows the being esse of certain evils from which some good results.

X. But since, as was said¹⁷, that response mixes in a mode of causing, namely through the will, by attributing the permission of evil to the divine will, to which permission pertains; therefore it is particular. Universally, however, the antecedent seems to need to be distinguished. For the infinite is opposed in two ways. In one way, as communicable to others according to the same ratio, as if fire were infinitely hot: for heat is communicable to others according to the same ratio by which it is in fire. In another way, as incommunicable to others according to the same ratio, though it may be participated by a certain analogy: just as God's esse is infinite, yet not communicable to others according to the same ratio (otherwise there could be several gods), though it is participable by all, more and less.

I say therefore that, if one of two opposites, communicable according to the same ratio, is infinite, the other will be neither in the same subject nor in any other whatsoever. But if one of the opposites, incommunicable according to the same ratio yet participable, is infinite, it follows very well that the other will formally exclude it from itself: but it does not follow, therefore, that the other will effectively exclude it from every subject, even if it is posited to act naturally. And the reason is that an infinite agent, finitely participated, does not totally exclude its opposite from those participating it: but an infinite incommunicable opposite, or an infinite good, is of this kind: therefore. – The major premise is evident by induction. For if the sun were infinitely hot, and heat were not communicable to lower things according to the same ratio, but only according to a certain analogical imitation; then the sun, insofar as hot, would be an infinite agent, yet finitely participated, because not according to the same ratio. And hence it would produce in anything only a finite participation of heat: and consequently it would not exclude all cold from those participating it, since with a finitely impressed heat some degree of cold can stand. – It is also evident by reason. Because an agent, of whatever power, does not effectively exclude the opposite except insofar as it is incompossible with the effect. But with an agent existing as infinite in itself, yet finitely participated, the effect need not be incompossible with any degree whatever of the opposite: for the effect, being finite, has the ratio of one of the opposites. Therefore an infinite agent, only finitely participated, does not totally remove its opposite effectively.

And therefore God, glorious, who is infinite goodness, even if he acted naturally, would not remove all evil from the universe. For only a finite good is participated by any creature whatsoever; and from his goodness there would proceed the whole ensemble of goods constituting diverse grades in the universe, from whose natures it is necessary that evil arise; just as from the nature of the wolf comes the death of the lamb, and from the nature of the elements the corruption of mixtures, etc. And so, elevating the argument to the sense assigned in the text, the consequence is rightly denied: for from God's infinite goodness there arises that evil be (for the good of the universe, however); and not that evil not be. And thus it pertains to God's infinite goodness that evil should be in his effects, not in himself.