Commentaria in Summam contra Gentiles, Liber II

After Saint Thomas has determined the nature of intellectual substance in itself, he now determines its nature by comparison with the esse of actual existence ¹. Concerning this he does two things: first, he treats of the distinction of essence from esse; second, of their inseparability, chapter LV.

As to the first, he does three things: first, he shows that in them the essence is distinguished from esse, and therefore that they do not equal the divine simplicity, even though they are incorporeal and immaterial; second, he draws a certain corollary, in the following chapter; third, he removes one doubt, in chapter LIV.

I. As to the first, this conclusion is proposed: In intellectual substances, esse and that which is—that is, the supposit—are not the same: for the supposit is that which is.

It is proved, first, that subsistent esse is one alone. But God is subsistent esse. Therefore nothing other than God is subsistent esse. Therefore in every created substance the substance itself is one thing and its esse another. — The antecedent is proved. For if it were diversified, it would be diversified either insofar as it is esse, or by something else joined to itself. Not the first: for esse, insofar as it is esse, cannot be diverse; but it can well be diversified by something that is beyond esse; just as the esse of a stone is other than the esse of a man, on account of the different natures of stone and of man. Nor yet the second: because nothing beyond itself is joined to subsistent esse. This is evident because even in those things whose esse is not subsistent, what inheres in the existent thing besides its esse, although united to the existent thing, is nevertheless not one with its esse except per accidens, insofar as there is one subject having esse and that which is besides esse.

For the declaration of this argument, it must be noted that esse itself can have nothing united to it in the way an act is united to potency, since esse is the ultimate actuality and the act of all forms. Hence also in Book III Metaphysics ² it is said that being cannot be divided by differences. And therefore, if something must be united to it, this must be in one of two ways: namely, either because that thing is a receptive subject of esse; or because both esse and that other thing are in one common receptive subject. But if esse is posited as subsisting through itself, it will have no receiver: otherwise it would not be subsisting through itself. Therefore, if it is posited as subsisting, nothing can be added to it. And if it is further added that esse itself, insofar as it is esse, cannot be diverse, just as man, insofar as he is man, is not diversified, there will remain the conclusion that subsisting esse can be one only. And this is the foundation of this argument.

II. Second: and this is a confirmation of the preceding. Subsistent and separate esse is only one. Therefore, etc. — The antecedent is proved. Either esse is common, as a genus divided by its differences, or it is divided by being this or that. If the first, then separate and self-subsistent esse cannot be other than one: just as, if the nature of animal subsisted apart from the differences, it would be only one, because it would not have what belongs to man or ox, etc. If the second, it will be much more true ³ that what is separate from every receptive subject will be only one. Therefore, etc.

2. It will perhaps be said that esse is divided by the fact that it is the esse of this thing and of that; and that, if it is posited as subsistent, it need not be posited as separate from all those things that are distinguished from it according to reason; but, just as the subsistent essence of Gabriel is one thing and that of Raphael another, so too there is one subsistent esse and another, which is really identical with the essence and distinct from it only ex natura rei. And thus, even if esse is posited as subsistent, it is not thereby deprived of being the esse of this thing and of that.

But against that response it is argued. For from the response itself it follows that Gabriel's esse is not really received in another, since it is distinguished from his essence only by the distinction of reason; but what is the same cannot really be its own receiver. And consequently it has receptivity only according to a mode of understanding. Therefore it will be, according to the thing itself, separate from every limiting principle, since it cannot be limited except through something receptive. And consequently there will be many subsistent esse's that are separate, since God too is subsistent esse itself. But this is repugnant to everything common when it is considered without a distinctive principle. Therefore etc.

III. Third. If it were so, there would be given a multiplicity of esse each wholly infinite: for subsistent esse must be infinite, since it is not terminated by any recipient. But this is impossible: because no way would be found by which one differed from the other, since infinite esse comprehends every perfection of being. Therefore, etc.

2. To this argument it could be said that not every subsistent esse is infinite, but only that which subsists in such a way as to be limited to no degree of being. Now, although some esse may be so subsistent as to be received in no subject really distinct from itself, as the esse of a separate substance would be if it were identical with its essence; nevertheless, it can be limited to some degree of being, namely, so that it be the esse of Gabriel or of Raphael. Therefore, it need not be infinite.

But this response does not remove the difficulty. For, since esse cannot be limited by formal differences, because nothing is more actual than it, it is necessary that, if it must be determined to some degree, it be determined through a receptive subject. For nothing common can be multiplied in reality except either through differences or through a receptive subject. If, therefore, it be posited that it has no real receptive subject; and with this, that it is not divisible through differences: it follows that it must be limited to no degree of being. And consequently it must be pure esse and infinite.

IV. Fourth. Subsistent esse must not be a caused thing. Therefore no created being is its own esse. — The antecedent is proved. Nothing belongs to subsistent esse except what belongs to being inasmuch as it is being. But being caused does not belong to being inasmuch as it is being; otherwise every being would be caused. Therefore, etc. The major is proved: because what belongs to something not inasmuch as it is of this sort belongs to it only accidentally, by reason of the subject; hence, if it were posited separately from the subject, it would in no way belong to it.

2. Against this argument, the antecedent could be denied; and against the proof, it could be said that the major premise is false, and likewise that what is assumed for its proof is false. For the essence of an angel is subsistent through itself, and yet many things belong to it that do not belong to it insofar as it is of this kind, but only accidentally.

Item, if that argument concluded, then by it one could conclude that God is not being necessary of himself. For just as caused esse does not belong to a being insofar as it is a being, so neither does being necessary of itself; otherwise every being would be necessary esse. Therefore, if subsistent esse does not belong to caused esse because it does not belong to a being insofar as it is, then to God, who is subsistent esse, there will not belong, for the same reason, being necessary of himself. But this is unfitting. — Therefore that argument does not conclude: rather, what it assumes is false, namely, that nothing belongs to subsistent esse except what belongs to being insofar as it is a being, and that whatever belongs to something not insofar as it is of this kind belongs to it only accidentally by reason of the subject.

3. But that this response does not dissolve the argument is evident. For Saint Thomas, in proving the antecedent, speaks of that which subsists per se, separated from every receptive principle, in the manner of an abstractly signified thing, as is actual existence itself. For it is clear that to whiteness, if it were posited as subsisting per se and separated from every subject, nothing would belong that was not intrinsic to it: because the formal abstract signifies that by which alone and by which wholly something is formally such as it is signified by the concrete. Hence it is called abstract because it is separated from those things which, besides its own account, can belong to it in a subject. The instance, therefore, is not to the point: because the essence of an angel is not subsisting in the manner of the abstract, but is a substance individual in itself and this supposit.

To the other objection, setting aside the answer that can be had from Capreolus, in Book I, distinction VIII, question 1 ⁴ — for to anyone who examines this argument carefully it is evident that his response is not according to the mind of St. Thomas in this place, especially from the fact that he says that if caused esse belonged to being inasmuch as it is being, it would belong to every being — one can first say that the argument concludes concerning caused esse, but not concerning esse which is necessary of itself. For that proposition, "Nothing belongs to subsistent esse except what belongs to being inasmuch as it is being," and likewise its proof, is understood of what is positive, not of what is said negatively. For to separated whiteness there would belong per se that it is not a body, is not a quantity, is not in matter, and the like, although nothing positive could be present in it. But to be necessary of itself, although by its wording it seems to be said affirmatively, nevertheless according to the thing itself it is said negatively; and it is the same as not having esse from another. But caused esse is said affirmatively. Therefore subsistent esse can have that it is necessary of itself, but not that it is caused.

Second, it can be answered that the proposition of St. Thomas is understood of those things that are attributed absolutely to subsistent esse, but not of those that accompany its very mode of being. For these are truly attributed to it, although they do not belong to being insofar as it is being: for example, that it is one, that it is infinite, and the like. And in this class is what I call necessary esse. For it belongs to esse, wholly abstract, by reason of its total abstraction, to be necessary esse. But this cannot be said of caused esse. For it does not belong to esse as abstract by reason of its abstraction to be caused; rather, its mode of being is repugnant to this, since from such a mode of being it belongs to it to be simply infinite. Therefore, since it does not even belong to being insofar as it is being, it follows that it can in no way belong to esse as abstract. What has been said of necessary esse must likewise be said of every perfection simply so called, such as wisdom, justice, goodness, and the like: for it belongs to esse as abstract, insofar as it is such, to contain every perfection of being simply. Hence the proposition of St. Thomas is to be understood thus: Nothing belongs to subsistent esse except what belongs to being insofar as it is being, or what accompanies its very subsistence and separation.

V. Fifth. Substance belongs to each thing of itself, that is, not through any productive cause. But esse belongs to it through another. Therefore, etc. — The antecedent is made clear from the opposite: for actual luminous esse is not of the substance of air, because it belongs to it through another.

It must be noted that it is one thing to say that the essence of some thing has a productive cause, and another to say that the essence itself belongs to the thing through some effective cause. For the first is true, and the second is false. Since every production terminates at the esse of actual existence, everything that has esse from another is said to have a productive cause. And thus, since every created essence has esse from another, it is necessary to say that every created essence has a productive cause. But when it is said that man is an animal, no esse of actual existence is signified, but only the composition of the predicate with the subject and the order of one to the other. And because this order belongs to the thing whether or not it exists in the nature of things, according to the mind of Avicenna, Algazel, Alpharabius, and Albert — for whether man exists or not, this is always true: Man is an animal — therefore that man is an animal has no productive cause, but that man exists does indeed have a productive cause. Nor does it stand in the way that doctors sometimes say that God made man rational: for he is not said to do so as if God makes rationality belong to man, but because he produced the intellective soul of man, from which man formally has it that he is rational.

2. But someone might reply to St. Thomas's argument that substance indeed belongs to a thing per se formally, but not effectively. And therefore it belongs to it from another, just as esse does.

But against this response an argument is brought by the Thomists. First, because, with all causality set aside, it is true that a man is a man, and that a man is an animal. Otherwise, the predicates of the first mode could be understood not to be present in the thing, and the definition would be separated from the thing defined. Which are contrary to all philosophy.

Then, because something would come about after it is. For, with all efficiency removed, it would still be true that a man is a man, since the predicate belongs to the subject formally of itself, and therefore this is of eternal truth. And so, if some cause made a man be a man, it would follow that it makes something come about after it is.

Then, since it is equally necessary that man be man and that God be one—because their opposites are equally impossible, namely by the implication of contradiction—it is evident that God's being one has no efficient cause.

Nor does it avail if it be said that propositions of this kind are necessary supposing the existence of the subject. For in that way this one, "Two and three are five," would be no more necessary than this one, "The earth is," "The heavens are," and the like, which are admittedly necessary by supposition. And that is both against philosophy and against Augustine, On Free Choice ⁵.

3. For the clarification of this point—how the said propositions, in which the predicate is predicated of the definition of the subject, are of everlasting truth; and since they have no efficient cause with respect to the inherence of the predicate in the subject—it must be considered that, since a nature can be considered in three ways: namely, absolutely, abstracting from every esse both in the intellect and outside the intellect; as it has esse in the intellect; and as it has esse outside the intellect in the things themselves—the quidditative predicates belong to the nature not from the esse it has in the intellect, nor from the esse it has in things, but in itself, as it abstracts from every esse. For even with no intellect considering, nor indeed any man existing in the nature of things, man is a rational animal. I say, moreover, that these predicates belong to the nature not with respect to actual predication, for that occurs only through the operation of the intellect, but fundamentally and with respect to the thing. Yet although such predicates do not belong fundamentally and with respect to the thing to the nature from the esse it has in the intellect—as if, namely, were there no intellect, man would not be a rational animal—nevertheless this inherence of the predicate in the subject is knowable by the intellect, both divine and created. And therefore it is true in two ways that propositions of this kind are of eternal truth. First, because eternally the thing itself is such essentially, and is by nature apt to be truly understood with the attribution of such a predicate. In another way, because by the divine intellect they are known eternally to be true, not only on the side of the one understanding, but also on the side of the thing understood. For since in the divine mind there are eternally the ideas of all natures, once these are posited there results the connection of a substantial predicate with its subject; therefore by the divine intellect such propositions are understood to be true from eternity. And consequently no efficient cause is required which would make the predicate belong to the subject.

VI. Sixth. God alone is the first agent. Therefore it belongs to God alone to be in act in the most perfect way. Therefore it belongs to him to be the most perfect act itself. Therefore he alone is ipsum esse. Therefore etc. The first consequence is proved: because every agent acts insofar as it is in act. The second is also proved: because what is in act more perfectly is that which is itself the act, rather than one having an act, since it is on account of the act itself that the one having it is in act. The third likewise is proved: because esse is that toward which every generation and motion is terminated; and an act is the more perfect the later it stands in the way of generation.

Concerning that proposition, That which is itself act is more perfect in act than that which has an act, it must be noted that this is understood other things being equal: namely, if both are first in act and subsist. For if one were to take a composite, which is first in act, and its form, by which it is in act, the form would not be more perfect in act than the composite: because its form is not first in act.

It may also be said that it is understood in the sense of act: so that the meaning is that what is essentially act approaches more perfectly to the sense of act than that which participates in act. And this too is found to be most true.

VII. Seventh. Esse belongs to God according to his own nature. Therefore it belongs to all others by participation. Therefore it is impossible that the substance of any being other than the first be esse itself. — The antecedent is proved. Because that God's esse is his substance was shown above. — The first consequence is proved. Because what belongs to something according to its own proper nature does not belong to others except by way of participation: as heat belongs to other bodies from fire. — The second consequence, however, is proved. Because what belongs to something by participation is not its substance.

VIII. But this argument does not seem to conclude. First, because it would thereby be proved that nothing is predicated of a creature substantially. For every perfection of a creature is a certain participated likeness of the divine nature. If, therefore, what belongs to something by participation is not its substance, it follows that no perfection of a creature is its substance.

Second ⁶. Either to participate in some form is to have it not according to its whole account, or it is to have it indeed according to its whole account, but not according to every one of its modes and degrees of amplitude. If the first way, then it seems false that a creature participates in esse. For just as the whole account of being belongs to all beings, so too does the whole account of esse itself. — If the second way, then it seems false that what belongs to something by participation is not its substance. For animal belongs to horse by participation, since it does not belong to it according to all of its differences; and yet horse is animal substantially.

IX. To the first doubt it is answered that the perfection of a creature is a participated likeness of the divine nature can be understood in two ways. In one way, so that the word participated is taken as a noun, and as determining the likeness taken formally. Then the sense will be that the perfection of the creature is a certain partial and diminished likeness of the divine nature. — In another way, so that it is taken as a passive participle, and as determining the thing that is called a likeness. Then the sense will be that the perfection of the creature is a thing possessed participatively and partially, which is a likeness of the divine nature.

If the proposition is taken in the first sense, it is indeed universally true, but it is not to the point. For when St. Thomas says that what belongs to something by participation is not the substance of the thing, he does not mean that a diminished and imperfect likeness of another cannot be the substance of anything; but rather that what is participated from another and possessed partially cannot be its substance. — If, however, it is taken in the second sense, then that proposition is not universally true. For many perfections of creatures, which are likenesses of God, are possessed totally, not partially.

X. For the clarification of the second doubt ⁷ it must first be considered that the phrase to belong to something according to its proper nature can be understood in three ways. In one way, because it is its very essence and nature absolutely and simply: as being a rational animal belongs to man. — In another way, because it naturally and primarily accompanies its proper nature and essence: as being hot belongs to fire. — In a third way, because it is a part of its substance, either logically or naturally: as being an animal belongs to man.

It must be considered second, that belonging to something by participation is opposed to the first and second of the modes described, but not to the third. For since to participate in something is to have it partially, not totally; whereas what belongs to something according to its own nature in the first or second mode is possessed most perfectly and totally: the same thing cannot belong to something both according to its own nature and by participation. Yet there is no incongruity in something being a part of a substance, and nevertheless being had partially, not according to its totality and universality. Therefore something can belong to something else in the third mode both according to its own nature and by participation: just as animal belongs to man in both ways.

Saint Thomas therefore takes it here that to belong to something according to its proper nature holds in the first and second ways, but not in the third. Hence it is true that esse belongs to God according to his proper nature in the first way: for esse is the divine nature itself. — It is also true that, when something belongs to a thing according to its proper nature in these ways, it cannot belong to another nature except partially and imperfectly, which is to belong by participation. — Likewise it is true that what belongs to a thing by participation is not its substance: for a thing's essence and nature do not belong to it partially and imperfectly. — Finally, it is true that esse belongs to no creature according to its proper essence, but only by participation: since it belongs to God according to his proper substance, and it also befits him first and most perfectly.

2. To the doubt, therefore, it is said that in this passage participare is taken according to the second of the modes laid down in the objection, namely for having something not according to every degree and fullness of it. And when it is argued that because animal belongs to the substance of a horse, and yet a horse does not have the nature of animal according to all its fullness, and thus that proposition will be false, What belongs to something by participation is not its substance: — it is said that Saint Thomas does not say that what belongs to something by participation is not of its substance: but that it is not its substance. For these differ greatly. For something is said to be the substantia of something when it is its whole essence and nothing else: as rational animal is the substantia of man, because the whole essence of man is rational animal; and whiteness, if it were separate, would be the very essence of whiteness. But for something to be of the substantia of something, it suffices that it be an essential part of it. Now what is the substantia and essence of something belongs to it according to every degree of it, as rational animal belongs to man: because the nature of the one is the nature of the other. But to a nature, as signified absolutely, every perfection of that nature belongs. And so, if esse were the substantia and essence of a creature, the creature would have to possess every mode and perfection of being. Since this is not so, one must say that esse is not the essence of a creature. It is therefore clear that the objection brought forward is not against the meaning of the text.

3. But against this response, insofar as it says that esse does not belong to the creature according to its essence but only by participation, a doubt is raised. For the opposite of this seems to be said by Saint Thomas in the Prima, q. 50, a. 5. For there he says that esse belongs to form in itself. Since, therefore, in separate substances the form is the essence of the thing, it follows that esse belongs to them through their essence.

It is answered that that esse agrees with the form per se can be understood in two ways: in one way, essentially; in another way, formally. In the first way, it does not agree with it per se, as though esse were the essence of the form; but well indeed in the second way, because, I say, it does not agree with it through another, formally—in which it differs from the composite, to which esse does not belong except through the form. Therefore what St. Thomas says is not contradicted: for here it is understood that esse does not belong to anything per essence, as though it were its essence; but in the First Part it is understood that esse belongs to the form per se formally, that is, not through some other formal principle.

The conclusion is confirmed by the authority of Exodus 3, where the proper name of God is given as He Who Is.

Other difficulties that arise concerning this conclusion, see in Capreolus, distinction 8 of book I Sent.; and in other Thomists.