In De ente et essentia D. Thomae Aquinatis commentaria

What the essence of God is, and what it is in separated substances; whence the intention of genus and difference is drawn in them, and in what way they are multiplied, is investigated.

Having seen these things, it is clear how essence is found in diverse things. There are, however, three ways of having essence in substances. For one thing is like God, whose essence is his very being; and therefore some philosophers are found saying that God does not have an essence, because his essence is nothing other than his being. This is the beginning of the sixth chapter, which is divided into four parts. The first treats of the essence of God. The second treats of the essence of intelligences and of the soul. The third shows how these relate to logical intentions. In the fourth he returns to composite essences.

Therefore, about the essence of God, intending to posit two conclusions and exclude two errors, he posits the first affirmative conclusion as follows: Essence in God signifies his very being. He posits this conclusion by deducing it from what was said above and in no other way, for it was proved above and is conceded by all. The meaning of the conclusion is that the divine being of actual existence is his very quiddity, so that it is predicated of God as the predicate of the first mode of per se predication; thus “God is” is in the first mode of perseity. The common way concedes this of no one other than God, even if being and essence in creatures are held to be really the same. And because existing itself is the essence of God, some philosophers, namely the Platonists, say that God does not have an essence, as though he were pure existence.

From this it follows that he is not in a genus, because everything that is in a genus must have a quiddity besides its being. For the quiddity or nature of genus or species is not distinguished according to the account of nature in those of which it is the genus or species, but being is in diverse things in diverse ways.

Here is posited the second, negative conclusion: God is not in a genus. It is proved in the text from the foregoing as follows: Everything that is in a genus has a quiddity besides its being; God does not have a quiddity besides his being; therefore God is not in a genus. The minor is the preceding conclusion. The major is proved thus: All things that are in a genus are indistinct in the essence of the genus or species, but are distinct through possessing the being of that generic or specific nature in different ways; therefore the being of the generic or specific nature is besides the generic or specific nature itself; and thus everything that is in a genus has a nature besides its being. The antecedent of this consequence is self-evident: man and lion, for example, are indistinct in the nature of animal, but are distinguished from one another by the fact that they possess animate being in different ways; for a genus has diverse being in its species. Similarly, Socrates and Plato are indistinct in human nature, but are distinguished from one another because they have diverse human being; for it is not intelligible that man should have the same being in Socrates and Plato. The consequence is clear from the fact that it does not seem imaginable that that by which some things are distinguished should not be besides that by which some things agree.

And note that, for the purpose of this argument, it is enough that being be besides essence, that is, besides the quidditative concept. For it is enough that the principle of agreement differ from the principle of difference, as is clear of genus and differences: species agree through the one and differ through the other. And because in God alone being belongs to the quidditative concept, therefore God alone is placed outside a genus.

But since being is besides the quidditative concept because it is really distinct from essence, and therefore belongs to the quidditative concept because it is really identical with essence, from this root—namely, that being and essence are really identical—it is said to follow in God that God is not in a genus. Nor should it trouble you that this argument seems to depart from the being of actual existence to quidditative being. For although in the minor there is speech about the being of actual existence, and afterward in the proof of the major—where one must speak of the same being—it passes to quidditative being when it says that species agree in genus and differ in diverse being. For this is verified of quidditative being taken specifically: man and ox, for example, agree in animal, and are distinguished by specific differences, through which animal acquires diverse specific being in them. For this reason, I say, one ought not to be disturbed, since (as will become clear in this chapter) differences diversify generic nature only in relation to diverse being of actual existence. Thus, with admirable subtlety, St. Thomas has not departed from attending to the first reason for the distinction of generic nature in inferiors. This, however, will be better understood below, when the most common rule will be assigned, from which genus and difference are taken.

For clarity concerning what is presupposed here—namely, that in God being belongs to the quidditative concept because it is identical with essence—note three propositions. The first is: A quiddity that is its own actual existence is not determined to any genus. This is briefly declared by a single middle term taken from Against the Gentiles I, chapter XXV, as follows: Every quiddity limited within a genus is essentially designable through a difference from which it begs being in act; no quiddity identical with its actual existence is essentially designable through a difference from which it begs being in act; therefore no quiddity identical with its actual existence is determined to any genus. The major is made known by induction: animal, for example, is essentially determinable by the differences rational and irrational, and begs being in act from them, since it is impossible for animal to exist in actual existence unless it be rational or irrational. Similarly, color is essentially determinable by its differences, through which it obtains actual existence; for color cannot be found except as white or black, and so on. The minor, for those who understand the terms, is clear in itself. For how would actual existence formally beg being in act from something else? If it formally begs being in act from some difference, then, since being in act is nothing other than having actual existence, it would follow that actual existence would formally have actual existence through something else being: just as animal formally acquires actual existence through rationality. But this does not seem intelligible; therefore, and so forth. per rationale formaliter acquires actual existence: but this does not seem intelligible; therefore, and so forth.

The second proposition is this: Actual existence determined to no genus is pure existence. This is clear from similar cases: if animal is not determined to any species, it will be pure animal; and if whiteness is not restricted in some subject, it will be pure whiteness. Thus being, not determined to the capacity of any predicamental nature, must be pure being. This abstraction is through the work of the intellect; therefore the purity itself is according to reason. But if it were according to the thing, the purity itself would also be according to the thing, and this is self-evident.

The third proposition is this: Being belongs to the quidditative concept of pure being alone. This is clear under either interpretation, and under the first indeed because it is not intelligible that being itself should not be predicated quidditatively of pure being. For if something can be predicated quidditatively of it, that something must be pure being, and pure being is posited. That other things do not receive being in their quidditative concepts is clear from this: since they do not have being in its purity, but being is adapted to quiddities, they can be defined according to their quiddities without being and without not-being. From these points the purpose is deduced as follows: Existence belongs to God's quidditative concept because the whole of it is pure being; that thing is pure being because it is not limited to any genus; and that thing is not limited to any genus because it is identical with its existence. Therefore, from first to last: existence belongs to the quidditative concept of a thing because that thing is identical with its existence.

But since, for observation, affirmation is precisely the cause of affirmation and negation the cause of negation, from the fact that a created thing is not identical with its existence, being does not belong to its quidditative concept. Hence, since glorious God is his own being, he is nothing other than being itself, according to the thing separated from predicamental things and subsisting in its purity.

Nor, if we say that God is being alone, should we fall into the error of those who said that God is that universal being by which every thing formally is. For this being which God is has the condition that no addition can be made to it. Hence, through its very purity, it is being distinct from every other being, and for this reason the commentary on the ninth proposition of the Book of Causes says that the individuation of the First Cause, which is being alone, is through its pure goodness. But common being, just as its concept does not include any addition in the intellect, likewise does not include in its concept the exclusion of addition; for if this were so, nothing could be understood to be in which something were added above being.

Here the first error of certain persons is excluded, namely this: God is the common being of all. They imagined that, since all things agree in having being, the being itself of all things, by which things formally are in common or universally, is glorious God himself. They were moved by this argument: Being specified by no addition is common being; God is being specified by no addition; therefore God is common being. But that argument errs because of the multiple meaning of the major. For “being is specified by no addition” can be understood in two ways: one, by subsisting according to the thing outside the soul; the other, according to the thought of the intellect alone. In the first way the major is false but the minor true; in the second way the major is true but the minor false. For common being, taken by the intellect from its abstraction, includes no contraction; but insofar as it is outside the intellect it is not found without contraction, since every being is contracted to substance or accident. But the being that is the divine quiddity is pure, without any addition, according to the thing, and from its very purity is, according to the thing, distinct from the being of others; and this is in no way common, just as separate whiteness, by the very fact that it were pure whiteness, would be a whiteness distinct from other whitenesses mixed with substances, and would not be whiteness in common.

That major errs a second time, because it is still possible for being to be specified or contracted without addition in two ways: in one way in act alone, in another way in act and potency. In the first way the major is true but the minor false; in the second way the major is false but the minor true. For common being, although contracted by no addition, is nevertheless contractible; otherwise no thing would have being that adds anything above being itself, and thus man would not have being, since beyond being he has humanity, quantity, and so on. Hence common being lacks specification in act alone; but divine being has no specification in act and can have none in potency, and therefore lacks addition in act and potency. This is the solution that St. Thomas gives in the text under other words, saying that every common thing neither includes nor excludes addition—that is, it does not include it in act, although it can have it. But divine being not only does not include it; rather, it excludes it: not only does it fail to include it in act, it cannot include it even in potency, and so excludes it. For what is impossible to belong to something is wholly excluded from it. On these matters you have a detailed treatment in Against the Gentiles I, chapter XXV.

Likewise, although God is being alone, it does not follow that the remaining perfections or nobilities are lacking; rather, he has all the perfections that are in all the genera, on account of which he is called simply perfect, as the Philosopher and the Commentator say in Metaphysics V. But he has them in a way more excellent than all things, because in him they are all one, whereas in other things they have diversity. This is because all those perfections belong to him according to his simple being. Just as, if someone could produce the operations of all qualities through one quality, he would have all qualities in that one quality, so God has all perfections in his very being.

Here the second error is excluded, namely this: God is not simply perfect. The reason for this error in the present matter is: That which has being alone is imperfect in comparison with that which has being, life, and understanding; but God has being alone; therefore God is less perfect than other things. The major is self-evident. The minor is deduced from what has been said as follows: What is pure being is not mixed with other things, such as life and understanding; otherwise it would be pure and not pure. God is pure being; therefore he is not mixed with other things, namely life and understanding, and consequently God has nothing but being; which was to be proved. The defect in this argument is not explained in the text; but in Against the Gentiles I, chapter XXVI, it is shown that from this proposition, “God is subsisting pure being,” it follows that God is universally most perfect. And therefore the text deliberately says, “Rather, he has all perfections,” and so forth, as if saying that it does not follow from this that God lacks some perfection; rather, the opposite is concluded from it.

The way of deducing the purpose from that foundation is as follows: That to which being belongs according to the whole power or potency of being itself lacks no perfection or nobility of being; but subsisting pure being is that to which being belongs according to the whole power or potency of being itself; therefore subsisting pure being lacks no perfection or nobility of being. The major is explained by the fact that every perfection of any genus exists only according to some being. For wisdom does not perfect a man unless the man is wise through it; nor can justice be called a perfection of man unless the man is just through it. If, then, every perfection is considered according to some being, it is clear that that in which the whole fullness of being is found has every perfection; and thus it is incompatible that something should have being according to its whole amplitude and lack some perfection of being. The minor is made known by an example: just as, if separate whiteness were found, nothing of the power of whiteness could be lacking to it. For, as was said above, the reason why this whiteness does not possess the whole perfection possible to be found in the species of whiteness is that it is adapted to a receiver which does not receive it according to its whole capacity. So being itself, if it is received in another, is restricted to the limits of the nature receiving it, namely substance or accident, and consequently limited to the nobility of that genus. But if it is pure and not received in any nature, it is simply unlimited and infinite, and simply possesses beforehand all perfections capable of being found in a being. When you hear that, if whiteness were separate, it would have every perfection possible to its species, do not understand—as the opponents of truth object—that the negation, namely its reception in another, would give it that perfection. Rather, just as reception of whiteness is a condition required for its imperfection, so the negation of reception is a condition accompanying its unlimited perfection. Hence an efficacious argument is taken from its reception and separation as from necessary and inseparable conditions.

And since having the perfections of all genera can be understood in two ways—either in themselves, or in something of a higher order—therefore, to declare how God himself, who is being itself essentially, has all perfections, he says that God does not have all perfections in themselves, that is, distinct from one another in their proper natures, as man has wisdom, justice, prudence, and so on. For in that case there would have to be maximal composition in God. Rather, he has them indistinctly united in his most simple being. For that divine being is equivalent to all the perfections of all genera, and exceeds each one and all together, as a thing of a higher and inaccessible order. You have an example of this in the light of the sun, by which alone the sun can do whatever all inferior things can do through so many diverse qualities. For this reason the Philosopher and the Commentator say in Metaphysics V, in the chapter on the perfect, that God alone is a being simply perfect, possessing in himself the universe of perfections.