"The good of the grace of one soul is greater than the good of the nature of the whole universe"
- St Thomas Aquinas Ia IIa, q.24, a. 3, ad 2

— A Commentary on the First Part of St Thomas' Theological Summa

by Reginald Garrigou-Lagrange, O. P.


The Simplicity of God



Reply to the first objection. The divine being is being to which nothing can be added, because being is the ultimate actuality of essence, and therefore divine being is neither received nor receivable, but is irreceptive, and is not in potentiality to further actuality; wherefore, as stated in the sixth article, there can be no superaddition of any accident in God. In fact, it is only in an improper sense that addition can be attributed to God in His external operatioris by way of causality and creation. For after creation, although there are more beings, there is not more of being, of perfection, because God already possesses unlimited being and perfection. Contrary to this, universal being is that to which something can be added, as in the determination of the genus and the species, or in the modifications of being, and these are contained actually and implicitly in being.

Reply to the second objection. From the fact that we know a posteriori that God is, we do not, however, know that God's existence is His essence; but from the effects we know that this proposition is true, when we say: "God is." In creatures, "to be" concerns in itself only the question of the existence, not of the quiddity, of a being. In God, "to be" concerns also, and even in the strict sense, the question of His quiddity, for God alone is the self-subsisting Being, and what this self-subsisting Being is in Himself, this we shall see only in heaven, because, as stated farther on, in this life we know God only by means of His effects, from the concepts derived from creatures, and "every effect which is not an adequate result of the power of the efficient cause, receives the similitude of the agent not in its full degree, but in a measure that falls short." (31) This existence in creatures is a contingent, but in God an essential, predicate, which is not really distinct from God's essence that is unknown to us. Hence in this life we know God's essence not as it is in itself, but as it is the foundation for the truth of the proposition known from effects, namely, "God is."

Doubt. Has St. Thomas clearly deduced the corollary of this article, namely, that in every creature its essence differs from its existence? He explains this at length in another of his works (Contra Gentes), where he says: "Now being, as being, cannot be diverse, but it can be differentiated by something besides being: thus the being of a stone is other than the being of a man. Hence that which is subsistent being can be one only. Now it was shown above (Bk. I, chaps. 22, 42) that God is His own subsistent being: therefore nothing besides Him can be its own being. Therefore in every substance, besides Him, the substance itself must be distinct from its being."(32) Likewise in every creature, what is (or the suppositum) and existence are different.

Father del Prado (33) proposes this fundamental argument in the deduction of the above corollary as follows: Act is multiplied and limited by the really distinct potency in which it is received; but in creatures existence is multiplied and limited by the essences of different creatures; therefore in creatures essence is potency, or real capacity, which is really distinct from existence, just as matter is real capacity for the form, and really distinct from the form. In other words, previous to the mind's consideration, essence and existence are not identical in creatures, just as matter is not form.

The major is explained by stating that the division of being into potency and act is absolutely necessary for the understanding of change and multiplicity, as Aristotle shows (34) in solving the arguments of Parmenicles against change and multiplicity in beings, by appealing to the real distinction between potency and act. Being does not come from what is already being, just as a statue does not come from a statue, for it is already such. Nothing comes from nothing. But being comes from potential being, just as the statue can be sculptured from the wood, and just as the plant is developed from the seed.

In like manner, the act of existence cannot be multiplied or limited by itself, because in its formal concept it implies no limitation. Therefore it can be limited and multiplied only by the real capacity in which it is received, that is, by the essence which is capable of existing, for instance, by the essence of either stone, plant, animal, or man. Thus the form is limited and multiplied by the matter, which is the principle of individuation; thus intellection is limited and multiplied according to the various intellectual capacities of human beings, and so forth.

Thus by means of the distinction between potency and act we have not only the reconciliation of the principle of identity or of contradiction, a principle to which Parmenides always appealed, but also change and multiplicity, which Heraclitus defended. In other words, it is only in this way that the first principle of reason is reconciled with the most certain facts of experience. But because there is a certain lack of identity in change and multiplicity, in virtue of the principles of identity and causality our mind of necessity soars to the first Cause who is absolutely identical with Himself, who is to being as A is to A, and in whom there can be neither change nor composition, but who is absolutely simple. This point will be made still clearer in the subsequent articles.



State of the question. By genus, in the strict sense, is meant the logical genus. Thus, according to Aristotle, there are ten genera or categories, namely, substance, quantity, quality . . . and under the supreme genus come the less universal genera ranging down to the proximate genus, and this latter is expressed together with the specific difference in a definition, for instance, by the words rational animal by which man is defined.

The principal difficulty is that God seems to come at least under the genus of substance, because substance is a being that subsists of itself and we speak of the divine substance. But, on the other hand, it is generally admitted that God transcends the genera and species,. But it may be asked whether God is at least reducible to the genus of substance, as habitual grace is to the genus of quality, or as the point is to the genus of quantity, as the terminus of the line.

Conclusion. God is not in any genus either directly or as reducible to it.

It is proved in many ways that God does not come directly under any genus, and this first of all in the counterargument from general notions. For genus is prior in the mind to what it contains. But nothing is prior to God either really (because He is the first Being), or mentally, because He is the self-subsisting Being, and all formal concepts, such as those of substance, quality, presuppose being whose act is to exist. Yet for us there is something prior to God, namely, being in general.

In the body of the article three proofs are given why God is not directly in any genus. The first is founded on the notion of genus, the second on the notion of being, and the third on the identity of essence and existence in God.

1. On the notion of genus. Genus takes the place of potency, whereas the specific difference takes the place of act. But God is pure act. Therefore God is not in a genus.

The minor has been proved. The major needs explanation. Genus is not indeed matter; but it is to the specific difference as matter is to form. For just as the matter is determined by the form, so the genus is determined by the specific difference. Thus, for instance, the genus animality is determined by rationability; for animality is derived from the material body endowed with sensitive life, and rationability is derived from the rational soul. Hence no being is in a genus unless there is really something potential in it susceptible of further determination. The genus is in potentiality for the differences by which it is determined.

2. On the notion of being. Being cannot be a genus, but transcends the genera. But if God were in a genus, then being would be His genus. Therefore God is not a genus.

The major is proved by Aristotle.(35) For the genus is diversified by the differences that are extrinsic to it, for instance, animality by rationality. But being cannot be diversified by differences that are extrinsic to it, for what is not being is nothing. Whereas rationality is not animality, substantiality still is being, and the same is true of vitality and other notes. Whereas the genus contains only virtually the differences extrinsic to it and is not contained in them, being contains actually and implicitly the modes of being and is contained in them. Therefore being is transcendent, or transcends the genera or the categories of being, and hence is analogous. It signifies in the different categories something that is proportionately alike, namely, that whose act is to exist. But the existence of substance is existence not in another, whereas the existence of accidence is inexistence or existence in another. Hence being is not a genus.

The minor. If God were in a genus, being would be His genus, because God is essential being, since He is His existence. Manifestly, if God were in a genus, His genus would have to be most universal and unlimited being.

3) On the identity of essence and existence in God. Essence and existence differ in all things that are in a genus. But essence does not differ from existence in God. Therefore God is not in a genus.

Cajetan given us the following explanation of the major: "When St. Thomas says that 'all in a genus differ in existence,' 'esse' is taken both for specific existence (specific difference) and for actual existence; and from the verification of one is inferred the verification of the other"; for those things that differ in species differ also in existence, because specific (and individual) existences are the proper recipients of the act of existence. Hence from the fact that God is His existence, He is above all the genera. This proves that God is not at least directly in a genus.

Corollary. God cannot be defined by genus and differentia.

In the last part of the body of the article it is proved that God is not in any genus as reducible to it. For "a principle reducible to any genus does not extend beyond that genus; as a point is the principle only of continuous quantity; and unity, of discontinuous quantity. But God is the principle of all being" and of all the genera of being. Likewise habitual grace, which is reduced to the genus of a quality, is not in the other genera. The solution of the objections confirms this.

Reply to the first objection. God is not in the genus of substance, because the word "substance" does not signify the self-subsisting Being, but an essence that has the property of existing in itself and not in another. Now existence is predicated contingently of every substance, for the substance of a stone, plant, animal, man, or angel exists contingently. Spinoza refuses to give this consideration, defining substance as being that exists of itself, in this sense, that existence is not a contingent but an essential predicate of substance. It follows from this that there can be only one substance.

Reply to second objection. If God is said to be the measure of things, He is not the homogeneous measure, as unity is the principle of nuimber, but He is the heterogeneous measure since everything has being only according as it resembles God, who is the maximum in being (fourth way).

Thus it is evident that God is not in a genus, and this is commonly admitted, even by Scotus, although he holds that being is univocal. We shall comment on this farther on.(36)


Index Top


31. Summa theol., Ia, q.13, a.5.

32. Contra Gentes, Bk. II, chap. 52; see also Summa theol., Ia, q.7, a,1; q.54, a.2; De ente et essentia, chap. 5.

33. Op. cit., p. 26.

34. Physics, Bk. 1.

35. Met., Bk. III, chap. 3.

36. Summa Theol., Ia, q. 13, a.5.



"The greatest glory we can give to God is to do his will in everything."

St Alphonsus de Liguori

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"God has no need of men."

St Philip Neri

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"Many words do not satisfy the soul; but a good life eases the mind and a clean conscience inspires great trust in God."

Thomas á Kempis

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