Thomas Aquinas - Summa Theologica, Part I (Prima Pars)

Reply Obj. 1: A thing that has nothing added to it can be of two kinds. Either its essence precludes any addition; thus, for example, it is of the essence of an irrational animal to be without reason. Or we may understand a thing to have nothing added to it, inasmuch as its essence does not require that anything should be added to it; thus the genus animal is without reason, because it is not of the essence of animal in general to have reason; but neither is it to lack reason. And so the divine being has nothing added to it in the first sense; whereas universal being has nothing added to it in the second sense.

Reply Obj. 2: "To be" can mean either of two things. It may mean the act of essence, or it may mean the composition of a proposition effected by the mind in joining a predicate to a subject. Taking "to be" in the first sense, we cannot understand God's existence nor His essence; but only in the second sense. We know that this proposition which we form about God when we say "God is," is true; and this we know from His effects (Q. 2, A. 2). ______________________

FIFTH ARTICLE [I, Q. 3, Art. 5]

Whether God Is Contained in a Genus?

Objection 1: It seems that God is contained in a genus. For a substance is a being that subsists of itself. But this is especially true of God. Therefore God is in a genus of substance.

Obj. 2: Further, nothing can be measured save by something of its

own genus; as length is measured by length and numbers by number. But

God is the measure of all substances, as the Commentator shows

(Metaph. x). Therefore God is in the genus of substance.

On the contrary, In the mind, genus is prior to what it contains. But nothing is prior to God either really or mentally. Therefore God is not in any genus.

I answer that, A thing can be in a genus in two ways; either absolutely and properly, as a species contained under a genus; or as being reducible to it, as principles and privations. For example, a point and unity are reduced to the genus of quantity, as its principles; while blindness and all other privations are reduced to the genus of habit. But in neither way is God in a genus. That He cannot be a species of any genus may be shown in three ways. First, because a species is constituted of genus and difference. Now that from which the difference constituting the species is derived, is always related to that from which the genus is derived, as actuality is related to potentiality. For animal is derived from sensitive nature, by concretion as it were, for that is animal, which has a sensitive nature. Rational being, on the other hand, is derived from intellectual nature, because that is rational, which has an intellectual nature, and intelligence is compared to sense, as actuality is to potentiality. The same argument holds good in other things. Hence since in God actuality is not added to potentiality, it is impossible that He should be in any genus as a species. Secondly, since the existence of God is His essence, if God were in any genus, He would be the genus being, because, since genus is predicated as an essential it refers to the essence of a thing. But the Philosopher has shown (Metaph. iii) that being cannot be a genus, for every genus has differences distinct from its generic essence. Now no difference can exist distinct from being; for non-being cannot be a difference. It follows then that God is not in a genus. Thirdly, because all in one genus agree in the quiddity or essence of the genus which is predicated of them as an essential, but they differ in their existence. For the existence of man and of horse is not the same; as also of this man and that man: thus in every member of a genus, existence and quiddity—i.e. essence—must differ. But in God they do not differ, as shown in the preceding article. Therefore it is plain that God is not in a genus as if He were a species. From this it is also plain that He has no genus nor difference, nor can there be any definition of Him; nor, save through His effects, a demonstration of Him: for a definition is from genus and difference; and the mean of a demonstration is a definition. That God is not in a genus, as reducible to it as its principle, is clear from this, that a principle reducible to any genus does not extend beyond that genus; as, a point is the principle of continuous quantity alone; and unity, of discontinuous quantity. But God is the principle of all being. Therefore He is not contained in any genus as its principle.

Reply Obj. 1: The word substance signifies not only what exists of itself—for existence cannot of itself be a genus, as shown in the body of the article; but, it also signifies an essence that has the property of existing in this way—namely, of existing of itself; this existence, however, is not its essence. Thus it is clear that God is not in the genus of substance.

Reply Obj. 2: This objection turns upon proportionate measure which must be homogeneous with what is measured. Now, God is not a measure proportionate to anything. Still, He is called the measure of all things, in the sense that everything has being only according as it resembles Him. _______________________

SIXTH ARTICLE [I, Q. 3, Art. 6]

Whether in God There Are Any Accidents?

Objection 1: It seems that there are accidents in God. For substance cannot be an accident, as Aristotle says (Phys. i). Therefore that which is an accident in one, cannot, in another, be a substance. Thus it is proved that heat cannot be the substantial form of fire, because it is an accident in other things. But wisdom, virtue, and the like, which are accidents in us, are attributes of God. Therefore in God there are accidents.

Obj. 2: Further, in every genus there is a first principle. But there are many genera of accidents. If, therefore, the primal members of these genera are not in God, there will be many primal beings other than God—which is absurd.

On the contrary, Every accident is in a subject. But God cannot be a subject, for "no simple form can be a subject", as Boethius says (De Trin.). Therefore in God there cannot be any accident.

I answer that, From all we have said, it is clear there can be no accident in God. First, because a subject is compared to its accidents as potentiality to actuality; for a subject is in some sense made actual by its accidents. But there can be no potentiality in God, as was shown (Q. 2, A. 3). Secondly, because God is His own existence; and as Boethius says (Hebdom.), although every essence may have something superadded to it, this cannot apply to absolute being: thus a heated substance can have something extraneous to heat added to it, as whiteness, nevertheless absolute heat can have nothing else than heat. Thirdly, because what is essential is prior to what is accidental. Whence as God is absolute primal being, there can be in Him nothing accidental. Neither can He have any essential accidents (as the capability of laughing is an essential accident of man), because such accidents are caused by the constituent principles of the subject. Now there can be nothing caused in God, since He is the first cause. Hence it follows that there is no accident in God.

Reply Obj. 1: Virtue and wisdom are not predicated of God and of us univocally. Hence it does not follow that there are accidents in God as there are in us.

Reply Obj. 2: Since substance is prior to its accidents, the principles of accidents are reducible to the principles of the substance as to that which is prior; although God is not first as if contained in the genus of substance; yet He is first in respect to all being, outside of every genus. _______________________

SEVENTH ARTICLE [I, Q. 3, Art. 7]

Whether God Is Altogether Simple?

Objection 1: It seems that God is not altogether simple. For whatever is from God must imitate Him. Thus from the first being are all beings; and from the first good is all good. But in the things which God has made, nothing is altogether simple. Therefore neither is God altogether simple.