4.4 God as Simple (SCG 1,20–27)
4.4 God as Simple (SCG 1,20–27)
In SCG 1,18 it becomes clear that, when Aquinas says that God is not composite, he is claiming that God is simple (simplex). Hence, as part of his defense of the claim that there is no composition in God, Aquinas holds that something “which is at the peak of nobility among all beings must be at the peak of simplicity.”14 That Aquinas understands the assertion “God is not composite” to mean “God is simple” is, perhaps, clearer from Summa Theologiae 1a,3 than it is from SCG 1,20–27.15 For Summa Theologiae 1a,3, though raising some questions that Aquinas addresses in SCG 1,20–27, is explicitly titled God’s Simplicity (De Dei Simplicitate), and it breaks down into articles asking “Is God composed of this, that, or the other?” However, what Aquinas means by “divine simplicity” in Summa Theologiae 1a,3 is very much what he is also concerned with in SCG 1,20–27.
To start with, he assumes that something might be composite by being a body and having bodily parts. Correspondingly, therefore, he holds that something might be simple inasmuch as it is not a body with bodily parts.
Aquinas also thinks that something might be composite by being distinct from its nature or essence, by being an individual having an essence. Correspondingly, therefore, he holds that something might be simple by just being an essence, not having an essence.
Again, Aquinas holds that something might be composite if its essence and existence differ, if its essence is not just to be or exist. Correspondingly, therefore, he holds that something might be simple if its very essence is to exist.
So in the SCG Aquinas argues that God is simple in that (1) God is not a body, (2) God and God’s essence are not distinct, and (3) God is not something having existence conferred on it as the kind of thing it is. But Aquinas also draws out two other senses of “simple” and “composite” so as to deny that God is composite.
The first turns on a distinction between substance and accident. Largely under the influence of Aristotle, Aquinas holds that any particular naturally occurring thing in the world is an individual having a definite nature or essence. He thinks that such naturally occurring things are substances of various kinds. Now, in Aquinas’s view, a substance retains its nature or essence for as long as it exists; for example, I am a human being throughout my entire life. As we know, though, things like me can acquire and lose various genuine features without actually ceasing to exist as what they are essentially or by nature. Hence, for example, I can become thin and then fat while still being me, while still being a human being. Or I can have a full head of hair and a smooth face at one time while proceeding to be bald and have wrinkles. So Aquinas generally takes substances to be things having what he calls “accidents.” That is to say, he takes them to have features that they can acquire or lose while still being the substances that they are. So he claims that something might be composite just because it is a combination of substance and accidents. Correspondingly, Aquinas thinks that something lacking accidents can be thought of as, in a sense, simple.
The second distinction Aquinas draws out concerning composition and simplicity is grounded in the notions of genus and species.
Aquinas believes that it is possible to identify some things as members of a genus or species and as sharing a nature with other things. This leads him to suppose that members of a genus or species are composite in that the individuals that they are can be distinguished from the nature that they have. Correspondingly, Aquinas holds that something that just is its nature is simple in a way that members of a genus or species are not.
So, in terms of Aquinas’s SCG thinking, X might be composite for any of the following reasons: (1) X is a body with parts; (2) X is an individual having a nature distinct from itself; (3) X is something having existence considered as derived from what is distinct from its nature; (4) X is something with accidents; (5) X is a member of a genus or species. Correspondingly, in terms of Aquinas’s SCG thinking, X might be simple, even if not entirely simple, for any of the following reasons: (1) X is not a body with parts; (2) X is not an individual having a nature distinct from itself; (3) X is not something having existence considered as derived from what is distinct from its nature; (4) X is not something with accidents; (5) X is not a member of a genus or species.
All of the above theses concerning composition and simplicity run through what Aquinas writes in SCG 1,20–27, and they lead him to deny that God is composite. In reaching this conclusion, which, as I have said, is floated in SCG 1,18 and 19, Aquinas draws heavily on his distinction between act and potency. His presiding idea is that if God is the immutable first cause (see SCG 1,13–17), then God is not changeable, not something to be strictly classified together with other things, and not something whose existence derives in any way from something other than God. I shall leave it to you to pick through SCG 1,20–27 so as to see how Aquinas defends this idea in detail and with an eye to various objections to it with which he is familiar, but we can represent the main stages of the argument of these chapters as follows.
1. Every body has parts, is moved, is potentially divisible, and is something than which we can think of something greater. But God does not have parts, is not moved, is not divisible, and is absolutely perfect. So God is not a body (SCG 1,20).
2. Something that can be distinguished from its essence is related to what is not identical with it, this being an essence that it can share with some other things. It is also something with accidents, since accidents cannot enter into a definition of what something is essentially. So such a thing has something that can be distinguished from it considered as the individual that it is, and it is, therefore, something with a potential for change. But God is not material, has no parts, is immutable, and does not depend for existence on anything else. So for God to exist is for him to exist as whatever his essence is, not as something having an essence shareable with other things (SCG 1,21).
3. God, whose essence or nature is not distinguishable from God or shareable by anything, has to be that whose essence or nature is to exist. What does not belong to something because of its essence has to be derived from what is other than it. Yet God does not depend for existence on anything other than God. So it is God’s nature or essence to exist. For God to be what he is and for God to exist amount to the same thing, this meaning that God is pure being with no potentiality for nonexistence and no potentiality for change (SCG 1,22).
4. If nothing can be added to what God’s essence amounts to, there are obviously no accidents in God. If God lacks the ability to undergo change, then accidental change cannot be ascribed to the divine nature since the existence of accidents in a substance depends on the subject being able to change by the agency of something else. But God is unchangeable and is not caused to change by anything (SCG 1,23).
5. If God is just pure being, then God cannot be a member of a genus or species. To classify in terms of genus or species is to circumscribe or identify a way of being, while God is pure being and is, therefore, not something classifiable along with things that can be categorized in terms of genus and species (SCG 1,24 and 25).
6. God is not what all things are insofar as they exist. God is not the “formal being” of all things and is, therefore, neither a substance nor an accident. God is not mixed up in the being of things in the world and is not a part of what is other than God. Rather, God is the distinct and simple cause of all that is not divine and, as such, is above all of them (SCG 1,26).
7. God is not the form of any body but is Being Itself (ipsum esse), unlike the form of a body (SCG 1,27).