4.2 God as Lacking Passive Potency and Matter (SCG 1,16 and 17)
4.2 God as Lacking Passive Potency and Matter (SCG 1,16 and 17)
The next two chapters of SCG 1 amount to a drawing out of some implications of what Aquinas has already argued. In SCG 1,16 he claims that there is no passive potency in God. In SCG 1,17 he maintains that there is no matter in God.
By “passive potency” (potentia passiva) Aquinas means “an ability or power to be acted on or changed by something else.” He would say, for example, that I have a passive potency to be pushed by you, to be lifted up by someone, or to be injured. Given that he has already argued that God is the first unmoved source of change, Aquinas obviously has to conclude that God cannot be subject to alteration by the agency of something else, which is the drift of SCG 1,16. Indeed, he says, if God is eternal, God cannot even not exist. “God is the first being and the first cause. Hence, he has no admixture of potency in himself.”9 On this account, God is “pure act” (actus purus) and not something actually thus and so while potentially different in some way or to some degree.
By “matter” (materia) Aquinas means something that is always in potency. We might naturally speak of the matter left in a test tube at the end of an experiment, and we would think of this as stuff of some kind that is able to interact with things causally. In SCG 1,17, however, Aquinas is using the word “matter” in a more technical and restricted sense, one that is not very easy to grasp. On his view, matter is not stuff of some kind. It is the precondition for change or coming to exist in the physical world. For this reason it is not a special member of the world or something to be classified in terms of genus, species, or acquired or acquirable characteristics.
We sometimes say that we live in a material world. When we do this, and unless we assume that everything that exists has to be physical, we are not describing the nature of the world considered as a thing of some kind, as, for example, when we say that such and such is wooden or made of gold. We are basically saying that we live in a world in which things come to be and pass away, a world that contains things subject to change for as long as they exist, a world in which things of various kinds can emerge from things of other kinds.10 Running through this notion of “material” is the idea of the “material world” being made up of a series of changes within a whole that is, so to speak, able to accommodate or favor them; and it is this idea that Aquinas is working with when he speaks of “matter.” Here, “matter” is, so to speak, the playground in which various changes take place. So, of course, Aquinas concludes that God does not contain matter since God is wholly actual and lacks any real potentiality.11