Note: I do not claim expertise on the 24 Thomistic Theses; on the contrary, I write that I may learn. Throughout this series, I'll be citing various sources that will help explain each thesis. Enjoy! Find all the theses here: THE 24 THOMISTIC THESES.

The first Thomistic Thesis highlights the most foundational truth about God's pure actuality (the first three Theses deal with this). The metaphysical structure of Scholasticism relies on the distinction between act and potency that exhaustively encompasses the totality of being.1

Latin: Potentia et actus ita dividunt ens, ut quidquid est, vel sit actus purus, vel ex potentia et actu tamquam primis atque intrinsecis principiis necessario coalescat.

Texts from Thomas:

Summa theologiae Ia, Q.77, a.1: "potency and act divide being and every kind of being…."

In Metaph. Book VII, Lect. 1: "Now essential being, which exists outside the mind, is divided in two ways, as has been stated in Book V; for it is divided, first, into the ten categories, and second, into the potential and the actual."

In Metaph. Book IX, Lect. 1: "the Philosopher's aim here is to establish the truth about being as divided into potency and actuality."

Here's a translation by Hugh McDonald: Potency and Act so divide being that whatsoever exists either is a Pure Act, or is necessarily composed of Potency and Act, as to its primordial and intrinsic principles.

Commentary by P. Lumbreras, O.P., S.T.Lr., Ph.D.:

Every actual subsisting being — inanimate bodies and animals, men and angels, creatures and Creator — must be either Pure Act — a perfection which is neither the complement of Potency, nor the Potency which lacks further complement — or Potency mixed with Act — something capable of perfection and some perfection fulfilling this capacity. This statement is true both in the existential and in the essential order. In each of these orders the composition of Act and Potency is that of two real, really distinct principles, as Being itself; intrinsic to the existing being or to its essence; into which, finally, all other principles can be resolved, while they cannot be resolved into any other. [Summa Theologiae, Iª q. 77 a. 1; Sententia Metaphysicae, lib. 7 l. 1 et lib. 9 l. 1 et l. 9]

Gatewood notes, "Thomas's metaphysical commitment to act and potency forms the foundation of many arguments concerning the doctrine of God, including his belief in divine simplicity, perfection, immutability, analogical predication, and the famous Thomistic dictum actus essendi."2

Let me cite three statements that further explain this, and also its implications in our understanding of God as pure act.

The distinction between potency and act is fundamental not only to Thomism but to Scholastic philosophy in general (though as we will see, Scotists and Suarezians disagree with Thomists about how to interpret the distinction). It is absolutely crucial to the Scholastic approach to questions about the metaphysics of substance, essence, and causation (and for that matter to Scholastic philosophy of nature, philosophical psychology, natural theology, and even ethics)… We have, then, the following basic argument for the distinction between potency and act: That change and permanence, multiplicity and unity, are all real features of the world cannot coherently be denied; but they can be real features of the world only if there is a distinction in things between what they are in act and what they are in potency; therefore there is a distinction to be made in things between what they are in act and what they are in potency.3

As Aquinas argued long ago, "potency and act are a complete division of being. Hence, whatever is must be either pure act or a unit composed of potency and act," so that there can be no univocal core of being predicated of the Creator (who is pure act) and creature (who is composed of act and potency). Neglect of this distinction, or dismissing it altogether, will inevitably produce a view of analogy that will eventually surrender divine discourse to a univocal concept of being, in which the infinite God is nothing more than a greater version of ourselves, a god in our image.4

What must be grasped and remembered, something which Aquinas' critics never seem to do, is that esse is an act, that esse is a verb. As ipsum esse God's very nature, as with the persons of the Trinity, is not then designated or signified by a noun, but by a verb. Being pure act (pure verb) as ipsum esse does not mean that God is something fully in act, such as a creature might actualize its full potential, but rather that God is act pure and simple. Because God is ipsum esse he has no self-constituting potency which needs to be actualized in order for him to be more fully who he is, not because he is something fully in act, but again, because he is act pure and simple. God is actus purus.5

Without this metaphysical composition, the distinction between different individuals or things sharing the same nature (e.g. human) would become unintelligible, as they would lack a principle of individuation to restrict their specific forms. This distinction also ensures that the infinite God is not simply viewed as someone who is just a greater version of finite creatures or a better being, but as a being of an entirely different, or we can say other-worldly, ontological order.

Since God alone is act pure and simple, all other things that are not God are composed of act and potency. God's existence is necessary since none of any creature can cause its own existence, as Aquinas says, "potency does not raise itself to act; it must be raised to act by something that is in act" (SCG I.16.3). This is the foundation of the famous Aristotelian–Thomistic principle that "whatever is moved is moved by another" (In Phys VII.2.891).3

Main References

Footnotes

  1. Marshner writes, "The noun ens means either 'a being' or the whole set of them. A being is 'a thing which is,' hence a thing which is 'in being' and hence in that set. Without qualifiers, 'a being' is a thing which exists. Given a qualifier, a being is 'a thing which is such-and-such.'" ↩

  2. Gatewood, Timothy A. (2021). Truth Not Served by Human Hands. Eugene: Wipf and Stock Publishers. ↩

  3. Feser, Edward. Scholastic Metaphysics: A Contemporary Introduction. Heusenstamm: Editiones Scholasticae, 2014. pp. 33, 38. ↩ ↩2

  4. Baines, Ronald S., Richard C. Barcellos, James P. Butler, Stefan T. Lindblad, and James M. Renihan, eds. Confessing the Impassible God: The Biblical, Classical, and Confessional Case for Divine Impassibility. Palmdale, CA: RBAP, 2014. ↩

  5. Weinandy, Thomas G. Does God Suffer? Notre Dame, IN: University of Notre Dame Press, 2000. ↩