The Real Distinction Between Act and Potency

Introduction

This talk proceeds from a metaphysics that makes three claims: the primordial grammar of being is the grammar of being-in-act and being-in-potency; throughout our experience of finite being, we encounter an interweaving of being-in-act and being-in-potency; yet there is one case of pure being-in-act, and this we call God. These claims are the structural bones of any truly Thomist metaphysics. My goal today is to enliven something of the unshakable certainty that comes from first principles and an inchoate grasp of per se necessities. We will proceed in three sections:

1˚ “Raising the Issue”: Some Philosophical Examples of Being Haunted by Being

2˚ What are some of the ways in which being-in-act and being-in-potency are experienced as really distinct? Must we always experience being-in-act intermingled with being-in-potency?

3˚ Why is the distinction between act and potency centrally structural for metaphysics itself?¹

1˚ “Raising the Issue”: Some Philosophical Examples of Being Haunted by Being

It is a classic move for a reader of Thomas Aquinas (or of Aristotle) to harken back to the stylized debate between Heraclitus and Parmenides. I ask your indulgence for one more return to it. These two figures map a dilemma that has not gone away, and the act-potency distinction is best seen against the pressure they exert.

In our own day, we are all perhaps Heracliteans, at least in our social-philosophical imagination. The pre-Socratic philosopher from Ephesus was, in truth, more sophisticated than the dicta most famously associated with him.² Nonetheless, in the hands of Plato and Aristotle above all, he became the mouthpiece for a metaphysics of becoming: all things flow; being is nothing but constant change, like fire; one cannot step into the same river twice…

Call this a metaphysics—and, before that, a natural philosophy—of becoming. Even if our contemporaries do not cite “Father Heraclitus” by name, the imagination of a universe that is “pan-mutative” is not far from our hearts. Faced with the scientific data that call for an explanation of the evolutionary progress of material beings, is it not tempting to speak of the constant change of all things? Have we not heard the story that the old metaphysics of “fixed essences” has been replaced by a metaphysics of evolutionary forms and history, in which nothing is fixed and reality is nothing more than flow, a flux?

And if this is what reality is, what does that mean for our knowledge of reality? We speak about fixed things — trees, animals, justice, snakes, rivers. But these words are mere tools to fix our grasp of an ever-changing reality, are they not? Are they not pragmatic freeze-frames on the becoming-flow that is reality?³

Yet such a claim is self-destructive. Why stop with the representations we make of reality? Why would any of these be fixed? To be consistent, they too must flow, change, become. Such ideas, such words, themselves never are. Nothing is. There would be only becoming-flow. And if the sense of all things changes, if sense itself is ever-changing, then sense is also non-sense. Reality would be, in fact, realized contradiction, realized absurdity.

To express even a word, even a single sense,⁴ to find any foundation at all, one must seek a foothold on solid reality, on that which is. This too brings its own problems. You are familiar with the famous poem of Parmenides, in which he poses a dilemma between night and day, between truth and mere opinion, between being for which it is impossible not to be and non-being for which it is impossible to be.⁵ His path of truth would require a great asceticism of the mind, for now multiplicity and change seem impossible: what is is, and what is not is not. There is no river. There just is is. And our words are once again as unreal as before — only now in the face of a kind of Uncreated Being, outside of which there is only non-Being.

The position seems so extreme that we are tempted to ignore it. Yet it has familiar emulators. If we take the experience of multiplicity seriously, we find ourselves haunted by the question: what really is and cannot not be? Various solutions have presented themselves historically. Ancient atomism is one attempt to retain the Parmenidean is, but now within a framework of small, unsplittable particles of different sizes and shapes. Only they are. All wholes are not, in fact, wholes; they are atoms aggregated. The position can be—and has been and should be—criticized for reducing causality to the material without the formal, and the efficient without the final. That is not our purpose here. What I wish to point out is this: atomism represents one supposed “solution” to the question of being, a peculiar valorization of being-in-act in the form of atomic wholes.

Another famous path was that of the Pythagoreans, for whom number and ratio are the true reality of things. The Parmenidean One-Being is broken up into many mathematical realities, each being what it is and unable not to be what it is. We moderns are inheritors of Renaissance neo-Pythagoreanism, which exercised important influences on modern science. Do we not think that the mathematical is, in fact, the real?

Yet Plato too was an inheritor of Pythagoreanism. His Forms were an attempt to do justice to “Father Parmenides.” On the side of mutable reality, one could say, he was quite akin to Heraclitus:⁶ all the changing realities of our experience really are not, for they are always changing. What is real? It is the noetically stable intelligibility we glimpse through these things: Justice-Itself, Piety-Itself, Sameness-Itself, Beauty-Itself, Goodness-Itself…

Yet if the Sophist and the Parmenides (arguably also the Timaeus) are any hint, Plato himself was haunted by a series of perplexities. Justice-Itself is Justice-Itself. But it is not Piety-Itself. And somehow the changing things of reality, the objects of our experience, have the Forms present within them. They are agitated and changing reflections of the Forms; yet they are not the Forms. Plato felt himself a parricide because he had to call into question the Parmenidean maxim. Even among the things that are—the Forms—there is also a kind of not-being, namely, other Forms.

Whatever shape these positions take across the centuries, they share a common quietism. On one side, a nominalist quietism in which all reality both is and is-not, in which we ride the flow of becoming, with none of this being—neither us nor the flow itself.⁷ On the other side, a fixed reality, but wherever that fixed reality is not, there is only non-being and illusion. These are the stakes of metaphysics because they are the stakes of being and non-being. A subtler understanding of to-be and to-not-be is needed. We need, in fact, the distinction between to-be-in-potency and to-be-in-act.

2˚ What are some of the ways in which being-in-act and being-in-potency are experienced as really distinct? Must we always experience being-in-act intermingled with being-in-potency?

Let us begin anew, with a simple datum: changing things around us. Rather than begin with a grand theory that explains everything away, we can take as our starting point, in the manner of Aristotelian natural philosophy, a rather obvious fact: we experience things changing around us. Trees grow gradually from seed to their last day; animals live out their lifecycles; we gain skills as human agents. Change of this sort—motion—is all around us, in a variety of forms.

We have, moreover, several simple principles for understanding such changes: there is something that changes (a subject of change), and it passes from not-being something (potency) to actually being something (a terminus or having, sometimes called “form,” in the sense of being-formed in a new way). These are the classic principles of nature discussed in the opening books of Aristotle's Physics and laid out so clearly in Thomas's opusculum on the principles of nature.

What is this motion from not-being-informed to being-informed, from not-being to being? It is not mere negation or privation. When the tree in early spring passes from being bare to having leaves, or when I pass from not knowing how to play the piano to having some ability to play, there is something more here than the mere not-being-leaved or not-being-a-pianist. Before the change began, we can say that, unlike the tree, I was the sort of being that could learn the piano; and prior to the spring bloom, the tree, unlike me, was the sort of being that could grow leaves. There is something real in each of us, a real capacity for being something. This real capacity to be something is potency.

We should not miss the importance of this, something too readily taken for granted by Thomists, who often are guilty of thinking that the whole world talks and thinks like Thomists. Before I learned to play the piano, I was not actually a pianist; before the tree grows its leaves, it is not actually green-leaved and ready for a summer of photosynthesis. And yet, as a human being, I am potentially a pianist; and as a dogwood, the tree is potentially leaved. At one and the same time, I both am and am not a pianist, though in different respects: in potency I am; in act I am not.

And what is this motion itself? It is a kind of actualization. Receiving from a tradition of music (whether a living teacher or a text), I sit and work at the piano, not yet able to say that I have the skill of musicianship, yet no longer able to say that I am merely in potency to it. I am in the process of becoming actual. My practicing the piano is a state of being actualized, even as I remain in potency to being a pianist. Motion is, as the jargon has it, the actualization of a potency inasmuch as it is potency. My prior potency for being a pianist, this motion-actualization, and the eventual state in which I can say “I am a pianist”—we have no reason to think these are the same. Each is a distinct principle of my being. Even without the laser-focused vocabulary of developed scholasticism, even here in the phenomenon of motion, we have a basic indicator that potency and act (whether motion-act or act as such) are distinct. My actually-being-a-pianist was not actually pre-contained in my being-capable-of-piano-craft the way a coiled pressure is pre-contained in a spring. Actualization was needed, so that potency could be what it actually was not. Here already we find ourselves bumping up against an important thesis: the real distinction between act and potency.

Let us take another example, building on the piano case. Once I have qualified as a pianist, I am the sort of being who can, when I so desire, readily and with ease take up at least certain pieces of music and play them well. I can interpret them differently, emphasizing certain nuances for my listeners; I can alter the style in a whimsical way. Yet all of this remains potential unless I am actually playing. In the scholastic jargon, I am a pianist in first act. But I am not yet playing; I am not yet a pianist in second act. In habit, I actually am a pianist. As a performer, I am not actually a pianist, though I am a performer potentially. If we do not say that being-potentially and being-actually are really distinct, we will imagine that future actuality is wholly pre-contained in present potentiality, as though a pressure were merely waiting to be released. But to the Thomist, the distinction is real, and the future a mixture of nature and adventure.⁸

Let us now take for granted a piece of shared Thomistic knowledge: the notion of matter and form. I have one and the same life, one intelligible actuality of being human. From my first moment until my death and even beyond, to the “last things,” I am always actually human. That is, I have the actual structure of life that belongs to human existence. Yet my body changes—I grow, my cells undergo many changes, my neurology and musculature change with each era of my being. The potential “planks” of Theseus’s human ship change; the actuality remains the same. All the while, I live a human life. This actuality is my form, humanity. The materiality is what is in potency to this humanity; it is what receives the dynamism of the particular actuality that is human life.

Let us note, therefore, another important aspect of the real distinction between act and potency. Potency is a real capacity for being. We have already seen this, but consider it again in the case of a substantial essence. My humanity is received in this or that particular, quantitatively determined matter. Humanity-act is received and limited—not by act, but by the potency that is materiality. Here Plato's insight is maintained after a fashion: precisely as a species, humanity is not self-limiting; it specifies what it is to be human. For the Thomist, however, it does not exist as a free-floating and abstract humanity. It exists as a particular actuality, an actuality that is received and limited to me, to you, to each and every other human. It is one and the same actuality, one and the same life form in us all,⁹ but received in various material-potencies. If one were to deny the real distinction between act and potency, one would risk a nominalism in which form-actuality would be forever trapped within its matter-potency.

Consider now how this real distinction between form-act and matter-potency underlies the very possibility of realist cognition. When I know and articulate for myself what something else is—through definition, judgment, or reasoning—I truly am that other thing. This is, for the Thomist, the very nature of speculative cognition: to be the other as other.¹⁰ But this is only possible because form and matter are distinct. To-be-human is not, of itself, limited to the conditions of the potency (matter) that receives it. It could itself be received in another.

But is humanity—or treeness, or termiteness, or justice—known merely by being what it is in the world?¹¹ No. Humans might exist, as might trees, termites, or even just acts¹² without being speculatively known as such. Yet as the determining actuality of termites, trees, humans, and just acts, these forms are potentially intelligible, for to-be-actual is to be intelligible: to be is to be manifest and manifestable—to be true.

In relation to the matter they inform, the forms of things are act. In relation to the mode of being that is cognitional, they are in potency. It is only through the human person's activity—the person, through his nature, operating through the power-quality that is the (agent) intellect—that the termite-form comes to be actually knowable and actually known. Before this, the form, received in its various particular materialities, was the act-principle of an operative substance. But as known it is actually known as actually manifesting itself to this or that knower; in the order of cognitional being, it is actually known, and the knower actually is it. This is the nature of knowledge: the knower is the known, by one and the same act of cognitional being. But this is only possible because the form in question was not intrinsically conscripted to its limitation in the matter that it informed. The form was, instead, really distinct from this matter and thus able to communicate cognitionally. Form is already something non-material, something divine, in things.¹³ But this non-material principle is only fully actualized as knowable when it meets the human person, this embodied spiritual knower made in the image and likeness of God.

What we have said also hints at a further distinction at the heart of the real distinction between act and potency: the real distinction between to-be (esse) and essence. Already in the Thomist theory of noetics, we begin to see that the essences of things are not only received (by their matter) but are themselves the receiver of being. A termite essence, for example, is the recipient of the esse that terminates this essence and makes it actually exist as a pernicious and destructive force—at least for the homeowner whose house is under attack. Yet the termite essence can also receive another kind of being, a super-existing that goes beyond its substantial existence. It can have the being of knowledge: objective or intentional existence. The essence remains one and the same. Yet in the living termite, it is a nature, a per se principle of motion and rest; for the knower, it is a known “whatness,” a quiddity. It is one and the same essence, subject to two different esse. If the distinction between essence and existence were not real, we would once again find ourselves unable to be realists. Essence would be trapped in its subjective, “extramental” existence.¹⁴

If potency receives and limits act, must we say that act must always be received?¹⁵ Not always. Already in the order of finite being, there is a kind of actuality that is, in one order, not received: angelic essence. For on Thomas's metaphysics, the angel's essence is not received in matter. As form-act, the being of “Gabrielity” is not received in a potential matter that must constantly be Gabrielized, as is the case for hylomorphic beings. The subject of Gabriel's existence is his very Gabrielity. From the first instant of his creation, he is wholly what he is. His wayfaring moment prior to entrance into eternal bliss therefore involves no motion of the kind we find in human pilgrims amid salvation history. Each angel is fully in possession of what he is and acts in the light of that primordial self-knowledge. But he is not pure actuality; he receives—both his substantial esse and the accidental being of his various acts of knowledge and willing.

Yet at the consummation of even the most evident of the “ways to God”—the proof through motion, which already terminates in the assertion that there must be a First Act upon which every motion depends—we find ourselves faced with a further assertion: there is an Actuality, a Pure Actuality, limited in no way, subject to no change, to no particularity, to no potency. This Pure Act stands at the culmination of the perfection that is act. Potency is a real capacity to receive perfection. But at its height, perfection does not need to be received. It is neither in another nor in itself. He is from himself, a se. Act and potency remain really distinct even here, but here the distinction in question is the pure transcendence of God, above all potency.

3˚ Why is the distinction between act and potency centrally structural for metaphysics itself?

The real distinction between act and potency is the keystone of Thomist metaphysics. It is understandable why a certain Aristotelian reading of metaphysics would identify the primary subject of attribution as being-in-se, substance, the first referent among the ten categories of being. This is in fact how Aristotle unifies the subject of metaphysics (notably in books Γ and Ε): the multiple senses of being find their unity in substance. Yet a Thomist, aware that esse-in-se (substance) is not the same as esse-a-se (the aseity of Pure Act),¹⁶ should already be uneasy with the purely Aristotelian metaphysics often presented as the Thomist's native metaphysical grammar.¹⁷

Deeper than the division of being into the ten categories is the division of being into act and potency. The metaphysician, concerned with being as being, can take the ten categories as a starting point, the place where being inasmuch as it is being manifests itself in the “common being” proportionally present in each category. What is most explanatory of this categoriality is the act-potency structure present not only within each category but also among the categories themselves. The being-in-act / being-in-potency structure is ultimately more explanatory than the categorial. He whose existence is pure act does not fall under the subject matter of metaphysics. He is attained, nonetheless, by way of the grammar of being, the act-potency structure that is the royal highway to his Transcendence.

Moreover, if knowledge and love are ways of being—though in a way not wholly reducible to substance-accident analysis, for to know and to love are new ways of having esse, in the manner that is cognitional or intentional—then Thomist metaphysics must find its most genuine sense of being through a careful treatment of the analogical senses in which being is said to be actual and to be potential.¹⁸ The point of continual reference for a sound Thomist metaphysics will therefore be to ask: how does this point relate to the first and most important division of the common being of our experience, namely the division of being into act and potency?

Today’s lecture has only begun to lay out that distinction. I hope, however, that I have indicated something of its lineaments. To close, allow me to trace through the various senses of act and potency by way of summary. Act and potency are properly proportional analogical notions, irreducible to a single, generic meaning.¹⁹ To grasp this analogical unity, we must consider the various members of the set of analogates.²⁰ We will do so in ascending fashion, first considering act (the more intelligible of the two) and then potency — partly repeating ourselves, in the hope of stabilizing in your mind these correlative but distinct senses.

[With the following two outlines, I will close with a somewhat open-ended but quick summary, on occasion filling in details. The outlines will be presented in a handout. This is not, however, meant to be comprehensive, given the way that act and potency are present throughout the various realities properly belonging to the domain of intentional existence. The outline is adapted from Austin Woodbury, Ostensive Metaphysics, nos. 727 and 732.]

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1. The classic text concerning the ubiquity of the distinction between act and potency throughout the whole of Thomism is Gallus Manser, The Essence of Thomism, trans. Michael J. Miller (Emmaus Academic, 2025). For some more or less detailed pedagogical indications, see Ambroise Gardeil, “Acte,” Dictionnaire de théologie Catholique, vol. 1, ed. Alfred Vacant (Letouzey et Ané, 1899), cols. 334–337 (Acte et puissance); Réginald Garrigou-Lagrange, Reality: A Thomistic Synthesis, trans. Patrick Cummmins (St. Louis, MO: Herder, 1950), 37–57; Édouard Hugon, Cursus philosophiae thomisticae, vol. 4 (Lethielleux, 1935), 278–287; idem., “Les vignt-quatre these Thomistes,” Revue Thomiste (1920): 116–142 (esp. 116–130)↩︎

2. For a better context concerning his received dicta, see G.S. Kirk, J.E. Raven, and M. Schofield (ed. and trans.), The Presocratic Philosophers (Cambridge University Press, 1985), 181–212.↩︎

3. The reader familiar with 20^th-century francophone Philosophy might sense the figure of Henri Bergson, whom I have in mind in this paragraph, although, admittedly, this kind of nominalist cognitional theory is quite widespread. Bergson, not perhaps a first-rate philosopher, nonetheless has the merit of putting in very stark terms the implications of a kind of pragmatic theory of truth at the heart of modern nominalism, itself undergirded by a kind of implicit Heracliteanism. I could not help but hear echoes of the same epistemology, years ago, while reading an Atlantic article sent to me by a relative. See the comments of Donald D. Hoffmann in Amanda Gefter and Quanta Magazine, “The Case against Reality,” The Atlantic (April 25, 2016):

   Snakes and trains, like the particles of physics, have no objective, observer-independent features. The snake I see is a description created by my sensory system to inform me of the fitness consequences of my actions. Evolution shapes acceptable solutions, not optimal ones. A snake is an acceptable solution to the problem of telling me how to act in a situation. My snakes and trains are my mental representations; your snakes and trains are your mental representations (emphases added).

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4. Implicit in my comment is one of the classic defenses of the principle of non-contradiction, found among others, in Aristotle, Metaphysics, Γ(4).4 (trans. W.D. Ross):

   First then this at least is obviously true, that the word 'be' or 'not be' has a definite meaning, so that not everything will be 'so and not so'. Again, if 'man' has one meaning, let this be 'two-footed animal'; by having one meaning I understand this:-if 'man' means 'X', then if A is a man 'X' will be what 'being a man' means for him. (It makes no difference even if one were to say a word has several meanings, if only they are limited in number; for to each definition there might be assigned a different word. For instance, we might say that 'man' has not one meaning but several, one of which would have one definition, viz. 'two-footed animal', while there might be also several other definitions if only they were limited in number; for a peculiar name might be assigned to each of the definitions. If, however, they were not limited but one were to say that the word has an infinite number of meanings, obviously reasoning would be impossible; for not to have one meaning is to have no meaning, and if words have no meaning our reasoning with one another, and indeed with ourselves, has been annihilated; for it is impossible to think of anything if we do not think of one thing; but if this is possible, one name might be assigned to this thing.)

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5. For relevant commentary and various fragments, see The Presocratic Philosophers, 214–262.↩︎

6. Or, rather, to the neo-Heraclitean Cratylus.↩︎

7. The quietist vitalism of Schopenhauer is a kind of defeated form of quietism. It takes the superhuman, self-divinization of the Nietzschean Übermensch to overcome this negative nihilism with a supposedly positive nihilism.↩︎

8. The words “nature” and “adventure” are chosen purposively. See Jacques Maritain, The Degrees of Knowledge, trans. Gerald Phelan et al. (University of Notre Dame Press, 1995), 29:

   To the question why does not the necessity of laws—and these are the objects of science—extend to each of the particular events that takes place here below? this answer must be made: the world of actual existence and concrete reality is not the world of pure intelligible necessities. Essences or natures do exist within existing reality; from it they (or their substitutes) are drawn by our mind, but they do not exist there in a pure state. Every existing thing has its own nature or essence. But the existential positing of things is not implied in their nature, and amongst them there are encounters which are themselves not natures, the necessity for which is not prescribed in any nature. Existing reality is therefore composed of nature and adventure. That is why it has a direction in time and by its duration constitutes an (irreversible) history—these two elements are demanded for history, for a world of pure natures would not stir in time; there is no history for Platonic archetypes; nor would a world of pure adventure have any direction; there is no history for a thermodynamic equilibrium.

   Also, Jacques Maritain, Existence and the Existent, trans. Lewis Galantiere and Gerald B. Phelan (Pantheon: 1948), 65–67:

   God does not create essences to which He can be imagined as giving a last rub of the sandpaper of subsistence before sending them forth into existence! God creates existent subjects or supposita which subsist in the individual nature that constitutes them and which receive from the creative influx their nature as well as their subsistence, their existence, and their activity. Each of them possesses an essence and pours itself out in action. Each is, for us, in its individual existing reality, an inexhaustible well of knowability. We shall never know everything there is to know about the tiniest blade of grass or the least ripple in a stream. In the world of existence there are only subjects or supposita, and that which emanates from them into being. This is why ours is a world of nature and adventure, filled with events, contingency, chance, and where the course of events is flexible and mutable whereas the laws of essence are necessary. We know those subjects, we shall never get through knowing them. We do not know them as subjects, we know them by objectising them, by achieving objective insights of them and making them our objects; for the object is nothing other than something of the subject transferred into the state of immaterial existence of intellection in act. We know subjects not as subjects, but as objects, and therefore only in such-and-such of the intelligible aspects, or rather inspects, and perspectives in which they are rendered present to the mind and which we shall never get through discovering in them.

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9. I would, however, register certain qualifications for the case of human beings in comparison with purely hylomorphic forms. However, this is beyond the technicality possible for a lecture like this. See my remarks on To Be A Thomist, “The Providential Structuring of Humanity through the Spiritual Soul’s Relation to the Body” (https://www.athomist.com/articles/the-providential-structuring-of-humanity-through-the-spiritual-souls-relation-to-the-body).↩︎

10. For a clear exposition of this, see Reginald Garrigou-Lagrange, “Cognoscens quodammodo fit vel est aliud a se (On the Nature of Knowledge as Union with the Other as Other),” Philosophizing in Faith: Essays on the Beginning and End of Wisdom, ed. and trans. Matthew K. Minerd (Providence, RI: Cluny Media, 2019), 63-78. Also see Yves R. Simon, “To Be and To Know,” in Philosopher at Work, 173-193. John N. Deely, “The Immateriality of the Intentional as Such,” The New Scholasticism 42 (1968): 293-306. Also, see Yves R. Simon, “An Essay on Sensation,” in Philosopher at Work, ed. Anthony O. Simon (Lanham, MD: Rowman & Littlefield Publishers, 1999), 57-109. From a somewhat different perspective than my own and that of the aforementioned authors yet nonetheless relevant, see Thérèse Cory, “Knowing as Being? A Metaphysical Reading of the Identity of Intellect and Intelligibles in Aquinas,” American Catholic Philosophical Quarterly” 91, no. 3 (Summer 2017): 333–351.↩︎

11. We are setting aside of the dependence of all things upon the divine science of vision, which is the extrinsic formal cause of all that is.↩︎

12. Though they will be dependent upon the practical knowledge of the one performing them.↩︎

13. For a study of this theme, see the insightful work of Lawrence Dewan, St. Thomas and Form as Something Divine in Things (Milwaukee: Marquette University Press, 2007).↩︎

14. For some examples of the various philosophical positions that are dependent upon affirming the real distinction between essence and existence, see Maritain, Existence and the Existent, 39–42. The classic detailed study of this topic is found in Norbert del Prado, De veritate fundamentali philosophiae christianae (Fribourg: St. Paul, 1911).↩︎

15. On this, see Joseph Gredt, O.S.B., "Doctrina thomistica de actu et potentia contra recentes impugnationes vindicata" Acta Pontificiae Academiae S. Thomae Aquinatis NS 1 (1934): 33–49. A rough translation of this article can be found at https://medium.com/@thomisticae/actus-non-limitatur-nisi-per-potentiam-a-defense-of-thomistic-doctrine-e35d53ff412c. As summarized by Pedro Lumbreras, concerning the second of the twenty-four Thomist theses promulgated in 1914 by the Sacred Congregation of Studies (Actus, utpote perfectio, non limitatur nisi per potentiam, quae est capacitas perfectionis. Proinde in quo ordine actus est purus, in eodem nonnisi illimitatus et unicus exsistit; ubi vero est finitus ac multiplex, in veram incidit cum potentia compositionem):

    Since Act means perfection, perfection belongs to Act by reason of itself; imperfection, then, by reason of something else. Limits, therefore, belong to Act but on account of Potency. Consequently, if an Act is pure, it is perfection without limits, and gives no ground for distinction and multiplicity. On the contrary, any finite or manifold Act is mixed with Potency: for it is only as subjected in Potency that it is limited and multiplied according to the capacity of the subject.

    As textual references in Thomas, see ST I, q. 7, a. 1 and 2; ST I, q. 11, a. 3; SCG, bk. 1, ch. 43; In I Sent. d. 43, q. 2; De spiritualibus creaturis, a. 8. Also, for a variety of relevant texts, see the bibliography in Joseph Gredt, Elementa philosophiae aristotelico-thomisticae, vol. 2, 13^th ed., ed. Eucharius Zenzen (Herder, 1961), no. 657 (p. 50–51).↩︎

16. See ST I, q. 3, a. 5 (Utrum Deus in genere aliquo sit). Also see parallel loci In I Sent., d.8, q. 4 and d. 19, q. 4, a. 2; SCG bk. 1, ch. 17 and 25; De potentia, q. 7, a. 3.↩︎

17. The reader alive to the stakes of this question concerning the subject matter of metaphysics will recognize the historical tension between a certain Aristotelian reading of the subject of attribution and a super-transcendental reading of it. I believe one can hold that the ultimate primary subject of attribution of metaphysics is being as divided into act and potency. Handled carefully, the qualifier "as divided" prevents one from placing God under the subject of metaphysics: one is concerned primarily with that being which is variously and correlatively divided into act and potency, such that Pure Act stands only as the cause of this subject matter, not within the ambit of the subject matter itself. This claim is ambitious and requires more thought — and, doubtless, more discussion with those who have long pondered these matters, above all Fr. Philip Neri Reese, O.P., to whom I owe a debt of gratitude for certain precisions, even though I am not sure he will agree with the directions of my thought. For some initial notes on super-transcendentality, see my

    For some initial notes on supertranscendtality, see my “To Supertranscendentality and Back Again” on To Be a Thomist, https://www.athomist.com/articles/to-supertranscendentality-and-back.↩︎

18. See John Deely, The Tradition via Heidegger: An Essay on the Meaning of Being in the Philosophy of Martin Heidegger (The Hague: Martinus Nijhoff, 1971), 7:

    If the intentional order does not formally touch the entitative order in the particular kind of act / potency relation known as substance / accident composition, yet it does permeate it through other modes of act / potency composition—which is but to say that act / potency analysis as such cannot be reduced to substance / accident ontology, and that it is the former, not the latter, which provides the genuine categories of first philosophy, that is, of Metaphysics.

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19. This is no vague appeal to the analogy of proper proportionality but, rather, the very method of Aristotle himself when he looks to summarize what he has said about act and potency in book Θ (9).6 (trans. Ross):

    Since we have treated of the kind of potency which is related to movement, let us discuss actuality-what, and what kind of thing, actuality is. For in the course of our analysis it will also become clear, with regard to the potential, that we not only ascribe potency to that whose nature it is to move something else, or to be moved by something else, either without qualification or in some particular way, but also use the word in another sense, which is the reason of the inquiry in the course of which we have discussed these previous senses also.

    Actuality, then, is the existence of a thing not in the way which we express by 'potentially'; we say that potentially, for instance, a statue of Hermes is in the block of wood and the half-line is in the whole, because it might be separated out, and we call even the man who is not studying a man of science, if he is capable of studying; the thing that stands in contrast to each of these exists actually. Our meaning can be seen in the particular cases by induction, and we must not seek a definition of everything but be content to grasp the analogy, that it is as that which is building is to that which is capable of building, and the waking to the sleeping, and that which is seeing to that which has its eyes shut but has sight, and that which has been shaped out of the matter to the matter, and that which has been wrought up to the unwrought. Let actuality be defined by one member of this antithesis, and the potential by the other. But all things are not said in the same sense to exist actually, but only by analogy-as A is in B or to B, C is in D or to D; for some are as movement to potency, and the others as substance to some sort of matter (emphasis added).

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20. See Yves R. Simon, “On Order in Analogical Sets,” The New Scholasticism 34, no. 1 (Jan. 1960): 1–42; also included in Philosopher at Work, ed. Anthony O. Simon (Lanham, Maryland: Rowman & Littlefield, 1999), 135–171↩︎