The title of this article echoes that of one of the most remarkable and provocative books in the history of American Thomism, William Carlo’s The Ultimate Reducibility of Essence to Existence in Existential Metaphysics,¹ which was one of the finest fruits of the 20th century Thomist renaissance in metaphysics in North America. But its radical nature, the eclipse of Thomism, and the death of its author not long after it appeared, have rendered it almost invisible, especially the challenge it lay down in regard to matter.

William Carlo was born in Yonkers, New York, studied at the Pontifical Institute of Medieval Studies and the University of Toronto, went on to teach at St. John’s University, Boston College, and the University of Ottawa, and was the father of five children. When he was 36 years old he responded to a paper called "The Being of Creatures" given by Gerald Phelan at the 1957 meeting of the American Catholic Philosophical Association.² In his short response, he articulated the heart of the metaphysical insights that he was to elaborate in an article that appeared in the International Philosophical Quarterly in 1964,³ and in a paper on matter at the American Catholic Philosophical Association meeting of that same year.⁴ And both of these articles were to be taken up, in large part verbatim, in his 1966 book on essence and existence.

The Ultimate Reducibility of Essence to Existence

Gerald Phelan had realized that the doctrine of creation had played a vital role in the development of metaphysics in a Christian context. It could even be said to have helped inspire St. Thomas to transform Aristotle’s world of essences in the light of existence. Fr. Phelan expressed this transformation in a provocative fashion by replacing the word essence with mode of existence.

"To be, for a creature, is always to exercise being (esse) IN SOME MODE. It is the mode of existence which limits and restricts the esse. To call it "essence" is all very well, provided essence is not regarded as some positive thing, but simply the "by which" (quo), or the mode, measure or manner in which the act, esse, is exercised... What exists is neither the esse nor the mode of its exercise (or essence) but the ens which results from the placing of a limit upon esse in the very act by which God creates. Just as esse has no meaning, is inconceivable, except as exercised in some mode, so essence, or the mode of exercise of esse is inconceivable and meaningless without reference to the act by which it is... By imposing from within the thing (res) a limitation on its esse (which, incidentally, actively posits aliquid in re) essence positively restricts the dynamism of the act of being (esse) within the limits of the ontological definition of the being (ens) or thing (res) which exercises that act."⁵

These remarks served as a catalyst for Carlo to try to explore the relationship between essence and existence as deeply as possible. The very notion of essence, he felt, so central to Greek philosophy, had been transformed by St. Thomas who had to express his revolutionary metaphysical intuitions in the common metaphysical language of his day. "Thus there are two sets of apparently contradictory texts in Thomas Aquinas. There are those texts where he speaks of essence as somehow possessing an actuality of its own, as that which receives esse, as that which limits esse. There is the other group of texts where St. Thomas speaks of essence as non-being, as concreated rather than created, as co-existent rather than existent."⁶ And Carlo is impelled not only to unify these two strands of texts, but to set out to reduce essence to existence as much as possible.

"We certainly agree with Father Phelan that essences are modes of being, that they are intrinsic modifications of esse. But when this doctrine is coupled with that of the non-being of essence, what happens to essence? It is non-ens because it is other than ipsum esse which it receives from another. That which participates esse has to be non-ens... Essence flows from esse. Esse gives rise to essence. Essence is the intrinsic modification of the dynamism of actual exercise of the act of being. Why not describe essence, then, as the place where esse stops, bordered by nothingness?... This doctrine of the non-being of essence and the ultimate reducibility of essence to esse is, I think, a logical consequence of the interpretation of essence as a mode of being."⁷ And submerged in his preoccupation of the relationship between essence and existence is a hint of what is to come. Just as in the case of essence, St. Thomas has two strands of texts about matter. "Matter is pure potency, in the genus of substance. It has an esse, is a similitudo of the Divine Esse, and finally it is non-being - non-ens."⁸ This tension, too, will have to be resolved.

The second response to Fr. Phelan’s paper was by Norris Clarke who put what Phelan was doing in perspective. Underlying the apparent agreement among Thomists about a real distinction between essence and existence, he tells us, exists an unexamined divergence between those who look at esse as merely conferring existence on an essence that already has its formal perfection, and those who find the "positive content of perfection in a finite being... within the very act of existence itself..."⁹ He goes on to indicate the relationship of Fr. Phelan’s article to the recent Thomist literature, especially that of the Le Saulchoir Dominican School, and the earlier works of the rediscoverers of an existential Thomism. Fr. Clarke was to present Carlo’s article to the world and write a remarkable preface to his book.

The general context, then, of Carlo’s work is clear. Drawing on the rich 20th century of existential Thomism, he is going to try to distill it into some sort of ultimate expression of the relationship between essence and existence, and he is going to take the insights he has forged in the fire of this reduction and apply them to the question of matter.

Essences "are intrinsic modifications of esse." Or inversely, "Esse as knowable in its limitation is called essence and form."¹⁰ "To essence belongs the capacity of contracting esse."¹¹

If Giles of Rome and much of the scholastic tradition pictured esse as an ocean, and essences as the vessels in which its water is poured, Carlo wants to transform this metaphor. Imagine, he tells us, that the water from one of these vessels is poured out and freezes before it hits the ground, or a stream suddenly freezes, and we hew it into pieces with an ax. "The shape it assumes is the determination of its own substance. Essence is not something extrinsic to existence which limits and determines it in the way that a pitcher shapes its recipient liquid, but essence is rather the place where existence stops. There is nothing in water which is not water. There is nothing in an existent which is not existence. Essence is the intrinsic limitation of esse, the crystallization of existence, bordered by nothingness."¹²

"Perhaps it would be more precise to say it (the creature) is an imperfect esse, or even more precisely, it is constituted as a certain level of perfection, a particular magnitude of esse, an existential quantum, a degree of being."¹³ "Essence gives to being that it is of a certain type or kind. Esse gives to essence its existence."¹⁴ "Essence is not a positive being apart from the existence of which it is the limitation, but it is definitely a positive principle of philosophy when understood as the intrinsic limitation of esse. Its function can be designated by affirmative terms, contraction, refraction, channeling of perfection, specification, determination."¹⁵ "All essences are modes of esse."¹⁶ "The created essence is not its esse, it is the intrinsic limitation of esse, the prism through which the intelligible riches and perfections of esse are refracted and contracted to this kind of being."¹⁷

Carlo’s central insight is clear. Essence is a mode of esse, and an intrinsic modification or limitation of it; it is its crystallization or specification, determination, refraction, prism or capacity for contracting existence. Carlo is setting before our eyes a many-faceted metaphysical gem, but each facet leads us to the luminous heart of metaphysics. Essence is a certain capacity to exist. It is this or that capacity to exist. Essences don’t exist. Existents exist. We know essences by abstracting them from existents as the intrinsic limitations of existence. And we know existence not first in its purity without limit, but in this or that existent about which we can assert that it exists. But it exists in this or that way or mode.

This doctrine of the relationship between essence and existence that Carlo is expressing in such a forceful way and with a certain panache is rooted in St. Thomas and the revolution of metaphysics that he brought about. It is the same insight that can be found in varying ways in the founders of this century’s existential Thomism like Maritain, de Finance, Gilson, and so forth. But even if we might be willing to follow Carlo into this land of radical Thomist existentialism when it comes to the relationship of essence to existence, will we continue to follow him when it comes to the question of matter?

The Ultimate Reducibility of Matter to Substance

If we are to have a truly existential metaphysics, Carlo reasoned, then one of its greatest challenges is to show how matter, itself, can be reduced to esse, and he envisions it as a bold metaphysical experiment.

Aristotle needed to explain substantial change in which one thing loses its form and gains another. And so there must be, he reasoned, a substrate underlying this kind of change that remains, and yet is not a form. But if it is not a form, it must be a pure potentiality, for given the fact that essence is the highest principle, there is no other conclusion that he could have arrived at. But when Aristotle’s world of essences was transformed by St. Thomas, this revolutionary transformation did not completely alter how St. Thomas expressed himself about matter. At times he uses the language of Aristotle, and at times the new language of esse. In this new world of esse the substrate of substantial change need not be a pure potentiality because there is something that is not form or essence, yet still is, and that is esse. Thus, there are two strands of text in St. Thomas, but since they lack complete integration, the Thomist notion of prime matter has always been an insolvable riddle.

What Carlo is going to try to do is to resolve this tension by reducing matter to esse. But because he is breaking new ground, the going is harder. Matter is a "deficient esse."¹⁸ It "is the limitation of form, the place where form stops, in what is basically an immaterial universe."¹⁹ "Matter does not seem to be some principle standing apart from form, but is rooted in the concrete thing as an aspect of the individual by reason of its perfectibility."²⁰ Matter is "the ability of a being to become something other, by an increase or decrease of esse. Matter as potency, then, might be called the ‘elasticity or plasticity of esse’."²¹ "...Perhaps it (matter) is esse as limited, as, to put it crudely, existential quanta approaching but not completely, one of the Primal Modes or Stages of esse as unfolding, i.e. essence."²² "Essence is the primary limitation, a mode of esse, essence as imperfect esse. Matter signifies a secondary limitation, this imperfect being as deficient when a point is reached in the descent of creatures from God at which the esse does not correspond to, is more or less than, one of the Primal Stages of being expressed by the doctrine of the Divine Ideas."²³ "Essences are the primal stages of esse, and make things to be the kind of things they are. But within this primal stage there is a secondary stage which enables a thing to be more or less what it is, to increase in being without becoming other than what it is."²⁴

Matter is a deficient or debile esse, an increase or decrease of esse, the plasticity or elasticity of esse. But Carlo also says matter is the limitation of form, the place where form stops. But this apparent ambiguity resolves itself when Carlo writes: "St. Thomas calls matter ens in potentia. It is a pure potentia. But does he mean that there is a pure potency existing as prime matter like the eternal matter of Aristotle, or does he refer to the simple fact that a substance which is already in existence, still possesses the capacity of being further perfected? It is, but it is not all that it could be... It would seem that he is referring simply to the developmental aspect of an already existing substance - the fact that it is capable of further perfection. It is true that it is the aspect of potentiality, of insufficiency of the existent substance, that is called matter, but it seems to me that this is as far as Thomas Aquinas would go in asserting the being of prime matter as a philosophical principle in its proper metaphysical location. When we term matter substance we mean only the very potency in itself which is nothing but an imperfection of the existing substance, in the order of substance."²⁵

If we describe matter in relationship to form, then existence is in the background. If we describe matter in relationship to esse, then form is in the background. If we describe it in relationship to substance, then we are speaking of essences or forms inasmuch as they are oriented to existence. But in Carlo all these ways of speaking are roughly equivalent.

As strange as Carlo’s ideas on matter may first appear, are they really different from what St. Thomas writes? It is "that which is in potency to substantial existence."²⁶ "...(P)otency to substantial existence is not something outside the genus of substance."²⁷

Matter, we could say, is a substantial potency to substantial existence. But what does this mean? Matter is not potency in relationship to all substances, but an aspect of those substances that fall below a certain threshold of being, substances that lack a certain intensity of being by which they would be present to themselves in knowledge and love. In contrast to spiritual creatures, these substances, once existing, can lose their existence, and in this way they contain a substantial potency to their substantial existence. A substantial mutability of substance exists in them.

But to see this is difficult because we have to first reverse a deeply rooted attitude in which matter is somehow something separate which form informs. We imagine it as the hot wax that forms imprint, the very stuff out of which things are made. Without matter what will undergird substantial change? Without matter, how can there be many individuals of the same species? And without matter, how will things spread out in space and time?

Matter is not really destroyed in Carlo’s view of it, but relocated into actually existing substances. And while I find the idea of matter as pure potentiality somehow satisfyingly mysterious and romantic, it is fundamentally incoherent and unnecessary.

What exist are substances, whether spiritual or material. But what differentiates them is not that the forms of the material substances are somehow spiritual, and are diluted and dimmed by informing matter, but rather, that they are forms whose intensity for being, or capacities for existence, are such that they do not have an irreversible grasp on existence as witnessed by the fact that they can undergo substantial change. It is these substances that change in the dynamic field of esse, not forms that are educed from pure potentiality. All the qualities we are used to giving to matter are better attributed to these substances in virtue of the fact that they contain a substantial potency to substantial existence.

To follow the flow of Carlo’s language, we might say that matter is a contraction and refraction of form, the intrinsic limitation of form, the place where form stops below the threshold of spiritual creatures. But form cannot be understood in abstraction from esse, but rather, as a capacity for it. It might be objected that this is a much too negative view of matter. What will happen to the richness of matter that is intimately connected to space and time and the multiplication of individuals of the same species? Have we bleached the color and vibrancy from the universe by making matter virtually disappear? Quite the contrary. Matter does not disappear, but rather is seen in its true ontological location in regard to existence, and in this way it gains in richness.

Essence and matter are not negative in a truly existential metaphysics, but they are totally transparent and subordinate to existence. Essence is supremely positive inasmuch as it enables all of creation. And matter is supremely positive because it enables the existence of a whole fascinating order of existents beyond spiritual creatures.

The Ultimate Reducibility of Matter and Essence to Existence

Carlo spoke of essence as a primal mode, or stage, of esse, and matter as a secondary stage, or limitation. But that should not mislead us into imagining that there are two separate processes going on. It is the one and the same act of existence that is contracted by essence and by matter, and there are not two contractions, but one. When the act of existence is contracted by an essence, which is below the threshold of spiritual creatures, then we have a concrete individual or material substance. Essence is not first contracted to essence, and then to matter. It is contracted to a certain kind of essence that contains a substantial potency to its own substantial existence. As a result of this contraction, multiplicity, substantial transformation, and space and time blossom forth, and these are the very strategies of matter by which material substances overcome the low intensity of their substantial existence. We live, not in a universe of static material objects, but of existents constantly bathed in a dynamic sea of existence, and deeply interacting with each other. ²⁸

1. William E. Carlo, The Ultimate Reducibility of Essence to Existence in Existential Metaphysics, Martinus Nijhoff, The Hague, 1966.

2. The Proceedings of the American Catholic Philosophical Association, 1957, pp. 118-125.

3. "The Role of Essence in Existential Metaphysics: A Reappraisal," International Philosophical Quarterly, 11, 4, December 1964, pp. 557-590.

4. "The Ontological Status of Matter," in The Proceedings of the American Catholic Philosophical Association, 1964, pp. 142-154.

5. Cf. note 2, p. 124.

6. Ibid., pp. 126-127.

7. Ibid., pp. 127-128.

8. Ibid., p. 126.

9. Ibid., p. 129.

10. The Ultimate Reducibility of Essence to Existence, p. 95 and 101.

11. Ibid., p. 103.

12. Ibid., pp. 103-104.

13. Ibid., p. 113.

14. Ibid., p. 114.

15. Ibid., p. 139.

16. Ibid., p. 140.

17. Ibid., p. 140.

18. Ibid., p. 122.

19. Ibid., p. 125.

20. Ibid., p. 126.

21. Ibid., p. 127.

22. Ibid., p. 128.

23. Ibid., p. 130.

24. Ibid., p. 135.

25. Ibid., p. 134.

26. "The Principles of Nature," No. 3.

27. "On the Physics of Aristotle," XV, No. 3.