Against Existential Inertia: A First Attempt

Metaphysics is the science of being qua being. It attempts to give an intelligible account of being (ens), of its first principles and ultimate causes –of its origin and its ends. Many great thinkers have endeavored to give a coherent and comprehensive account of reality as such and thus to do metaphysics.¹ I believe the case could be made that many of the greatest ones have in common is that they make sense of reality through an explanatory hierarchy,² whereby the more particular is accounted for in terms of the universal and the potential in terms of the actual.

In some sense, they all are heirs of Plato and his notion of participation, whereby the sensible particulars are only made intelligible in light of universal forms or ideas. Even Aristotle, who takes issue with participation, employs such a notion in the background to account for being and truth in Metaphysics II.

This reality, then, that gives their truth to the objects of knowledge and the power of knowing to the knower, you must say is the idea of good, and you must conceive it as being the cause of knowledge, and of truth in so far as known. […]

[T]he objects of knowledge not only receive from the presence of the good they're being known, but their very existence and essence is derived to them from it. (Plato, Republic VI)

Now every thing through which a common quality is communicated to other things is itself of all those things in the highest degree possessed of that quality (e.g. fire is hottest, because it is the cause of heat in everything else); hence that also is most true which causes all subsequent things to be true. Therefore in every case, the first principles of things must necessarily be true above everything else. (Aristotle, Metaphysics II)

And of course, citing Plotinus and Aquinas we could multiply examples that are way more explicit on the notion of participation and the explanatory hierarchy I am talking about. But the point still stands that these great thinkers saw particular and contingent reality as dependent and derived from higher causes, such that their very being and truth were in some sense derived from these higher causes.

Now, within the contemporary conversation, it seems to me that there are two big threats to classic metaphysics in general and proofs for God in particular. The first one is to deny that metaphysics as such is possible. One can do this in two different ways. The first one would be to deny that reality as such yields to the categorization that metaphysics subjects it to, which would ultimately mean that reality and such is unintelligible (one can find such a position in Nietzsche and his postmodern followers). The second one would be to say that for all we know reality might be intelligible as such but it is not intelligible to us, or at least not wholly intelligible. Here we have the distinction between the per se and quad nos. Something might be one way in itself, but if it lies beyond our intellectual reach as far as we are concerned it is unintelligible. One can find variations of this position in Kant and his followers, who restrict such intelligibility to the phenomenal realm whilst leaving the noumenal realm outside of our sense-making abilities. Hence physics and the rest of the modern sciences are safe and out of threat, but classic metaphysics and proofs of God are out of the question.

The second biggest threat, to my mind, is any metaphysical account that denies that we can and should account for the particular in terms of the universal and for the potential in terms of the actual. In short, whatever account denies this classic view that makes sense of reality in terms of an explanatory hierarchy, this view that was hinted at above as expounded by Plato, Aristotle, et al.

The reader might benefit from a statement of the two positions here considered. As they have been referred to in the literature they are the Doctrine of Divine Conservation (DDC) and the Doctrine of Existential Inertia (DEI) or Existential Inertia Thesis (EIT), as has more recently been called. I will give a first rough definition of both to help the reader be situated in the discussion, but they are definitions I will challenge and qualify later. DDC could be characterized as claiming that all creatures exist only insofar as they are held (or conserved) in being by a divine primary cause, such that without its conservation they would fall out of existence. EIT claims there are at least some non-divine things that exist inertially, that is once they begin existing they are not in need of any conserving cause to continue existing and will continue doing so as long as they are not destroyed.

EIT comes into the picture, as such an account that would challenge this explanatory hierarchy. Existential inertia has been articulated in different ways by different authors,³ but since my concern is not with any author's specific account, but rather with the essence of what I see as one of the greatest threats to classic metaphysics let us formulate it in the following way. Existential inertia asserts that things that would traditionally have been seen as dependent beings are not really dependent in their very being on a primary cause, but rather have their being in an autonomous way and thus can continue to exist without a primary cause giving being to them.

One important note. The dialectic of existential inertia mentions concepts related to time quite a lot. The authors in this discussion tend to speak of a "concurring cause", or "persistence through time" or use phrases such as "depends for its being in every moment." I will studiously avoid talking about such matters here since I believe they shift our attention away from what really is the issue here. I believe that the true point of disagreement between proposers of EIT and DDC is related to participation and dependence, whether created being is dependent on a primary cause and hence reducible to it,⁴ or whether it has a certain ontological autonomy. Thus, I would rather frame the question as concerning ontological autonomy more than existential inertia.

As I said above, my interest here is not to identify a certain position on offer in the literature and merely offer a rebuttal. My concern is of a deeper nature. Within EIT I see a more profound claim of creaturely autonomy that can have radical religious and ethical consequences, and also a radical break with the explanatory categories of classic metaphysics. Hence my aim in this essay is more of a taxonomical nature. Although later I will seek to offer a rebuttal, my main interest here is to identify what really are the issues at stake in this discussion. For this reason, the reader might finish reading this paper and not have moved an inch in his support for EIT, but at least, I hope, he will have a deeper appreciation of the deeper religious and ethical issues at stake here.

Indeed, I believe that ontological autonomy gets to the heart of the matter better than existential inertia, which shifts our focus to persistence through time rather than the real issues that divide proponents of DDC and those of EIT. These issues pertain to dependence and participation in being. The classical theist which holds to every created being dependence on God as a primary cause and hence affirms the dependence of creatures for their very being on God can without any issue affirm that things tend to persist. Aquinas himself claims so: “Every substance seeks the preservation of its own being.”⁵ Thus there is a sense in which the proponent of DDC can hold to a kind of existential inertia if this merely means that things strive to continue in existence. He would, however, deny fervently that things are autonomous and independent in their very being.

This all has been to say that it seems to me that the very question has been framed wrongly, and we would benefit from shifting our focus from inertia and its time-related connotations to autonomy, which better gets to the heart of the matter. For these reasons let us talk in the following of the ontological autonomy thesis or OAT.

With this preliminary remarks aside let us summarize the main argument. The main argument is that granting realism about metaphysics and Aquinas' account of esse, existential inertia is impossible. The first thing we need to assume, realism about metaphysics, is something with which I believe proponents of OAT would not take an issue–at least those that would even propose metaphysical accounts of existential inertia. It seems that it is the second thing we need to grant that is the most controversial one. Thus, if I succeed in showing that Aquinas' account of esse rules out OAT, the OAT proponent's best move would be to attack Aquinas' account of esse.

I should remark that it is not as if no ink had been spilled defending the Thomistic account of existence against alternative accounts. Fabro dedicates the beginning of his monumental work to do precisely this and shows how alternative accounts fall short of Thomistic esse. Kerr does something similar, contrasting esse with analytic and more contemporary accounts such as Frege’s and Russell’s.⁶

Edward Feser claims that "the main arguments for God’s existence within classical philosophical theology are, when properly understood, themselves arguments for DDC and against DEI."⁷ I am inclined to agree with him here, insofar as what the Thomistic proofs do is to isolate a certain causal feature of things in our experience and show that these features are had in a merely derived or participated way and hence can only be properly accounted for in terms of something that has this causal feature in an underived and unparticipated way, that is, in itself or per se. But this cannot be any causal feature such as, say locomotion. For example, take a thing that has the ability to move in a mere derivative way such as a stick being moved by a hand. The stick has motion in a mere derivative way, and does not account for its motion in itself. The hand also does not move by itself, but rather, there is an intentional agent moving his hand and with it the stick. Hence, it is the intentional agent that has this causal feature in himself and imparts it to the intermediary causes. Thus, we can say that the motion in the stick and the hand is had in a merely derivative and participated way and their motion is reduced to the motion that of the intentional agent. This is not to say that the stick and the hand do not have motion, for they do, but only in a secondary way. This is all to say that not all such causal series need to end up in God, only those that isolate a special kind of causal feature. The causal feature that Aquinas isolates in his De Ente is esse, and if he succeeds in showing that esse is such a causal feature that in creatures is had in a dependent and derivative way which is ultimately causally grounded in an extrinsic agent that has esse per se then he has shown that OAT untenable.

For this reason in the following, I will focus on St. Thomas’s argumentation in the De Ente. The focus here is not so much the proof of the existence of God, but rather the argument that establishes that existence is not something that can be had inertially or autonomously. That is, being non-divine goes hand in hand with having existence as received and being divine just is to be “to be”.⁸

St. Thomas, as it is known, distinguishes between essence and esse. Essence is the whatness, is what is signified by the thing's definition. In the case of a man, his essence or whatness is humanity and it's what is signified by the definition of "rational animal." In other words, "rational animal" signifies humanity. In short, essence corresponds to what a thing is and esse is the principle by which the thing is.

"Esse" is a Latin infinitive verb, equivalent to "to be" in English and "sein" in German. Esse figures extensively in the Thomistic corpus and many prominent authors have recognised therein maybe the key insight and the most pregnant original thought of Aquinas. Some authors choose to translate St. Thomas' esse with the English word “existence.” I will use the original latin esse instead. The reason for this is that, as Cornelio Fabro among others has argued, existence speaks to the fact of existence, namely the fact that a thing is. But when St. Thomas talks about esse he does not merely have in mind the fact that some thing exists, but rather a principle which is that by which the thing is at all, which is also the source of all its reality and activity. That is why St. Thomas calls esse the “act of all acts and the perfection of all perfections.”⁹ In short, St. Thomas has in mind a principle of actuality and not a mere fact.

In his famous work, the De Ente et Essentia, St. Thomas very shortly and succinctly argues for the existence of God. Though it is not the main aim of his work he does it in such a masterful way that this work has generated ample scholarly commentary, some would argue that in this early work, one can already see very succinctly put some of the main and most fundamental aspects of his thought, aspects that will permeate his later works, such as the notion of participation and the real distinction between essence and esse.

In this work, St. Thomas first argues for a real distinction between essence and esse. This means that although they are not two separate things they are to be understood as two really distinct intrinsic principles of a thing. One example should help illustrate what is meant by intrinsic principle. Aristotle famously distinguishes between matter and form as two intrinsic principles of every material substance. Take the statue of David as an example. The matter in this case would be the marble out of which the statue is made, while the form is what makes the marble not mere marble, but the statue of David. Here one could understand the form to be the intrinsic structure. Now consider a cat –this case of an actual substance and not a mere artifact. Say we take a cat and put it into a woodchipper. Whatever comes out will be the matter of the cat, but it won't be the cat. The cat is gone. Dead. But the matter of the cat has not disappeared. We could say that the form is no longer there, and therefore this is a case of corruption, but the matter has remained In short we could say that the matter is that out of which the thing is made and the form is what makes this particular clump of matter be this determinate being and not something else, say a cat rather than a dog.

Now we should introduce Michelangelo into the picture. Michelangelo is the efficient cause of the statue, for he gives the form to the marble. The marble stands in potency to Michelangelo insofar as it receives the form of David which is its act. These two examples hopefully illustrate matter and form as two real and distinct intrinsic principles of material substances. It is important to remark that these two principles relate to one another as act to potency. Form actualizes matter, and matter stands in potency towards form. We could also say that matter participates in form, since it receives form in a particular and limited manner, for this cat is not catness as such, but a particular and limited instantiation of catness. Hence, form accounts for intelligibility and universality, and matter for particularity and limitation.

Having hinted at what should be understood by two really distinct intrinsic principles of a thing, we can return to the issue at hand and the real distinction between essence and esse. Similarly, as matter stands in potency and participates in its form, essence stands in potency and participates in esse. Esse is the actuality of essence. This could be worded with different and less Thomistic language, and perhaps aid in the understanding of those not deeply acquainted with the tradition. Think of esse as the most fundamental, intensive, and intrinsic principle of reality, that by which something is really and actively present in the world. That by which something is "really real" and does not fall into nothingness. Now think of essence as that by which being is determinate. A dog is a certain kind of real entity. It is not a cat, nor a tree. There are different ways of being. This variety points to restriction and limitation since different beings are restricted in different ways. For example, the dog is a higher expression of reality since the dog is more active and capable of doing more than a plant. And a plant is still more active than a stone. Esse and activity are closely related, since it is esse which is the ground of activity, for only real things can act, and whatever is more active is a higher expression of being.¹⁰

With these (hopefully helpful) clarifications in place, let us go back to St. Thomas and his De Ente. Before arguing for the existence of God he offers two arguments for the real distinction between essence and esse. The first one is known as the intellectus essentiae argument, and the second one let us call the impossibility of multiplication argument. Following Gaven Kerr I take that the intellectus essentiae St. Thomas does not really establish the real distinction but merely establishes a logical distinction or distinction of reason. This means a distinction in our way of thinking about things, but not necessarily a distinction in the way things really are. The classic example is the morning star and the evening star. They both correspond to the same reality, namely the planet Venus, but the distinction between the two names bears only on our way of thinking about it. Similarly, I hold that this argument only shows us that essence and esse are distinct in our way of making sense out of reality.

Let us take a look at the argument:

Whatever is not in the concept of the essence or the quiddity comes from outside the essence and makes a composition with the essence, because no essence can be understood without the things that are its parts. But every essence or quiddity can be understood without understanding anything about its existence: I can understand what a man is or what a phoenix is, and nevertheless not know whether either has existence in reality. Therefore, it is clear that existence is something other than the essence or quiddity, unless perhaps there is something whose quiddity is its very own existence, and, if so, this thing must be one and primary.¹¹

What St. Thomas is saying here is that when we understand what something is we are not thereby understanding whether that thing indeed is. That is, the esse of a thing is not implied or logically necessitated by its essence. While this does establish a distinction in our ways of understanding essence and esse it is not necessarily the case that they are two really distinct principles of a thing. That is to say, while they might be distinct in ratio they need not be distinct in re. Now we move to the part of the argument that shows a real distinction, and that is the impossibility of multiplication argument.

For there can be no plurification of something except by the addition of some difference, as the nature of a genus is multiplied in its species; or as the nature of the species is multiplied in diverse individuals since the form is received in diverse matters; or again as when one thing is absolute and another is received in something else, as if there were a certain separate heat that was other than unseparated heat by reason of its separation. But if we posit a thing that is esse only, such that it is subsisting existence itself, this existence will not receive the addition of a difference. For, if there were added a difference, it would be not only esse, but esse and also some form beyond this. Much less would such a thing receive the addition of matter, for then the thing would be not subsisting existence but material. Hence, it remains that a thing that is its own existence cannot be other than one, and so in every other thing, the thing's existence is one thing, and its essence or quiddity or nature or form is another.

At this point, Aquinas asks us to think of something in which there is no real distinction between essence and esse, something where this distinction breaks down. If we consider where no such distinction obtains we are considering commenting whose essence just is its esse or as he later calls it, something that is pure esse (or esse tantum). Now considering esse tantum we ask ourselves whether there could be more than one such a thing, whether it is subject to multiplication. Aquinas here considers the ways anything can be multiplied and in particular two different ways in which we can say that something universal is multiplied in particulars and concludes that esse tantum cannot be multiplied in any such way. The genus is multiplied in the species by the addition of a specific difference, just like the genus animal is multiplied in different species, such as man and horse by the addition of specific differences such as rationality and horse-ness. Similarly, a species is multiplied in different members of the species by the form of the species being received into different chunks of matter. While we have a common humanity I differ from you, dear reader, insofar my humanity is instantiated in a different chunk of meat and bones than yours. Both of these ways of multiplication have in common that the thing is multiplied by the addition of a differentiating feature which necessarily implies composition, and thus a real distinction between the substratum and the differentiating feature. Pure esse cannot be composed, otherwise, it would not be pure esse but rather esse composed with something else. This implies that esse tantum is absolutely unique and hence not subject to any kind of multiplication. From this, it necessarily follows that whatever is subject to multiplication (this includes trees, cats, electrons, and so forth) is not esse tantum, and hence it is a composite of essence and esse.

We have thus established that in beings that are subject to multiplication –basically anything in the physical universe we can think of– is a composite of essence and esse and hence not pure esse. In the following, we will endeavor to show that essence-esse composites cannot have esse unless as received from another, or in other words, in a limited and participated way, and hence in a way that cannot by any means be called autonomously.

Now, we proceed to consider the causal principle St. Thomas presents. This is a very basic causal principle that anyone who believes metaphysics is possible –i.e. that reality is intelligible and we can make broad sense of its structures– should be able to accept.

Everything that pertains to a thing, however, either is caused by the principles of its own nature, as risibility in man, or else comes from some extrinsic principle, as light in the air from the influence of the sun.

This is very self-explanatory. St. Thomas claims that we should be able to give an account of every ontologically positive thing we can find in a substance. Either the thing properly belongs to the substance and flows from its essence as the ability to laugh flows from man’s rationality; or it is given by an extrinsic cause –trough another or per aliud–, such as the illumination in the atmosphere caused by the sun, or the motion of the stick is caused by the intentional agent that holds the stick and moves it.

This is the key part of the essay, where we most clearly can see Aquinas’ opposition to anything like ontological autonomy on the part of non-divine beings.

Now, it cannot be that esse itself is caused by the very form or quiddity of the thing (I mean as by an efficient cause), because then the thing would be its own efficient cause, and the thing would produce itself in existence, which is impossible. Therefore, everything the esse of which is other than its own nature has esse from another.

Grating that esse is something found in real existing beings (hardly a controversial claim, for otherwise we would be saying that things don’t exist, and we have to at least be able to say that something exists) he argues that, in essence-esse composites, it cannot be the case the esse properly flows from their essence. For this to be the case their essence or quiddity has to pre-exist the esse, or rather be able to be and act without having esse, which is impossible, for the thing would pre-exist itself and cause itself. Since the very notion of something pre-existing itself and being a causa sui in the strong sense is incoherent we have to grant that esse is something that essence-esse composites have by virtue of another, as given and not in themselves.

All of the preceding makes clear that everything (i) either is pure esse, such that there is no real distinction or composition in it between essence and esse, (ii) or is an essence-esse composite. In the second case, it is only possible that esse can be had as from an extrinsic principle. In other words, everything is either divine and self-existing or is a creature and is ontologically dependent on another for its very being.

Note that at this stage of the argument, the existence of God has not been yet proven and hence the notion of a being that is pure esse is purely hypothetical. We just posited a being that is pure esse as a way to show that anything that should be pure esse cannot possibly be more than one, from which it follows that whatever can be more than one (whatever belongs to a kind of which there can be multiple instantiations at least in principle) is an essence-esse composite. And any such composite must be dependent for its being (esse) on another, i.e. it is ontologically dependent. This suffices to offer a rebuttal to OAT.

Of course, the skeptic can deny that we can do metaphysics, be that introducing double on the power of reason to engage in metaphysics or hinting at the possibility of reality being unintelligible as such. Or, on the other hand, he can try to preserve metaphysics by simply denying Aquinas’ account of esse. But at least on my part, I cannot see how to do the latter without engaging in the former at least to some extent.

Of course, this is not the end of Aquinas’ reasoning in the De Ente. He proceeds to show that the fact that ontologically dependent beings have esse is something that is not intelligible unless grounded in something that has esse independently. But since we have already established that whatever is an essence-esse competitive has esse in a derivative and dependent manner whatever grounds the beings of such composites has to be pure esse. Thus we have established the actual existence of the purely hypothetical pure esse being that we posited above as a way to show the real distinction of essence and esse in the beings of our experience.

This is how Aquinas himself puts it:

And since everything that is through another is reduced to that which is through itself as to a first cause, there is something that is the cause of existence in all things in that this thing is pure esse. Otherwise, we would have to go to infinity in causes, for everything that is not existence alone has a cause of its existence, as was said above.

Conclusion

Let us summarize and recollect all these various thoughts. We have established that in things that are subject to multiplication, there is a real distinction between the what a thing is (essence) and the principle whereby that thing is (esse). From the causal principle it follows that esse can only be had as given by an extrinsic cause, it can only be had per aliud, and not as something self-caused, since this would involve the notion of a causa sui, which is an incoherent notion. The fact that in essence-esse composites esse is had per aliud just means that essence-esse composites cannot account for their own esse. If their esse (or rather their having it) is to be intelligible, we must posit something that has esse per se and in which the essence-esse composite participates. But in this thing, no real distinction between essence and esse can obtain, otherwise, it would be subject to the same analysis and we would have accounted for nothing. It must escape this explanatory category and hence this distinction must break down at this level, which is just a more dramatic way of saying that in this primary cause essence and esse must be identified. But such a thing is precisely the hypothetical entity we posited at the beginning of the impossibility of multiplication argument for the real distinction. Recall that an entity where this distinction does not obtain is an entity that is absolutely unique and hence not subject to multiplication. Hence this entity is absolutely unique. Also, since essence and esse are not really distinct in this entity it must be the case that they are identical, and whatever distinction we posit here is merely a logical one. From this, it is clear that this entity is pure esse or esse tantum.

This esse tantum is what Aquinas identifies as God. Whether that is indeed the case is not my concern here. I wish to call our focus back to the part that is at the most odds with OAT, which is the application of the causal principle to esse, for the only way OAT could be plausible is if esse was something that non-divine beings (beings that are not esse tantum) could have independently of esse tantum. For this to be the case they should either be pure esse –and then they would be God, absolutely unique, and hence not multiple–, or be essence-esse composites that have esse not by an extrinsic cause but rather as something that properly flows from themselves. The first one concedes the existence of God and might lead us to a pantheism akin to that of Spinoza. The second one was rebutted above for it involves the incoherent notion of something causing itself and thus pre-existing itself.

The OAT adherent might still want to ask, but why cannot a thing first receive existence and keep it inertially as something distinct from itself? A chair might be painted red and thus receive redness as from another but then keep the redness inertially independently from anyone. It’s not as if we still continuously paint the chair red in order for it to stay red.¹² Cannot we just use Aquinas' causal principle against him? The red in the chair is, after all, something given by another, but yet it is had inertially. The chair need not participate and continuously receive the red from some source. This looks like a good counter-example, but if we look at it close and analyze it in terms of the act-potency distinction it becomes clear it is not a threat to the argument here presented.

As was outlined above, it is not actuality that participates in potency or receives it, but rather it is potency that participates in actuality and receives it in a particular and limited way. Matter is the principle of potency and it participates and receives form. In the case of the chair and the color red, there is a way we can say that the matter is the chair and it receives the actuality of the accidental form of the red. But at a deeper level –if we really ask ourselves what is the fundamental source of actuality here– we have to say that it is really the accident of the color red that participates in the substance of the wood of the chair. We can think of it in terms of dependence. What depends on what for its being? The red-in-the-chair depends on the chair or the chair depends on the red-in-the-chair? It is of course the former, for the chair is more fundamental and grounds the being of the red-in-the-chair. More generally, it is the accident that is grounded in the substance and participates in it for its being. Thus the red-in-the-chair is not autonomous in its being, but rather it is ontologically dependent on the wood of the chair, which is the substance. So could we say that the red-in-the-chair exists inertially in the chair? Yes, insofar as it will stay there unless destroyed. But does it subsist independently from the chair that grounds its being? Certainly not. In an analogous way, esse is more fundamental and grounds esse, and more generally essence-esse compositives only have their esse as received from that which is pure esse, which ultimately ontologically grounds them so in no way can we say that they have esse autonomously and independently.

The Thomist would simply say that this example only counts as a counter-example if we assume a truncated account of causation, a mechanical push and pull of the Humean variety. On the other hand, if we assume a richer and more-encompassing account of causation as ontological explanation this counter-example can quickly be seen as something our metaphysics can account for without positing any danger to the account of existence here presented.

As a conclusion, let us revisit what this essay has aimed at. The first thing was to reframe the question of existential inertia into a question about ontological autonomy. Second, to present how Aquinas’ account of esse and his realist metaphysics show that in whatever is subject to multiplication existence is something had in a dependent way and thus offer an argument against the thesis of ontological autonomy on the part of non-divine beings.

1. Great metaphysicians and their main works include Plato’s Republic, Aristotle’s Metaphysics, Plotinus’ Enneads, Proclus’ The Elements of Theology, Boethius’ The Consolation of Philosophy, Augustine’s City of God, Avicenna (Ibn Sina)’s The Book of Healing, and Aquinas’ Summa Theologiae. While not all of them penned such a systematic account as Hegel did with his Logic, one can deduce that a comprehensive metaphysical foundation underpins their ideas. For instance, St. Thomas did not write a Summa Philosophicae, but as John Wippel elucidates in his work The Metaphysical Thought of Thomas Aquinas, such a metaphysical is indeed present as buttressing the rest of his thought.

2. See, in particular Proclus’ The Elements of Theology.

3. See Schmid, J. C., & Linford, D. J. (2022). Existential inertia and classical theistic proofs. Springer Nature. Oppy, G. (2021). On stage one of Feser's ‘Aristotelian proof’. Religious studies, 57(3), 491-502. Beaudoin, J. (2007). The world’s continuance: divine conservation or existential inertia? International Journal for Philosophy of Religion, 61, 83-98.

4. “[E]verything that is through another is reduced to that which is through itself as to a first cause”, Aquinas, De Ente et Essentia, ch. 4.

5. ST I-II, q. 94, a. 2.

6. I believe that Aquinas's account of esse is the best offer of the metaphysics of existence, but giving a defense would go beyond the scope of this essay. For treatments of the question see Kerr, G. (2015). Aquinas’s Way to God, ch. 3 for an engagement with analytic accounts of existence and Fabro, C. (1961). Participation et causalité selon S. Thomas d'Aquin. For a wider comparison with other accounts of existence.

7. Feser, E. (2011). Existential inertia and the five ways. American Catholic Philosophical Quarterly, 85(2), 237-267.

8. cf. Ex. 3, 14 - God said to Moses, “I AM WHO I AM” He said further, “Thus you shall say to the Israelites, ‘I AM has sent me to you.’”

9. De Potentia q. 7, a. 2, ad 9

10. See Clarke, W. N. (2015). The one and the many: a contemporary Thomistic metaphysics. University of Notre Dame Press for a detailed account of these existential Thomistic metaphysics.

11. Ibid.

12. This proposed counter-example is from Oppy, G. (2021).