The following is an excerpt from a longer paper presented by SES Provost Dr. Richard G. Howe at a post meeting of the International Society of Christian Apologetics. The complete paper, and footnotes, can be found here.
Aquinas’s doctrine of the structure of existence and its relation to essence is critical to his entire metaphysic, but most importantly to his understanding of God. It is somewhat controversial as to whether Aquinas utilized the essence/existence distinction as an argument for God’s existence. I will argue that he does. Further, the relevance for Aquinas of the essence/existence distinction is most evident in how the denial of the essence/existence distinction in God entails all the classical attributes of God.
Aquinas’s doctrine of existence together with his doctrine of the distinction of essence and existence serve as the most radical break he has with Aristotle. I mention Aquinas’s accounting of these doctrines vis-à-vis Aristotle mainly because of the great extent to which the philosophy of Aquinas tracks the philosophy of Aristotle. These doctrines of existence and the distinction of essence and existence (but not necessarily these doctrines alone) constitute a metaphysical innovation whose significance is virtually inestimable. They are what enable Aquinas to turn the pagan philosophy of Aristotle into the Christian philosophy that Thomism is, particularly regarding the existence and attributes of God and the doctrine of creation.
It should be noted that Aquinas’s accounting of these doctrines is not without its antecedent inspirations. Indeed, both the discussion of existence and the discussion of the distinction between essence and existence (including whether there is any distinction and, if so, what might be the nature of that distinction) were topics of philosophical interest to some going back to Liber de Causis (The Book of Causes), an anonymous work at one time wrongly attributed to Aristotle the contents of which is largely taken from Proclus’s (412 – 485) Elements of Theology; to the works of Pseudo-Dionysius (late 400s – early 500s), especially his On the Divine Names which is referenced frequently by Aquinas in his discussion of God’s attributes; and to certain Islamic philosophers including al-Farabi (872-950) and Avicenna (980-1037). Aquinas readily acknowledges such influences, adopting, modifying, or inverting their ideas as seems to him most appropriate to advance his own views.
Much ink has been spilled in exploring these influences and the influences of others, looking both at the doctrines as they are found in these various sources and looking at the degree of influence these had on Aquinas’s views (both by example and counter-example). It is not my purpose here to explore these influences in any appreciable degree nor to referee specific controversies surrounding such exploration. I shall proceed with the tacit acknowledgement that there are these influences, thus avoiding the charge of over-stating Aquinas’s originality regarding his own views about these matters. At the same time, however, I am (so far) of the opinion that the crux of Aquinas’s accounting of existence and the essence/existence distinction does constitute an innovation whose philosophical significance and subsequent influence is profound. To my knowledge, none of these predecessors pressed their own accounting of existence and/or the essence/existence distinction into the service of their overall philosophy to the extent that Aquinas did for his.
Aquinas lays out his understanding of existence and the essence/existence distinction in works such as On Being and Essence, Truth, On the Power of God, and the Summa Theologiae.
I should first like to state very directly what the essence/existence distinction is. I shall then, by way of rehearsing a few basics in Aristotle’s metaphysics that Aquinas takes up as his own (with some slight modifications in certain places), set the philosophical background. Afterwards I will explore more in-depth the essence/existence distinction and then visit specifically Aquinas’s notion of existence.
The essence/existence distinction maintains that there is a real distinction in a create thing between its essence and its existence. A thing’s essence is what it is. Its existence is that it is. To illustrate, consider yourself as a human being: Your essence is what makes you a human. Your existence is what makes you a being. That essence and existence are distinct in sensible objects (i.e., objects that are evident to the senses) is evident from the fact that one can understand the essence of a thing without knowing whether it exists. Aquinas argues in On Being and Essence, “Now, every essence … can be understood without knowing anything about its being. I can know, for instance, what a man or a phoenix is and still be ignorant whether it has being in reality [esse habeat in rerum natura]. From this it is clear that being is other than essence … unless perhaps there is a reality who quiddity [i.e., essence] is its being.”
Aquinas adopts Aristotle’s metaphysical categories of act and potency. These categories provide the basis for how Aristotle (and then Aquinas) accounts for change in a sensible object. Definitionally, act (or Actuality) is to be real whereas potency is the power or capacity to be actual or real. Potencies can be thought of, roughly, as a capacity in a substance or thing. As such, a potency cannot exist on its own, but can only “exist” as a potency that a thing possess. But here, the term ‘exists’ can be misleading. Potency occupies a sort of middle ground between existing in full reality and not existing at all.
Aristotle utilized act and potency as a means (in principle) of countering the arguments of Parmenides who denied the reality of change and multiplicity. Parmenides did so by arguing that there was only two ways that things could differ: either by their being or by their non-being (an excluded middle). He argued that things could not differ by their being since “being” was the one thing in respect to which they were the same; which is to say, their both being “beings” was the very way in which they alike. But they also could not differ by their non-being since to differ by non-being was just not to differ at all. Thus, Parmenides concluded, things could not differ at all and, thus, all things were the same thing and that there was no change.
Aristotle countered that there was a tertium quid—a third alternative between being and non-being—viz., that of potentiality or potency. He comments, “So it is possible that a thing may be capable of being and not be, and capable of not being and yet be…. For of non-existent things some exist potentially; but they do not exist because they do not exist in complete reality.”
Aquinas employs the same notions of act and potency as Aristotle. “By non-existence we understand not simply those things which do not exist, but those which are potential, and not actual.”8 Elsewhere Aquinas says, “Observe that some things can exist though they do not exist, while other things do exist. That which can be is said to exist in potency; that which already exists is said to be in act.”
To illustrate act and potency, consider a person who is actually sitting but not actually standing. Such a person, though sitting, nevertheless has the potential or power or capacity (different English words for the same metaphysical reality) to stand. Upon standing, the person actualizes his potential to stand, his standing becomes actual and his sitting now becomes potential. In all these instances, the potency to stand while sitting and the potency to sit while standing must be actualized, if they are to be actualized at all, by something that is already in act, viz., the same subject in some other respect. Philosopher Bernard J. Wuellner summarizes, “Howsoever anything acts, it does so inasmuch as it is in act; howsoever anything receives, it does so inasmuch as it is in potency.”
To focus in on the fact that such a potential is something real in the person, compare the sitting and standing of the person to a rock. While a man who is actually sitting has the potential to stand, or who is actually standing has the potential to sit, a rock lacks the potency to stand or sit. Note, then, the difference between the non-existing of the standing in a sitting man and the non-existing of the standing in the rock. While both are non-existing, there remains a modicum of reality to the non-existing of the standing in the sitting man. It “exists” as a potential in the man in a way in which its non-existing does not in any way exist in the rock.
One should notice already that such parsing out of things in the categories of act and potency gives rise to a robust accounting of causality. The ability for a potential to actualized, which is to say, the ability for the standing or sitting to be caused, must be either from the nature of the thing possessing the potency or from something outside the nature of the thing. So far this is just like Aristotle. Aquinas will argue that sensible things are not able to ultimately account for the actualization of all of their own potentialities. The act/potency of sensible things stands in stark contrast to God’s nature of being pure actuality. But act/potency cannot get one beyond the multiple, impersonal gods of Aristotle. It will take Aquinas’s accounting of existence and the essence/existence distinction to take us all the way to the God of classical theism.
Not surprisingly, Aquinas follows Aristotle in the notions of Form and Matter. “Because the definition telling what a thing is signifies that by which a thing is located in its genus or species, philosophers have substituted the term ‘quiddity’ for the term ‘essence.’ The Philosopher [i.e., Aristotle] frequently calls this ‘what something was to be’ [quod quid erat esse; to; tiv h\n ei\nai]; that is to say, that which makes a thing to be what it is. It is also called ‘form.'”
The Form of a sensible object is what makes it be the kind of thing that it is. Not surprisingly, the Form is the “formal” cause of a thing. The formal cause does not cause a thing to exist (at least, not for Aquinas), but, more narrowly, it makes a thing to exist in a certain way, as, for example, a human or a horse.
Matter is that metaphysical aspect of a sensible object by which the Form is individuated to be this man or this horse. Utilizing the act/potency categories, Form actualizes Matter; Matter in is potency to Form. Matter and Form together constitute the essence of the sensible object. Such a Matter/Form combination (which characterizes all sensible objects) is called hylomorphism—from uJlhv (hule), Matter and morfhv (morphe), Form.
The significance of Aquinas’s employment of Form and Matter is that Thomas will argue that sensible things, being composed of Form and Matter, are not ultimately able to account for their own existence and thus will need a First Efficient Cause as their cause. Further, he will unpack the metaphysical attributes of God demonstrating that the particular aspects of the nature of God stand in stark contrast to the Form and Matter aspects of sensible things.
Aristotle’s highest category in his metaphysics is Form. To be is to be a Form. This is to say that Aristotle does not have a philosophical category of existence. As such, there can be no philosophical distinction in Aristotle’s philosophy between essence and existence. He says, “For ‘one man’ and ‘man’ are the same thing, and so are ‘existing man’ and ‘man’ and the doubling of the words in ‘one man’ and ‘one existing man’ does not express anything different.” Charles Kahn observes, “The upshot is that, although we can recognize at least three different kinds of existential questions discussed by Aristotle, Aristotle himself neither distinguishes these questions from one another nor brings them together under any common head or topic which might be set in contrast to other themes in his general discussion of Being.” Joseph Owens remarks, “From the viewpoint of the much later distinction between essence and the act of existing, this treatment must mean that Aristotle is leaving the act of existence entirely outside the scope of his philosophy. The act of existing must be wholly escaping his scientific consideration. All necessary and definite connections between things can be reduced to essence.”
Aristotle is not alone here, for there does not seem to be a distinctive philosophical discussion of existence as such in any Ancient Greek philosophy, and, thus, no notion of an essence/existence distinction among the Ancient Greeks. Charles Kahn again, in his aptly titled article “Why Existence Does Not Emerge as a Distinct Concept in Greek Philosophy” says,
In the extended discussion of the concept (or concepts) of Being in Greek philosophy from Parmenides to Aristotle, the theme of existence does not figure as a distinct topic for philosophical reflection. … I must make clear that my thesis about the non-emergence of existence as a distinct topic is not intended as a denial of the obvious fact that the Greek philosophers occasionally discuss questions of existence. My thesis is rather that the concept of existence is never “thematized”: it itself does not become a subject for philosophical reflection.
Kahn then interestingly goes on to observe, “My general view of the historical development is that existence in the modern sense becomes a central concept in philosophy only in the period when Greek ontology is radically revised in the light of a metaphysics of creation: that is to say, under the influence of Biblical religion.”
Various opinions of the nature of the essence/existence distinction, or, indeed, whether the distinction was real, arose right after Aquinas’s death. What is more, controversy over the place of existence in Aquinas’ philosophy in light of the essence/existence distinction erupted right after Aquinas’s death as well. By the sixteenth century, Dominic Báñez in his commentary on Aquinas’s Summa Theologiae defended the notion against his contemporaries that in the philosophy of Thomas Aquinas, existence is the primary metaphysical notion.
The full import of the essence/existence distinction is easily missed until Aquinas’s notion of existence is unpacked. Once one appreciates what Aquinas says about existence, then, when coupled with the real distinction between essence and existence, one can begin to see its profound implications for the existence and attributes of the God of Classical Christianity.
As I seek to unpack Aquinas’s accounting of existence, for the sake of clarity I should like to introduce some vocabulary. The infinitive of the Latin verb to be ‘sum’ (I am) is ‘esse’ and is often translated into English as ‘being’ or ‘existence.’ This can be misleading for the English reader since the English ‘being’ can be both a noun and a verb. Further, ‘existence’ is always a noun. What will be important in due course is the emphasis upon the infinitive sense of esse. A literal translation of ‘to be’, however, tends to be awkward and probably no less misleading than the more common English renderings.
While it was not uncommon in the Middle Ages for philosophers to use the term ‘esse’ as a synonym for ‘essence,’ Aquinas explicitly distinguished the two, describing the latter as that which receives esse. In Aquinas’s metaphysical schema, Form and Matter in sensible things together constitute an essence. Essence and esse together constitute a being (ens, the participle of the Latin verb “to be”). As Matter is in potency to Form, Matter and Form together (i.e., an essence) is in potency to existence (esse). Form actualizes Matter; existence (esse) actualizes essence. Owens summarizes, “When existence is considered in relation to the thing it makes exist, it may be regarded as actualizing the thing and, accordingly, it appears as the actuality that gives the thing existence.”23 Aquinas puts it thus, “Wherefore it is clear that being as we understand it here is the actuality of all acts, and therefore the perfection of all perfections.”
But what is Aquinas getting at here? There are at least two aspects of Aquinas’s accounting of existence that are crucial to understand, viz., that the existing of a created thing is constantly being caused and, second, that existence as such, i.e., existence per se, contains all perfections.
As for the first (that the existing of a created thing is constantly being caused), consider this illustration, despite the fact that, when pressed to far, the illustration gets the point more wrong than right. If you saw a giant glass ball in front of you, you might ask how did it come to be. If someone answered that the giant glass ball was manufactured in a nearby factory and moved here as a promotional gimmick for a local retail service, you would likely be satisfied with that answer. What is more, your satisfaction would have nothing to do with knowing much more about the factory that made the glass ball beyond the fact that it manufactured it. Indeed, while it might be interesting for other reasons, whether the factory still exists would, for the most part, be irrelevant to your satisfaction with the explanation of the glass ball in front of you.
Contrast your encounter with the glass ball with a different kind of encounter. Suppose, as you were looking at the glass ball, you were hearing music. In this case, you would not ask where did the music came from or how did the music come to be. Rather, you would ask what is causing the music to be right now. This so because, unlike the glass ball (as far as my illustration goes) you realize that music is music only as it is being caused to be music at every instance that it is music. As soon as the cause of the music stops causing the music, the music goes out of existence. Music as music must constantly be caused to be music if it is to be music at all.
In a parallel way, this is how Aquinas regards existence in creatures. As that which actualizes an essence, that essence exists only as it is being caused to exist at every moment of its existence, which is to say, that essence exists only as it is being continuously actualized. As soon as the cause of the existence of the essence stops causing the existence of the essence, the essence goes out of existence.
As for the second (that existence contains all perfections), bear in mind here that the notion of “perfection” is not a moral one. While moral perfection can be parsed out within this category, here ‘perfection’ is a broader notion.26 For the most part, to perfect something is to actualize it. Aristotle used these terms interchangeably (ejnergavzomai, ejnergevia: actualize, actuality; ejntelevceia: perfection). That ‘perfection’ is an apt word to use in this context is argued by Owens. “An alternate word for actuality in this respect is “perfection” (entelecheia). It was used by Aristotle along with actuality to designate the formal elements in the things. These perfected the material element in the sense of filling its potentiality and completing the thing. Since existence is required to complete the thing and all the formal elements and activities, it may be aptly called the perfection of all perfections.”
These notions of current causality (i.e., existence as an act) and existence as possessing all perfections are crucial to understanding the whole of Aquinas’s metaphysics. Their “cash value” (if you will) is how they philosophically deliver both the existence of God and also all of the classical attributes of God (sans those attributes contained exclusively in revealed truth like, for example, the Trinity). It is to these two considerations that I would like to turn my attention.
Aquinas sets forth some of the basics of his accounting of existence and essence in his On Being and Essence. Whether he is there pressing these elements into the service of an argument for the existence of God is somewhat (perhaps mildly) disputed. In Q3 of his Summa Theologiae, Aquinas discusses the essence/existence distinction as a means of demonstrating God’s simplicity. Having already in the previous question demonstrated God’s existence with his famous “Five Ways,” it seems clear to some that here in Q3 in the Summa he is not using the essence/existence distinction as an argument for God’s existence. But Owens argues that not only is Aquinas making an argument for God’s existence here in On Being and Essence, but that he makes this same argument in other places as well.
With this, let us look directly at the argument. Consider yourself as a human being. Whatever is true of you, is true of you either because of your essence or not. In other words, whatever properties, conditions, states, etc. that obtain with you must arise either because of the kind of thing you are (i.e., because of your essence) or because of something besides your essence. Aquinas argues, “Whatever belongs to a thing is either caused by the principles of its nature … or comes to it from an extrinsic principle ….”
For example, the reason you as a human being have rationality is because you are a human. It is part of your essence as a human to have rationality. You have rationality by virtue of being human. Rationality is caused by your essence. These are four ways of saying the same thing. Again, the reason you have risibility (to use Aquinas’s own example) is because you are a human. It is part of your essence as a human to have risibility. You have risibility by virtue of being human. Risibility is caused by your essence.
But consider something else that is true of you. Is the reason you are here at the International Society of Christian Apologetics (or wherever you happen to be as you hear or read this paper) because you are a human? Is it part of your essence as a human to be here at ISCA? Are you here at ISCA by virtue of being a human? Is being here at ISCA caused by your essence? The answer is clearly ‘no’ since, if you were here at ISCA by virtue of being a human, then all others who are not here at ISCA would not be human. You can also think about it this way. Sometimes both Aristotle and Aquinas understand Form as that which constitutes the definition of a thing. But one should be careful not to think of ‘definition’ here as merely being a modern logical notion. Instead it is a metaphysical notion. In Aristotle and Aquinas, a thing is defined precisely because of its occupation within its species.
Given that you are here at ISCA, one must ask how this can be the case. Why are you able to be here at ISCA even though it is not part of your essence to be here at ISCA? The answer, of course is quite simple. You are here at ISCA because you caused yourself to be here at ISCA. Let us, then, press the matter. Instead of your rationality, risibility, or being here at ISCA, consider your existence. Is the reason you exist because you are a human? Is it part of your essence to exist? Do you exist by virtue of being human? Is your existence caused by your essence? Here the answer is, again, clearly ‘no’; and it should be easy to see why. As Aquinas points out, “Now being itself cannot be caused by the form … of a thing (by ’caused’ I mean by an efficient cause), because that thing would then be its own cause and it would bring itself into being, which is impossible.”
We all learned in Apologetics 101 that nothing can be the cause if its own existence, the atheist philosopher Quintin Smith notwithstanding. But if you cannot be the cause of your own existence, then your existence must be caused by something else. Aquinas summarizes, “It follows that everything whose being is distinct from its nature must have being from another.”
But what about that thing’s existence? It either exists by virtue of its essence or it is caused to exist by something else. Now, can this go on to infinity? Aquinas again, “There must be a reality that is the cause of being for all other things, because it is pure being. If this were not so, we would go on to infinity in causes, for everything that is not pure being has a cause of its being, as has been said.”
This specter of the infinite regress arises within three of Aquinas’s “Five Ways.”40 The question can be asked, “why can there not be an infinite regress?” One thing that needs to be noted here is that Aquinas’s argument in these three of his Five Ways goes in the opposite direction than how he is often taken. Usually, Aquinas is taken to mean that since there cannot be an infinite regress (for whatever reasons), then there must be a first cause. In other words, it is common for the critic to take Aquinas to be arguing a Kalam Cosmological argument. From this point, the critic of Aquinas’s arguments would go on to challenge the assertion that there cannot be such an infinite regress, mistakenly thinking that the impossibility of an infinite regress is a necessary condition for the truth of Aquinas’s conclusions.
I submit, however, that he is actually arguing the reverse, viz., that since there must be a first cause, then there cannot be an infinite regress. This interpretation that Aquinas is not making the Kalam type of argument here is supported by the fact that in the Summa Theologiae Q46, he explicitly rejects that philosophy can disprove the possibility of such an infinite regress.
Taking this interpretation of the Five Ways requires the discussion to focus, not on whether there could be an infinite regress of the Kalam type, but why it is that the necessity of a first cause precludes the possibility of an infinite regress. What one finds upon a closer examination not very much further along into the Summa Theologiae is that, for Aquinas, there are in fact two different types of infinites—an infinite per se and an infinite per accidens. Aquinas discusses the differences in Q46 of the Summa. There he says, “In efficient causes it is impossible to proceed to infinity per se—thus, there cannot be an infinite number of causes that are per se required for a certain effect. … But it is not impossible to proceed to infinity accidentally as regards efficient causes ….”
Aquinas illustrates the difference by contrasting the causal sequence of father to son with the causal sequences of a hand moving a stick that is moving a stone. With the former, a man can father a son who can then grow up to father a son and so on infinitely (according to Aquinas); or, if you need to think of it in the opposite order, a son was fathered by his father who was, in turn, fathered by his father, and so on. The reason he thinks that such a causal sequence can be infinite (or, at least, this infinite cannot be philosophically demonstrated to be impossible) is because the causal connections are only accidental. When the son goes on to father a son, his own father is causally uninvolved. His own father could go out of existence and yet the son could go on to father his own son. Thus, the father, while being a cause of the son, is not a cause of the son’s causing his own son. To say it another way, the father, while being a cause of the son, is not a cause of the son’s being a father. Aquinas says, “It is accidental to this particular man as generator to be generated by another man; for he generates as a man, and not as the son of another man.”
But contrast this with the nature of the causal sequence of a hand moving a stick which is moving a stone. It is not only the case that the hand is moving the stick and that the stick is moving the stone, but more than that, the hand is the cause of the stick being a cause of the moving of the stone. In contrast to the father/son illustration, the father is not the cause of the son’s being a cause of his own son. However, the hand is not only the cause of the stick’s moving, but it is also the cause of the stick being a mover of the stone. The father is the cause of the son, but he is not the cause of the son’s being a father. The hand not only causes the stick to move, but it also causes the stick to be a mover of the stone. Here, then, the hand/stick/stone causal relationship is per se and the father/son/son causal relationship is per accidens.
Where, then, does this leave us. Returning back to our original argument about a thing’s existence being caused by something outside itself: it follows that whatever is being caused to exist must be being caused to exist by something that is uncaused. It must be bring cause to exist by something whose existence is its essence, which is to say a thing that exists because its very essence is existence. Anything that exists for which existence is not part of its essence must be being caused by that for which there is no essence/existence distinction. It is substantial existence itself—ipsum esse subsistens.
To round out the topic at hand, I want to say a few things about how Aquinas’s accounting of existence entails the classical attributes of God. Since esse is the actualization of all actualities and the perfection of all perfections, Aquinas would insist that esse as such is unlimited and contains all perfections. All the perfections that are exemplified by creatures are made actual by esse. The esse of a thing is limited when conjoined with Form or with Form and Matter, which is to say, an essence. But since there has to be something whose essence does not have existence but, rather, whose essence is existence, then that thing’s perfections are unlimited since they are not limited by the esse of the thing being conjoined with a Form or essence that is other than its existence.
Perhaps an illustration will help—what I call the balloon illustration (which I borrowed from the philosopher Max Herrera). When one blows up a balloon, the air expands to fill the balloon up to the extent of and according to the shape of the balloon. By parallel, the esse (the act of existing) of a creature “fills up” the Form or essence of the creature to the extent of and according to the “shape” of the Form or essence of that creature. Thus, a horse contains all the perfections of esse (existence) up to the extent of and according to the limitations of the essence of horse. A human contains all the perfections of existence and up to the extent of and according to the limitations of the essence of human. Since in God there is no essence/existence distinction, then all the perfections of existence are in God because God’s being is not conjoined with (and, thus, not limited by) Form. He is his own form or his own being. As Aquinas points out, “God is absolute form, or rather absolute being.” He argues that a being whose essence is esse possesses all perfections in superabundance. As he says it, “All perfections existing in creatures divided and multiplied, pre-exist in God unitedly.”
For Aquinas, once one understands what existence is and what it means to say that in God there is no essence/existence distinction, then all the classical attributes of God—simplicity, perfection, goodness, infinity, immutability, eternity, unity, omniscience, living, love, just, omnipotence, and more—cascade seamlessly. As a word of warning to my fellow evangelicals, it would seem on this account that these classical attributes are tethered together such that, if one of them is rejected, there is nothing to forestall the others disappearing as well.
Marrying the metaphysics of Aristotle with the innovations of esse and the essence/existence distinction, Aquinas was able to demonstrate the existence and attributes of a God that Aristotle’s philosophy could never foresee. Aquinas concludes, “It is evident, then, … that it holds its being from the first being, which is being in all its purity; and this is the first cause, God.” As he aphoristically goes on to say, “All men know this to be God.”
Some suggest that this is how God identified Himself to Moses in Exodus 3. “Indeed, when I come to the children of Israel and say to them, ‘The God of your fathers has sent me to you,’ and they say to me, ‘What is His name?’ what shall I say to them?” And God said to Moses, “I AM WHO I AM.” And He said, “Thus you shall say to the children of Israel, ‘I AM has sent metoyou.'” If we are right in making this connection, then Gaven Kerr’s comment in his Aquinas’s Way to God is spot on. “So it seems that without any deep metaphysical insight nor with any explicit prior determination as such, the author of the biblical text has managed to offer an expression of God that just happens to be in accord with some of the most profound metaphysical reasoning about the nature of God and His relation to the world in the history of Western thought.”
Subscribe to follow this blog and receive email notifications of new posts.