Thomas Aquinas on Existence/Essence and Identity

“Therefore that thing, whose existence differs from its essence, must have its existence caused by another. But this cannot be true of God; because we call God the first efficient cause. Therefore it is impossible that in God His existence should differ from His essence.” – ST Ia. Q.3 A.4

“Therefore “suppositum” and nature in them are identified. Since God then is not composed of matter and form, He must be His own Godhead, His own Life, and whatever else is thus predicated of Him.” – ST Ia. Q.3 A.3

“The truth of this question is quite clear if we consider the divine simplicity. For it was shown above (Question 3, Article 3) that the divine simplicity requires that in God essence is the same as “suppositum,” which in intellectual substances is nothing else than person. But a difficulty seems to arise from the fact that while the divine persons are multiplied, the essence nevertheless retains its unity. And because, as Boethius says (De Trin. i), “relation multiplies the Trinity of persons,” some have thought that in God essence and person differ, forasmuch as they held the relations to be “adjacent”; considering only in the relations the idea of “reference to another,” and not the relations as realities. But as it was shown above (Question 28, Article 2) in creatures relations are accidental, whereas in God they are the divine essence itself. Thence it follows that in God essence is not really distinct from person; and yet that the persons are really distinguished from each other. For person, as above stated (29, 4), signifies relation as subsisting in the divine nature. But relation as referred to the essence does not differ therefrom really, but only in our way of thinking; while as referred to an opposite relation, it has a real distinction by virtue of that opposition. Thus there are one essence and three persons.” – ST Ia. Q.39 A.1

And for future discussion, to counter Boethius, does Relation establish Person or does Person establish Relation?

36 Responses to Thomas Aquinas on Existence/Essence and Identity

  1. Fr. Maximus says:


    I don’t think there is anything wrong with using Aristotelian terms. Look at what a big role the concept of energy plays in Orthodox theology, and that word was invented by Aristotle. It is not the words that are important, but the meaning and the theory (or baggage) that is behind them. Aquinas doesn’t simply use Aristotelian concepts or terminology: he takes over whole arguments from Aristotle and transports them into his theology. While he’s quite right to reject the necessary reasons for the Trinity, he certainly does try to prove Christain doctrine starting from Aristotelian premises. I don’t mean basics like the Trinity or the Incarnation, but a lot of specifics like each angel being its own species since matter is the principle of individuation and angels don’t have matter. Maybe that is not a dogma in the strict sense of the word, but it’s one example that is emblematic of many such teachings. And of course divine simplicity is definitely philosophical in origin. Actually, I think most of Aquinas’ greatest errors come not from his Aristotelianism, but from his Platonism which he inherited from Augustine and Boethius.

    There seems to be no need to introduce absolute divine simplicity to safeguard God as the first cause, anymore than there was a need to introduce the Filioque to safeguard against Arianism. Good motives can lead in bad directions.

  2. lee faber says:

    Fr. Maximos (and Kenny)
    then how can you say what you do about Aquinas? Why is using Aristotelian terms worse than Proclean? Aquinas nowhere tries to prove Christian doctrine from Aristotle; in fact he argues against Victorine attempts to give “necessary reasons” for the Trinity, just one example among many.

    regarding divine simplicity: the arguments in favor of it are all designed to safeguard the fact that God is first cause. that is what the scholastics or whoever mean when they deny that God is composed of essence or existence or act and potency or whatever. clearly you don’t think some other being is God’s efficient cause, so you accept part of these arguments. In the end, I suspect you don’t mean by “real distinction” the same thing that the West does. Because even the western “omnino simplex” (note: its the manuels, not the church that adds the “absolute” part) admits of really distinct persons.

  3. kepha says:

    I don’t mean to disrupt the thread, but can someone contact Perry Robinson for me? I’ve sent him an e-mail about a week ago but he has not responded. It is very important.

  4. Fr. Maximus says:


    There is a big difference. The western doctrine of divine simplicity is basically identical to the platonist version from whence it was borrowed. The arguments used to support it are the same. But the Dionysian exitus-reditus is similar to Proclus only in terminology. St. Dionysius bases himself on scripture and doesn’t really use any arguments to support himself: he simply states the facts. That he borrows terminology from the platonists really means nothing, any more than C.S. Lewis was a Taoist simply because he called the natural law the Tao in one of his works. Proclus, however, bases his exitus-reditus theory on a intricate theory of causality which he lays out in the Elements as proofs deliberately modeled on Euclid’s geometry. Proclus is writing as a philosopher, while Dionysius is writing as an Orthodox theologian: the two approaches are totally unalike, and the only similarity is verbal.

  5. Fr. John says:

    What happened to speaking the truth in love?

    If I speak words of peace, where there is no peace, I do not serve God, but the Devil.

    I believe Isaiah wrote about that…. IF the filioque is ‘the root of all sorts of evil’, and, it having once been the ‘coin of the realm’ in Scholasticism, and the Reformers’ theology as well, to ignore it, or pretend it doesn’t exist, is like saying to the Orthodox when confronting the Arians in 325 A.D., ‘Oh come on, it’s only a vowel!’ ….’NOt ONE iota.’

    Hmm. Sometimes it’s time for ‘tough love.’ LIke calling a heresy a heresy, for starters.

  6. lee faber says:

    Fr. Golitzin, pardon my ignorance, but does the East regard him as THE areopagite? I assume he’s connected to Proclus because all of the secondary literature does (and you seem to push secondary literature around here, albeit your own). Why is absolute divine simplicity (of which the only mention is Lateran IV’s “omnino simplex” in any official document) part of the perennial evil philosophy, but exitus-reditus isn’t? It’s just as platonic.

  7. Lee,
    You mean St. Dionysios the Areopagite.

    Fr. Alexander Golitzin
    The question is do we read him as a Neoplatonist. Or as a Christian who is using Neoplatonic terms and who’s concepts have nothing to do with the mysteries of Egypt.

    Why would you assume that Proclus has anything to do with Dionysios and Dionysios anything to do with him?


  8. lee faber says:

    The elephant in the room being the pseudo-Denys; not a whiff of Proclus there.

  9. Matthew,
    I don’t want to hear any more about your assessment of the problem. You came here and started attacking us personally. My criticism of Roman Catholic theology is not personal towards anyone. If the criticism of that theology offends you, get over it, or find another place to express your opinion, please.

    You are very correct to point out that Alexandria and some of the Greek Fathers have some Platonist leanings. I say “some” because I would not consider Athanasius or Cyril a Platonist. In fact, Alexandria seems to be the source of much of the problematic driving the Ecumenical Councils. I say this because its no coincidence that NeoPlatonism has its home base in Alexandria.

    The best person to read that articulates the distinction between Neoplatonism and the Orthodox Fathers is +Photius Farrell (Dr. Joseph P. Farrell). He has a 4 volume set called “God, History, and Dialectic” that you can find here:

    It’s rather expensive, but worth the money, and I think someone like you might appreciate it based on what I’ve seen you write so far.


  10. An inability to admit fault is an almost certain proof that his side is wrong. While your inability to recognize any faults of the Orthodox (granted the ones I listed are not actual faults of the Orthodox) does not prove that the Orthodox are wrong, it does offer rather compelling proof that you are not very Orthodox, and as such have no business (from an Orthodox perspective) doing theology.

  11. Diakrisis Logismon says:

    Philosophy Joke

    An eccentric philosophy professor gave a one question final exam after a semester dealing with a broad array of topics.

    The class was already seated and ready to go when the professor picked up his chair, plopped it on his desk and wrote on the board: “Using everything we have learned this semester, prove that this chair does not exist.”

    Fingers flew, erasers erased, notebooks were filled in furious fashion. Some students wrote over 30 pages in one hour attempting to refute the existence of the chair. One member of the class however, was up and finished in less than a minute.

    Weeks later when the grades were posted, the student who finished in one minute got an A.

    The rest of the group wondered how he could have gotten an A when he had barely written anything at all.

    This is what he wrote:

    “What chair?”

  12. Kenny,
    You’ll want to do some research on the Carolingians, specifically the type of criticism that I describe. A nice little Introduction can be found here:

    Of course, even in the Franks themselves there are some problems of dissenting voices.

    Augustine had some rationalistic tendencies but he also was a “part” of that “mystical empiricism.” That’s what I mean by saying that the “roots” of the schism are present in him. This is why, in my opinion, you can have two horns of that dilemma in a Blaise Pascal or a Jansenius, who were hostile to scholastic methods, and the rationalistic mindset of a Thomas Aquinas. This is the problem of Augustine and “his interpreters.” Though Blaise Pascal and Jansenius differ from me on quite a number of dotrinal points sharply, much of there theological outlook, method, and world-view is much closer to Orthodoxy than the Jesuits and the Dominicans.


  13. Kenny says:

    Well, yes, but the case of Aquinas and friends is much different, because that’s where we begin to get these constant appeals to Aristotle, as if Aristotle knew anything about Christian theology. Augustine has Platonist leanings, but so do most of the Greek fathers, especially the Alexandrian school, and Augustine is not a full-blown Platonist in the way Aquinas is a full-blown Aristotelian. He doesn’t make a habit of citing Plato as authority for his theological views. So, although Augustine had some rationalistic tendencies, as opposed to what might be called the ‘mystical empiricism’* of the East, this really isn’t the same thing as what happened with Aquinas. I’m not an expert on Medieval philosophy/theology, but it is hard for me to imagine the most problematic portions of the scholastic ‘program’ beginning before the reintroduction of Aristotle to the West.

    * By ‘mystical empiricism’ I mean the view that our religious epistemology ‘grounds out’ in the collective religious experience of the Church, and this is how we know the reliability of Scripture and the other basic truths from which we derive our theology.

  14. Kenny,

    Yeah I would more or less agree with that. The only thing I would add is that I would push the problem back to the inception of scholasticism as a “program” for the West with the Carolingian Renaissance. That’s where it seems to really get off the ground. There were those starting the program since Augustine, but they always had their antagonists in the monasteries, e.g. Sts. Vincent of Lerins and John Cassian. And even in the person of Augustine himself the roots of the schism of Orthodoxy vs. Scholasticism are present in him.


  15. Kenny says:

    Have you seen Metropolitan Kallistos’s (Timothy Ware’s) paper, “Scholasticism and Orthodoxy: Theological Method as a Factor in the Schism”? It appears to have been published in a journal called “Eastern Church Review”, but I think it was originally presented as a lecture at one of the dialogues with the Anglicans. At any rate, I think it argues very convincingly that the sort of Aristotelian rationalism Aquinas and friends were engaged in was (and is) one of the major reasons the Schism has (thus far ) proved irreconcilable.

  16. Matthew,
    You stated that we are throwing rocks. My point was to persuade you to change your language of “throwing rocks,” as if you are trying to paint us as violent people. That I believe Rome to be a dogmatically bankrupt system and a false gospel is not throwing rocks, no more than some Reformed protestants think that traditional Orthodoxy teaches a false gospel. I am not in the least offended by this claim. For if they are correct and we are wrong, Orthodoxy is a false gospel. And I can appreciate that. I’d rather see someone stick to their roots than to opt for programs of “compatibility.” I do not go along with the fuzzy feel good ways of modern ecumenism that Rome is trying direct everybody toward. Sorry, but I don’t want anything to do with it.

    You’ll have to document where we’ve displayed “hate” toward someone. I don’t buy it. As for James Cuttsinger goes, I don’t know enough about him to say either way, accept that I respectfully disagree with the point you are articulating about him (and I know the point being made by other’s who tried that program in late antiquity). The purpose of this blog is to have a forum for Traditional Orthodox dogmatics. There are plenty of other blogs where the programs of ecumenism are taking place. But if you are looking for that here, you won’t find it.


  17. Carl says:

    I hesitate to ask, but what about James Cuttsinger? He is Orthodox, and yet he is an advocate of Philosophia Perennis. His position on the matter is that various world traditions are valuable, not because they worked out the divine mysteries through pure ratiocination, but rather, that a select few of the world’s religious traditions are local manifestations of divine revelation.

  18. Fr. Maximus says:

    Samuel was persecuted by monotheletes, not Orthodox. We don’t take responsibility for the crimes of heretics. And the russian pogroms were condemned by the Orthodox Church even as they were taking place. There has never been an inquisition in Orthodoxy.

  19. Moreover, “you think this is bad, look how much worse it could be” is absolutely pointless.

    I mean if you said “you think I’m rock throwing, look what earlier Orthodox did to St. Samuel the Confessor” it actually attacks you and the Orthodox rather than supporting them.

  20. Photius,

    Is it just chance that the people you are attacking are Catholic? Wouldn’t it be far more Orthodox to list Orthodox faults rather than pointing out the faults of others? Particularly if when you point out their faults you aren’t attempting to bring about repentance. As such, if your point is as you say it is and not just a raised ante with a tu quoque, pointing to the Orthodox treatment of St. Samuel the Confessor, or to Orthodox pograms would be much more Orthodox.

  21. Fr. Maximus says:

    The evil force I was referring to is ADS, not some hidden cabal of occult masters. This doctrine originated in later platonism and was subsequently adopted in the west by Augustine and Boethius – from whence it passed to the modern Roman Catholics and Protostants – by Judaism and most of Islam, Al-Ghazali being a notable esception. Hindu thought of the adviata vedanta strain (which is by far the dominant in India) not only accepts ADS but goes even further to identify all things with Brahman. While it is true that samkhya does not seem to accept it, and so by extension yoga, in reality most samkhya metaphysics in modern yoga have been replaced by some form of vedanta. Buddhism would seem to be the major exception in that it is non-theistic, but Ananda Coomaraswamy (a major perennialist) has demonstrated that early Buddhism did in fact accept all the essentials of the doctrine. Thus most major religions of the world accept some form of ADS.

    Now surely Mike Liccione and company did not pick the title of their blog by accident. Being all profient philosophers they know what the Philosophia Perennis is: that there is a core set of truths about God and the world that can be attained by human reason; and that since they are thus attainable, have in fact been attained – at least in part – by the great philosophers of all traditions. Among the chief of these truths is ADS.

    Since this doctrine, attained purely by the excersize of the unaided intellect, is so widespread, and since its very defenders aver that it is part of the philosophia perennis, I stand by my claim that there is ain fact a philosophia perennis, just as its proponents hold. the only problem with it is that the God that it preaches is not the Christian God: it is the God of intellectually advanced paganism.

    Now I do not deny that there is much in the philosophia perennis that is beautiful and noble and true, but taken as a body – especially in its most fundamental point, which is the doctrine of God – it is at variance with the truth and at war with it. Unaided by revelation, the most brilliant and sincere human minds always seem to arrive at the same conclusion, a fact which the proponents of the philosophia perennis hold to prove the truth of their position, but which an Orthodox Christian sees as proof that philosophy is not the starting point for theology, but for heresy.

  22. Carl says:

    I’m a fan of Orthodox theology, but the amount of vitriol in this blog directed toward anyone and everyone with a different understanding really turns me off. What happened to speaking the truth in love? Remember, in Orthodox one is not saved by one’s gnosis (and in this sense “Orthodox” is a misnomer for the faith), but by receiving from Christ a heart that can withstand the purifying fire of theosis on the last day. How can you say that you love God who you have not seen if you hate your commenters who you have seen? How can one acquire the Holy Spirit while judging others?

  23. logismon says:

    Matthew, How so, specifically ?


  24. Lee,
    Many Augustinians thought that God damned people without recourse to their actions, e.g. Gregory of Rimini. That’s the doctrine of massa damnata. So what? Is that a reason to burn someone at the stake? I sure hope you don’t think so.

    I put forward Jan Huss as an example of real rock throwing to put it in perspective for you. Or how about the examples of the USCCB that has paid out millions in hush money over the sex abuse scandal? And I’m “rock throwing” ? Get a grip.


  25. Or St. Samuel the Confessor?

    Come on tu quoque isn’t valid.

  26. lee faber says:

    I thought I might dry my tears for Tammuz and take off my Dagon-hat for a moment to ask Photius if you chaps really aren’t just Alexander Hislop or Lorraine Boettner in disguise; that is, are really just still a prot?

    Yes, poor Hus, Claiming that God positive damns people irrespective of their actions ab eterno had nothing to do with it. He was smothered by popery.

  27. Matthew,

    I’m not going to tolerate profanity on the blog, especially to an Orthodox clergyman. So please if you wish to express yourself that way, keep it to yourself.

    We have very good reasons for being suspicious of the filioque and its methods in theology.

    BTW-Ask Jan Huss someday what real rock-throwing is like.


  28. Fr. Maximus

    That’s just shit. Partisan rock-throwing.

  29. Fr. Maximus says:

    It is very telling that Mike Liccione and company have named their new blog “Philosophia Perennis.” Virtually every attempt of man to come to an intellectual understanding with religion has resulted in something close to the same doctrine of God: there is not much difference between Neo-Platonism and Hinduism, and all modern religions of east and west are intellectually offshoots of one or the other. All religions except Orthodoxy end up virtually identifying metaphysics with theology. It seems that there really is a perennial philosophy which is like the default mode of human thinking apart from revelation.

  30. Fr. Maximus,
    “There is an evil force pushing this system forward into a total denial of the Trinity”

    I’m afraid so, which is why I’m ready to start looking at the very esoteric aspects to the filioque. I believe this dogma was to ensure the survival of Hermeticism and “sacred science” and its methods under the cover of religion.


  31. Fr. Maximus says:

    Existence is essence and that is a real identity. Person is relation and that is a real identity. Person is essence and that is a real idenity. relation is also essence and that is a real identity. How then can they object when we point out that one person must be the same as another person, and that there cannot be a relation between something and itself other than simple identity? Even on his own terms, it makes no sense.

    Thence it follows that in God essence is not really distinct from person…”

    That certainly does follow, most unfortunately.

    “…and yet that the persons are really distinguished from each other. For person, as above stated (29, 4), signifies relation as subsisting in the divine nature. But relation as referred to the essence does not differ therefrom really, but only in our way of thinking; while as referred to an opposite relation, it has a real distinction by virtue of that opposition.”

    If the relations are identical to the essence, then they do not exist, because relations are between more than one. And there can be no distinction by virtue of opposition, because something cannot be opposed to or distinguished from itself.

    “Thus there are one essence and three persons.”

    A non sequitur, which contradicts his earlier statement that person and essence are not distinct. There is an evil force pushing this system forward into a total denial of the Trinity, and Aquinas can resist it only by abandoning his own logic at the last moment in order to presrve the Trinity in name, if not if fact. The result is total confusion and blatant contradition.

  32. “The Persons are really distinct from one another, not notionally. Because of this we have to say that the identity of the persons with the nature is not the identity of the = sign, as is the case (for Thomas) with God’s essence and existence and essential properties.”

    And this is what we don’t buy. We don’t see any *logical* reason to say that the attributes, existence, and essence all function with the identity of an equal sign and then say that the Persons do not, especially when he says that the Person (any person of the trinity) and the essence are the SAME THING! Persons are “things” ? This is an assertion without an argument.

    “To the extent, then, that Father/=Son, or Paternity/=Filiation, and yet Father=God and Son=God, there is a difference between the *kind* of identity Thomas postulates between the Person(s) and the essence and that between the existence and the essence/attributes.”

    Really. Perhaps you can demonstrate lexically, syntactically, semantically *as defined by the author* himself that “identity” is being used in different kinds of ways. Show it.

    You say that the Father is not the Son and vice versa, but that doesn’t follow from the natural theology so contrued. That is something you know from external data: revelation and then attempting to read that into your philosophy. In fact, there is no *reason* to even name them Father and Son from this logic. Any name for 1st, 2nd, and 3rd hypostasis/essence will do.

    As Ockham said, is “relation” any thing that even exists in reality (prior to person)?


  33. Michael says:

    I posted this back on the other argument but it’s obviously just as appropriate here.

    Mr Jones, the combination of your insulting tone, your arrogance, and your lack of competence make discussion with you fruitless and infuriating. This is the last time I will post here.

    Yes, the identity of essence and existence in God and the identity of person and nature in God are not exactly the same. The quotes in your latest post show this clearly.

    The identity of essence and existence, due to God’s simplicity, is such as to make each of God’s essential attributes really identical with each other and only notionally distinct (for Thomas, let’s be clear, not for me). God’s existence, goodness, eternity, are all really one and the same “item”.

    The identity of the persons with the essence is not the same. They are identical in the sense that there is in one sense one “item” and in another sense three “items”. In no sense are there four “items”: essence, Father, Son, and Spirit, such as there would be if any or all of the divine Persons were *really* distinct from the essence in any way. This is in fact precisely Thomas’ denial of your “God in general” accusation–the divine essence is not a universal property to which is added an individuating difference, i.e. Divinity+Paternity=God the Father. Thomas denies this. Rather, the Person who has God’s Paternity=God. In that sense, God the Father (the supposit) is the same “thing” or “reality” (rem) as the divine existence/essence. There is no actually existing reality in God other than the divine ousia–God the Father is not something other than God, more, less, or different. There is no composition of personal properties with nature in God which would produce an additional something.

    BUT the divine existence/essence and God the Father are NOT identical in the sense that referring to the single divine nature refers to a single divine supposit or person. God the Father is God (the existence/essence, ousia), God the Son is God, but God the Father is not God the Son. The Persons are really distinct from one another, not notionally. Because of this we have to say that the identity of the persons with the nature is not the identity of the = sign, as is the case (for Thomas) with God’s essence and existence and essential properties.

    God the Father cannot be really distinct from the divine essence because he is wholly God and in no way something other than God. There is no reality in God the Father which is not God. Nevertheless, it is not the case that, simply, Divinity=Paternity, the way that Divine Immensity=Divine Eternity, because God the Son is God, he has all Divinity, but he has no Paternity. There are two related but distinct senses of identity in play. All three Persons are identical with the essence (and with each other) in the sense that there is only one SOMETHING. There are, however, really three SOMEONES. All three persons are really distinct from each other, because the Father is not the Son is not the Spirit. To the extent, then, that Father/=Son, or Paternity/=Filiation, and yet Father=God and Son=God, there is a difference between the *kind* of identity Thomas postulates between the Person(s) and the essence and that between the existence and the essence/attributes.

    I think this is clear enough in Thomas, although it could be clearer. And it is not my position–I don’t think Thomas has the conceptual tools to adequately express the different kinds of identity he has in mind, which makes him a bit confusing and occasionally sounds almost contradictory–but I don’t think it’s heretical and I don’t think it falls prey to your objections. Rather, I think you misunderstand and misconstrue Thomas, because you give him the least possible sympathetic reading. You’re looking for heresy and so you find it. But you should know how easy it is to apply the same trick to any of the Fathers.

    In any case, it’s easy to call something sophistry when you make no attempt to understand it on its own terms and show no inclination or ability to think through difficult distinctions. Thomas may not be perfectly clear and his conceptual structure may not be fully adequate to the problems he’s grappling with–I think it’s not–but that’s not the same thing as sophistry.

  34. Notice that in the last quote that the divine simplicity is presupposition to understand essence and “suppositum” (nothing else than person as Thomas says) as the same thing.

    Error from my estimation: Thomas, in his “systematic theology,” doesn’t start first with the Bible and the Incarnation and THEN after that is established [as a presupposition] and discussed, work out a doctrine of divine simplicity that would be compatible with the Orthodox Christological doctrine. No, rather he assumes a pagan view and then reads everything into that. This method, as the Apologists were wont to do as well, might have some apologetic appeal in dialoguing with pagans but in doing so it undermines the faith. It is a secular outlook and program in explaining the faith.


  35. Fr. Maximus says:

    If there ever was sophistry, this is it.

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