Aristotelianism in Eucharistic Theology

Father Thomas Reese and Transubstantiation

This article has been reworked from a paper entitled “They Must Fall into Being: The Son’s Power as Quasi-Subject of the Accidents of Bread and Wine in the Sacrament of the Eucharist” which I delivered on Feb. 4, 2023, at The Holiness of God and the Mystery of the Eucharist conference at Ave Maria University co-sponsored by the Aquinas Center for Theological Renewal (Ave Maria, FL) and the St. Paul Center for Biblical Theology (Steubenville, OH).

Several months ago, the Reverend Father Thomas Reese of the Society of Jesus (Ph.D. Political Science: University of California, Berkeley) wrote a series of articles on the Eucharist for the National Catholic Reporter.1 He led it by saying:

Since my critics often accuse me of heresy, before I go further, let me affirm that I believe in the real presence of Christ in the Eucharist. I just don’t believe in transubstantiation because I don’t believe in prime matter, substantial forms and accidents that are part of Aristotelian metaphysics. Thomas Aquinas used Aristotelianism, the avant-garde philosophy of his time, to explain the Eucharist to his generation. What worked in the 13th century will not work today. If he were alive today, he would not use Aristotelianism because nobody grasps it in the 21st century.2

In one fell swoop, Father Reese denies the dogma of Transubstantiation — he refuses belief in it — and would disparage the modern Catholic’s intellectual ability.

To the first, it is easy to point out that the Ecumenical Council of Trent defined Transubstantiation as a dogma of the Catholic Church in its thirteenth session:

If anyone says that in the venerable sacrament of the eucharist the substance (substantiam) of bread and wine remains together with the body and blood of our lord Jesus Christ, and denies that marvellous and unique change of the whole substance (substantiae) of the bread into the body, and of the whole substance (substantiae) of the wine into the blood, while only the appearance (speciebus) of bread and wine remains, a change which the catholic church most apply calls transubstantiation (transsubstantiationem): let him be anathema.3

This is the second canon of the thirteenth session of the Council of Trent, right after the canon defining the Real Presence which Fr. Reese admits he believes in, as his personal defense against repeated accusations of heresy.4

If Fr. Reese had merely stated that he could not teach a rigorous Aristotelian-Thomism to the baptized as the necessary meaning of the Council of Trent’s use of the terms “substance,” “appearance,” and “transubstantiation,” then this would be understandable. Such an admission would not mean that he would have to declaim, “I just don’t believe in transubstantiation.” Rather, Father could admit belief in this “marvellous and unique change . . . which the catholic church . . . calls transubstantiation,” and just admit that he does not grasp how to theologically parse the vocabulary that the Church has used to explain this sacramental mystery. This would allow one to retain this sanctified term, following the 1965 command of Pope St. Paul VI that the faithful must retain the language that the Church has used in her doctrinal formulas through the centuries:

And so the rule of language which the Church has established through the long labor of centuries, with the help of the Holy Spirit, and which she has confirmed with the authority of the Councils, and which has more than once been the watchword and banner of orthodox faith, is to be religiously preserved, and no one may presume to change it at his own pleasure or under the pretext of new knowledge. Who would ever tolerate that the dogmatic formulas used by the ecumenical councils for the mysteries of the Holy Trinity and the Incarnation be judged as no longer appropriate for men of our times, and let others be rashly substituted for them? In the same way, it cannot be tolerated that any individual should on his own authority take something away from the formulas which were used by the Council of Trent to propose the Eucharistic Mystery for our belief. These formulas — like the others that the Church used to propose the dogmas of faith — express concepts that are not tied to a certain specific form of human culture, or to a certain level of scientific progress, or to one or another theological school. Instead they set forth what the human mind grasps of reality through necessary and universal experience and what it expresses in apt and exact words, whether it be in ordinary or more refined language. For this reason, these formulas are adapted to all men of all times and all places.5

Instead, Father Reese denies this solemn canon of the Council of Trent on the grounds of twenty-first century humanity’s inability to understand this generally Aristotelian language.

Such is unfair. These sorts of old terms are sufficiently simple for anyone who wishes to apply themselves a little in learning the bones of orthodox Catholic theology. There is no reason to completely reject the language of Aristotle for such a theology; rather, it just requires some very basic outlines to understand the basic thrust of the Council of Trent’s dogmatic definition. To wit, a similarly basic question may be asked. Inasmuch as we perceive the appearances of bread and wine in receiving the most holy sacrament of the Eucharist and account for them as Aristotelian accidents, how do they exist when it is Christ Jesus who is present in this sacrament and not the substances bread and wine? In other words, what is the relation of “accidents” to their “subjects” or “substances”? To answer this question, I will explain the relation between accidents and the underlying subjects through which these accidental beings exist. In a certain sense, we will see how these terms may be understood without too much difficulty, despite their antiquity and the debates of the learned over some of the niceties of these Aristotelian categories.

The philosophical terms of “accident,” “substance,” or the term “subject” which we will see to be useful here, had a long history and development during the ancient and medieval periods before being used by St. Thomas Aquinas or the Council of Trent. Such crystallization of positive and deep concepts can obscure the basic realities being discussed, however. Therefore, to speak of subjects and accidents in natural philosophy, it is best to return to the most basic aspects which characterize these concepts. Thankfully, this does not require a high-level dive into a graduate seminar on Aristotelianism. We only need a swift review of a few points from Aristotle’s Metaphysics, using it only as a sort of dictionary.

The appearances of bread and wine are the merely perceptible and material aspects of bread and wine without any objectively existing bread or wine in a mysterious fashion. These various aspects are what Aristotle considered “accidentals,” or realities which do not themselves make up a whole stable being. The pale tan color of bread does not itself make bread, for example. One of Aristotle’s definitions of this sort of reality is, “‘Accident’ means that which attaches to something and can be truly asserted, but neither of necessity nor usually . . . for neither does [it] come of necessity from the other or after the other . . . . ‘Accident’ has also another meaning, i.e. what attaches to each thing in virtue of itself but is not in its essence.”6 Aristotle is here pointing out that if there are attributes of things which are not necessary to it, just like my hair color, weight, height, habits of knowledge, etc. are not necessary to my being the same sort of thing as all of you — a human being — then these attributes exist as something different than my individual humanity but still exist relative to me in my individual being.

In Aristotle’s own Greek, the word for “accident” is “συμβεβηκός” (symbebēkós) which literally is translated as “to come with” or “to go together” (συνβαίνω – syn-bainō). The Greek word expresses its concept in a way that has been effaced in English when I say “accident.” “Συμβεβηκός” (symbebēkós), this thing which goes together, simply names those attributes which come together with a recognizably individual thing (again, as height comes together with a man, though this height is not determined by human nature nor by an individual person’s own existence).

Again, Aristotle speaks in the same way elsewhere, while defining what the term “to be” means. He uses this same word “συμβεβηκός” (symbebēkós) as a direct object, or accusative, in a prepositional phrase instead of as the subject of a sentence, or a nominative. Therefore, Aristotle is capitalizing on a more pedantic use of the Greek word by adding a preposition meaning “down to,” in Greek “κατά” (katá). Therefore, an accidental reality, or the mere appearance of a thing, is described as “κατὰ συμβεβηκὸς7 (kata symbebēkós) which technically translated to “downward/in coming together with [another].” This is again reflected in the Latin that a theologian like St. Thomas Aquinas uses “accidens” or, rather, the phrase “per accidens” derived from the verb “accido.” “Accido” is itself a combination of the words “ad” (to/towards/into) and “cado” or “to fall.”

Therefore, the etymology of the English word “accident” depends upon this very same understanding as Aristotle’s “ συμβεβηκός” (symbebēkós); it denotes “that which falls into” or in an ontological context, “that being which falls into another.”8 The term and concept in this most basic form does not require more than this — for example, it says nothing about how such accidents would determine or modify things.

What these accidents/appearances fall into, however, still must be explained. Only a little more ancient philosophy is required for this. Now we must understand how to account for the stably existing being which has these appearances. Most properly, this “being” which these attributes fall into and which they are predicated of are called “substances.” Aristotle says:

We call “substance” the simple bodies, i.e. earth and fire and water and everything of the sort, and in general bodies and the things composed of them, both animals and divine beings, and the parts of these. All these are called substance because they are not predicated of a subject but everything else is predicated of them.9

Aristotle does not define substances as large complex material beings, though it is obvious that such complex beings made of basic elements are substances but prefers to define “substance” as what other things are predicated of without also being themselves predicated of another. In other words, substances are what exist independently and not by depending upon the prior power of some other being. When Aristotle says that substances are not predicated of a subject, he means that substances are themselves the ultimate subject of all other aspects of reality making up a whole. For example, the really existing humanity of Pope Francis is the subject to his age, skin tone, pastoral wisdom, etc.

The word that Aristotle uses for “subject” in this quote is “ὑποκειμὲνον” (hypokeimenon)10 This word is a combination of “ὑπό” (hypó) and “κεῖμαι” (keimai) — under-lie — which is well translated by both the Latin words for “substance” (“substantia’) and “subject” (“subiectum.”) Thus, the former is “what stands under”— from “sub” and “stare” — and the latter is “what is thrown under” — from “sub” and “iacere.” Substance is, in this respect, very simply defined according to its relationship to its accidents; that which is subject to characteristics which depend upon it (the subject) for their own existence.

This complicated Aristotelian language most basically is a descriptive vocabulary for the relation of the aspects of a thing which cannot exist independently and the aspect of the thing which is the stable being itself. Pope Francis’ height will never be met walking down the street, but the human which is Pope Francis has been — accidents/appearances vs. their substance/subject.

Normally, the substance/subject of any accidents or appearances is so straightforward that only philosophers and theologians would try to parse through what a substance/subject is relative to its accidents or appearances. The appearances of bread and wine normally belong to real substantial bread and wine. This is not a special statement. However, what if there were an atypical case of how appearances of bread and wine related to their subject? What if there is an omnipotent God who has chosen to use His creative power to change the substances of bread and wine into the body and blood of Christ Jesus while keeping the appearances of bread and wine in existence?

These are the basic terms needed to understand this dogma of Transubstantiation from the Council of Trent and its basic problem. The Council of Trent declared that the natural substances of bread and wine do not remain in the Eucharist but are replaced by the Real Presence of Christ Jesus under the mere appearances of bread and wine.11 These mere appearances of bread and wine — their tan and red color, their respective tastes, their isolated mass, etc. — do not exist through themselves. Nobody has ever come across Red the Thing existing comfortably in the cosmos or Mass Itself (in the sense belonging to physics) floating around without it making up a recognizable thing or in relation to a wider phenomenon. The appearances of bread and wine require some sort of subject when the original substance of bread and the original substance of wine are transubstantiated into the body and blood of Christ Jesus really present in the Eucharist.

It would be monstrous to claim that the Second Person of the Trinity incarnate — Christ Jesus — was present in the Eucharist as if He were personally being modified by the accidents/appearances of bread and wine. Such would be the case if He were the proper substance in which they naturally existed, according to St. Thomas Aquinas.12 For this reason, St. Thomas recognizes that Christ’s body and blood are not the subjects of these accidents (speaking in a precise Aristotelian sense) either as the subjects of the changes of bread and wine to Christ’s Body and Blood or as the subjects of these accidents after said changes.13 However, it remains true 1) that the accidents/appearances of bread and wine must fall into being and 2) that Christ Jesus is really present under said appearances/accidents.

St. Thomas, declining to speak of Christ Jesus as a subject to these accidents/appearances of bread and wine, prefers to say:

[T]he accidents continue in this sacrament without a subject. This can be done by Divine power: for since an effect depends more upon the first cause than on the second, God Who is the first cause both of substance and accident, can by His unlimited power preserve an accident in existence when the substance is withdrawn whereby it was preserved in existence as by its proper cause.14

In other words, St. Thomas claims that the appearances of bread and wine do not exist in anything in the Eucharist (as when such appearances are supported by a stably existing thing) because God’s omnipotence is able to supernaturally work in creation such that the normal way that a whole stable being exists does not apply in this great sacramental mystery. This does not mean that these philosophical terms are bankrupt or that they need be too obstruse for the average educated Catholic who wishes to engage with the Faith. The relationship of accident/appearance to subject which we have discussed above does indeed exist in Transubstantiation, this presentation has only glossed over some of the philosophical niceties which St. Thomas himself covers in depth and in a slightly different way befitting of a science.

Therefore, I would like to jog over to how St. Thomas Aquinas proves that God is the cause of all being, not only creating the essential natures of things15 but also creating individual substances.16 Thus, all substantial things participate in being by having their own created existence. This obviously means that the substances bread and wine are effects of the Divine Power — as are their accidents/appearances. Moreover, all actions of created beings are caused by God.17 I would like to focus on the capacities of substantial being, considering them also as the effects of Divine Power that they are. Here, God is the cause of that power whereby quantity, quality, relation, etc. exist through their relevant subject, and He is such a cause in a pre-eminently perfect manner.18 Therefore, God is the ultimate cause of the existence of all accidental beings; indeed, He is the cause of the immediate capacity of their existing in a substantial thing.

Granted that there is the miraculous change of bread and wine into the body, blood, soul, and divinity of Christ Jesus, one may then ask how these accidents of bread and wine exist without their natural subject of the substances of bread and wine. We can answer by simply deploying the relation of accidents to subjects — appearances which exist through something else and a being which exists under appearances. These accidents/appearances, which must fall into being, are kept in existence by directly being granted their relative existence through this same Divine Power now Personally present in a sacramental mode to them. Indeed, St. Thomas himself admits that these appearances of bread and wine are truly accidents, “they do not cease to be accidents, because neither is the definition of accident withdrawn from them.”19

Whatever power of being is needed for these accidents to exist is found in a more eminent mode in the Incarnate Word than in the natural substances of bread and wine. Therefore, He is more able to give this power of being than such natural substances can, relative to their own accidents/appearances. Whatever the natural subjects of bread and wine did before transubstantiation to their apparent accidents is still done by Christ Jesus in His Divine Power hence the Power of the Son is like an Aristotelian subject. It is as a quasi-subject. This supernatural mode of upholding these accidents in being would not contradict St. Thomas’ teachings, since all the accidents and appearances of bread and wine ultimately still fall into being by this unique act of the Word’s Power.

This simple relation of the 1) aspects of things which must exist in a subject and 2) the subject in which its appearances or perceivable contingent attributes exist suffices for the Aristotelian language found in the Council of Trent’s dogma of Transubstantiation. Indeed, introducing the term “subject” as a near synonym to substance makes it even easier to see this relationship of the appearances of bread and wine and the real presence of Christ Jesus under them. Seeing how Christ Jesus with His divine power as the subject of these appearances is not violent to the general definitions of these Aristotelian words and shows how this relationship is always present either for natural bread and wine before transubstantiation or the Eucharist after transubstantiation. Unlike Fr. Reese, we do not need to say that this general Aristotelianism is too difficult for modern people, as if we could never see this sort of relationship in things, but rather we may believe in this “marvellous and unique change . . . which the Catholic Church . . . calls transubstantiation.”20 More difficult questions surrounding this dogma may then be left to the experts.

  1. Cf. Thomas Reese, “The Eucharist Is About More than the Real Presence,” National Catholic Reporter: The Independent News Source, January 31, 2023,; Thomas Reese, “The Jewish Roots of the Eucharist,” National Catholic Reporter, February 6, 2023,; Thomas Reese, “Eucharistic Prayer Is the Most Important and Least Understood Prayer in Mass,” National Catholic Reporter, February 14, 2023,
  2. Thomas Reese, “The Eucharist Is About More than the Real Presence,” National Catholic Reporter: The Independent News Source, January 31, 2023,
  3. Norman P. Tanner, ed., “Council of Trent: 1545–1563,” in Decrees of the Ecumenical Councils. Volume Two: Trent to Vatican II (Washington, DC: Georgetown University Press, 1990), pp. 657–799, 697.
  4. Cf. Tanner, “Council of Trent,” 697; Reese, “The Eucharist Is About More than the Real Presence.”
  5. “Mysterium Fidei: Encyclical of Paul VI on the Holy Eucharist,” The Holy See (Libreria Editrice Vaticana), accessed April 2, 2023,, § 24. Italics added.
  6. Aristotle, “Metaphysics,” trans. W. D. Ross, The Internet Classics Archive, accessed February 2, 2023,, V.30.
  7. Aristotle, Aristotle’s Metaphysics: A Revised Text with Introduction and Commentary, ed. W. D. Ross, vol. 1 (Oxford: Clarendon Press, 1924), V.7.
  8. For these Greek and Latin etymologies, see Henry George Liddell et al., eds., A Greek-English Lexicon (Oxford: Clarendon Press, 1996); Charlton T. Lewis, ed., A Latin Dictionary Founded on Andrew’s Edition of Freund’s Latin Dictionary (Oxford: Clarendon Press, 1980).
  9. Aristotle, “Metaphysics,” V.8.
  10. Aristotle, Metaphysics: A Revised Text, V.8.
  11. Cf. Tanner, ed., “Council of Trent,” 697.
  12. Cf. Thomas Aquinas, “Summa Theologiae,” Aquinas Online (The Aquinas Institute), accessed February 27, 2023,, ST, III, q76, a1, ad1.
  13. Cf. Aquinas, ST, III, q75, a5, ad3; ibid, q77, a1, resp.
  14. Aquinas, ST, III, q77, a1, resp.
  15. Cf. Aquinas, ST, I, q2, a3, resp. for St. Thomas’ “fourth way.”
  16. Cf. Aquinas, ST, I, q2, a3, resp. for St. Thomas’ “second way” through “fifth way.”
  17. Cf. Aquinas, ST, I, q2, a3, resp.; ibid, I-II, q9, a6, resp.
  18. Aquinas, ST, I, q4, a2, resp.
  19. Aquinas, ST, III, q77, a1, ad2.
  20. Tanner, ed., “Council of Trent,” 697.
David Francis Sherwood About David Francis Sherwood

David Francis Sherwood is a PhD Theology student at Ave Maria University where he studies systematic and biblical theology. Previously, he studied at the ITI Catholic University in Trumau, Austria, receiving a Licentiate in Sacred Theology in 2022 and a Master's in Sacred Theology in 2020. His undergraduate degree is from Thomas Aquinas College in Santa Paula, CA.


  1. Avatar P Thomas McGuire says:

    David, You are a master of Aristotle and Thomas, but happens when you require a person from China to take on such terms in order to be a faithful Catholic. I am not a scholar, but I do not understand why faith in the Eucharist MUST be based only on Greek philosophical concepts. Is it not time to at least try to come to an understanding of the MYSTERY of Eucharist using Chinese concepts rather than Greek concepts.

    • Avatar David Francis Sherwood says:

      There is no automatic “a priori” reason why Greek concepts are *necessary* to understand the Eucharist. There are reasons subsequent to the institution of the Eucharist by the Lord, mainly the doctrinal language and dogmas found in the Ecumenical Councils–even in their infallible sacred canons. Moreover, as the mystery of the Eucharist and its various aspects (Real Presence, Transubstantiation) is a matter of *reality* and *truth*, the key duty is always and everywhere maintain the truth about the Eucharist. The language of the Church has chosen these Aristotelian terms, without endorsing the rest of the Greek conceptual background beyond the basic understanding of these very terms or any other Greek philosophical concepts.

      In fact, the power of the most bare-bones lexical understanding of the Church’s chosen terms of “substance,” “subject,” “accidents,” and “appearance” is the key point of this paper. This has very little to do with the Greeks, Aristotle, or St. Thomas Aquinas. Rather, it has more to do with perceivable aspects of reality which could have been discovered or expressed by any piercing mind–Greek, Chinese, or any other. It just so happens that history has recorded them best from the mind of Aristotle, St. Thomas, and their like–which, again, were picked up by the Church. Moreover, considering that participation in the Eucharistic mystery is the summation of the life of the Church in this world, it takes very little training in this Greco-Latin philosophy and vocabulary to sufficiently understand the Eucharistic doctrinal language and dogmas. It should not be surprising that an active understanding of it requires work, especially for all of our cultures and nations which was not either Jewish or Hellenistic–since these were the types of cultures and people who originally encountered God’s Revelation. However, the Gospels have been preached for two millennia based on an original Hebrew and Greek body of Revelation. There has always been difficulty in explaining certain terms or concepts to cultures “far away.” Going through a paper like this and the philosophy behind it is not great burden when held up to the importance of the mystery that the Church hands on to us now.

      The reason why this paper returns to the specifically Greek vocabulary is simple. People reject the Church’s language (as Fr. Reese did). Therefore, the return to this kind of “traditional” exposition becomes important again and again. The desire to reach to other cultures to doctrinally and dogmatically explain the Eucharist mystery is not necessarily expedient–or possible–as a matter of *truth*. It might be possible. However, this would not abrogate the Church’s doctrinal and dogmatic language or the faithful’s faithful reception thereof–which is the focus of this paper and Fr. Reese’s statement. This desire for inter-cultural investigation and exposition is, therefore, a secondary concern to maintaining dogma and dogmatic language. Moreover, the question of the *truth* of other philosophies would be important here. While it is understandable that someone who agrees with the principles and many conclusions from the Chinese sages would wish to attempt a new theological synthesis, this would not make sense for those who do not think said principles or conclusions are *real*.

      The Church is both an institution taking up 1) real mysteries and truths and 2) one which takes up history. While it could have been that the distinction between act and potency, with all its analogous instantiations, could have been discovered, expanded upon, and written down by anyone in the world it remains the historical fact that these have been most found in the Aristotelian tradition of the West. This seems to be the best perception and expression of ontological truth found anywhere insofar as it parses the different aspects of created beings (as in the substance-accident discussion above), respects the hierarchy of Creation amongst creatures and under God, is applicable to creation ex nihilo, etc. This discussion about truth and reality; while perceived, debated, and expressed throughout history, then has been recognized by the Church to contain some few concepts and terms useful as part of Her own explanation of the revealed mystery of the Eucharist.

      I hope these thoughts are useful to you–I’m sure my betters would have more to say or may have even written about this kind of issue. However, if you are convicted of the truths found in a Chinese philosopher, then I would encourage you to either pursue it yourself within the Church or to find like-minded people. And while it is true that there is not an *antecedent* reason why Greek terms are superior to any other culture’s, it is also true that there should not be anxiety over the *comparatively* low difficulty of teaching a few basic terms for those who dedicate themselves to understanding the Church’s dogmas on the greatest mysteries in a normal “every day” capacity. God bless!