Transubstantiation in Thomas Aquinas: part three

Benozzo Gozzoli, The Triumph of St. Thomas Aquinas, with Aristotle and Plato, Musee du Louvre 1471

Image: “The Triumph of St. Thomas Aquinas” (AD 1471) by Benozzo Gozzoli, with Aristotle on the left and Plato on the right. Musée du Louvre.


This is the third and final installment in a three-part series on the doctrine of Transubstantiation in the sacramental theology of Thomas Aquinas.

Part One

Part Two

Part Three


The question remains whether these particular categories, substance and accidents, are aiding or hindering our understanding of the doctrine of the Eucharist. But first, let us review some praiseworthy features of the Thomist account.

We can commend the extent to which these distinctions remove any crude understanding of the Real Presence. As we have seen, it is precisely because Thomas makes a clear distinction between substance and accident that he is able to guard against any vulgar understanding of an actual eating of blood and flesh, which appears to be, given the polemics of the time period, what many Protestants supposed that Rome taught (and perhaps not a few Catholics themselves). The numerous miracles of the host turning into actual flesh and the wine turning into actual blood, which are often then venerated in shrines, have only reinforced this crude understanding of Transubstantiation.[1] Yet for Thomas at least, the compositional make-up of the bread, at the level of physical properties (species), remains as before. Thus, even though its ontological status has changed, what is being consumed is still, at the chemical level, bread. (By the way, the most significant criticism of the Mass by Protestants was, and remains, the Catholic belief in the Mass as a recurring sacrifice.)

Moreover, we can commend the extent to which Thomas repeatedly affirms the bodily presence of Christ in heaven, as distinct from his sacramental presence on earth. The corporal integrity of Christ’s ascended and glorified existence is important for a Reformed understanding of Christ’s high priesthood. If the body of the ascended Christ is given the divine properties of omnipresence, which may be the Lutheran position, then we would no longer have a glorified human body but something altogether different – a tertium quid that is a commingling of human and divine properties. Thomas rejects any such implications in his rejection of local and movable presence. For Thomas, the body of Christ in heaven remains and is at rest, not extended or moved into our space and time.

Yet, even with these commendations in mind, the Protestant is still faced with whether “substance” is a proper category for understanding the presence of Christ in the Eucharist. In regards to the bodily presence, the existence of a “substance” that is distinct from its physical “accidents” is necessary for underwriting Thomas’ whole conception of a real presence that is in “very truth” real (not merely a symbol) and yet not local. However, it is highly debatable whether any particular thing has a substance that, in some way, transcends the physical properties we perceive by our senses. Without the accidents, at least some of them, what can be predicated of substance?

Also, what gain is achieved by positing such a substance? In particular, is it even possible to conceive of a substance without conceiving of at least some of its accidents? Indeed, such accidents are necessary for the “what-ness” (substance) of a thing to be articulated with any comprehension. Therefore, can there be a clear separation of substance and accident?

In other words, in any meaningful description of substance (of body, blood, etc.), it seems to be necessary to include certain accidents; otherwise, we have a concept without content. While some accidents can be described as “non-essential,” such as the color of one’s skin, the skin itself surely requires some accidents to make it skin and not, say, a plastic bottle. Skin is a composite of accidents (all that is observable by the senses), some of which are required to make it skin. Without these “essential” accidents, we do not have skin. Likewise with body or blood, all that is available to our sense perception will include certain essential attributes that make the body a body and the blood to be blood. In the Thomist formulation of the Eucharistic elements, we have the substance of Christ’s body in the accidents of bread; yet, what is the content of this substance of Christ’s body? There is no content. It is completely void, once all “accidental” predicates are removed. This may be a limitation of our modern understanding, given that a substance (that which makes a thing what it is) is invariably understood according to its physical composition, at least in part. Terence Nichols, professor of theology at the University of St. Thomas, explains the problem:

But it would seem that what makes bread bread and wine wine are the chemical and molecular structures of their elements (flour, water, alcohol, etc.). But these are not changed in transubstantiation. “Substance” therefore must mean something else, some ghostly reality behind the chemical structures of bread and wine. But it is very hard for modern hearers to grasp what this occult “substance” might be, or how it makes the bread what it is and the wine what it is.[2]

Given that a Thomist-Aristotelian understanding of substance is especially difficult to comprehend today (if ever!), the problem is now whether the formulation of Trent is irrevocably bound to these philosophical categories. The Tridentine decrees follow Thomas in its formulation of Transubstantiation.[3] Edward Schillebeeckx affirms that, indeed, the bishops at Trent were authorizing Aristotelian categories of substance and accident. According to Schillebeeckx, even though they preferred to use “species” instead of “accidents,” the conciliar records indicate that they understood the two terms to mean the same thing. Trent is thereby not philosophy-neutral in its formulation of the Real Presence. As Schillebeeckx writes, “The fathers of the Council of Trent were not trying to dissociate themselves from the word ‘accidents’ for the very good reason that, whether they were strict Thomists or Scotists or whatever they were, they were all in their own way Aristotelian scholastics in their manner of thinking….”[4]

Thus, a significant question today is how the Roman Catholic understanding of Real Presence can be formulated in different categories that may complement, not replace, the substance ontology that has received conciliar sanction. And perhaps such an alternate formulation may approach nearer to the Reformed understanding. After all, both Thomas and the Reformed tradition affirm a “sacramental presence” without analogy in nature and without local presence, for Christ remains in his glorified body at the right hand of the Father.

[1] See the Real Presence Eucharistic Education and Adoration Association:

[2] Terence Nichols, “Transubstantiation and Eucharistic Presence,” Pro Ecclesia 11: 1 (2002): 59.

[3] The canons and decrees of the sacred and oecumenical Council of Trent, ed. and trans. J. Waterworth (London: Dolman, 1848), 78.

[4] Edward Schillebeeckx, The Eucharist (London: Burns & Oats, 2005 [1968]), 55. Terence Nichols disagrees with Schillebeeckx on this point. See “Transubstantiation and Eucharistic Presence,” 62.


  1. Thanks for this series. Do you have any thoughts to share on what Thomas’ doctrine implies with respect to Eucharistic adoration? ST III, q 25 rankles some Orthodox, since the way it uses ‘dulia’ and ‘latria’ seems out of step with Second Nicaea (though later Thomists make a distinction between ‘relative latria’ and absolute).

    • Thanks, John. Thomas seems to be saying that latria of an icon (or other representation) of Christ is part of one movement that always passes into the latria of Christ himself. If the latria were to stop at the icon/representation itself (a “non-rational creature”), then it would be an illegitimate worship of the icon. I am pretty sure that is what he means with his use of the Aristotle quote in the third article.

      As for Eucharistic adoration, I suppose that Thomas would say that the veneration of the host entails true worship of God (latria) because the host is truly substantially God. I didn’t mention it in the series, but Thomas teaches (as does Trent) that the whole of Christ is present with the body and blood. I forget the technical Latin term for this. Anyway, since an icon does not “contain” the substance of Christ himself, it is not quite the same thing as Eucharistic adoration. Indeed, according to Thomas (and official Catholic dogma), the bread is actually no longer present, because its substance has been replaced by the substance of Christ’s body. Thus, even though the bread remains as before in its entire chemical composition, it is bread without the substance of bread. So it’s not bread. Even though it has the same composition as any other bread, it is really the body of Christ.

      • Thanks, Kevin. Thinking about this tonight, I was reminded of a passage in Bellarmine:

        “We say that Christ is by Himself and properly to be adored with the worship of latria; and that that adoration belongs also the the symbols of Bread and Wine, so far as they are apprehended as a something that is one with Christ Himself, whom they contain. As they who adored Christ clothed on earth, did not adore Him only, but even His garments in some sort (for they did not bid Him be stripped of clothing before they adored Him, or in mind and thought separated Him from His garments, when they adored), but simply adored Christ as He then was, although the ground of their adoration was not His clothing, nay, not His humanity itself, but His Divinity alone.” (trans. W. E. Scudamore)

        The example is interesting because an adoration of the garments “in some sort” would have to be relative latria. Although I do not think this would be possible given Catholicism’s dogmatic commitments, if it could be declared that adoration of the sacrament is only relative, I could see some basis for ecumenical rapprochement. The reason is that relative latria might, with some stretching and if given a charitable reading, fall more under the heading of proskynesis than latreia as Second Nicaea uses those terms. Specifically, the council says that all images, be they of the saints or even of Christ himself, “should be given due salutation and honourable reverence (ἀσπασμὸν καὶ τιμητικὴν προσκύνησιν), not indeed that true worship of faith (λατρείαν) which pertains alone to the divine nature.” The next sentence offers the same justification that Thomas gives, “For the honour which is paid to the image passes on to that which the image represents, and he who reveres the image reveres in it the subject represented.”

      • Yeah, I think you’re right about the relative/absolute distinction as a way to harmonize East and West, and I think a good number of us catholic-minded Protestants could accept it as well. Though my experience with Eastern Orthodox folks has not been altogether pleasant experiences — blanket condemnations of the West (rationalist, not properly Trinitarian, etc.) compared to the purity and spiritual superiority of the East. I’m sure that’s not representative of the whole, but it’s a common enough mindset among EO’s to pose problems.

  2. Another thanks for this series. It has helped me unclutter my mind in regards to a Thomist/Roman understanding of the Eucharist.

    Now I’m one who believes in the ‘Real Presence’ and yet hitch my criticism on that made by Chelcicky during the Bohemian reformation. He opposed the Taborites, who preconditioned the Supper’s reality upon the faith of the recipient, and Rome. While he agreed with the unconditional ‘Real Presence’ at the Table, he thought Rome operated on an almost magical understanding.

    He criticized the Ambrosian formula that, in summary, by saying the words ‘hoc est meus corpus’ you have the Body and Blood of the Lord. Chelcicky took the Supper’s Real Presence as a mystery, but the reality of the Presence was upon Christ’s faithfulness to His own promise. It had nothing to do with a formula of institution, but upon the actual gathering where Christ said He would be.

    Granted, Chelcicky was before Trent and the Reformers, I think his criticism is necessary. The language of altar, priest(sacerdos), and bloodless sacrifice belie a continued magic. Thomists/Aristotelians speak of a swapping of substances but nothing of the Person. We’re partaking of the sacrifice of Christ and in so finding life. This is personal not substantive. The bread is still bread, the wine still wine, yet Christ is there. It is his flesh and blood, the sacrament being Christ for us, a means for life.

    My 2 cents,

  3. The real problem of Aquinas’ theology of transubstantiation seems to be that after the substantial change the accidents of bread and wine exist without the support of a substantial subject. This is not a matter of the accidents of bread existing without their natural substance. They exist without any substance at all. For after the conversion the substance of Christ’s body doesn’t become the substantial subject of the accidents of the sacramental species of bread and wine, since these accidents are incompatible to Christ’s body as Aquinas explains.

    The consequence of this state of affairs is that it is completely unclear what it means to say that Christ’s body is present “under” the accidents of bread. What relation is meant here by this term “under” if not the relation of accidents to a subject? But exactly this is what is excluded. The body of Christ doesn’t become the supporting subject of these accidents. Neither is the body of Christ their efficient cause, since these accidents are held in existence by the direct miraculous power of God.

    Thus it seems that there is no real relation at all between the body of Christ, which is taught to be “substantially present” and this bundle of accidents which exist without a bearer-subject. They are two completely separated and distinct realities without any relation to each other. And thus it is not clear at all how the body of Christ is present in the sacramental species.

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