Introduction
Contemporary Catholic theology faces a crisis of confidence in the intellectus fidei, rooted in uncertainty about the nature and task of dogmatic theology and its relation to Scripture, Tradition, and the Magisterium. This doctrinal instability is most acutely felt in the Church’s understanding of the Eucharist, where post-conciliar theology—shaped by modernist and post-metaphysical assumptions—has muted or bypassed the metaphysical clarity articulated by the Council of Trent. As a result, the Real Presence is often reduced to symbolic meaning, a shift lamented by John Paul II in Ecclesia de Eucharistia (2003). In response, Reinhard Hütter proposes a double ressourcement through the theology of St. Thomas Aquinas: first, a return to the authoritative sources of divine revelation, and second, a recovery of Aquinas’s metaphysical and theological vision of Christ’s real, corporeal, and personal presence in the sacrament. For Aquinas, sacra doctrina is not speculative abstraction but a contemplative ascent into the living truth revealed in Christ and made sacramentally present. Against the backdrop of a theological culture that privileges novelty and critique over fidelity and contemplation, Hütter insists that the Thomistic framework—grounded in both positive and speculative theology—is essential for restoring doctrinal coherence and Eucharistic faith.
At the heart of Aquinas’s theology is the inseparable union of positive and speculative dimensions: positive theology receives the revealed Word through the Church’s authoritative tradition; speculative theology seeks the inner coherence of that Word through disciplined reason. Nowhere is this synthesis more evident than in Aquinas’s doctrine of transubstantiation. Contrary to the charge that it reflects outdated metaphysical excess, Aquinas’s account secures the literal truth of Christ’s words—Hoc est corpus meum—and the Church’s unwavering confession of his true presence. As Fides et Ratio (§83) affirms, metaphysical inquiry is indispensable to the intellectus fidei, since revelation speaks of realities that transcend empirical experience. For Aquinas, metaphysics is not a barrier but theology’s proper instrument, enabling the mind to affirm and contemplate what faith reveals. As Hütter puts it, “Thomas’s metaphysical contemplation of Eucharistic conversion—precisely as an integral component of sacred theology—provides surpassing intelligibility to the dogma of transubstantiation as defined and circumscribed by the Council of Trent and as continuously taught by the church’s magisterium. Thomas’s contemplation gestures toward the blinding light of superintelligibility, experienced as the unique darkness that surrounds this sublime mystery of faith” (5). Aquinas’s theology does not rationalize away the mystery but safeguards it, guiding the intellect to behold, through the light of grace, the radiant obscurity of the mysterium fidei.
Chapter 1: Mysterium Fidei: The Mystery of Faith Proposed in Sacred Scripture
At the outset of his treatment of sacramental conversion, Aquinas exemplifies sacra doctrina—holy teaching—as a theological discipline rooted in divine revelation and mediated through the Church’s living tradition. For Aquinas, theology is not the product of autonomous speculation but a subalternata scientia, ordered by the higher wisdom of God and the blessed. In ST III.75.1, he begins not with metaphysical explanation but with the revealed truth of Christ’s real presence in the Eucharist—a truth accessible sola fide, resting on divine authority. The center of this doctrine is the dominical utterance: “This is My Body,” which Aquinas receives not as historical reconstruction nor metaphor, but as divine speech—Deus ipse loquitur. Citing Fathers from both East and West—Cyril of Alexandria, Hilary, and Ambrose—Aquinas demonstrates that the Church has always received the literal sense of these words as a truth revealed by God and faithfully transmitted through the Church’s magisterium.
From this revealed foundation, Aquinas offers three theological reasons for the fittingness of Christ’s real, corporeal presence: as the fulfillment of Old Testament types, it must be true and not merely symbolic; as a sacrament of friendship, it expresses Christ’s desire to abide with the faithful; and as a mystery of faith, it mirrors the hiddenness of divinity beneath the veil of humanity. This movement from positive reception to contemplative appropriation expresses the very essence of the intellectus fidei: faith seeking understanding, not to dispel the mystery but to enter it more deeply. The metaphysical analysis that follows is not the origin of belief but its fruit, illuminating what faith already confesses. As Aquinas writes in ST II-II.1.1 ad 3, the object of faith is the First Truth as manifested in Scripture and taught by the Church. This conviction is beautifully expressed in his liturgical hymn Lauda Sion: “Dogma datur Christianis…“—“this truth is proclaimed to Christians.” For Aquinas, Eucharistic doctrine is not a speculative overlay but the living traditio of God’s Word—received, confessed, and adored in the Church.
Chapter 2: Dogma datur Christianis: The Truth Is Given to Christians by Tradition and the Magisterium
At the heart of Aquinas’s vision of sacra doctrina is the Church’s faithful reception of divine truth as revealed by God and interpreted through her magisterium. Theology is not shaped by cultural trends or speculative innovation but by the revealed truth handed down in Scripture and Tradition. This is especially evident in the doctrine of the Eucharist, where the Council of Trent’s teaching on sacrifice and transubstantiation remains normative. Modern popes—Leo XIII, Pius XII, Paul VI, and John Paul II—have reaffirmed this tradition, with Mysterium Fidei (1965) standing out as a crucial magisterial response to contemporary theological distortions. Rejecting symbolic reductions like “transignification” or “transfinalization,” Paul VI insists on the metaphysical reality of Christ’s substantial presence in the Eucharist.
The magisterium affirms that dogmatic formulations, shaped through centuries of reflection, express perennial truths accessible to all cultures and times. Their language, rooted in metaphysical principles like substance, cannot be replaced without compromising doctrinal integrity. As then-Cardinal Ratzinger warned, theology must avoid the error of “double accounting,” where faith professes transubstantiation while philosophy embraces a contrary explanation like “consubstantiation” or “transignification.” For Aquinas, theological truth is not endlessly malleable but divinely given, to be received in faith and illuminated by reason. The Eucharist, as the Church confesses, is not a symbol to be reinterpreted but the enduring mystery of Christ’s real presence—celebrated, adored, and handed down without deviation.
Chapter 3: Eucharistic Conversion and the Categories “Substance” and “Quantity”
Chapter 3 explores how a faithful understanding of Eucharistic transubstantiation hinges on the metaphysical framework of Thomas Aquinas, especially his doctrine of substance and quantity. In light of modern objections—such as Schillebeeckx’s appeal to quantum physics to render substance obsolete—Aquinas’s metaphysical theology proves essential for preserving the Church’s teaching. As Hütter affirms, it is precisely “the metaphysical concept of substance—as deployed in Thomas’s metaphysical elucidation of the Eucharistic mystery—that saves the Tridentine dogmatic notion of complete substantial conversion from turning into a doctrinally protected, but nevertheless mere metaphor” (29). Against the reduction of Eucharistic presence to symbol or subjective experience, Aquinas provides the metaphysical grammar that allows faith to seek understanding. Substance, which denotes what exists in itself (ens per se), and quantity, which gives a body its dimensionality, together uphold the intelligibility of the real presence. As one summary puts it: “If Christ’s words, ‘This is my body, this is my blood,’ are to be taken at face value and not as spiritual or metaphorical flights from reality, the proper metaphysical avenue available to the intellectus fidei is material substance as inherently modified by quantity… this kind of rigorous metaphysical contemplation lets the mysterium shine forth in its consummate glory” (54).
Aquinas argues that even though bread and wine are produced through human art, they are true substances with natural forms, capable of undergoing transubstantiation. His account, drawing on biblical analogies and Aristotelian principles, shows how human action can cooperate with natural processes to bring about substances rather than mere artifacts. Moreover, his distinction between substance and quantity is indispensable for understanding how Christ’s whole body, blood, soul, and divinity can be truly present under the appearances of bread and wine. Quantity, as the intrinsic ordering of parts within a body, allows for Christ’s bodily integrity to remain, even as His presence is sacramental rather than spatial. This distinction becomes especially vital in response to post-Thomistic objections—Franciscan, Nominalist, and Cartesian—that sought to collapse substance into quantity or reframe Christ’s presence in spatial or symbolic terms. The Thomist tradition defended Aquinas’s metaphysical clarity, ensuring that Christ remains truly, personally, and substantially present in the Eucharist, even without local extension.
Mysterium Fidei, reaffirming Trent, insists that after consecration, Christ is present “really, truly, and substantially”—not through metaphor or mental projection, but through a miraculous conversion of substance itself. While the accidents of bread and wine remain, Christ’s glorified body is wholly present under each species by a sacramental mode of being. This real presence is made intelligible only through Aquinas’s metaphysics, which distinguishes between substance and quantity, and between the intrinsic ordering of parts (ordo partium in toto) and their local placement (ordo partium in loco). Far from abstracting the mystery, this precision safeguards the Church’s Eucharistic faith and enables a deeper contemplation of Christ’s gift. The Eucharist is not a symbol of Christ but Christ Himself—personally present, gloriously real, and substantially offered for the salvation of the world.
Chapter 4: “This Is My Body”: Faith Preserves the Intellect from Deception
Aquinas situates the mystery of Eucharistic transubstantiation within the broader framework of sacramental causality, rooted in the Passion of Christ. For him, sacraments are not mere symbols but instrumental causes that communicate the saving power of Christ’s Passion to the faithful. Since Christ’s humanity is the instrument of his divinity, and the sacraments were instituted by Christ, they act through that sacred humanity to produce real spiritual effects. As Abbot Vonier notes, this introduces us into a “sacramental world,” in which signs truly cause what they signify. The Eucharist, the greatest of the sacraments, therefore effects what it signifies: the real, substantial, and personal presence of Christ under the sacramental species. This sacramental realism enables Aquinas to avoid both Berengar’s reductionist spiritualism and Humbert’s crude physicalism by upholding a metaphysical transformation that is both real and veiled—accessible only through faith.
To preserve this realism, Aquinas makes key distinctions: sacramentum tantum (the sign only), res et sacramentum (the reality and the sign), and res tantum (the reality alone). The bread and wine, once consecrated by Christ’s words, become the sacramentum tantum. The res et sacramentum is Christ’s true body and blood, truly present and signifying both his Passion and the communion it effects with the faithful. The res tantum is the grace received—union with Christ and incorporation into his mystical body. The separate consecrations signify Christ’s sacrificial death, yet the whole Christ is present under each species. As Hütter asks: “Is there a more abiding personal presence possible of Christ to the Church in its state of pilgrimage than in the sacramental form of his perfect, final oblation to the Father on the cross?” (60–61). Thus, the Eucharist is at once sacrificial, corporeal, and transformative—uniting the Church to Christ’s redemptive offering.
This mystery is made accessible through faith, which, for Aquinas, protects the intellect from error by enabling it to behold what the senses cannot perceive. As Stephen Brock explains, the word “this” (hoc) in the formula “This is my body” points the intellect to a substance now present under the accidents of bread. Faith, informed by grace and moved solo auditu, allows the soul to assent to this hidden reality: “the intellect obscurely beholds Christ’s substantial presence under the Eucharistic species… thus the truth is given to Christians (dogma datur Christianis)” (63–64). In the words of Adoro te devote: “What God’s Son has told me, take for truth I do; Truth Himself speaks truly or there’s nothing true.” In this sacrament, Christ shows us his flesh “in an invisible manner” (ST III.75.1), revealing not a symbolic abstraction but the very heart of sacra doctrina. As Hütter concludes, transubstantiation is the “hidden power” that enables faith to preserve the intellect from deception and contemplate, in the darkness of superintelligibility, the real and personal presence of Christ in the Eucharist (65).
Chapter 5: “You Are My Friends” Christ’s Eucharistic Presence, Central Token of Christ’s Surpassing Friendship
In ST III, q. 75, Aquinas identifies the Eucharist as the supreme sign of Christ’s surpassing friendship, rooted in the Lord’s own words: “You are my friends” (Jn 15:14). Friendship, as Aristotle noted, desires shared presence, and for Aquinas, the Eucharist is Christ’s way of abiding bodily with the faithful during their earthly pilgrimage—not merely in symbol, but in truth. This sacramental presence is not in propria specie, but in specie aliena, ensuring that while the elements retain their sign-character, they now contain the reality: Christ’s true body and blood (res et sacramentum), which signifies and communicates the grace of mystical incorporation into his body—the res sacramenti. This grace, however, is received only by those united to Christ through living faith (that is, faith informed by charity); mortal sin, by severing charity, makes one guilty of profaning the sign of unity. As Aquinas insists, “Whoever receives this sacrament, expresses thereby that he is made one with Christ” and thus to receive unworthily is to “lie to the sacrament” (III.80.4) The Holy Spirit, as Scheeben and de Lubac echo, infuses this unity by charity, joining the members to the head, such that the Church becomes one organic body nourished by the Eucharist. The danger, anticipated by de Lubac after Vatican II, is reducing this unity to mere communal sentiment, forgetting that it arises from sacramental participation in Christ’s oblation on the Cross. Only the real presence of the head sustains the mystical body; “the Eucharist makes the Church” precisely because Christ first makes the Eucharist. This divine causality is affirmed by the Church’s tradition and by magisterial teaching (cf. Ecclesia de Eucharistia, §22), which recognizes in every reception of the Eucharist a mutual abiding—Christ receiving us as we receive him. In this most intimate act of friendship, he fulfills our deepest longing to dwell with him, having already answered the cry, “Stay with us” (Lk 24:29), by instituting a sacrament in which he remains with us until the end of time.
Review
Reinhard Hütter’s Aquinas on Transubstantiation was a great resource during my studies at the Angelicum, offering a clear and faithful presentation of St. Thomas’s Eucharistic theology in the face of modern distortions. As part of a course assignment, it helped me see how Aquinas’s metaphysical framework—particularly his doctrine of substance and quantity—remains indispensable for understanding the Church’s teaching on the Real Presence. Hütter convincingly shows that “Thomas’s metaphysical contemplation of Eucharistic conversion—precisely as an integral component of sacred theology—provides surpassing intelligibility to the dogma of transubstantiation… gesturing toward the blinding light of superintelligibility, experienced as the unique darkness that surrounds this sublime mystery of faith” (5). For anyone seeking a renewed appreciation of the Eucharist grounded in both Scripture and metaphysics, this work is an accessible and theologically rich resource.
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