The Substance of the Matter: Dietrich of Freiberg’s Critique of Transubstantiation

The Substance of the Matter: Dietrich of Freiberg’s Critique of Transubstantiation

J. Neil Daniels

Understanding Transubstantiation

Transubstantiation is the Roman Catholic doctrine that, during the consecration in the Mass, the entire substance of the bread and wine is miraculously transformed into the actual body and blood of Christ, while the outward appearances (or accidents) of bread and wine remain unchanged. This teaching was formally codified at the Fourth Lateran Council in 1215 and reaffirmed at the Council of Trent in response to the Reformation.

While Roman Catholicism regards this transformation as a literal change of substance, both Eastern Orthodox and Protestant traditions have historically expressed reservations—albeit for different reasons. The Eastern Orthodox typically reject the scholastic explanation of the Eucharist via Aristotelian categories, opting instead for a more mystical realism without detailed philosophical definitions. Protestants, especially those in the Reformed and Lutheran streams, reject the notion of a change in substance altogether, emphasizing either a spiritual presence (Calvin) or sacramental union (Luther), while others, like Zwingli, emphasize a symbolic memorial. Across these traditions, the doctrine of Transubstantiation has been critiqued as philosophically incoherent and theologically overreaching.

One of the earliest and most incisive critiques of Transubstantiation from within the medieval scholastic tradition came not from a Protestant or Orthodox voice, but from a Dominican philosopher and theologian: Dietrich of Freiberg (ca. 1250–ca. 1310).

Dietrich of Freiberg’s Philosophical Challenge

In his work De Accidentibus, Dietrich addressed a key aspect of Aquinas’ Eucharistic doctrine: the assertion that the accidents of bread and wine (such as color, texture, and taste) remain after the substance has been changed into the body and blood of Christ. Aquinas argued that by divine power, these accidents could exist without their usual substance—an exception to normal metaphysical rules, justified by the uniqueness of the sacrament.

To explain this, Aquinas redefined an accident as “that to which it is owed to be in another” (id cui debetur esse in alio), suggesting that while accidents ordinarily inhere in substances, God could suspend this requirement in the case of the Eucharist.

Accidents Without Substances? Dietrich’s Aristotelian Objection

Dietrich’s response drew deeply from Aristotelian metaphysics, which dominated medieval scholasticism. According to Aristotle, accidents are non-substantial properties that cannot exist on their own. Whiteness, for instance, cannot simply “be”—it must be the whiteness of a thing. An accident, by nature, is dependent on a subject in which it inheres.

Dietrich therefore contended that Aquinas’ notion of “free-floating” accidents was not merely improbable but metaphysically impossible. The separation of accidents from substance undermines their very definition and coherence. In his view, to claim that accidents could exist without a substance was to destroy the logical structure of Aristotelian ontology.

Divine Power and Logical Coherence

Crucially, Dietrich did not base his argument on a limitation of divine power but on the consistency of divine reason. He maintained that God cannot actualize logical contradictions. Just as God cannot create a square circle or make two plus two equal five, so too He cannot cause accidents to exist without a substance. Such a claim, Dietrich argued, would be akin to asserting that properties can exist as properties of nothing—a metaphysical absurdity.

This led him to one of his most forceful conclusions: if one accepts Aquinas’ account, then one must accept the reality of “floating whiteness,” or taste without a taster—qualities with no subject. Such a notion is not only counterintuitive but collapses under the weight of its own contradiction.

Theological Caution: Mystery and Philosophy

In sum, Dietrich of Freiberg’s Aristotelian critique of Transubstantiation centers on the argument that accidents, by their very nature, must inhere in a substance. To separate them results in metaphysical incoherence and logical absurdity. By pressing this point, Dietrich’s critique becomes more than an internal philosophical disagreement; it is a cautionary example of the dangers of overdefining theological mysteries with speculative metaphysical categories.

His challenge invites a broader theological reflection: How far should human reason be permitted to go in articulating divine mysteries? What are the limits of philosophical explanation in service of sacramental theology? And at what point does speculative theology risk undermining the very coherence of the truths it seeks to defend?

For Protestants, Dietrich’s argument offers an early and sophisticated critique of the metaphysical foundation of Transubstantiation—one that resonates with the Reformers’ concerns centuries later. His voice, though situated within the scholastic tradition, underscores the enduring importance of ensuring that theological affirmations remain not only reverent but rational.