Abstract

In this study I investigate the metaphysical, logical, and epistemological tensions generated by the classical doctrine of transubstantiation, focusing especially on the Thomistic claim that in the Eucharist the sensible accidents of bread and wine remain without their natural subject. I identify this configuration as the “inverse” of divine simplicity whereas God is “a substance without accidents,” the Eucharist presents “accidents without a subject.” I further examine whether the classical framework of substance and accident, act and potency, immutability and simplicity can coherently sustain such an inversion or whether it requires conceptual exceptions that exceed the limits of metaphysical explanation. Methodologically, the study employs comparative metaphysics, textual‑historical analysis of patristic and scholastic sources, and cross‑tradition theological comparison (e.g., Catholic, Orthodox, Lutheran, Reformed, and Zwinglian). This is further supplemented by contemporary logical evaluation, scientific‑philosophical critique, and biblical analysis of the sensory, public pattern of miracles in Scripture. These methods allow assessment of both the internal coherence of the Thomistic model and its external plausibility in light of modern metaphysical and empirical expectations. The study also evaluates Aquinas’s proposal that dimensive quantity serves as a metaphysical “placeholder” enabling accidents to persist without a subject. It considers whether this resolves or simply relocates the logical problem, especially when contrasted with biblical miracles that engage the senses in ways the Eucharistic change does not. I further aim to clarify the conceptual architecture of the doctrine and to evaluate its defensibility across philosophical, scientific, and ecumenical contexts. The goals are to produce a clearer account of the commitments required to affirm transubstantiation, the tensions inherent in sustaining accidents without a subject, the comparative strengths of alternative Eucharistic models, and the epistemic reasons the doctrine persists as a “mystery of faith.” Ultimately, I argue that while transubstantiation is internally coherent within its Aristotelian‑Thomistic framework, it remains the most metaphysically demanding model of real presence, and therefore, one whose acceptance depends less on demonstrative reason than on one’s epistemic position toward ecclesial authority, metaphysical realism, and the theological logic of trust.