Quantum Mechanics, Transubstantiation & Why Aristotle Was Right After All

Is there a conflict between modern physics and the Aristotelian-Thomistic interpretation of Catholic doctrine? A contemporary Jesuit writer has dismissed transubstantiation as intellectually obsolete, claiming that its reliance on Aristotelian notions of substance and accidents belongs to a premodern physics that quantum mechanics has rendered unintelligible. This argument, which recurs frequently in modern theological discussions, assumes that quantum theory supports a materialist understanding of reality.

There is only one problem with this argument: it is backwards. Quantum mechanics does not invalidate Aristotelian metaphysics — it vindicates it. Quantum theory requires precisely the kinds of distinctions — between potentiality and actuality, and between underlying being and observable properties — that Aristotelian and Thomistic philosophy articulates. If Aristotelian categories resolve the paradoxes of quantum theory, it follows that they can also provide a coherent metaphysical context for understanding transubstantiation. This is not to say, however, that quantum theory explains transubstantiation. That the consecrated host and wine become the Body and Blood of Our Lord Jesus Christ is not a natural process but a miracle and, therefore, a mystery in the most profound sense of the word.

To show why quantum mechanics calls for an Aristotelian-Thomistic interpretation, I will briefly examine several well-known quantum phenomena — often described as “mysteries” — that demand explanation. Although a number of contemporary philosophers of science have shown how Aristotelian metaphysical concepts render quantum theory intelligible, this work has had little impact on how most physicists interpret the theory.

The Quantum Mysteries

Some 75 years ago I heard Richard Feynman, a Nobel Prize winner for his work in quantum electrodynamics, declare, “I think I can safely say that nobody understands quantum mechanics.” I was an undergraduate student at Caltech in Pasadena, auditing his graduate course, and I remember thinking, What the Hell does that mean? Now, after a lifetime of research using quantum mechanics, I am beginning to understand his remark.