The really odd aspect of this is that neither the teacher nor the parish priest appear to have understood the doctrine of transubstantiation, which is that the substance (essence) is changed while the accidents (properties) are not. Aquinas would have agreed that no physical measuring apparatus or microscope could detect any change, and therefore there is no scientific way of testing the doctrine.

I remember concluding as a teenager that the whole distinction between substance and accidents in the philosophy of Aquinas and other thinkers is a prime example of mistakenly attempting to infer the structure of the world from the structure of language. This perception was met with blank incomprehension.