Most theologians would have categorised this miracle of transubstantiation, as it is called, in the same class of events as Jesus turning water into wine or Moses parting the waters of the Red Sea. It involves intervention of the divine and was thereby not expected to conform to the usual rules that apply to normal life. Aquinas, however, was convinced that he could incorporate even miracles into his scientific model of the world. To do so, he reached for another gift from the ancient world, philosophical realism.
