Medieval Philosophy

by Peter S. Adamson

that it does not exist, because the soul’s knowing anything presupposes that it does exist (§1.4). Moreover, to deny the existence of soul in the impressively functional human body would be like seeing an expertly steered ship and denying that it has a helmsman (§1.7). To his credit, William anticipates the objection that may leap to mind for the modern reader: some machines are capable of very impressive functions despite being lifeless and without soul. William’s version of the objection considers a water clock. He says that this is no counterargument at all, because human intervention is needed to set up the water clock and keep it functioning properly (§1.7). He also singles out for criticism Alexander of Aphrodisias, the most important late antique commentator on Aristotle. William is appalled by Alexander’s suggestion that the soul could somehow emerge from, and hence depend on, the physical states of the body. This must be wrong, because the soul is superior to the body, and the better can never be generated by the worse. Besides, William adds, the soul is a substance, so it cannot just be an accidental side effect of bodily composition (§5.3–4).