Simplicius' greatest contribution in his commentary on Aristotle on Physics 1.5-9 lies in his treatment of matter. The sixth-century philosopher starts with a valuable elucidation of what Aristotle means by 'principle' and 'element' in Physics. Simplicius' own conception of matter is of a quantity that is utterly diffuse because of its extreme distance from its source, the Neoplatonic One, and he tries to find this conception both...