Philoponus' commentary on the last part of Aristotle's Physics Book 4 does not offer major alternatives to Aristotle's science, as did his commentary on the earlier parts, concerning place, vacuum and motion in a vacuum. Aristotle's subject here is time, and his treatment of it had led to controversy in earlier writers. Philoponus does offer novelties when he treats motion round a bend as in one sense faster than motion on the straight over...