Keimpe Algra is Professor of Ancient and Medieval Philosophy at the University of Utrecht. He has published widely on ancient philosophy, in particular on Hellenistic philosophy and ancient science. He co-edited The Cambridge History of Hellenistic Philosophy (1999, with Jonathan Barnes, Jaap Mansfeld and Malcolm Schofield) and was managing editor of the international journal Phronesis. His most recent book is Philoponus: On Aristotle Physics 4.1-5 (2012), published in the series The Ancient Commentators on Aristotle (with Johannes van Ophuijsen). His current research focuses on the relation b...