 After presenting the objections to and opinions about time, Avicenna begins his own account of time (Avicenna, [Ph], 2.10–13) by filling this lacuna in Aristotle’s presentation. Avicenna’s general strategy is to take as empirically obvious certain facts about motion and then show that these facts cannot be explained unless there is associated with motion a certain magnitude, which we commonly identify with time. Only having shown that time exists does Avicenna then provide a scientifically adequate explanation of what time essentially is. 