 The fifth question (fols. 160v-175r), but second related to the fourth book of Aristotle’s Physics, is whether time is the measure of change in respect of the before and after. Sharpe’s answer is affirmative, as always, but he specifies that this is not properly the definition of time, but rather the description of its nature. In his view, it follows from this description that (1) time measures mutable things only, but not immutable; and (2) time is closely connected exclusively with that kind of motion which entails a before and an after.