Abstract

Aristotle defines time as “the number of movement with respect to before and after”. The relation between sublunar substances, which have within themselves a principle of movement and rest, and time, therefore, appears unproblematic. Sensible substances, however, also perform perfect activities and, in the passages in which he most clearly outlines the nature of such activities, the philosopher leaves the issue of their temporality unresolved. As a result, scholars have speculated about different ways of understanding it. This paper argues that the Aristotelian corpus does offer precise indications on this issue. The Physics distinguishes between two modalities of being in time, namely, being-in-time in virtue of one’s nature and being-in-time accidentally. The case is made that energeiai belong to the class of things that are in time accidentally and that this way of understanding their relation to time fits their distinctive nature and is faithful to the phenomena.