Having distinguished the various aspects of our own concept of time, we should now examine what I take to be for Aristotle two very obvious though importantly different sources of thought on the subject of time: the common conception of time in fourth-century Athens, and his philosophical predecessors' views on time.

While Aristotle does not explicitly appeal to the first source of thought in the course of developing his theory, he was not immune to the sway of “common wisdom” in his day. Certain features of his account clearly engage some of the remarks on time made by antiquity's greatest historians, and as we shall see, there can be no doubt that his view is driven in part by considerations having to do with the two types of chronometers with which he would have been very familiar.

As the second source of thought, the views of Aristotle's predecessors are always given consideration in his own work, and Plato figures as a looming presence throughout all of Aristotle's treatises. It is my view that Aristotle's theory of time is profoundly influenced by Plato, and much insight into Aristotle's project can be gained when it is cast in the light of Plato's theory. Although there are a number of dialogues containing considerations relevant to a discussion of time, Plato's most developed thoughts on the subject are contained in the Timaeus. Consequently, I shall focus my attention on this work in particular.