Aquinas and Aristotle

Aristotle and Augustine on Time

Aristotle's and Augustine's texts on time—the fourth book of Aristotle's Physics and the eleventh book of Augustine's Confessions—describe two theories that seem difficult to reconcile with each other: Whereas Aristotle defines time as the “number of changes in respect of before and after” (Phys. IV 11, 219b 1; R. Waterfield, Trans.) and makes its existence and definition dependent upon change or, as the medieval translations had it, motion, Augustine defines time exclusively as a “distension of the mind” (distentio animi). Furthermore, Augustine explicitly denies that motion can be an adequate definition of time and that there can be time at all without the human mind, which counts the uninterrupted stream of the sensible world. In spite of not addressing directly Aristotle's definition (which he probably did not know), Augustine cannot have seen in it a serious option. Aristotle, on the other hand, is somewhat ambiguous regarding the relation between time and soul. He writes that there could not be time, if there is not be a soul, because without a soul there would not be any number to determine change and therefore time. However, he grants “that there might still be whatever it is that time is” (IV 14, 223a 21–29). Previously (219b 5–9) he had defined time as that number “which is numbered,” not “that by which we number,” that is, not as the mental activity of numbering, but as the flow of things that is apt for being counted, such that time should not depend entirely upon an activity of soul. Furthermore, it may well be that he is not talking here about the individual human soul but about soul as a cosmological phenomenon. Thus he would surely have rejected Augustine's solution.

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