Full Idea
Time is a number of change in respect of the before and after. So time is not change but in the way in which change has a number. We discern the greater and the less by number, and greater and less change by time. Hence time is a kind of number.
Gist of Idea
Time is not change, but the number we associate with change
Source
Aristotle (Physics [c.337 BCE], 219b01)
Book Reference
Aristotle: 'Physics Books III and IV', ed/tr. Hussey,Edward [OUP 1983], p.44
A Reaction
This is Aristotle's firmest assertion of the nature of time. It seems to be false to say that we need number in order to discern size (e.g. seeing who was given the biggest slice of cake). Surely we discern time before we measure it?
Related Ideas
Idea 22963 We measure change by time, and time by change, as they are interdefined [Aristotle]
Idea 22967 It is unclear whether time depends on the existence of soul [Aristotle]