It is also worth investigating how time is related to the soul, and for what reason it is that time is thought to be in everything – on earth and in the sea and in the heavens. Is it that it is a property or a state of change, being the number [of it], and all these things are changeable, since they are all in place, and time and change are together both in potentiality and in actual operation? One might find it a difficult question, whether if there were no soul there would be time or not. For if it is impossible that there should be something to do the counting, it is also impossible that anything should be countable, so that it is clear that there would be no number either, for number is either that which has been counted or that which can be. But if there is nothing that has it in its nature to count except soul, and of soul [the part which is] intellect, then it is impossible that there should be time if there is no soul, except that there could be that X which time is, whatever X makes it what it is; as, for example, if it is possible for there to be change without soul. The before and after are in change, and time is these qua countable. (223^a16–29)