アリストテレスにおける時間の実在性

抄録

Aristotle discusses time in PhysicsIV, 10-14. Before his main discussion, he introduces a paradox about the existence of time at 217b32-218a9. This paradox is, briefly,“A. Time consists of past and future, B. Past existed but does not exist at present, and future will exist but does not at present, C.“Now”is not any part of time, D. Therefore time does not exist”. One of the difficulties of interpretation here is that his own solution is not found in Physics, nor elsewhere in his Corpus, though he concludes at 222b27-29“that time exists, and what it is, ... was stated”. In this paper I will offer one solution to the paradox from his definition of time,“time is a number of change (kinesis) in respect of before and after”(219b1-2). This definition seems to imply that time does not exist independently but depends on change, because Aristotle never allows any number to exist independently, see for example Metaphysics Iota, 2. Thus, the problem of the existence of time is indeed that of change for him. But the paradox can be easily expanded to the existence of change, modifying B above. Any change either has existed or will exist, but does not exist at present. In PhysicsIII 1, however, he defines change without reference to time, as the“actuality of that which potentially is, qua such”(201a10-11). If this definition is understood as“change is the actuality of that whose potentiality is Y, but only Y”, the changing object has two statuses at least, actually X and potentially Y. And at PhysicsIV, 11, 219b12-33 Aristotle maintains“nows”correspond to the statuses of some changing objects. Although only one now”indicates the genuine present, the other“now”, corresponding with potential status Y, can indicate a potential present. So, Aristotle can state there are two presents at the same instant and therefore time exists between two“nows”at present. In this way, the paradox of the existence of time can be dissolved for Aristotle by regarding time as dependent on change.