Abstract

In the end of the section 219a 10-21 of the 11th chapter of Physics IV Aristotle defines the ‘before and after’ in movement as follows: «The ‘before and after’ in motion is identical ὅ ποτε ὂυ with motion, yet differs from it τò εἶυατ αύτῷ, and is not identical with motion t (11. 19-21)». These lines convey the answer to the question whether the ‘before’ and after’ are the same thing as movement or not: in one sense, ὅ ποτε ὂυ, they are, in another sense, τò εἶυαι, they are not. But, first and foremost, the opposition of ὅ ποτε ὂυ to то τò εἶυαι is very useful to Aristotle to solve the main aporia of the chapter about the contradictory – at a first sight – and concurrent diversity and identity of the instant, τò υῠυ. Therefore, this aporia will be solved, if only ὅ ποτε ὂυ and то τò εἶυαι mean two really opposing points of view. But what are these points of view? What do they really mean? As it is well known, the phrase ὅ ποτε ὂυ is one of the most enigmatic in the Aristotelian corpus, and yet one of the most important in his physical research because concerns the nature and definition of time. The lower was the agreement among the scholars, with greater force the debate has flared up. An alternative way for attempting to successfully tackle the problem is take in consideration the occurrence of the same phrase in other works than Physica, since the other occurrences of it in the 11th and 14th chapter of the same book are of no help. It is present in only two other works: On Generation and Corruption, I, 3, 319b 3 and Parts of Animals, II, 2, 649a 15; II, 3, 649b 24. In both works we are led to take ὅ ποτε ὂυ as being associated to such terms as ύποκεἰμενον and ύπóκειται. So, Aristotle seems to point out a contrast between a formal respect and a material respect by the opposition of τò εἶυαι to ὅ ποτε ὂυ. The reading of all passages from Physics – particularly, 219a 20-21 – wherein ὅ ποτε ὂυ occurs provides further confirmation of this contrast. As matter of fact, in all three works τò εἶυαι was employed by Aristotle for the same purpose: to set out the difference between a substratum of its own and its ability to actually exist just as substratum underlying worldly things. This difference implies that a substratum cannot but be limited by or relating to time. A condition which is emphasized by the presence of the term ποτε. In conclusion, each instant comes out from the division by the ‘before and after’ of movement’s substratum. If this substratum is found to exist in time, the ‘before and after’ turns out to be ‘what that is now and then’ (ὅ ποτε ὂυ), which, reversely, is the same as the ‘before and after’ in the movement. The occurrences of the incomplete phrase (as ὅ ποτε plus other verbal voices than ὂυ) in other works substantiate this view.