But as Alexander says, one might confront Aristotle   with the following problem. If matter always remains the same, and the efficient cause is also [192] always the same, what cause would prevent numerically the same things existing again from the same matter, through the same agencies over some enormous cycle of time? Some people say this happens in the recurrence (palingenesia) of the world and the Great Year in which the reinstatement of all the same things occurs. In that case, there would be rebirth and numerically identical return also for particulars whose essence is mortal.

Against this it must be said that, even if it were granted that Socrates   is born again, the Socrates who is born later would not be numerically one and the same as the one who was born first. For what is numerically one and the same thing cannot be intermittent (dialeipein). For it attains to being numerically one and the same not by being made of the same things, but by persisting (diamenein) as the same thing both earlier, and later. That is why the sun is numerically the same, but Socrates, as Aristotle said [338bl6?] is not numerically the same, since the individual form (atomon eidos) does not remain, even if [sc. on the hypothesis of 314,9-13] the matter does. [SorabjiPC3  ; Alexander ap. Philoponum in GC 314,9-22]