Let us take this from the top. Just think of two creatures: one notoriously swift of foot, the other not so. Then think that the slower creature has a short head-start in a race. Of course the former will catch up with and pass the later. That is inherent in what we mean by such notions as slow and fast. But ... what if we assume with ancient geometers that space, and so every possible distance, is infinitely divisible? Does that throw a wrench into things? Fast creature (Achilles) starts ten meters behind slow creature (Turtle). Achilles moves ten times as fast. Within some period of time (we will call it a nonce), Achilles has advanced those ten meters. Ah, but Turtle has now advanced one meter, and so is still ahead. Achilles advances THAT distance in one-tenth of a nonce. Yet he still has not caught up, for the Turtle has by now advanced one-hundredth of a meter. And so forth, depressingly, on and on. It is impossible...