The philosopher is in love with truth, that is, not with the changing world of sensation, which is the object of opinion, but with the unchanging reality which is the object of knowledge.
PlatoEach living creature is said to be alive and to be the same individual - as for example someone is said to be the same person from when he is a child until he comes to be an old man. And yet, if he's called the same, that's despite the fact that he's never made up from the same things, but is always being renewed, and losing what he had before, whether it's hair, or flesh, or bones, or blood, in fact the whole body.
Plato