The object of knowledge is what exists and its function to know about reality.

Each 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.

Between knowledge of what really exists and ignorance of what does not exist lies the domain of opinion. It is more obscure than knowledge, but clearer than ignorance.

What I say is that 'just' or 'right' means nothing but what is in the interest of the stronger party.

Avoid compulsion and let early education be a matter of amusement. Young children learn by games; compulsory education cannot remain in the soul.

Integrity is your destiny-it is the light that guides your way.

Physical excellence does not of itself produce a good mind and character: on the other hand, excellence of mind and character will make the best of the physique it is given.