... suppose that there are two sorts of existences, one seen, and the other unseen.... The seen is the changing, and the unseen is the unchanging.... And further, is not one part of us body, and the rest of us soul?... Then the soul is more like to the unseen, and the body to the seen?... the soul is then dragged by the body into the region of the changeable, and wanders and is confused; the world spins round her, and she is like a drunkard when under their influence?

Plato - Phaedo