All soul is immortal. For that which is always in movement is immortal; that which moves something else, and is moved by something else, in ceasing from movement ceases from living. So only that which moves itself, because it does not abandon itself, never stops moving. But it is also source and first principle of movement for the other things which move.
PlatoWhat is at issue is the conversion of the mind from the twilight of error to the truth, that climb up into the real world which we shall call true philosophy.
Plato