Parmenides

Parmenides is the central figure of the Eleatic school. In verse fragments he sets out the ways of Being and non-Being, elevating what reason grasps over the changing world of the senses.

True Being, for him, cannot come to be, perish, or be divided; it is whole, motionless, and continuous—a One. Change and plurality belong to the way of opinion, not the way of truth.

This stance deeply shaped Plato and the metaphysical tradition: how to reconcile sensory becoming with the stable Being that reason demands became a lasting philosophical problem.