Parmenides c. 515 BC – c. 460 BC

Parmenides of Elea was a Pre-Socratic Greek philosopher of the late sixth and early fifth centuries BC, the founder of the Eleatic school and one of the most influential thinkers of the Pre-Socratic period. His one philosophical work, On Nature, surviving in roughly 150 fragments, is a hexameter poem in two parts: the Way of Truth, arguing that what is must be eternal, indivisible, unchanging, and one, and the Way of Opinion, an account of the deceptive world of mortal sense. His arguments against the reality of change and plurality decisively shaped subsequent Greek philosophy, prompting the responses of Empedocles, Anaxagoras, the Atomists, and Plato. Plato devoted an entire late dialogue to him, and his influence on Western metaphysics has been profound.