Parmenides
Parmenides of Elea (5th century BC) was an ancient Greek philosopher from Southern Italy.
In On Nature, under 'way of truth', he argued that the existence of a thing implied that it could not have "come into being" because "nothing comes from nothing." Moreover he argued that movement was impossible because it requires moving into "the void", and Parmenides identified "the void" with nothing, and therefore (by definition) it does not exist. Under 'way of seeming', in the same work, he set out a contrasting but more conventional view of the world, thereby becoming an early exponent of the duality of appearance and reality. For him and his pupils the phenomena of movement and change are simply appearances of a static, eternal reality.
He and his pupils formed the so-called Eleatic School (founded by Xenophanes) and included Zeno of Elea and Melissus.
In Plato's dialogue Parmenides the eleatic philosopher and Socrates argue about dialectic.
