Parmenides

Parmenides (late 6th or early 5th century BC) was a pre-Socratic Greek philosopher from Elea. He is considered to be the founder of metaphysics or ontology. He was the founder of the Eleatic school of philosophy which included Melissus and Zeno. Parmenides was said to be a follower of Xenophanes. Zeno's paradoxes of motion were to prove Parmenides's view.

The single surviving work of Parmenides is a poem, now known as On Nature. Only fragments of it still survive to this day.

Parmenides argued that whatever was not being was non-being. What is non-being is nothing. Whatever is other than being, is thus, nothing. But Parmenides held being to be one. Whatever is other than one is nothing. There is only one being, therefore. Parmenides considered being under the account of being, and considered it to be finite and one.