Melissus of Samos c. 470 BC – c. 400 BC

Melissus of Samos was a Greek pre-Socratic philosopher and the last great representative of the Eleatic school founded by Parmenides. Active in the mid-fifth century BC, he commanded the Samian fleet that defeated the Athenians under Pericles in 441 BC. His treatise On Nature, partly preserved by Simplicius, defends Parmenidean monism in carefully argued prose, holding that what is must be ungenerated, eternal, unlimited, and one. His arguments for the indivisibility and immobility of being shaped later atomist replies and left a lasting mark on the Greek dialectical tradition.

Melissus of Samos was born around 470 BC and is the third major figure of the Eleatic school after Parmenides and Zeno. Apart from his philosophy, what is best known of his life is his political and military career: as commander of the Samian fleet he is reported by Plutarch to have defeated an Athenian squadron under Pericles in the war over Samos in 441–440 BC, although the Samians were eventually subdued. Aristotle and Diogenes Laertius describe him as a pupil or follower of Parmenides.

His one work, On Nature or On What Is, has not survived as a continuous text; it is preserved as a set of substantial fragments in the commentary of Simplicius on Aristotle's Physics, and as a paraphrastic summary in the late Aristotelian work De Melisso, Xenophane, Gorgia.

Melissus reformulated the Parmenidean argument that what is must be ungenerated, eternal, indivisible, motionless, full, and altogether of one quality, but departed from Parmenides on a key point: where Parmenides' Being was 'like a well-rounded sphere' and so finite, Melissus argued that the One must be infinite in extent as well as in time. His prose reasoning was the form in which the Eleatic position reached the atomists Leucippus and Democritus, Aristotle's Physics, and the doxographical tradition. He is presumed to have died around 400 BC.