Greek philosopher who was the last significant member of the Eleatic school of philosophy, which adhered to Parmenides' doctrine of reality as a single, unchanging whole. Although Melissus defended Parmenides, he differed from him in that he held reality to be boundless and of infinite duration (having a past and a present). He is also known as the commander of the Samian fleet, which was victorious over the Athenians in 441/440 BC.