Fifth century B.C.

Greek philosopher of the Eleatic school of Parmenides (and most likely his student) whose work About Nature and Reality has survived only as a fragment. The extant text reflects Melissus's attempt to integrate the ideas of Parmenides with the earliest Greek philosophy of the Ionian school. He criticized sense knowledge, noting the concepts of change, motion, and the multiplicity in nature as illusions. He defined "infinity" as being that which has neither "body" or "beginning or end."