Parmenides of Elea, a town on the west coast of southern Italy, is perhaps the most celebrated of all the early Greek philosophers. His fame and importance derive from his one known work: a poem in the hexameter metre used also by the Homeric epics, which was perhaps entitled On Nature or On What Is. There is no doubt that he was also very influential in his own time, and caused quite a stir in the Greek intellectual world. He is the first of our philosophers whose followers are themselves well-known – the paradox- monger Zeno of Elea and Melissus of Samos – and who can be said to constitute some sort of philosophical movement. Parmenides cast a tremendous shadow over all succeeding Greek philosophy, not only of the period before Socrates, but long after too. Plato names one of his dialogues in Parmenides' honour, and the philosophical problems first emphasized by Parmenides exercised Plato, Aristotle, and their successors.

It is easy to overstate the discontinuities between Parmenides and what had come before. He does, it seems, seek to offer a deductive argument about the necessary characteristics of “what is” without reliance on empirical information. His argument, as a result, is highly abstract and difficult, and we shall see that it has therefore both attracted and frustrated interpreters ever since. There is evidently a new turn towards a self-conscious application of principles of logical analysis and argumentation that has not previously been centrestage.