Parmenides, on this view, was an idealist. Moreover, Parmenides has clearly made the distinction between sense and reason. True Being is not known to {49} the senses, but only to reason, and this distinction is an essential feature of all idealism. Materialism is precisely the view that reality is to be found in the world of sense. But the proposition of Parmenides is the exact opposite of this, namely, that reality is to be found only in reason. Again, there begins to appear for the first time in Parmenides the distinction between reality and appearance. Parmenides, of course, would not have used these terms, which have been adopted in modern times. But the thought which they express is unmistakably there. This outward world, the world of sense, he proclaims to be illusion and appearance. Reality is something which lies behind, and is invisible to the senses. Now the very essence of materialism is that this material world, this world of sense, is the real world. Idealism is the doctrine that the sense-world is an appearance. How then can Parmenides be called a materialist? How are we to reconcile these two conflicting views of Parmenides? I think the truth is that these two contradictories lie side by side in Parmenides unreconciled, and still mutually contradicting each other. Parmenides himself did not see the contradiction. If we emphasize the one side, then Parmenides was a materialist. If we emphasize the other side, then he is to be interpreted as an idealist. In point of fact, in the history of Greek philosophy, both these sides of Parmenides were successively emphasized. He became the father both of materialism and of idealism. His immediate successors, Empedocles and Democritus, seized upon the materialistic aspect of his thought, and developed it. The essential thought of Parmenides was that Being cannot arise from not-being, and that Being neither {50} arises nor passes away. If we apply this idea to matter we get what in modern times is called the doctrine of the "indestructibility of matter." Matter has no beginning and no end. The apparent arising and passing away of things is simply the aggregation and separation of particles of matter which, in themselves, are indestructible. This is precisely the position of Democritus. And his doctrine, therefore, is a materialistic rendering of the main thought of Parmenides that Being cannot arise from not-being or pass into not-being. It was not till the time of Plato that the idealistic aspect of the Parmenidean doctrine was developed. It was the genius of Plato which seized upon the germs of idealism in Parmenides and developed them. Plato was deeply influenced by Parmenides. His main doctrine was that the reality of the world is to be found in thought, in concepts, in what is called "the Idea." And he identified the Idea with the Being of Parmenides.