Its only quality is, so to speak, "isness." But in Parmenides there emerges for the first time a distinction of fundamental importance in philosophy, the distinction between Sense and Reason. The world of falsity and appearance, of becoming, of not-being, this is, says Parmenides, the world which is presented to us by the senses. True and veritable Being is known to us only by reason, by thought. The senses therefore, are, for Parmenides, the sources of all illusion and error. Truth lies only in reason. This is exceedingly important, because this, _that truth lies in reason and not in the world of sense_, is the fundamental position of idealism. The doctrine of Being, just described, occupies the first part of the poem of Parmenides. The second part is the way of false opinion. But whether Parmenides is here simply giving an account of the false philosophies {46} of his day, (and in doing this there does not seem much point,) or whether he was, with total inconsistency, attempting, in a cosmological theory of his own, to explain the origin of that world of appearance and illusion, whose very being he has, in the first part of the poem, denied--this does not seem to be clear. The theory here propounded, at any rate, is that the sense-world is composed of the two opposites, the hot and the cold, or light and darkness. The more hot there is, the more life, the more reality; the more cold, the more unreality and death. What position, now, are we to assign to Parmenides in philosophy? How are we to characterize his system? Such writers as Hegel, Erdmann, and Schwegler, have always interpreted his philosophy in an idealistic sense. Professor Burnet, however, takes the opposite view. To quote his own words: "Parmenides is not, as some have said, the father of idealism. On the contrary, all materialism depends upon his view." [Footnote 5] Now if we cannot say whether Parmenides was a materialist or an idealist, we cannot be said to understand much about his philosophy. The question is therefore of cardinal importance. Let us see, in the first place, upon what grounds the materialistic interpretation of Parmenides is based. It is based upon a fact which I have so far not mentioned, leaving it for explanation at this moment. Parmenides said that Being, which is for him the ultimate reality, occupies space, is finite, and is spherical or globe-shaped. Now that which occupies space, and has shape, is matter. The ultimate reality of things, therefore, is conceived by Parmenides as material, and this, of course, is the {47} cardinal thesis of materialism. This interpretation of Parmenides is further emphasized in the disagreement between himself and Melissus, as to whether Being is finite or infinite. Melissus was a younger adherent of the Eleatic School, whose chief interest lies in his views on this question. His philosophical position in general is the same as that of Parmenides. But on this point they differed.