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exist, or neither: the two are as inseparable as concave and convex.
Here then lies the radical difference between Parmenides and Plato. Parmenides said, Being is at rest, therefore Motion is not; Being is one, therefore Multitude is not; Being is, therefore Not-being is not at all. Plato said, since there is Rest, there must be Motion; since Being is one, it must also be many; that Being may really be, Not-being must also be real. The chasm between the two sides must be bridged, the antinomy conciliated: Rest must agree with Motion, Unity with Multitude, Being with Not-being.
But, it may be objected, is not this the very thing we just now said that the theory of Herakleitos achieved? Is it not his great merit to have shown that each thing becomes, that is to say, it is at once and is not? True, Herakleitos shows this in the case of particulars: he exhibits "is" and "is not" combined in the processes of material nature. But as his universal result he gives us the negation of Being, just as Parmenides gives us the negation of Not-Being: each in the universal is one-sided. This Becoming, to which Herakleitos points in the material world, must be the symbol of a far profounder truth, of which Herakleitos never dreamed, which even Plato failed at first to realize.
So then these are our results up to the present point. On the one side we have Multitude, Motion, Becoming; on the other Unity, Rest, Being. The two rival principles confront each other in sheer opposition, stiff, unyielding, impracticable. And till they can be reconciled, human thought is at a standstill. The partisans of either side waste their strength in idle wrangling that ends in nothing. And indeed, as we have them so far, these two principles are hopelessly conflicting: some all-powerful solvent must be found which shall be able to subdue them and hold them in coalescence. Now this very thing is the contribution of the last of the three great thinkers who are at present under consideration: he brought into the light, though he could not use, the medium wherein the fundamental antithesis of things was to be reconciled.
Anaxagoras.
§ 9. Anaxagoras belongs to the Ionian school of thought and mainly concerned himself with physics. But such was the originality of his genius and such the importance of his service to philosophy that he stands forth from the rest, as prominent and imposing a figure as Herakleitos himself. With his physical