devoted to the cultivation of physics. Protagoras and Gorgias were the only sceptics; and it was not by setting one theory against another, but by working out a single theory to its last consequences, that their scepticism was reached; with no more effect, be it observed, than was exercised by Pyrrho on the science of his day. For the two great thinkers, with the aid of whose conclusions it was attempted to discredit objective reality, were already left far behind at the close of the fifth century; and neither their reasonings nor reasonings based on theirs, could exercise much influence on a generation which had Anaxagoras on Nature and the encyclopaedia of Democritus in its hands. There was, however, one critic who really did what the Sophists are charged with doing; who derided and denounced physical science on the ground that its professors were hopelessly at issue with one another; and this critic was no other than Socrates himself. He maintained, on purely popular and superficial grounds, the same sceptical attitude to which Protagoras gave at least the semblance of a psychological justification. And he wished that attention should be concentrated on the very subjects which Protagoras undertook to teach—namely, ethics, politics, and dialectics. Once more, to say that Socrates was conscious of not coming up to his own standard of true knowledge is inconsistent with Xenophon’s account, where he is represented as quite ready to answer every question put to him, and to offer a definition of everything that he considered worth defining. His scepticism, if it ever existed, was as artificial and short-lived as the scepticism of Descartes.