I.

In the last chapter we considered the philosophy of Plato chiefly under its critical and negative aspects. We saw how it was exclusively from that side that he at first apprehended¹ and enlarged the dialectic of Socrates, how deeply his scepticism was coloured by the religious reaction of the age, and how he attempted, out of his master’s mouth, to overturn the positive teaching of the master himself. We saw how, in the Protagoras, he sketched³ a theory of ethics⁴, which was no sooner completed than it became the starting-point of a still more extended and arduous⁵ enquiry. We followed the widening horizon of his speculations⁶ until they embraced the whole contemporary life of Hellas, and involved it in a common condemnation⁸ as either hopelessly corrupt⁹, or containing within itself the seeds of corruption¹⁰. We then saw how, by a farther generalisation, he was led to look for the sources of error in the laws of man’s sensuous¹¹ nature and of the phenomenal world with which it holds communion; how, moreover, under the guidance of suggestions coming both from within and from without, he reverted¹³ to the earlier schools of Greek thought, and brought their results into parallelism with the main lines of Socratic dialectic. And finally, we watched him planting a firm foothold on the basis of mathematical demonstration¹⁴; seeking in the very constitution of the soul itself for a derivation of the truths which sensuous experience could not impart, and winning back from215 a more profoundly reasoned religion the hope, the self-confidence, the assurance of perfect knowledge, which had been