and the artificial ethics of social life, would remain unreconciled. In short, all the perplexities and doubts and difficulties called forth and set in motion by the speculations of the Sophists would continue uncounteracted, and would subsist in full activity and force. As part, therefore, of the Socratic dialectic, it was quite indispensable to show that thought was an indigenous endowment, a quality of human nature no less than sensation, appetite, and desire. This proof, accordingly, was the main part of the business which Socrates was called upon to perform. He had to prove that thought was man's by nature, and that it was entirely different from sensation, and its accompaniments, passion and desire. Here I shall have to introduce, as I said, some links of speculation which are not to be found in any extant record of the Socratic doctrines; but I believe that I shall deviate in no respect from the spirit of the Socratic procedure, and that I shall advance nothing which has not a basis and warrant in the principles of the philosopher himself.
7. To determine whether thought is natural or acquired, is primary or derivative, we must of course ascertain first of all what thought is, what it is in itself, and as distinguished from everything else. This can only be effected by self-reflection, by rigorous self-examination. Hence the maxim which Socrates assumed as the very watchword of his system, as the very condition on which alone any phil-
