So far as he was concerned in the development of Grecian philosophy proper, he was probably inferior to some of his disciples. Yet he gave a turning-point to a new period, when he awakened the _idea_ of knowledge, and was the founder of the theory of scientific knowledge, since he separated the legitimate bounds of inquiry, and was thus the precursor of Bacon and Pascal. He did not attempt to make physics explain metaphysics, nor metaphysics the phenomena of the natural world. And he only reasoned from what was assumed to be true and invariable. He was a great pioneer of philosophy, since he resorted to inductive methods of proof, and gave general definiteness to ideas. [Footnote: Arist., _Metaph_., xiii. 4.] He gave a new method, and used great precision of language. Although he employed induction, it was his aim to withdraw the mind from the contemplation of nature, and to fix it on its own phenomena,--to look inward rather than outward, as carried out so admirably by Plato. The previous philosophers had given their attention to external nature; he gave up speculations about material phenomena, and directed his inquiries solely to the nature of knowledge. And, as he considered knowledge to be identical with virtue, he speculated on ethical questions mainly, and the method which he taught was that by which alone man could become better and wiser. To know one's self, in other words, "that the proper study of mankind is man," he was the first to proclaim. He did not disdain the subjects which chiefly interested the Sophists,--astronomy, rhetoric, physics; but he discussed moral questions, such as, what is piety? what is the just and the unjust? what is temperance? what is courage? what is the character fit for a citizen?--and such like ethical points. And he discussed them in a peculiar manner, in a method peculiarly his own. "Professing ignorance, he put perhaps this question--What is law? It was familiar and was answered off-hand. Socrates, having got the answer, then put fresh questions applicable to specific cases, to which the respondent was compelled to give an answer inconsistent with the first, thus showing that the _definition_ was too narrow or too wide, or defective in some essential condition. [Footnote: Grote, part ii. ch. 68.] The respondent then amended his answer; but this was a prelude to other questions, which could only be answered in ways inconsistent with the amendment; and the respondent, after many attempts to disentangle himself, was obliged to plead guilty to his inconsistencies, with an admission that he could make no satisfactory answer to the original inquiry which had at first appeared so easy." Thus, by this system of cross-examination, he showed the intimate connection between the dialectic method, and the logical distribution of particulars into species and genera. The discussion first turns upon the meaning of some generic term; the queries bring the answers into collision with various