[Footnote 571: "The Dialectitian is one who syllogistically infers the contradictions implied in popular opinions."--Aristotle, "Sophist," §§ 1, 2.] [Footnote 572: "Republic," bk. vi. ch. xiii.] [Footnote 573: "Sophist," § 33; "Republic," bk. iv. ch. xii.] [Footnote 574: See the "Phædo," § 119, and "Republic," bk. iv. ch. xiii., where the Law of Non-contradiction is announced.] [Footnote 575 "Parmenides," § 3.] The dialectic process thus consisted almost entirely of _refutation_,[576] or what both he and Aristotle denominated _elenchus_ (ἔλεγχος)--a process of reasoning by which the contradictory of a given proposition is inferred. "When refutation had done its utmost, and all the points of difficulty and objection had been fully brought out, the dialectic method had accomplished its purpose; and the affirmation which remained, after this discussion, might be regarded as setting forth the truth of the question under consideration;"[577] or in other words, _when a system of error is destroyed by refutation, the contradictory opposite principle, with its logical developments, must be accepted as an established truth_. [Footnote 576: Confutation is the greatest and chiefest of purification.--"Sophist," § 34.] [Footnote 577: Article "Plato," Encyclopædia Britannica.] By the application of this method, Plato had not only exposed the insufficiency and self-contradiction of all results obtained by a mere _à posteriori_ generalization of the simple facts of experience, but he demonstrated, as a consequence, that we are in possession of some elements of knowledge which have not been derived from sensation; that there are, in all minds, certain notions, principles, or ideas, which have been furnished by a higher faculty than sense; and that these notions, principles, or ideas, transcend the limits of experience, and reveal the knowledge of _real being_--τὸ ὄντως ὄν--_Being in se_. To determine what these principles or ideas are, Plato now addresses himself to the _analysis of thought_. "It is the glory of Plato to have borne the light of analysis into the most obscure and inmost region; he searched out what, in this totality which forms consciousness, is the province of reason; what comes from it, and not from the imagination and the senses--from within, and not from without."[578] Now to analyze is to decompose, that is, to divide, and to define, in order to see better that which really is. The chief logical instruments of the dialectic method are, therefore, _Division_ and _Definition_. "The being able to _divide_ according to genera, and not to consider the same species as different, nor a different as the same,"[579] and "to see under one aspect, and bring together under one general idea, many things scattered in various places, that, by _defining_ each, a person may make it clear what the subject is," is, according to Plato, "dialectical."[580] [Footnote 578: Cousin's "Lectures on the History of Philosophy," vol. i. p. 328.]