In addition to its other great lessons, the _Symposium_ has afforded Plato an opportunity for contrasting his own method of philosophising with pre-Socratic modes of thought. For it consists of a series of discourses in praise of love, so arranged as to typify the manner in which Greek speculation, after beginning with mythology, subsequently advanced to physical theories of phenomena, then passed from the historical to the contemporary method, asking, not whence did things come, but what are they in themselves; and finally arrived at the logical standpoint of analysis, classification, and induction. The nature of dialectic is still further elucidated in the _Phaedrus_, where it is also contrasted with the method, or rather the no-method, of popular rhetoric. Here, again, discussions about love are chosen as an illustration. A discourse on the subject by no less a writer than Lysias is quoted and shown to be deficient in the most elementary requisites of logical exposition. The different arguments are strung together without any principle of arrangement, and ambiguous terms are used without being defined. In insisting on the necessity of definition, Plato followed Socrates; but he defines according to a totally different method. Socrates had arrived at his general notions partly by a comparison of particular instances with a view to eliciting the points where they agreed, partly by amending the conceptions already in circulation. We have seen that the earliest Dialogues attributed to Plato are one long exposure of the difficulties attending such a procedure; and his subsequent investigations all went to prove that nothing solid could be built on such shifting foundations as sense and opinion. Meanwhile increasing familiarity with the great ontological systems had taught him to begin with the most general notions, and to work down from them to the most particular. The consequence was that dialectic came to mean nothing but classification or logical division. Definition was absorbed into this process, and reasoning by syllogism was not yet differentiated from it. To tell what a thing was, meant to fix its place in the universal order of existence, and its individual existence was sufficiently accounted for by the same determination. If we imagine first a series of concentric circles, then a series of contrasts symmetrically disposed on either side of a central dividing line, and finally a series of transitions descending from the most absolute unity to the most irregular diversity—we shall, by combining the three schemes, arrive at some understanding of the Platonic dialectic. To assign anything its place in these various sequences was at once to define it and to demonstrate the necessity of its existence. The arrangement is also equivalent to a theory of final causes; for everything has a function to perform, marked out by its position, and bringing it into relation with the universal order. Such a system would inevitably lead to the denial of