He may persuade the people under these circumstances (replies Sokrates), but if he does so, it will be to their misfortune and to his own. He ought to know the real truth--not merely what the public whom he addresses believe to be the truth--respecting just and unjust, good and evil, &c. There can be no genuine art of speaking, which is not founded upon knowledge of the truth, and upon adequate philosophical comprehension of the subject-matter.[63] The rhetorical teachers take too narrow a view of rhetoric, when they confine it to public harangues addressed to the assembly or to the Dikastery. Rhetoric embraces all guidance of the mind through words, whether in public harangue or private conversation, on matters important or trivial. Whether it be a controversy between two litigants in a Dikastery, causing the Dikasts to regard the same matters now as being just and good, presently as being unjust and evil: or between two dialecticians like Zeno, who could make his hearers view the same subjects as being both like and unlike--both one and many--both in motion and at rest: in either case the art (if there be any art) and its principles are the same. You ought to assimilate every thing to every thing, in all cases where assimilation is possible: if your adversary assimilates in like manner, concealing the process from his hearers, you must convict and expose his proceedings. Now the possibility or facility of deception in this way will depend upon the extent of likeness between things. If there be much real likeness, deception is easy, and one of them may easily be passed off as the other: if there be little likeness, deception will be difficult. An extensive acquaintance with the real resemblances of things, or in other words with truth, constitutes the necessary basis on which all oratorical art must proceed.[64] [Footnote 63: Plato, Phædrus, pp. 260-261.] [Footnote 64: Plato, Phædrus, p. 262.] [Side-note: Comparison made by Sokrates between the discourse of Lysias and his own. Eros is differently understood: Sokrates defined what he meant by it: Lysias did not define.]