[73] Plato, Phædrus, p. 269.
What the Art of Rhetoric ought to be — Analogy of Hippokrates and the medical Art.
The true art of rhetoric (continues Sokrates) embraces a larger range than these teachers imagine. It deals with mind, as the medical researches of Hippokrates deal with body — as a generic total with all its species and varieties, and as essentially relative to the totality of external circumstances. First, Hippokrates investigates how far the body is, in every particular man, simple, homogeneous, uniform: and how far it is complex, heterogeneous, multiform, in the diversity of individuals. If it be one and the same, or in so far as it is one and the same, he examines what are its properties in relation to each particular substance acting upon it or acted upon by it. In so far as it is multiform and various, he examines and compares each of the different varieties, in the same manner, to ascertain its properties in relation to every substance.[74] It is in this way that Hippokrates discovers the nature or essence of the human body, distinguishing its varieties, and bringing the medical art to bear upon each, according to its different properties. This is the only scientific or artistic way of proceeding.
[74] Plato, Phædrus, p. 270 D. Ἆρ’ οὐχ ὧδε δεῖ διανοεῖσθαι περὶ ὁτουοῦν φύσεως; Πρῶτον μὲν, ἁπλοῦν ἢ πολυειδές ἐστιν, οὗ περὶ βουλησόμεθα εἶναι αὐτοὶ τεχνικοὶ καὶ ἄλλον δυνατοὶ ποιεῖν; ἔπειτα δέ, ἐὰν μὲν ἁπλοῦν ᾖ, σκοπεῖν τὴν δύναμιν αὐτοῦ, τίνα πρὸς τί πέφυκεν εἰς τὸ δρᾷν ἔχον ἢ τίνα εἰς τὸ παθεῖν ὑπὸ τοῦ; ἐὰν δὲ πλείω εἴδη ἔχῃ, ταῦτα ἀριθμησάμενος, ὅπερ ἐφ’ ἑνός, τοῦτ’ ἰδεῖν ἐφ’ ἑκάστου, τῷ τί ποιεῖν αὐτὸ πέφυκεν ἢ τῷ τί παθεῖν ὑπὸ τοῦ;
Art of Rhetoric ought to include a systematic classification of minds with all their varieties, and of discourses with all their varieties. The Rhetor must know how to apply the one to the other, suitably to each particular case.
Now the true rhetor ought to deal with the human mind in like manner. His task is to work persuasion in the minds of certain men by means of discourse. He has therefore, first, to ascertain how far all mind is one and the same, and what are the affections belonging to it universally in relation to other things: next, to distinguish the different varieties of minds, together with the properties, susceptibilities, and active aptitudes, of each: carrying the subdivision down until he comes to a variety no longer admitting division.[75] He must then proceed to distinguish the different varieties of discourse, noting the effects which each is calculated to produce or to hinder, and the different ways in which it is likely to impress different minds.[76] Such and such men are persuadable by such and such discourses — or the contrary. Having framed these two general classifications, the rhetor must on each particular occasion acquire a rapid tact in discerning to which class of minds the persons whom he is about to address belong: and therefore what class of discourses will be likely to operate on them persuasively.[77] He must farther know those subordinate artifices of speech on which the professors insist; and he must also be aware of the proper season and limit within which each can be safely employed.[78]
[75] Plato, Phædrus, p. 277 B. ὁρισάμενός τε πάλιν κατ’ εἴδη μέχρι τοῦ ἀτμήτου τέμνειν ἐπιστηθῇ.
[76] Plato, Phædrus, p. 271 A. Πρῶτον, πάσῃ ἀκριβείᾳ γράψει τε καὶ ποιήσει ψυχὴν ἰδεῖν, πότερον ἓν καὶ ὅμοιον πέφυκεν ἢ κατὰ σώματος μορφὴν πολυειδές· τοῦτο γάρ φαμεν φύσιν εἶναι δεικνύναι.
Δεύτερον δέ γε, ὅτῳ τί ποιεῖν ἢ παθεῖν ὑπὸ τοῦ πέφυκεν.
Τρίτον δὲ δὴ διαταξάμενος τὰ λόγων τε καὶ ψυχῆς γένη καὶ τὰ τούτων παθήματα, δίεισι τὰς αἰτίας, προσαρμόττων ἕκαστον ἑκάστῳ, καὶ διδάσκων οἵα οὖσα ὑφ’ οἵων λόγων δι’ ἣν αἰτίαν ἐξ ἀνάγκης ἡ μὲν πείθεται, ἡ δὲ ἀπειθεῖ.