"Rhetoric," says Aristotle, "may be defined as a faculty of discovering all the possible means of persuasion in any subject."[[37]]
He compares rhetoric with medicine; for the purpose of medicine, he believes, is not "to restore a person to perfect health but only to bring him to as high a point of health as possible."[[38]] Neither medicine nor rhetoric can promise achievement, for in either case there is always something incalculable.
Although Aristotle, with philosophical caution, was careful to state that the function of rhetoric is not to persuade but to discover the available means of persuasion,[[39]] his successors were more direct, if less accurate. Hermagoras affirms that the purpose of rhetoric is persuasion,[[40]] and Dionysius of Halicarnassus defines rhetoric as the artistic mastery of persuasive speech in communal affairs.[[41]] But the anonymous author of the Latin rhetorical treatise addressed to C. Herennius, long believed to be the work of Cicero, qualifies this by defining the purpose of rhetoric as "so to speak as to gain the assent of the audience as far as possible."[[42]] And the sum of Cicero's opinion is that the office of the orator is to speak in a way adapted to win the assent of his audience.[[43]] In his definition of rhetoric Quintilian makes a departure from the habits of his predecessors by defining rhetoric as the ars bene dicendi, or good public speech.[[44]] Here the bene implies not only effectiveness, but moral worth; for in Quintilian's conception the orator is a good man skilled in public speech, and there are times when, as in the case of Socrates, who refused to defend himself, to persuade would be dishonorable.[[45]] Quintilian's precepts, however, are more in line with Aristotle than his definition. He busies himself throughout twelve books in teaching his students how to use all possible means to persuasion. The consensus of classical opinion, then, agrees that the purpose of rhetoric is persuasive public speaking.
2. Subject Matter
If then the purpose of classical rhetoric was to come as near persuasion as it could, what was its subject matter? Aristotle, following Plato,[[46]] says in his definition "any subject," for any subject can be made persuasive. But this was too philosophical for his contemporaries and successors, who saw in their own environment that in practice rhetoric was almost entirely concerned with persuading a jury that certain things were or were not so, or persuading a deliberative assembly that this or that should or should not be done. Consequently Hermagoras defines the subject matter of rhetoric as "public questions," Dionysius of Halicarnassus, as "communal affairs," and the Ad Herennium as "whatever in customs or laws is to the public benefit."[[47]] The same influence caused Cicero in his youthful De inventione to classify rhetoric as part of political science,[[48]] and in the De oratore to make Antonius restrict rhetoric to public and communal affairs,[[49]] although in another section he returns to Aristotle's "any subject" as the material of rhetoric[[50]] as does Quintilian later.[[51]]
Although Aristotle did state in his definition that any subject was the material of rhetoric, in his classification of the varieties of speeches he practically restricts rhetoric as did Hermagoras, Dionysius, and the Ad Herennium; for here he finds but three kinds of oratory: the deliberative, the forensic, and the occasional, ἐπιδεικτικός. Forensic oratory he defines as that of the law court; deliberative, of the senate or public assembly; and occasional, of eulogy and congratulation. Perhaps the most illustrative modern examples of the third would be Fourth-of-July addresses, funeral sermons, and appreciative articles or lectures. Aristotle suggests that exaggeration is most appropriate to the style of occasional oratory; for as the facts are taken for granted, it remains only to invest them with grandeur and dignity.[[52]]
Occasional oratory seems to have given no little concern to the classical rhetoricians. Since it existed to adorn an occasion, it had to be considered; but unlike the oratory of the forum or of the council chamber it was not primarily practical. Quintilian comments on this; for it seems to aim almost exclusively at gratifying its hearers,[[53]] in this respect resembling poetry, which to Quintilian, seems to have no visible aim but pleasure.[[54]] Occasional speeches relied much more on style than did those of the law court and senate, thus meriting Aristotle's adjective "literary," that is written to be read instead of spoken to be heard.[[55]] Cicero, like Quintilian, considers these less practical, as remote from the conflict of the forum, written to be read, "to be looked at, as it were, like a picture, for the sake of giving pleasure." Consequently he declines to classify this form of oratory separately, reducing Aristotle's three kinds of oratory to two. It is valuable, to his mind, as the wet-nurse of the young orator, who enlarges his vocabulary and learns composition from its practice.[[56]] Aristotle includes it in rhetoric; for in its field of eulogy, panegyric, felicitation, and congratulation, it too uses the available means of persuasion to prove some person or thing praiseworthy or the reverse.[[57]]
3. Content of Classical Rhetoric
Classical rhetoricians commonly divided their subject into five parts. This analysis of rhetoric into inventio, dispositio, elocutio, memoria, and pronuntiatio is to all intents and purposes universal in classical rhetoric and must be understood to give one a valid idea of its content.[[58]] Inventio, so often lazily mistranslated as "invention," is the art of exploring the material to discover all the arguments which may be brought to bear in support of a proposition and in refutation of the opposing arguments. It includes the study of arguments and fallacies; and is that part of rhetoric which is closest neighbor to logic. The kinds of argument treated in the classical rhetoric were two: the enthymeme, or rhetorical syllogism; and the rhetorical induction or example. In the practice of rhetoric inventio was thus the solidest and most important element. It included all of what to-day we might call "working up the case." Dispositio is the art of arranging the material gathered for presentation to an audience. Aristotle insists that the essential parts of a speech are but two: the statement and the proof. At most it may have four: the ex ordium, or introduction; the narratio, or statement of facts; the confirmatio, or proof proper, both direct and refutative; and the peroratio, or conclusion.[[59]] This is the characteristic movement of rhetoric, which, as is readily seen, is quite different from the plot movement of poetic.[[60]] The parts are capable of further analysis. Consequently most writers of the classical period subdivide the proof proper into probatio, or affirmative proof, and refutatio, or refutation.[[61]] And the Ad Herennium adds a divisio, which defines the issues, between the statement of facts and the proof.[[62]] Cassiodorus divides the speech into six parts[[63]] and so does Martianus Capella.[[64]] Thomas Wilson (1553) offers seven.[[65]]
The third part of rhetoric is elocutio, or style, the choice and arrangement of words in a sentence. Quintilian's treatment of style is typical. Words should be chosen which are in good use, clear, elegant, and appropriate. The sentences should be grammatically correct, artistically arranged, and adorned with such figures as antithesis, irony, and metaphor.[[66]] Correctness is usually presupposed by the rhetoricians. To the sound of sentences all classical treatises give an attention that seems amazing if we forget that in Greece and Rome all literature was spoken or read aloud. The sentence or period was considered more rhythmically than logically, and subdivided in speech into rhythmical parts called commas and cola. The end of the sentence was to be marked not by a printer's sign, but by the falling cadence of the rhythm itself. Furthermore, great care should be taken to avoid hiatus between words, as when the first word ends and the word following begins with a vowel. But the glory of style to the classical rhetorician lay in its use of figures. Here rhetoric vindicated its practicality by a preoccupation with the impractical; and here, as in analysis, rhetoric bore the seeds of its own decay. Although Aristotle devoted relatively little space to the rhetorical figures, later treatises emphasized them more and more until in post-classical and in mediaeval rhetoric little else is discussed. The figures of course had to be classified. First there were the figurae verborum, or figures of language, which sought agreeable sounds alone or in combination, such as antitheses, rhymes, and assonances. Then the figurae sententiarum, or figures of thought, such as rhetorical questions, hints, and exclamations.[[67]] Quintilian classifies as tropes words or phrases converted from their proper signification to another. Among these are metaphor, irony, and allegory. In our day we consider as figures of speech only the classical tropes, and indeed Aristotle pays little attention to the others. He says that in prose one should use only literal names of things, and metaphors, or tropes[[68]]--which therefore are not literal names but substituted names. For instance in this metaphor, which Aristotle quotes from Homer, "The arrow flew,"[[69]] "flew" is not the literal word to express the idea. Only birds fly, reminds the practical person. Max Eastman has pertinently called attention to the fact that it is only to rhetoric, which is a practical activity, that these figures are indirect expressions, or substituted names. Apostrophe is not a turning away in poetic, because in poetic there is no argument to turn away from. Rather in poetic it is a turning toward the essential images of realization, as metaphor in poetic is direct, not indirect, because in poetic a word that suggests the salient parts or qualities of things will always stand out over the general names of things.[[70]]