though. Aristotle professes to give them solely to be used in the cause of truth and justice.
With regard to the third “source of persuasion”—the arguments used by an orator must not be scientific demonstrations, nor even dialectical syllogisms, but rhetorical arguments, such as the conditions and circumstances of oratory will admit. For the orator is not like the scientific demonstrator before his pupils, nor is he like the dialectician with his respondent, who will grant him the premisses of his argument. The orator has to address a crowd of listeners, with whom as yet he is not in relation; he has to catch, without fatiguing, their attention, and to suggest conclusions without going through every step of the inference. All reasoning, however, must be either inductive or deductive, and the arguments of Rhetoric must each belong to one of these two forms. Aristotle, adapting special names for the purpose, says that the enthymeme of Rhetoric answers to the syllogism of Logic, and that the example of Rhetoric answers to the induction of Logic.
The word “enthymeme” seems to mean etymologically “a putting into one’s mind,” or “a suggestion.” It is a rhetorical syllogism with premisses constructed out of “likelihoods,” or “signs.” Some critics consider that it was essential to the “enthymeme” to have one of its premisses suppressed; but Aristotle only says (‘Rhet.’ I. ii. 13) that this was frequently the case. The real characteristic of the “enthymeme” was its suggestive, but non-conclusive, character; for the premisses, even if expressed in full, would not be sufficient to enforce the conclusion which is pointed at. The “enthymeme”
