Rhetoric, no less than logic, has subject-matter in every given case. Only its perverters teach it as merely an art of dealing with persons, of reaching an audience. No less than logic, it is a means of bringing out truth, of making people see what is true and fitting. But rhetoric contemplates having truth embraced. It is the application of proof to people. Its distinction from logic is here, in the typical mode of proof. The type in logic is the syllogism; the type in rhetoric Aristotle calls the enthymeme.[4] By this he means concrete proof, proof applicable to human affairs, such argument as is actually available in current discussion. The enthymeme is not inferior to the syllogism; it is merely different. Actually, public address on current public questions cannot be carried on by syllogisms or by final inductions. That by which it can be carried on, the strongest proof possible to actual discussion, Aristotle calls enthymeme. From this typical mode of rhetoric Aristotle gathers its fourfold function: first and foremost, to make truth prevail by presenting it effectively in the conditions of actual communication, to move; second, to advance inquiry by such methods as are open to men generally, to teach; third, to cultivate the habit of seeing both sides and of analyzing sophistries and fallacies, to debate; and finally to defend oneself and one’s cause. That truth does not always prevail shows the need of effective presentation. The first function, then, of rhetoric is to make truth prevail among men as they are. Truth cannot be learned by the mass of men through scientific investigation; for that demands special training. A second direction, then, of rhetoric is to make the results of investigation generally available, to teach truth in general human terms. Debate, Aristotle’s third item, which is one whole field of rhetoric, may indeed be mere logical fence, using terms and propositions as mere counters; but real skill in debate, the habit of seeing both sides and of analyzing sophistries and fallacies, tends to make truth emerge from current discussion. The fourth use of rhetoric, for self-defense, seems added merely for completeness and to rebut the common objection that rhetoric is abused. That, says Aristotle, is no argument against it.[5] The definition implied and sketched in Chapter I and formulated in Chapter II, may be summed up in the word persuasion, if we are careful to speak of persuasion not as achievement, but as method. Just as we ask of medicine, not that it shall infallibly heal—a degree of achievement impossible in human affairs—but that it shall discern and use all the means of healing available in the given case, so the true end of rhetoric is to induce such habitual skill as shall _discern in any given case the available means of persuasion_.[6]