Aristotle, Rhetoric
J. H. Freese, Ed.

but not disgraceful as far as speech is concerned, whose use is more characteristic of man than that of the body. [13] If it is argued that one who makes an unfair use of such faculty of speech may do a great deal of harm, this objection applies equally to all good things except virtue, and above all to those things which are most useful, such as strength, health, wealth, generalship; for as these, rightly used, may be of the greatest benefit, so, wrongly used, they may do an equal amount of harm.

[14] It is thus evident that Rhetoric does not deal with any one definite class of subjects, but, like Dialectic, [is of general application]; also, that it is useful; and further, that its function is not so much to persuade, as to find out in each case the existing means of persuasion.¹ The same holds good in respect to all the other arts. For instance, it is not the function of medicine to restore a patient to health, but only to promote this end as far as possible; for even those whose recovery is impossible may be properly treated. It is further evident that it belongs to Rhetoric to discover the real and apparent means of persuasion, just as it belongs to Dialectic to discover the real and apparent syllogism. For what makes the sophist is not the faculty but the moral purpose. But there is a difference: in Rhetoric, one who acts in accordance with sound argument, and one who acts in accordance with moral purpose,
are both called rhetoricians; but in Dialectic it is the moral purpose that makes the sophist, the dialectician being one whose arguments rest, not on moral purpose but on the faculty.²

Let us now endeavor to treat of the method itself, to see how and by what means we shall be able to attain our objects. And so let us as it were start again, and having defined Rhetoric anew, pass on to the remainder of the subject.

2. Rhetoric then may be defined as the faculty of discovering the possible means of persuasion in reference to any subject whatever. This is the function of no other of the arts, each of which is able to instruct and persuade in its own special subject; thus, medicine deals with health and sickness, geometry with the properties of magnitudes, arithmetic with number, and similarly with all the other arts and sciences. But Rhetoric, so to say, appears to be able to discover the means of persuasion in reference to any given subject. That is why we say that as an art its rules are not applied to any particular definite class of things.

[2] As for proofs, some are artificial, others inartificial. By the latter I understand all those which have not been furnished by ourselves but were already in existence, such as witnesses, tortures, contracts, and the like; by the former, all that can be constructed by system and by our own efforts. Thus we have only to make use of the latter, whereas we must invent the former.