Ethos, Pathos, and Logos
In his Rhetorica Aristotle delineates between artistic and inartistic proofs. Inartistic proofs are merely used by the rhetor; artistic proofs are invented. Aristotle then identifies the three canonical modes of artistic proof: ethos, pathos and logos on grounds that, in order to persuade, one must exude good character, move the audience by appealing to emotions, and, of course, advance good reasons. Aristotle further asserts that a trustworthy character is one of the requisites of persuading because persons are more readily persuaded by those whom they trust.
Ethos
At the beginning of Book II Aristotle subdivides ethos into phronesis, arete, and eunoia because, in order to establish credibility, the rhetor’s words must project practical wisdom, virtue, and good sense. Aristotle discusses this tripartite division in terms of the techne of rhetoric. However, a good deal more can be said about the relation of phronesis to rhetoric.
Pathos
The appeal to passion. Human beings are not moved by logic alone. One must also stir the emotions in order to move the audience to action, and the end of persuasion is action. The relationship of pathos and style is important in rhetoric.
Logos
The appeal to reason. If I am to be persuaded by you, I must hear good reasons.