That branch of logic which deals with arguments made on behalf of subjects of inquiry that fail to arouse definitive assent in one’s hearers.  Often, this is due to the contingency of the matter in question, especially in moral matters where particular actions cannot definitively determine the intellect of the hearer by means of demonstrative reasonings.  For this reason, as well as for the historical connection to the Rhetoric of Aristotle, as well as the political-legal writings of classical authors like Cicero and Quintilian, rhetorical logic is often associated solely with Moral and Political philosophy among classical philosophers.  Influenced by the Arabic reception of Aristotle and Neo-Platonism, figures in the medieval West, including Thomas Aquinas, included rhetoric as part of the logical corpus of Aristotle’s works.

In classical logic, three modes of persuasion are distinguished: ethos (based on the character of the speaker or that of a person who might hold a position being exposited by a orator); pathos (based on an emotional disposition aroused during oratory); and logos (based on the force of an argument, that is, at least apparently, established by means of rhetorical discursion).  Moreover, there are three kinds of rhetorical arguments, depending on the subject matter under discussion: deliberative rhetoric considers all those good and evil things that depend upon our action; judicial rhetoric makes clear the details concerning the commission of injustices, both regarding those who commit injustices and those who are its victims; and epideictic rhetoric sets forth or “displays” a topic in a grand way, above all in praise of virtue and in condemnation of vice.