in Aristotle's systematization of rhetoric, one important aspect of rhetoric to study and theorize was the three persuasive audience appeals:logos, pathos, and ethos, as well as the five canons of rhetoric: invention or discovery, rhetoric is one of the three ancient arts of discourse. rhetoric is one of the three ancient arts of discourse. From ancient Greece to the late 19th Century, it was a central part of Western education, filling the need to train public speakers and writers to move audiences to action with arguments.