|The Canons of Rhetoric: Invention
by Kelsey Shields, Writing Consultant
(printable version here)
As the famous Roman orator, Cicero, stated in De Inventione, invention is"the discovery of valid or seemingly valid arguments to render one's cause probable." That is, invention involves the research necessary for developing an argument, as well as deciding how you want to appeal to your audience, either with logos, ethos, or pathos.
Logos, or rational appeal, attempts to persuade your audience with facts, evidence, and examples. Jerskey and Raimes state that "such an appeal is appropriate for educated readers and useful when readers are uninformed or hostile" (63).
Ethos, or ethical appeal, refers to how you represent yourself and your sources in the argument. Typically you will appeal to your readers by making yourself appear reliable, objective, fair, and so on, even when discussing the opposite argument.
Pathos, or emotional appeal, utilizes empathy and/or sympathy in order to persuade your audience to support your side. This is normally done by using "descriptions, anecdotes, case studies, and visuals to appeal to those values" (Jerskey and Raimes, 64).