Historical Rhetorics/Cicero's Public and the Greek Tradition/Ochs, Donovan J. "Cicero and Philosophic ''Inventio''." ''Rhetoric Society Quarterly'' 19.3 (1989): 217-227.

Ochs argues that Cicero develops his topical systems as a form of joining philosophy and rhetoric. He first created a system of philosophical topics and then in De Oratore and Topica integrated these topics as a necessity for a unified system of topical invention for rhetoric/eloquence. Cicero’s system of invention shows direct influence from Hermagoras’ third century system of stasis classification, but also derives from skepticism in that probability is the objective of discourse, rather than certainty (Ochs 218). To show the ways in which Cicero collapses both theses and hypothesis into rhetorical invention/topics, Ochs outlines Cicero’s schema (219-221; also Book III of De Oratore) and then shows how each classification works in service of probability, reasoned argumentation, and ethical arguments to guide the state.