The concept of "commonplaces" (Greek, koinoi topoi; Latin, loci communes) originated as a rather abstract notion in the philosophical and rhetorical works of Aristotle. In his Topica, Aristotle distinguished between the various forms of argumentation that one may encounter in a philosophical discussion or debate. Aristotle referred to these forms of argument as commonplaces, that is, the principal tools of any logical and systematic interrogation of the truth or falsity of an opinion. In order to find and develop arguments in support of a philosophical proposition, one must consider his subject in terms of the most basic categories, or "topics," which Aristotle described as "definition," "property," "genus," and "accident." For Aristotle, one must repair to these various "species of reasoning," as a matter of course, in order to make a substantial, rational determination of truth. He extended his concept of the commonplaces beyond the rarefied atmosphere of philosophical discourse, into the more worldly and pragmatic art of persuasion in his Rhetorica. There he suggested that the commonplaces could be employed not only in the philosophical demonstration of certain truths, but in the lesser service of exploring, through rhetoric, the probability and validity of propositions as well. These observations provided an authoritative, if somewhat abstract, philosophical basis for subsequent developments of the commonplace as a formal and recognized category in Western thought.
Earl Havens, Commonplace Books: A History of Manuscripts and Printed Books from Antiquity to the Twentieth Century. Yale University, 2001.