"It is called a topos because starting from it as a 'place' we easily find arguments." (Theon, 106, Kennedy).Theon gives examples of commonplaces of good and bad men. For example, bad commonplaces for people are "tyrant, traitor, murderer, profligate," and for good people, "tyrannicide, hero, lawgiver."
Once one has established a commonplace, one can elaborate it in several ways, through comparison, past events, future events. Theon gives an example of a comparison between a temple robber and a thief. He writes:
"If the thief is punished for taking men's money, how much more will this man be punished for looting the possession of the gods?" (Theon, 108, Kennedy).In many ways then, the commonplace is a way of labeling someone or something, and then using stock arguments that are common to that type of person or thing.
There are several good examples of the commonplace in the New Testament. The following example comes from I Peter, where the author gives a commonplace, i.e., Gentiles, and then lists deeds common to Gentiles:
1Pet. 4:3 You have already spent enough time in doing what the Gentiles like to do, living in licentiousness, passions, drunkenness, revels, carousing, and lawless idolatry.Once the label "Gentile" is used, it opens up an entire list of stock arguments against Gentiles. Thus, the commonplace is a starting place from which to draw arguments. Notice, that commonplaces are always general, and they border on the stereotypical, but are nonetheless useful for finding arguments.