Roth's Law

When a man in conversation drops an obscure name—generally from distant history—and is called upon to explain himself, his first description of the figure in question will be that he is or was 'well-known', 'famous', or the like. The probability of this happening is directly proportional to the recondity of the explicandum. This trope, we note, serves to exculpate the careless erudition of the speaker, who could hardly have expected his interlocutor, or interlocutrix, to require clarification of so obvious a point of general knowledge.

Example.

George. The current crisis in the British educational system, so much anatomised and commented upon in the papers of late, rather reminds one of the remarks of Nathaniel Fairfax, does it not? 'Tis better to—

Cecil. Hang on there, buddy! Who's Nathaniel Fairfax?

George. Ah, my apologies. Fairfax was a very famous scholar of the seventeenth century. As I was saying, 'Tis better to question the. . .