Münchhausen Trilemma

The Münchhausen Trilemma (after Baron Münchhausen, who allegedly pulled himself (and the horse he was sitting on) out of a swamp by his own hair), also called Agrippa's Trilemma (after Agrippa the Skeptic), is a philosophical term coined to stress the purported impossibility to prove any truth even in the fields of logic and mathematics. It is the name of an argument in the theory of knowledge going back to the German philosopher Hans Albert, and more traditionally, in the name of Agrippa.