In epistemology, the Münchhausen trilemma is a thought experiment used to demonstrate the theoretical impossibility of proving any truth, even in the fields of logic and mathematics, without appealing to accepted assumptions. If it is asked how any given proposition is known to be true, proof may be provided. Yet that same question can be asked of the proof, and any subsequent proof. The Münchhausen trilemma is that there are only three ways of completing a proof: The trilemma, then, is the decision among the three equally unsatisfying options.