Proof by assertion, sometimes informally referred to as proof by repeated assertion, is an informal fallacy in which a proposition is repeatedly restated regardless of contradiction and refutation.[1] The proposition can sometimes be repeated until any challenges or opposition cease, letting the proponent assert it as fact, and solely due to a lack of challengers (argumentum ad nauseam).[2] In other cases, its repetition may be cited as evidence of its truth, in a variant of the appeal to authority or appeal to belief fallacies.[3]