Petitio principii
Petitio principii
or begging the question, is a fallacy involving the assumption as premisses of one or more propositions which are identical with (or in a simple fashion equivalent to) the conclusion to be proved, or which would require the conclusion for their proof, or which are stronger than the conclusion and contain it as a particular case or otherwise as an immediate consequence. There is a fallacy, however, only if the premisses assumed (without proof) are illegitimate for some other reason than merely their relation to the conclusion — e.g., if they are not among the avowed presuppositions of the argument, or if they are not admitted by an opponent in a dispute. — A.C.