PETITIO PRINCIPII, or BEGGING TIIE QUESTION (Gr. To v apxjj )  .a mj3h ttv, Toe apxfjs aireioOat), in

logic, the fourth of Aristotle's fallacies g re r s X swc or extra dictionem . Strictly this fallacy belongs to the language of disputation, when the questioner seeks (petit) to get his adversary to admit the very matter in question . Hence the word principium gives a wrong impression, for the fallacy consists not in seeking for the admission of a principle which will confute the particular proposition—a perfectly legitimate form of refutation—but in luring the adversary into confessing the contradictory . In the ordinary use, however, " begging the question " consists in assuming in the premises the conclusion which it is desired to prove .