Fallacy allegedly committed by Descartes, when he supposes that since he can know things about his mind while not knowing them about his body, his mind cannot be identical with his body. This, according to the charge, is like arguing that since I can know who my father is without knowing who the masked man is, the masked man cannot be my father. It is doubtful whether Descartes made such a superficial mistake.
Philosophy dictionary. Academic. 2011.