ABSTRACT
In doubt’s confrontation with its major dangers, Descartes realized that he could not be mad-though he was to acknowledge for a long time to come that all the powers of unreason kept vigil around his thought; but as a philosopher, resolutely undertaking to doubt, he could not be “one of these insane ones.” Rameau’s Nephew, though, knew quite well-and among his fleeting certainties, this was the most obstinate-that he was mad. “Before beginning, he heaved a profound sigh and raised his hands to his forehead; then he regained his calm demeanor and said to me: you know I am ignorant, mad, impertinent, and lazy.”1
