It is for the same reasons that a self evident truth is irresistible in fact, yet always questionable, which amounts to two ways of saying the same thing: namely, that it is irresistible because I take for granted a certain acquisition of experience, a certain field of thought, and precisely for this reason it appears to me as self evident for a certain thinking nature, the one which I enjoy and perpetuate, but which remains contingent and given to itself.