With these rhetorical questions Jacques Derrida casts general suspicion on what is primarily constitutive of the transcendental tradition: the authority of the "I think" as the source of laws for both knowing and acting. In this paper I wish to show some presuppositions under which the legislative ego can appear as traversed by "the a priori of a counter-law," by a condition of "impossibility"; how an element of transgression can be seen to "contaminate" transcendental legislation at its very heart. I will then point out some consequences of the formal identity between legislation and transgression for the status of the social and human sciences today.