 Borderline status has the mobility of a bubble in a level. The precisificationist’s mistake is to remove the bubble. Peirce’s mistake is to freeze the bubble into intrinsic uncertainty. This is the dual of the error Peirce attributes to René Descartes’ method of universal doubt. Doubting everything is impossible because doubt only gets leverage against a fulcrum of presuppositions. (Ludwig Wittgenstein’s analogy is with the hinges of a door that hold fast in order that the door of doubt can open and close.) These presuppositions are indubitable in the sense that they cannot be challenged within the inquiry. When the skeptic claims to doubt everything, he winds up doubting nothing. The skeptic’s sham doubts are belied by the absence of any interruption of his habits. A genuine doubt triggers inquiry. Inquiry requires presupposition. These background beliefs must be taken for granted. But the necessary existence of certainty does not entail any intrinsic certitudes. What must be presupposed for one inquiry need not be presupposed for another. By Fine’s reckoning, Peirce should have issued a parallel rejection of intrinsic uncertitudes. Within any inquiry, there must be some suspension of judgment. But it does not follow that any proposition must resist all inquiry.