Taking as its point of departure Edmund Husserl's 1935-36 text The Crisis of European Sciences, this essay attempts to develop a new conception of reason by means of a thoroughgoing critique of some ideas often used to support and define it. Because the notion of "enlightenment" has been tied since the time of Kant to a certain coming of age of reason or rationality, the "enlightenment" to come must at once draw upon the resources of this reason and open reason to some of the aporias it has traditionally rejected. Reducible neither to a simple irrationalism nor to a mere mode of calculative thought, such reason must ultimately challenge, it is argued, not only the sovereignty and identity of the (human) subject but the very concepts of sovereignty and identity. Only such a renewed thinking of reason or of what is reasonable, the essay suggests, can help us diagnose, analyze, and help treat some of the aporias posed by a whole host of contemporary issues, from cloning to the erosion of the nation-state to globalization and terrorism. Only in this way can we at once "save the honor of reason" - to use a phrase that runs throughout the essay - and help reorient the reason of politics, of the sciences, and, indeed, of philosophy along the lines of a more fundamental and urgent ethical imperative.