Abstract
The cause is clear: rationalism in its broadest sense - in other words, the conviction, in itself rather vague, that "reason" remains our best possible mode of access to the intelligibility of the world in general and the human condition more specifically - is not in law dependent on any particular metaphysical conception. Nevertheless, we would first like to argue that, despite appearances, there can be no future for rationalism, understood in this way, without taking its metaphysical underpinning seriously. Appearances : we don't necessarily need to go as far as Husserl, in the Krisis, who asserts that the "figure of the development of the ratio as Enlightenment rationalism was, however conceivable, an error" to see that, in any case, and paradoxically, the development of a new form of rationality during the same period was accompanied by a progressive questioning of the epistemological and metaphysical presuppositions of rationalism in the dual form - meta-philosophical and epistemological - that it had taken in the previous century. The paradox undoubtedly reached its climax in the twentieth century with the Vienna Circle, whose famous rejection of all forms of metaphysics was matched only by its defence, tooth and nail, of the initial ideal ofAufklärung.
Today, when various forms of irrationalism - more or less well disguised under various guises - are temporarily occupying centre stage, both outside and, alas, within the field of philosophy, the question is all the more pertinent, the question arises all the more acutely of the relationship between what must now be seen as a kind of collective program aimed at redefining "reason", itself in line with the scientific evolution of this notion and the examination of both its presuppositions and its metaphysical stakes. It is to the advancement of this program that we would very modestly like to contribute, by examining in particular the links - both natural and nonetheless problematic - between a (partly) normative theory of concepts and certain recent metaphysical theories on the subject of "essences" and categories.
