Abstract
The basic proposition I put forward in my paper is that the phenomenological project itself is implicitly practical: having effectuated the phenomenological reduction, the phenomenologist faces the world in its appearing, that is to say the world governed by laws (the material a priori) which are binding even for the natural attitude. This practical consequence of phenomenology was very important for Husserl: his first sketch of phenomenological project consists of three books, Ideen, in which the movement from a "pure phenomenology" to a much more practical question of "phenomenological foundations of sciences" is undeniable.
In the second part of my paper, I attempt to briefly present Husserl's idea of phenomenological foundation of sciences which constitutes the core of this practical interpretation of phenomenology and which is most systematically sketched in the third volume of Ideen. However, since one has to consider contemporary critics of classical phenomenology, its "subjectivism" in the words of Patočka, as justifiable, the whole problem of "foundation" has to be reconsidered: if phenomenology were to found sciences and more generally "our empirical lives", it would no longer be possible to proceed in the same way as Husserl did.
That is why, finally, I endeavour to think of how it is possible, in terms of contemporary French phenomenology, to found sciences.