Abstract
My research topics focus on the social responsability of researchers, their involvement and political engagement, all the way from the construction of knowledge to its formulation (research aesthetic) and dissemination.As I study others' engagement and their legitimation strategies, I also aim at formulating mine: a constructivism that holds itself accountable for its creations.This thesis discusses the role of experts in democracy; it is written in French. I highly doubt that I am able to summarize it in English, just as I doubt that exclusively English-speaking readers would be able to understand the manuscript in French.