Building a Common but Plural Techno-Scientific World. Questioning Epistemic Subsidiarity in Europe.

International audienceLiterature on the Community regulation has shown how the European Model faces foundational tensions between State sovereignty and integration. The principle of subsidiarity has been coined to regulate the exercise of power and to determine whether, in an area where there is joint competence, the Union can take action or should leave the matter to the Member States. The subsidiarity principle is based on the idea that decisions must be taken as closely as possible to the citizen: the Union should not undertake action, except on matters for which it alone is responsible, unless EU action is more effective than action taken at other levels. As far as regulation of technological objects is concerned, the traditional vision is that, as knowledge is supposed to be universal and harmonization of the European market is a key driver, the European level is the relevant level of governance. However, the analysis of subsidiarity in practice shows that we can hardly see a general rational at play. For instance, why nuclear energy production is considered as an issue of national sovereignty as monetary policy is now a European competence? Drawing upon two emblematic cases, this paper aims to go beyond an instrumental understanding of subsidiarity and to explore a set of interrelated questions: Who produces the knowledge used for regulating technological objects? How is knowledge translated and adapted to various local situations? What are the processes that contribute to the credibility of regulatory knowledge at national and European level? How are the boundaries between science and politics negotiated