Abstract
When considering the works produced in history of science and transnational history, one is struck by the wide range of issues covered, the profusion of ideas and analyses, the richness and variety of what is proposed. On the other hand, one is also struck by the presence of rather repetitive methodological professions of faith, of declarations of intent about categories and rules that are quite stable over time. This article considers in turn both issues. First, what we have learned in substantial terms, what these historiographical reassessments about science and transnational relations teach us, what has been displaced and what is currently being opened. In the second part, the paper considers what is at stake in these preliminary statements of principle. The article defends the idea that we are facing two major interpretative corpuses that both do count and are heuristically productive, that in practice both are often mixed by historians – but that it is intellectually and politically decisive to consider finely the epistemologies, ontologies and postures that are offered.