This chapter makes the claim that, although the embrace of a scientific project for international law did not systematically translate itself with a representation of international law as a positivist discipline, international legal positivism was, most of the time, invoked to vindicate the idea of an international legal science. In that sense, this chapter argues that the European portrayal of international law as a positivist discipline mainly boiled down to a project of endowing international law with scientificity, that is, a project to elevate international law into a discipline grounded in the real and geared towards discoursing the real. It simultaneously shows that, although Europeans themselves later came to contest their earlier project of scientifization of international law and even though that project eventually collapsed, the scientistic ambitions that accompanied the positivist representation of international law have proved resilient and still bear important marks on international legal thought and practice today.