Samenvatting

Seeing that the role of opinio juris in the identification of customary international law is essentially contested, this contribution seeks to explain how this concept plays a fruitful role in legal doctrine despite of, or perhaps even due to, this essential contestedness. To that effect the paper adopts a constructivist perspective, primarily drawing from Bourdieu’s theory of practice and Berger & Luckmann’s ideas about institutionalization. In this perspective, contested concepts such as opinio juris are conceived of as multifaceted tools of knowledge production in the hands of members of epistemic communities.