This paper explores the contribution by the contemporary legal realist Hanoch Dagan. Dagan’s brand of realism defines law on the basis of its institutions or social practices, not of its norms or rules. The paper first provides a critical overview of this realist theory of law: It is not synonymous with the predictive theory of law, with Leiter’s theory of judges, or Frank’s “breakfast theory”. By focusing on the role of judges and the methodology of legal reasoning, we discover that (...) the core difference between realism and positivism lies in the claim that law is affected by a strong form of indeterminacy, stemming from the plurality of legal sources, not from the open texture of legal language as expressed in rules; and we are also able to distinguish this form of realism from contemporary movements in legal theory, such as critical legal studies and law & economics. The normative dimension of realism is also addressed: This theory of law develops a specific concept of justice, on the ground of a cognitivist theory of value. (shrink)