In his work, On Law and Justice, Alf Ross sought to explain law in scientific/empirical terms, in terms that would require no recourse to what he called “metaphysics” or “idealism.” The result is a sort of translation of legal rules and official actions into propositions of behavior, predictions of behavior, and shared ideology. The present work raises questions about the tensions within Ross's work(s), and discusses the places where Ross's analysis seems to fall short of its ambitions. In the course (...) of the discussion, the article considers issues relating to legal mistake, explanations of judicial behavior, and different types of normativity. (shrink)