The starting point of this essay is the question “Under what conditions is the legal practitioner justified in ignoring the economic point of view?”. This question leads to an inquiry of the relation between the disagreements economists have with the law and theoretical disagreements. The essay makes two main claims. First, the disagreements economists have with the law can originate a particular kind of theoretical disagreement – an interdisciplinary theoretical disagreement. Interdisciplinary theoretical disagreements pre- suppose the solution of a translation problem from economics into law. The translation problem is solved when a proposition of economics becomes part of the external justification of a legal norm. It makes sense to use the expression «interdisciplinary translation» because meaning is moved from one practice to another. Second, the various positions with regard to the relation between law and morality are also a problem of interdisciplinary translation – this time from morality to law. In light of this insight, the essay concludes with the hope of more interest by philosophers of law and legal theorists for the relation between law and economics.