Is Finnis wrong?

Judges and lawyers believe that international law, customary law, and legal systems such as the Third Reich or apartheid law in South Africa are law. But how do we explain the fact that there is one concept of law when there are different conceptions of law with a variety of different features? Finnis, inspired by the Aristotelian notion of central case, adumbrates the idea that the concept of law might be unified by a primary concept which is the concept of “law as practical reason”; that is, law conceived from an ethical perspective. He advances two arguments to defend his methodology: the conceptual and the functional. Contra Finnis, the paper shows that neither the conceptual nor the functional argument can successfully support the view that “law as practical reason” is the central case of the concept of law. The study clarifies the Aristotelian notion of central case and illustrates the mistaken application of this notion to the concept of law. However, we also argue that Finnis's insight–the idea that all the different conceptions of law might be unified for the purposes of theoretical research–is fundamental and appealing. This paper aims to reconstruct Finnis's insight through the model of core resemblance. The result is that the different conceptions of law can be unified by resemblance to the concept of “law as practical reason,” though there is no identity among the different conceptions of law