A special regime is a subpart of the international legal system. This is why, in international legal discourse, there are several different conceptions of a special regime. For the same reason as lawyers disagree about the proper definition of the concept of international law, not only do they have different conceptions of an international legal system but they also assume different definitions of the concept of a special regime. There are considerable differences among the different conceptions of a special regime. This observation raises questions about their relative utility. Chapter 1 suggests the adoption of the conception that characterizes special regimes as communities of practice – as it helps to manage and control the effect of legal fragmentation compared to other conceptions.

The ILC Study Group on Fragmentation of International Law asserted that the proliferation of special regimes poses a threat to the unity of the international legal system. Chapter 6 challenges this assumption. It builds on the distinction made in epistemology between knowledge-that and knowledge-how. The idea of a special regime as a community of practice makes it a system of knowledge-how. As such, it is compatible with all of the legal positivist’s, legal realist’s and legal idealist’s conceptions of an international legal system, which either see it as a system of knowledge-that or a combination of a system of knowledge-that and a system of knowledge-how. In the former case, in no way does the proliferation of special regimes affect the unity of the international legal system. In the latter case, the unity of the international legal system is indeed affected, but only in a positive sense, as it increases the efficacy of international law relative to the assumed legal ideal.