Customary law has been criticized from very different angles. Rational choice theorists claim that what looks like custom is nothing but self-interest. Positivists doubt that anything beyond consent assumes the force of law. In this paper, we adopt an experimental approach to test these claims....

This chapter zeroes in on customary international law and examines the role played by this specific source of law in the development of international investment law. After a few considerations on the early phase of development of an international investment protection regime and the search for a...

Theory about the relevance of soft law abounds; empirical research on the topic does not. This study begins to even out this imbalance by not only developing a number of conjectures based on institutional economics, but also by testing them empirically. Based on all 2,289 soft laws concluded by...

This article looks at the emergence and evolution of the customary international humanitarian law applicable in situations of non-international armed conflict. In the years since the adoption of the Geneva Conventions and the Additional Protocols, a large number of rules relating to conduct in...