Author: Moshe Hirsch

[Moshe Hirsch is Professor of International Law at the Hebrew University of Jerusalem Faculty of Law.] Sociology of international law involves the study of how social factors influence the development and enforcement of international law. As elaborated below, sociological analysis casts a new light on a significant dimension of the relationships between different branches of international law, and enriches our understanding of social factors involved in in legal decision-makers' inclination to incorporate or reject legal rules developed in other branches of international law. This chapter aims to analyze the particular set of interactions between two branches of international law - human rights and investment treaties - from a socio-cultural perspective. Analysis of investment tribunals’ decisions relating to human rights instruments reveals that while these tribunals often incorporate rules of general international law (particularly on state responsibility and treaty law), they adopt a quite consistent approach opposing the incorporation of international human rights law in investment disputes.  Investment tribunals have generally declined to thoroughly examine the specific provisions of international human rights instruments invoked by the parties, notwithstanding the various arguments raised during different stages of litigation by the various parties. In all cases dealing with the interaction between investment and human rights instruments, not one investment tribunal has absolved a party from its investment obligations or reduced the amount of compensation as a result of the consideration of human rights instruments. Sociologists of law have long emphasized that law is "always rooted in communities"; and laws are considered by these scholars as expressive types of these communities. The basic argument of this chapter is that legal interactions between branches of international law may also be analyzed as social interactions between the relevant communities. These legal interactions are affected by the particular features of relevant social settings, as well as by the mutual relationships between the relevant social groups. More specifically, the socio-cultural distance between the particular international legal settings affects the inclination of relevant decision-makers to incorporate or reject legal rules developed in other branches of international law. Generally, greater socio-cultural ‘distance’ between the involved social settings and groups decreases the prospects for mutual incorporation of legal rules developed in the other legal sphere. The social settings in which international investment and human rights laws emerge and are interpreted, are very different.