International institutions in a functionally differentiated world society

In their introduction to this volume, Mathias Albert, Barry Buzan and Michael Zürn suggest that long-term structural change in the international system can be analysed in terms of the interaction between, and relative importance of, three different forms of social differentiation: segmentary, stratificatory and functional (see also Buzan and Albert, 2010). IR scholarship traditionally focuses on what sociologists would see as the result of segmentary differentiation, namely systems or societies of states, while paying attention also to stratificatory differentiation because of the role of great powers, superpowers and empires. According to prominent system theorists, this spatially differentiated political system should be seen as embedded in a ‘world society’ that is itself primarily differentiated along functional lines (Luhmann, 1971a). According to Niklas Luhmann, only the political system and the legal system are differentiated spatially in the form of states; all other systems ‘operate independently of spatial boundaries. Precisely the unambiguous character of spatial boundaries makes it clear that they are respected neither by truths nor by diseases, neither by education nor by television, neither by money (if the need for credit is considered) nor by love’. Luhmann added that ‘the importance of spatial boundaries lies in the interdependencies between the political and the legal system on the one hand and the other functional systems on the other’