In chapter 3 I used the language of ideas to argue against a materialist approach to the study of structure. As I see it, however, social constructivism is not just about idealism, it is also about structuralism or holism. Structures have effects not reducible to agents. With that in mind this chapter looks at the structure of ideas in the system and asks: What does it mean to say that there is an ideational structure in a system? And what effects can such a structure have?

The structure of any social system will contain three elements: material conditions, interests, and ideas. Although related these elements are also in some sense distinct and play different roles in explanation. The significance of material conditions is constituted in part by interests, but they are not the same thing. Oil does not have the same kind of causal powers as an interest in the status quo. Similarly, interests are constituted in part by ideas, but they are not the same thing. The ideas constituting an interest in revisionism do not have the same kind of causal powers as the belief that other states obey international law. These distinctions mean that it may be useful for analytical purposes to treat the distributions of the three elements as separate “structures” (material structure, structure of interests, ideational structure). If we do so, however, it is important to remember that they are always articulated and equally necessary to explain social outcomes. Without ideas there are no interests, without interests there are no meaningful material conditions, without material conditions there is no reality at all.