In Chapter 8, it was proposed that actions motivated by expressive and instrumental needs propel interactions with others beyond primordial groups so that social capital may be accessed. These purposive actions sustain two types of exchanges, as described in Chapter 9 – to gain and maintain two elementary payoffs: wealth and reputation. These two chapters describe the process from action to structure. Chapter 10 turns to the structure-to-action process by showing how hierarchical structures constrain actions accessing social capital. These are ideal types of linkage between action and structure; in reality, such processes are complicated by structures and processes mediating between actors and hierarchical structures. Unless we identify and describe how these middle-level structures and processes operate, we will be unable to understand how action and structure interact. Further, the two processes – from micro to macro and vice versa – should not be seen in isolation or each depicted as a one-way process. A comprehensive theory of social capital must capture the two-way process between action and structure, as mediated through certain middle-level structures and processes.

In this chapter, I argue that two such middle-level structures – institutions and networks – constitute the infrastructure of society. The framework conceives institutions and networks as the two main social forces guiding the interactions between actors and hierarchical structures and the flows of capital.