Robert Putnam is mainly famous for reviving the concept of “social capital.” As he measures it, social capital is the aggregate of certain habits and attitudes that individuals possess–especially trust for other people and membership in groups.

There are two main interpretations of social capital theory. The political interpretation says that people deliberately develop organizations and networks in order to solve public problems. Trust is a by-product of this work; it is also something that people deliberately enhance by developing personal relationships and by raising children as members of communities. It is good to develop social capital because it enhances a community’s capacity to solve problems in the future.

The apolitical interpretation assumes that social capital goes up or down because of large social forces and trends, such as suburbanization, the work environment, and exposure to television. (TV makes people less trusting and less sociable.) The reason we should care–according to this interpretation–is that social capital correlates with mental health, longevity, and good educational outcomes. Therefore, if we can, we should tinker with big institutions to increase social capital.

Although these two theories reflect different values, there are also empirical differences. It is either true or false that people can create social capital through deliberate action at the local level. I’m optimistic that they can, but I’m not sure how strong the evidence is.