Emile Durkhein theorized that there are two forms of "solidarity" that bind the individuals in a society together. Mechanical solidarity, said to be more common among primitive people, results from the people in a society all thinking alike -- sharing the same worldview and skill sets. As society develops and job specialization increases, societies become more characterized by organic solidarity. People develop different ways of thinking, since different jobs demand different skills, but people are bound together by the fact that they're dependent on each other -- the blacksmith doesn't know how to grow food, and the farmer can't make his own plows and pitchforks.

One problem that mechanical solidarity seems to pose is that people are interchangeable. Since everyone is more or less alike, there's no reason why you in particular are necessary to society -- you can't claim a specialized niche in society. (Tangentially, it seems that to the degree that industrialization makes people interchangeable, it is working against organic solidarity in order to increase the power of the employer -- hence the need for group actions like strikes that take advantage of the fact that, while individual workers may be interchangeable, the whole set of workers stands in an organic solidarity relationship to the rest of society. The proletarian class-consciousness that Marx anticipated developing on the shop floor is essentially a form of mechanical solidarity. Marx seemed to envision a wholesale return to mechanical solidarity, as shown by his musings about being able to pursue a different form of employment every day -- only possible if people lack specialized skill and knowledge sets.) It occurred to me that this interchangeability might account for the prevalence of comkplex kinship networks in "primitive" societies that lack strong job specialization. Kinship networks give everyone a place and a role, a special relationship to each other member of a group. They become linked together by socially constructed ties of obligation (as opposed to total communal sharing) that approximate some of the effects of the interdependence of people in societies with organic solidarity. This also seems to explain the decline in the importance of family ties in modernizing societies. People increasingly identify themselves by their position in the network of organic solidarity (e.g. their job) rather than their position in the kinship network. As job (and consumer?) specialization increases, extended families give way to nuclear families and then perhaps to the dreams of some radical leftists that the family will become obsolete.