Class structures differ not only in the distribution of people across the various locations in that structure, but also in the extent to which people's lives are bounded by specific class locations. At the micro-level, class is explanatory because it shapes the interests, strategic capacities and experiences of people, and each of these effects depends not simply on the static location of individuals in a job-class structure, but also on the complex ways in which their lives are linked to various classes through careers, mobility, voluntary associations and social ties. In some class structures, friendships, marriages, churches and sports clubs are largely homogeneous with respect to class. In such cases, class boundaries can be thought of as highly impermeable. In other class structures, these social processes frequently bring together people from different class locations. When this happens, class boundaries become relatively permeable.

In this chapter, I will begin by giving some precision to the concept of the permeability of class boundaries and then propose a general empirical strategy for analyzing permeability. This will be followed by an empirical examination of three kinds of permeability: the formation of friendship ties across class locations, the class composition of families, and intergenerational class mobility.

5.1 Theoretical issues

Permeability in the Marxist and Weberian traditions

The two primary sociological traditions of class analysis – Marxist and Weberian – have given different priorities to class structure and boundary permeability as objects of analysis.