The basic concept of class interest derives from Karl Marx's theory of social class. Marx argued that the social relations which define class generate inherently opposing interests. Hence, for example, the interests of the bourgeoisie are different from and antagonistic towards those of the proletariat. It is in the interests of the bourgeois class to exploit the proletariat and in the interests of the proletariat to overthrow the bourgeoisie. Note that this definition of interest is inbuilt to the definition of class: classes have objective interests. As the American Marxist Erik Olin Wright puts it, ‘class structure is…a terrain of social relations that determine objective material interests of actors, and class struggle is understood as the forms of social practices which attempt to realize those interests [and] class consciousness can be understood as the subjective processes that shape intentional choices with respect to those interests and struggles’ (see his Classes, 1985). Here it is possible to see the role assigned to the concept of class interests within a Marxist theory of class action.
However, there are many problems with this concept. In particular, it is more satisfactory to examine how far objective conditions actually exist, which are sufficiently similar for there to be the possibility of common interests emerging. What form those interests might take also becomes an empirical question. Hence, for example, David Lockwood has noted how workers form attachments to (rather than antagonisms towards) the existing form of capitalist society, through the activities of trade unions. John H. Goldthorpe, on the other hand, argues that whether or not individuals become conscious of possessing a class identity, and seek to pursue common class interests with others similarly placed, will depend in part upon the nature and degree of ‘demographic class formation’; that is, ‘the empirical question…of how far classes have in fact formed…in the sense of specific social collectivities…that are identifiable through the degree of continuity with which, in consequence of patterns of class mobility and immobility, their members are associated with particular sets of positions over time’ (see Social Mobility and Class Structure in Modern Britain, 1980). But neither Goldthorpe nor Lockwood assumes that there are objective class interests. Rather, each argues that the interests pursued by a class or its representatives are contingent upon a complex pattern of historical and political circumstances, and emerge out of social action rather than being an inherent condition of such action. In particular, people have to assume social identities as members of a class, before it becomes possible for sociologists to identify its interests.