Marx's analysis continually centers on how the relationships between men are shaped by their relative positions in regard to the means of production, that is, by their differential access to scarce resources and scarce power. He notes that unequal access need not at all times and under all conditions lead to active class struggle. But he considered it axiomatic that the potential for class conflict is inherent in every differentiated society, since such a society systematically generates conflicts of interest between persons and groups differentially located within the social structure, and, more particularly, in relation to the means of production. Marx was concerned with the ways in which specific positions in the social structure tended to shape the social experiences of their incumbents and to predispose them to actions oriented to improve their collective fate.

Yet class interests in Marxian sociology are not given ab initio. They develop through the exposure of people occupying particular social positions to particular social circumstances. Thus, in early industrial enterprises, competition divides the personal interests of "a crowd of people who are unknown to each other. . . But the maintenance of their wages, this common interest which they have against their employer, brings them together." "The separate individuals form a class only in so far as they have to carry on a common battle against another class; otherwise they are on hostile terms with each other as competitors."

Class interests are fundamentally different from, and cannot be derived from, the individual interests imputed by the utilitarian school and classical British political economy. Potential common interests of members of a particular stratum derive from the location of that stratum within particular social structures and productive relations. But potentiality is transformed into actuality, Klasse en sich (class in itself) into Klasse fuer sich (class for itself), only when individuals occupying similar positions become involved in common struggles; a network of communication develops, and they thereby become conscious of their common fate. It is then that individuals become part of a cohesive class that consciously articulates their common interests. As Carlyle once put it, "Great is the combined voice of men." Although an aggregate of people may occupy similar positions in the process of production and their lives may have objectively similar determinants, they become a class as a self-conscious and history- making body only if they become aware of the similarity of their interests through their conflicts with opposing classes.

To Marx, the basis upon which stratification systems rest is the relation of aggregates of men to the means of production. The major modern classes are "the owners merely of labor-power, owners of capital, and landowners, whose respective sources of income are wages, profit and ground-rent." Classes are aggregates of persons who perform the same function in the organization of production. Yet self-conscious classes, as distinct from aggregates of people sharing a common fate, need for their emergence a number of conditions among which are a network of communication, the concentration of masses of people, a common enemy, and some form of organization. Self-conscious classes arise only if and when there exists a convergence of what Max Weber later called "ideal" and "material" interests, that is, the combination of economic and political demands with moral and ideological quests.

The same mode of reasoning that led Marx to assert that the working class was bound to develop class consciousness once the appropriate conditions were present also led him to contend that the bourgeoisie, because of the inherent competitive relations between capitalist producers, was incapable of developing an overall consciousness of its collective interests.

The classical economists picture the economic system of a market economy as one in which each man, working in his own interest and solely concerned with the maximization of his own gains, nevertheless contributes to the interests and the harmony of the whole. Differing sharply, Marx contended, as Raymond Aron has put it, that "each man, working in his own interest, contributes both to the necessary functioning and to the final destruction of the regime."

In contrast to the utilitarians who conceive of self-interest as a regulator of a harmonious society, Marx sees individual self-interest among capitalists as destructive of their class interest in general, and as leading to the ultimate self-destruction of capitalism. The very fact that each capitalist acts rationally in his own self-interest leads to ever deepening economic crises and hence to the destruction of the interests common to all.

The conditions of work and the roles of workers dispose them to solidarity and to overcoming their initial competitiveness in favor of combined action for their collective class interests. Capitalists, however, being constrained by competition on the market, are in a structural positions that does not allow them to arrive at a consistent assertion of common interests. The market and the competitive mode of production that is characteristic of capitalism tend to separate individual producers. Marx granted that capitalists also found it possible to transcend their immediate self-interests, but he thought this possible primarily in the political and ideological spheres rather than in the economic. Capitalists, divided by the economic competition among themselves, evolved a justifying ideology and a political system of domination that served their collective interests. "The State is the form in which the individuals of a ruling class assert their common interests." "The ideas of the ruling class are. . .the ruling ideas." Political power and ideology thus seem to serve the same functions for capitalists that class consciousness serves for the working class. But the symmetry is only apparent. To Marx, the economic sphere was always the finally decisive realm within which the bourgeoisie was always the victim of the competitiveness inherent in its mode of economic existence. It can evolve a consciousness, but it is always a "false consciousness," that is, a consciousness that does not transcend its being rooted in an economically competitive mode of production. Hence neither the bourgeoisie as a class, nor the bourgeois state, nor the bourgeois ideology can serve truly to transcend the self-interest enjoined by the bourgeoisie. The bourgeois reign is doomed when economic conditions are ripe and when a working class united by solidarity, aware of its common interests and energized by an appropriate system of ideas, confronts its disunited antagonists. Once workers became aware that they are alienated from the process of production, the dusk of the capitalist era has set in.

From Coser, 1977:48-50