Only a historical view of the working class and of the theory of Marxism, in their mutual interrelations, can produce a theory of class consciousness. In the middle of the nineteenth century, Marx and Engels, working on various fields of learning, as well as analysing the experience of the struggle of the working class to that date, elaborated their theory of socialism. The theory is henceforth the essential component of the process by which the working class becomes a class 'for itself'. As a theory, it had first to penetrate beneath the day-to-day phenomenal form of capitalist society to the social relations of production. It demonstrated that production under capitalism continues, and society develops, not through any conscious plan, but through the drive to produce surplus value, consequent upon the reduction of labour-power to a commodity, to units of 'abstract labour'. This is the essence of the worker's exploitation, rather than the fact, say, that he does not own the cars he produces. What he produces is essentially surplus value, the augmentation of that same capital which oppresses him.
