3) Chapters 4-8: Surplus-value¶
Core Argument¶
In these pivotal chapters, Marx sets out to uncover the true origin of profit, beginning with a fundamental question: what is capital? Money becomes capital only when it is employed in the circuit M-C-M, buying in order to sell dearer, a process whose sole aim is the endless expansion of exchange-value, or surplus-value. This stands in stark contrast to the simple circuit C-M-C, where money is merely a medium to obtain use-values. Profit cannot arise from the sphere of circulation itself, Marx argues. If equivalents are exchanged, no surplus-value results; if non-equivalents are exchanged, one party’s gain is merely another’s loss. The capitalist class as a whole cannot enrich itself by defrauding itself.
The secret of surplus-value lies in a special commodity the capitalist finds on the market: labour-power, the capacity to work. The worker sells this capacity, not their actual labour, and this social relation is historically specific, requiring a class with no other means of survival. The value of labour-power, like any other commodity, is determined by the labour-time necessary for its production and reproduction, that is, the value of the means of subsistence required to maintain the worker and the working class as a whole. This is a social average, not an individual case, and it contains a historical and moral element, varying by country and epoch according to the level of civilisation and the class struggle. The social wage is not bare subsistence but the ‘going rate’, shaped by workers’ struggles and the needs of modern capitalism.
Surplus-value arises in production, not exchange. The labour process is a unity of purposeful activity on nature (the labour process) and the valorisation process. Marx distinguishes productive consumption, which creates new use-values, from unproductive consumption. Surplus-value is unpaid labour: the worker works beyond the time needed to reproduce the value of their labour-power. Constant capital (means of production) merely transfers its value unchanged, while variable capital (labour-power) alone creates new value and surplus-value. Competition drives capitalists to replace living labour with machinery, but only living labour creates surplus-value. Automation reduces the mass of surplus-value and destroys the workers’ purchasing power, generating crises of overproduction.