Part Six — Wages Chapters 19–22. The wage-form as the mystification of the value of labour-power, time-wages, piece-wages, and national differences in wages.

Part Six returns to the wage, the form in which the whole relation of exploitation presents itself on the surface of society — and conceals itself there. Chapter 19 is the conceptual heart: it shows that "the value of labour" is an irrational expression, that what is actually sold is labour-power, and that the wage-form systematically hides the division of the working day into paid and unpaid labour. Chapters 20 and 21 examine the two principal forms the wage takes, time-wages and piece-wages, and how each is used to intensify exploitation; Chapter 22 turns to national differences in wages. The Part is short, and its load lies almost entirely in Chapter 19, because the wage-form is the mystification on which "all the notions of justice held by both the worker and the capitalist" are built.

On the surface, the wage looks like the price of labour — so much money for so much labour, with a "value of labour" oscillating around a natural price. Marx shows the phrase is incoherent. Value is measured by labour-time, so "the value of labour" would mean the labour-time contained in a quantity of labour, an empty tautology; and labour has no independent existence to be sold before it is performed. What confronts the money-owner is not labour but the worker, and what is sold is labour-power.

Labour is the substance, and the immanent measure of value, but it has no value itself. In the expression ‘value of labour’, the concept of value is not only completely extinguished, but inverted, so that it becomes its contrary. It is an expression as imaginary as the value of the earth. These imaginary expressions arise, nevertheless, from the relations of production themselves. They are categories for the forms of appearance of essential relations.

Marx, Capital I, page 677.

Classical political economy, Marx argues, unconsciously replaced "the value of labour" with the value of labour-power without noticing it had done so — and so never grasped the result of its own analysis. The practical effect of the wage-form is the crucial thing: because the day's wage (the value of labour-power) is expressed as the price of the day's labour, the whole day appears to be paid for, and the unpaid surplus labour vanishes from view.

The wage-form thus extinguishes every trace of the division of the working day into necessary labour and surplus labour, into paid labour and unpaid labour. All labour appears as paid labour. Under the corvée system it is different. There the labour of the serf for himself, and his compulsory labour for the lord of the land, are demarcated very clearly both in space and time. In slave labour, even the part of the working day in which the slave is only replacing the value of his own means of subsistence, in which he therefore actually works for himself alone, appears as labour for his master. All his labour appears as unpaid labour. In wage-labour, on the contrary, even surplus labour, or unpaid labour, appears as paid.

Marx, Capital I, page 680.

On this inversion the entire ideological surface of capitalism rests. The wage-form is not a mistake to be corrected by clearer thinking; it is a real form of appearance that shows the eye the opposite of the underlying relation.

All the notions of justice held by both the worker and the capitalist, all the mystifications of the capitalist mode of production, all capitalism’s illusions about freedom, all the apologetic tricks of vulgar economics, have as their basis the form of appearance discussed above, which makes the actual relation invisible, and indeed presents to the eye the precise opposite of that relation.

Marx, Capital I, page 680.

The value of labour-power, converted into the wage, can be reckoned by time. Marx derives the "price of labour" as the day's value of labour-power divided by the number of hours in the average day, and shows how the capitalist exploits this: by lengthening the day while the daily wage stays fixed, the price of the hour falls; by offering work by the hour without guaranteeing a full day, the capitalist offloads the risk of underemployment onto the worker while still commanding overwork when it suits him. Time-wages thus become an instrument for depressing the hourly price of labour below the value of labour-power and for extending or contracting the day at will.

Piece-wages are only a converted form of time-wages — the piece-rate is the time-wage divided by the number of pieces an average worker produces in the time. But the converted form has powerful effects. It makes the wage appear to measure the worker's own product, supplies capital with a self-enforcing measure of intensity and quality (the worker polices himself, wasteful work costing him directly), fosters competition among workers, and lends the worker an illusory sense of independence even as it deepens self-exploitation. For these reasons Marx names it the wage-form that suits capital best.

From what has been shown so far, it is apparent that the piece-wage is the form of wage most appropriate to the capitalist mode of production.

Marx, Capital I, pages 697–698.

The final chapter compares wages across nations, warning that the many determinants of the value of labour-power — the historically formed standard of subsistence, the cost of training, the role of women's and children's labour, the productivity and intensity of labour — must all be weighed before national wage-rates can be compared. Marx shows that higher nominal money-wages in the more developed countries can coexist with a lower price of labour relative to the product, because more intense and more productive labour there yields more value in the same time. The apparent paradox — that the better-paid worker may be the more exploited — is a direct consequence of the analysis of relative surplus-value, and it closes the Part by returning wages to the framework Parts Three through Five built.