Labor theory of value and exploitation: is the LTV defensible against marginalist economics and analytical-Marxist reformulations?

Karl Marx, answered from the texts and cited to the page.

The position in brief

The labor theory of value is the inner logic of capital, not a price-theory and not a moral postulate.1 Socially necessary labor-time is the substance of value because human labor is the source of new value in production; the commodity is a crystallization of social labor that appears as a thing because labor under capital takes the form of abstract labor producing exchange-value.23

Surplus-value is the value produced by labor beyond what is required to reproduce labor-power as a commodity — the difference between the value labor creates in production and the value of labor-power as a commodity bought at its value. This is exploitation, structurally and exactly: the systematic appropriation of unpaid labor. Whether wages are "fairly" paid by bourgeois standards is irrelevant; the structural extraction is the inner logic of the wage-relation, not a deviation from a fair baseline.4

Sources

  1. He receives, then, a certain sum of money in which say ten hours ' labour are material - ised, if he works 12 hours for the capitalist. These wages are converted into means of subsistence. These means of subsistence are all commodities. Assume that the price of these commodities is equal to their value.
    Theories of Surplus Value Vol I, p. 109
  2. The value of these commodities is deter - mined by the necessary labour-time contained in them. If there - fore the commodities are sold at their value, the labourer buys with one commodity, which is the product of twelve hours ' labour-time, another twelve hours ' labour-time in the form of another commodity, that is to say, twelve hours ' labour-time which is embodied in another use-value.
    Theories of Surplus Value Vol I, p. 71
  3. While labor which creates exchange value is realized in the equality of commodities as universal equivalents, labor as a productive activity with a useful purpose is realized in the endless variety of use-values created by it.
    A Contribution to the Critique of Political Economy
  4. It is every bit as important, for a correct understanding surplus-value, to conceive it as a mere congelation of surplus-labour-time, as nothing but materialised surplus-labour, as it is, for a pi'oper comprehension of value, to conceive it as a mere congelation of so many hours labour, as nothing but materialised labour.
    Capital Vol I, pp. 236–237

Where the argument is made

  • Capital Vol I, Chapter 1 (the commodity, use-value and exchange-value, socially necessary labor-time, the dual character of labor)
  • Chapter 6 (the buying and selling of labor-power)
  • Part III (the production of absolute surplus-value)
  • Part IV (the production of relative surplus-value)
  • Vol III, Part II (the transformation of values into prices of production — the 'transformation problem')
  • the trinity formula in Vol III, Part VII

How the argument was received

The most technically-attacked element of Capital. Böhm-Bawerk raised the foundational marginalist objection in 1896. The transformation problem (how values become prices of production under uneven organic compositions of capital) has generated a century of mathematical literature. Sraffa's Production of Commodities (1960) provided a price-theory framework that Steedman (1977) used to argue Marx's LTV is redundant. John Roemer's analytical-Marxist project (1982 onward) attempts to ground exploitation theory without the LTV. The defense lines are Morishima's mathematical reconstruction, Harvey's contemporary engagement, and the structural-not-quantitative reading: the LTV is about the source of surplus, not a daily-pricing theory.