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The Labor Theory of Value and Surplus Value

2 March, 2015 - 12:11

In The Wealth of Nations, Adam Smith proposed the idea of the labor theory of value, which states that the relative values of different goods are ultimately determined by the relative amounts of labor used in their production. This idea was widely accepted at the time Marx was writing. Economists recognized the roles of demand and supply but argued that these would affect prices only in the short run. In the long run, it was labor that determined value.

Marx attached normative implications to the ideas of the labor theory of value. Not only was labor the ultimate determinant of value, it was the only legitimate determinant of value. The price of a good in Marx’s system equaled the sum of the labor and capital costs of its production, plus profit to the capitalist. Marx argued that capital costs were determined by the amount of labor used to produce the capital, so the price of a good equaled a return to labor plus profit. Marx defined profit as surplus value, the difference between the price of a good or service and the labor cost of producing it. Marx insisted that surplus value was unjustified and represented exploitation of workers.

Marx accepted another piece of conventional economic wisdom of the nineteenth century, the concept of subsistence wages. This idea held that wages would, in the long run, tend toward their subsistence level, a level just sufficient to keep workers alive. Any increase in wages above their subsistence level would simply attract more workers—or induce an increase in population, forcing wages back down. Marx suggested that unemployed workers were important in this process; they represented a surplus of labor that acted to push wages down.