Iron law of wages

The iron law of wages is a proposed law of economics that asserts that real wages always tend, in the long run, toward the minimum wage necessary to sustain the life of the worker. The theory was first named by Ferdinand Lassalle in the mid-nineteenth century. Karl Marx and Friedrich Engels attribute the doctrine to Lassalle (notably in Marx's 1875 Critique of the Gotha Programme), the idea to Thomas Malthus's An Essay on the Principle of Population, and the terminology to Goethe's "great, eternal iron laws" in Das Göttliche.

According to Alexander Gray,Ferdinand Lassalle "gets the credit of having invented" the phrase the "iron law of wages", as Lassalle wrote about "das eiserne und grausame Gesetz" (the iron and cruel law).

According to Lassalle, wages cannot fall below subsistence wage level because without subsistence, laborers will be unable to work. However, competition among laborers for employment will drive wages down to this minimal level. This follows from Malthus' demographic theory, according to which population rises when wages are above the "subsistence wage" and falls when wages are below subsistence. Assuming the demand for labor to be a given monotonically decreasing function of the real wage rate, the theory then predicted that, in the long-run equilibrium of the system, labor supply (i.e. population) will rise or fall to the number of workers needed at the subsistence wage.

The justification for this was that when wages are higher, the supply of labor will increase relative to demand, creating an excess supply and thus depressing market real wages; when wages are lower, labor supply will fall, increasing market real wages. This would create a dynamic convergence towards a subsistence-wage equilibrium with constant population.

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