Mill's fourth fundamental proposition on capital: a paradox explained

John Stuart Mill's Fourth Fundamental Proposition Respecting Capital, fi rst stated in 1848, had become an enigma well before the nineteenth century had come to an end. Never challenged in Mill's own lifetime and described in 1876 as "the best test of a sound economist," it has become a statement that not only fails to fi nd others in agreement, but fails even to fi nd an internally consistent interpretation that would make clear why Mill found it of such fundamental importance. Yet the fourth proposition should be easily understood as a continuation of the general glut debate. Economists led by Malthus had argued that demand defi ciency was the cause of recession and a body of unproductive consumers was needed to raise the level of demand if everyone who wished to work was to fi nd employment. Mill's answer was that to buy goods and services would not increase employment, or, in Mill's own words, "demand for commodities is not demand for labour."