Joan Robinson and the three cambridge revolutions

Joan Robinson's association with three Cambridge 'revolutions'—imperfect competition, effective demand and capital theory—is examined in the context of her personal and intellectual partnership with Richard Kahn, John Maynard Keynes and Piero Sraffa. Initially, imperfect competition appeared to have successfully extended marginal analysis to all market forms. It also allowed Richard Kahn and Joan Robinson to persuade Keynes to present the main argument of The General Theory in terms of aggregate demand and aggregate supply. By the early 1950s, however, Joan Robinson had rejected the Marshallian methodology and had become a strenuous censor of neoclassical theory. In this paper the origin of her critique is traced to her reading of Sraffa's Introduction to Ricardo's Principles.