Mill and Marx are widely recognized as the last of the classical political economists. While Marxism has since gone its own way, the liberal utilitarianism of Mill (1846) was refashioned from the 1870s onwards as the ‘neo-classical’ paradigm, which still defines economics today. The core of this paradigm, the notion of diminishing marginal utility, was independently pioneered by William Jevons in Manchester, Carl Menger in Vienna and Léon Walras in Lausanne during 1871-1874. They each located economic value in individuals conceived of as maximizing their utility, thus making a revolutionary break with the macro-sociological concerns of the classical economists (Hutchinson 1978). The new school achieved a synthesis in Alfred Marshall’s Principles of Economics (1890), a name that rhymes with mathematics and physics (Mirowski 1989). Following Edgworth’s example in Mathematical Psychics (1881), economists began to rely more on numerate methods, but to nothing like the same degree as today. Marshall’s neo-classical economics was challenged by an Austrian version and, during the Great Depression, by the even more contrary paradigm of his student, J. M. Keynes. In the United States the institutional economists, led by Veblen (1904) and Commons (1934), promoted a more explicitly political version of economic science. They were more than a match for the neo-classical economists there in the interwar period (Yonay 1998). The modern notion of ‘the economy’, along with Franklin Roosevelt’s New Deal, was a product of this era of general crisis (Mitchell 1998).