The role of language in Keynes’ General theory and Sraffa’s Production of commodities

John Maynard Keynes’ General Theory of Employment, Interest and Money, like Piero Sraffa’s Production of Commodities by Means of Commodities, were to a significant extent shaped by a reaction to the economic theory advanced by Alfred Marshall. Marshall distinguished direct effects from indirect effects, where the latter could be safely neglected as a second order of smalls, drawing on differential calculus. Keynes, in contrast, criticized the insistence on differential calculus, which presupposes strict independence between the various factors involved. Keynes suggests instead using ordinary language where, instead of manipulating what Keynes saw as pretentious and unhelpful symbols, we can keep at the back of our heads the interconnections between various aspects of reality. In so doing, however, Keynes retains much of the marginalist (Marshallian) terminology, in what is sometimes seen as a strategic approach aimed at best communicating with the established orthodoxy. Sraffa, in contrast, formulated a system of equations that takes into account the various interdependencies noted by Marshall and Keynes, while rejecting entirely the use of marginalist concepts. While Keynes employs mathematics without it limiting his narrative about the economy, for Sraffa, the mathematical structure of his equations shapes the structure of the narrative he constructs. However, Sraffa is also much careful regarding his use of mathematics, within a constructivist (rather than symbolic) approach that is combined with a consistent rejection of differential calculus (unlike Keynes, who employs it despite criticizing its excessive use). Here the use of language undertaken by Keynes and Sraffa will be compared, taking into account its connections to their views of the role of mathematics in economics, and how it helps them express their views of socio-economic reality.