The Concept of an Agricultural Surplus, from Petty to Smith

Everyone has to eat, so those who produce food must produce enough to feed themselves and to feed all those who do not produce their own food. Once stated. this is trivially obvious but, I will argue, making that simple relation between agriculture and the rest of the economy explicit and, at least in principle, quantifiable played a significant role in the development of economic thinking in the seventeenth and eighteenth centuries. This paper will focus on a very specific way of posing the question. Many of the most important economic writers of the period (Petty, Cantillon, Hutcheson, Hume, Steuart, Mirabeau, Smith and others) used arguments of the form: x men can feed y, where y > x. A series of questions naturally follow. Will the surplus be produced at all? How is it transferred to those who consume it? What are the 'superfluous hands' (in Hume’s terms) to do? It is impossible to pose these questions without thinking about the economy as a whole, and the way different sectors hang together. The common thread that runs through eighteenth-century discussions of surplus is a concern with the relation between industry and agriculture, and the potential for development arising from their interplay. There is, however, a clear discontinuity between the eighteenth-century view of agricultural surplus discussed here and the later tradition which links a concept of surplus to income distribution and pricing. Writers before Smith did not generally conceptualize income distribution in terms of the division of a defined total income between different functional shares, nor was there any consistent tradition linking income shares to the concept of an agricultural surplus as discussed here.