What a Difference a Sum Makes : Agony and Ecstasy in the Rationalization of Demand

Most historical discussions of Arrow-Debreu general equilibrium theory discuss the negative impact of the so-called Sonnenschein-Mantel-Debreu (SMD) results on aggregate excess demand functions. This paper argues that the SMD results were a natural extension of the integrability literature of the period 1959-71 - something that has not been recognized in the historical literature - and considers some of the implications of this for the history of modern economic thought