This paper argues, in opposition to P. A. Samuelson, that Piero Sraffa's 1920s contribution to the "cost controversy" pleaded for abandoning the Marshallian approach in favor of a simultaneous determination of all prices. His critique distinguished those Marshallian supply functions lacking rigorous foundations from those based on sound arguments, pointing out the validity of some nonconstant cases and focusing on the analysis of the conditions that make the ceteris paribus assumption legitimate when the effects of variable returns cannot be neglected, rather than on the negligible size of these returns or on "pure rhetoric," as Samuelson suggests. Sraffa's critique was soon misinterpreted along lines similar to those followed by Samuelson. Copyright 1991 by Royal Economic Society.
