Sraffa, the ‘marginal’ method and change

In the preface to Production of Commodities by Means of Commodities Sraffa emphasizes that his book does not make use of the method of marginal magnitudes. This paper, based mainly on the notes that Sraffa wrote over nearly forty years, shows that Sraffa’s rejection of this method, which he calls 'marginism', is not due to some aprioristic methodological preconception, but is part of his views on the appropriate method to deal with actual economic phenomena. Indeed, 'marginism' deals with changes, which occur in time, as if changes were always amenable to the difference between two situations which exist side by side. But change, outside the world of mechanics and in that of social phenomena, does not follow predetermined paths which are known a priori. Therefore, the marginist method appears to Sraffa as constraining economic analysis within particularly rigid patterns inadequate for the study of economics. In the light of this criticism, the paper sheds new light on Sraffa’s attention, which he never relented, for some passages of Marshall’s Principles.