Theories of value and ultimate standards in Sraffa's notes of summer 1927

The group of manuscripts titled 'Notes/London, Summer 1927/Physical real costs, etc.' (D3/12/3) is recognized as extremely important for the reconstruction of the evolution of Sraffa's thought after the articles published in 1925 and 1926. The present paper is aimed at analysing some relevant passages and ideas expressed by Sraffa in those manuscripts. We shall focus, in particular, on Sraffa's arguments about the existence of two different theories of value, with different aims: one aimed at determining the value of large aggregates of commodities, such as the national product, the necessary consumption and the social surplus, and the other aimed at determining the price of a single commodity, separately from the others. In Sraffa's view, if the values of many commodities are to be determined simultaneously, then the theory cannot dispense with an ultimate standard of value. That idea led Sraffa toward the conception (or the rediscovery) of the physical real cost.