Concluding Remarks
In this chapter we scrutinize the metaphor of “photograph” and the related one of “man from the moon” in Sraffa’s papers leading up to his 1960 book, in his annotations in his books and in his correspondence.
We show that the main purpose of the first metaphor was to emphasize the most important distinguishing feature of the classical approach to the theory of value and distribution as compared with the marginalist one. While the former analyzes a given system of production with regard to its properties concerning income distribution and relative prices, the latter confronts the given system with an imagined adjacent system, as is reflected in concepts such as marginal productivity and marginal cost. The metaphor of the photograph was meant to express the focus on a given system and the absence of changes in outputs and factor input proportions. The metaphor of the man from the moon was meant to express the data from which the classical theory of value and distribution starts its reasoning, which differ markedly from the marginalist data: given quantities of commodities as inputs (including means of subsistence of workers), on the one hand, and outputs, on the other. “Natural prices” or “prices of production” are fully determined in terms of these givens. In this context it is perhaps interesting to point out that up until the final stage of preparing his manuscript for print, Sraffa tinkered with the idea of giving the book the title “Production of Commodities by Commodities.” This is fully in accordance with the man from the moon metaphor and expresses well the objectivist nature of the analysis. We touch upon the relationship between Sraffa’s analysis and “a purely natural science point of view” by commenting on a statement in a book by Pantaleoni, Sraffa had annotated. Finally, we show that Roncaglia’s use of the metaphor of photograph is in the spirit Sraffa had intended.Acknowledgments
We are grateful to Christian Gehrke, Bertram Schefold and Alex Thomas for valuable comments on an earlier draft of this paper.