"The only way is to go through history in reverse, i.e.: from the present state of economics; how that came to be reached, showing the difference and superiority of the old theories. Then expound the theory. If a chronological order if followed—Petty, the Physiocrats, Ricardo, Marx, Jevons, Marshall—then it is necessary to give as a premise a statement of my own theory in order to explain what we are driving at; which means first expounding all of the theory. And then there is the danger of ending up like Marx, who started publishing his Capital and later was unable to complete the History of Doctrines. And what is worse he was unable to make himself understood without the historical explanation. My plan is: first, treat the history, which is what is really essential; second, make myself understood, which requires me to proceed from the known to the unknown, from Marshall to Marx, from disutility to material cost."
Sraffa (D3/12/11), November 1927, quoted in Porta - “Piero Sraffa’s early views on classical political economy,” p. 1368. Porta comments:
Sraffa’s ambitions are very clear. The lectures that he has been appointed to deliver at Cambridge are to be made the occasion for a book in which the historico-analytic method is adopted for an eminently theoretical purpose. Marx—not, however, Marx-in-general but Marx-the-historian-of-analysis-manqué (manqué is the point!)—must provide guidance in both method and contents—as also the list of past authors indicates. Marshall, of course (i.e. the present) is, as Sraffa writes, the proper starting point.
I was reminded of this quote by Mike Konczal’s article about teaching economics ‘backwards’, though what he has in mind is much different.