The "slogans not used". Sraffa's manuscripts, the standard system and the theories of profit of Smith, Malthus and Böhm-Bawerk

The two ‘slogans’ written by Sraffa in a draft of the preface to his book can be seen as the synthesis of a wider reasoning that he outlines in some manuscripts composed in 1955-56. We rationalise this reasoning by three statements. By discussing these statements in depth, we try to shed new light on the meaning of Sraffa’s slogans. Specifically, we argue that the first slogan refers to a point mentioned in Sraffa’s manuscripts – namely, that the Standard system can be used to criticise the theories of profit of Smith, Malthus, and Böhm-Bawerk – while the second refers to the determination of the profit rate of the Standard system separately from prices.