Joan Robinson as a teacher

Sraffa's construct, the standard commodity, responds to Ricardo's search for an ‘invariable’ measure of value, since it is a measurement unit invariant to changes in distribution. But Sraffa suggests that there is no ‘counterpart,’ no analogous search or needed construct, for the ‘problem’ of ‘difference’ as distinct from change (‘why two commodities produced by the same quantities of labour are not of the same exchangeable value’). Difference in this sense is crucial to Marx, who distinguishes value and surplus-value from capitalist price and profit in part in order to theorize differences as systematic value transfers. In that effort, Marx repeatedly poses commodities and capitals as ‘aliquot parts’ of the whole, so that profit is a redistributed share of aggregate surplus-value. This paper shows that, when Marx's aliquot part imagery is formalized, the resulting hypothetical system represents a meaningful ‘counterpart,’ a construct with a function in Marx's analysis of difference comparable to that of Sraffa's standard commodity in analyzing distributional change. A Marxian ‘standard system’ posing each commodity as an aliquot part of the social capital (a) defines the needed labor-time unit of social account by homogenizing heterogeneous concrete labors as socially average (‘abstract’) labor while simultaneously (b) allowing the derivation of exchange-value (e.g., capitalist production price) on that scale via summation of directly and indirectly embodied labor. Indeed, Marx's approach to production prices as resulting from an inter-industry redistribution of aggregate surplus-value is shown to be algebraically identical to the calculation of labor-embodied under ‘aliquot part’ production conditions.