In the Lobby of the Energy Hotel: Jevons's Formulation of the Postclassical "Economic Problem"

In the closing chapter of the first edition of his Theory of Political Economy (TPE), William Stanley Jevons (1871, 254) argued that within the terms of his marginalist theory of value and distribution, the "great problem of Economy" could be summarized as follows: "Given, a certain population, with various needs and powers of production, in possession of certain lands and other sources of material: required, the mode of employing their labour so as to maximise the utility of the produce."¹ Historians of economics have noted that this summary marked an analytical break with the work of his predecessors, such as John Stuart Mill and John Elliott Cairnes, in two ways. The first was to remove the Malthusian "doctrine of population" from the domain of a theory of value and distribution. Although Jevons did not "in the least doubt its truth and vast importance," the doctrine was "conspicuously absent" from TPE because "it forms no part of the direct problem of Economy" (255). Population size, like the quantity of natural resources and capital, was simply a parameter because "we originally start with labour as the first element of production, and aim at the most economical employment of that labour" (255).² The second aspect of the break, it has been suggested, was that "for the first time, economics truly became the science that studies the relation between given ends and given scarce means that have alternative uses for the achievement of those ends" (Blaug 1997, 278; see also Winch 1972, 328, 335). The summary is thus depicted as inaugurating the analytical framework of marginalism or postclassical economics³ that Lionel Robbins ([1935] 1949, 2, 16) subsequently characterized as the science of "Modern Economics." Given the historical importance of Jevons's summary, the principal purpose of this article is to explain how it came to be produced and its significance for understanding the analysis in TPE. It will be shown that the summary served as an index of Jevons's attempts to situate political economy in terms of contemporary debates in physics (or "natural philosophy") regarding the conservation of force or, subsequently, energy. Since the resources for the formulation of the summary became available to him when writing the two editions of The Coal Question (CQ) that were published during his lifetime (Jevons [1865] 1866), this article shows how Jevons reworked his first version of the marginalist theory, the "Brief Account" of 1862 ([1862] 1866), to produce TPE in 1871.⁴

The analysis in this article has a thematic congruity with Philip Mirowski's argument in More Heat Than Light (1989, chaps. 5 and 6) that the genesis of postclassical economic theory can be found in the conservation-of-energy framework after the mid-nineteenth century. Indeed, Jevons's summary of his program neatly combines variants of the "conservation" and "variational" principles that Mirowski uses to structure his account.⁵ It is, however, difficult to register this from the discussion in More Heat for two reasons. The first is a matter of omission. Mirowski makes no mention of Jevons's summary and hence the terms in which he referred to the conservation and variational principles. The second is a problem of commission. Mirowski (1989, 222–41) argues that Jevons was a poor mathematician and had a deficient understanding of energy physics. Hence there was little in the formal analysis of TPE that can be compared with the "canonical neoclassical model" that Mirowski uses to show the "full implications," for postclassical economic theory, of the energy framework. If that model has been criticized as a Whig construction (Wise 1992), it is now clear that in the mid-1860s, which is the relevant period for assessing Jevons's "conversion" to the energy framework, there was no accepted formulation of the framework that he could appropriate. Physicists and others were deeply divided as...