Published by EH.NET (November 2006)

Harro Maas, William Stanley Jevons and the Making of Modern Economics. New York: Cambridge University Press, 2005. xxii + 330 pp. $75 (cloth), ISBN: 0-521-82712-4.

Reviewed for EH.NET by Michael V. White, Department of Economics, Monash University.

In early November 1871 an unsigned obituary of Charles Babbage was published by the science journal Nature. It was a heart-felt piece of writing, the tone set by an opening observation that “to the majority of people he was little known except as an irritable and eccentric person, possessed by the strange idea of a calculating machine, which he failed to carry to completion.” Any “deficiencies in his character,” however, “arose … from excess of resolution … He sowed ideas, the fruit of which have been reaped by men less able but of more thrifty habits.” It was thus the tragedy of Babbage that only “those who have carefully studied a number of his writings can adequately conceive the nobility of his nature and the depth of his genius.” The work that placed Babbage “among the few greatest men who can create new methods or reform whole branches of knowledge” included early mathematical papers and the `calculating machine’ project, consisting of the Difference and Analytical engines. The latter was particularly remarkable in that it was projected “to be little less than the mind of a mathematician embodied in metallic wheels and laws. It was to be capable of any analytical operation, for instance solving equations and tabulating the most complicated formulae.” No less important was Babbage’s work in political economy. The Economy of Manufactures (1831) was “incomparably excellent” and “impossible to overpraise.” Noting Babbage’s role in the formation of the London Statistical Society, it was also argued that his analysis of the Clearing House (1856) “was probably the earliest paper in which complicated statistical fluctuations were carefully analysed.” If Babbage had “devoted his lofty powers to economic studies, the science of Political Economy would have stood by this time in something very different from its present pseudo-scientific form.”[1]

The obituarist was W. Stanley Jevons, whose own attempt to rework value and distribution theory in a scientific form had just rolled off the printing press as The Theory of Political Economy (TPE). Given Jevons’ marked tendency to depression, it might be wondered whether anxiety over the possible reception of TPE marked the obituary, particularly the evocative discussion of instruments for the Analytical Engine which he had seen when visiting Babbage:

Before 1851 he appears to have despaired of its completion, but his workshops were never wholly closed. It was his pleasure to lead any friend or visitor through these rooms and explain their contents. No more strange or melancholy sight could well be seen. Around these rooms in Dorset Street were the ruins of a life time of the most severe and ingenious mental labours perhaps ever exerted by man. The drawings of the machine were alone a wonderful result of skill and industry; cabinets full of tools, pieces of mechanism, and various contrivances for facilitating exact workmanship, were on every side, now lying useless.

I can guess that, if the attribution to Jevons had been well known before now, the obituary would have had a prominent place in William Stanley Jevons and the Making of Modern Economics by Harro Maas from the University of Amsterdam. This stimulating and innovative book argues that Jevons’ `theoretical’ and `statistical’ publications in political economy, often treated as analytically quite separate, were actually closely linked. They were underpinned by a mechanical representation of the human mind that was symbolized by Jevons’ own logical machine. Although Jevons paid homage to Babbage in that regard, Maas emphasizes how Jevons’ machine mimicked logical inference rather than numerical calculation. If, as the obituary noted, Babbage’s work appeared to be “highly fragmentary,” the same could be said today about Jevons’ oeuvre and one great merit of Maas’ analysis is to show how a number of linkages can be made to help explain the formation of Jevons’ political economy. Having immersed himself in the primary and secondary literature from a number of what are, today, quite separate disciplines, Maas combines detailed discussion of the analytical content and context of Jevons’ experimental machine work with a nice eye for evocative contrasts.

It should be noted that Maas does not provide a detailed overall account of Jevons’ political economy. There is, for example, no analysis of much of the arguments, the structure and objectives of TPE. Maas focuses, instead, on particular features of Jevons’ work such as the marginalist theory of behavior and the key characteristics of the statistical studies, such as the use of graphs and the construction of index numbers. The reason for that focus is the book’s central argument that Jevons’ principal and substantive analytical break with economists such as J.S. Mill and J.E. Cairnes lay in his “methods [of research] and goals of explanation” (p. 25). He followed and contributed to a British “style of reasoning” which, by the mid-nineteenth century, had blurred the distinction between mind and matter to represent the mind and behavior in mechanical terms. This dissolved the distinction between the `moral’ and the `natural’ sciences so that the methods of the latter could be used to rework political economy.

The methodological break had two interrelated components. The first was a representation of mind and behavior which drew on a number of resources, such as the formalization of logic, undertaken by Boole and De Morgan, which made logic “the embodiment of rationality par excellence” (p. 285). Jevons contributed to that literature, which Maas neatly links to his discussion of Jevons’ logical machine. Also important were developments in engineering mechanics, where human labor was analyzed as a `force’ and hence discussed in the same terms as work performed by inanimate machines. (Babbage’s Economy of Manufactures was used in that context). The decisive contribution, however, came from the new discourse of physiological psychology which, via Richard Jennings’ Natural Elements of Political Economy (1855), enabled the representation of behavior in a functional form. Jevons was then able to depict equilibrium conditions in production and exchange via the metaphor of a balance of pleasure and pain.

Maas clearly explains how Jevons’ use of the balance was based on his training in chemistry and work as an assayer while in Australia (1854-59). A focus on Jevons’ practice is also a feature of the second component of Jevons’ methodological break that Maas identifies. This was to provide a statistical basis for political economy by using a number of experimental devices from the natural sciences, once again underpinned by the use of mechanical analogies. Here, Maas considers Jevons’ well known statistical work on commercial fluctuations (business cycles), as well as his attempts to `verify’ the behavioral theory in TPE and his use of the balance metaphor to construct price indexes. One of the most innovative features of the book is the use of Jevons’ (Australian) experiments in simulating cloud formations to identify his more general procedures. Maas argues that, for Jevons, the objective was to produce natural laws of phenomena, expressed, if possible, in a “rational formula” by mathematics. That did not, however, involve fitting graphs and formulae to the “data,” that is, the actual empirical observations which were contaminated by errors. Instead, the formula identified the “phenomena” of causal connection between variable and variant postulated by the law. Suitably manipulated in the form of averages, the data then provided evidence for the existence of the phenomena. The analysis here is very illuminating. It moves the discussion well beyond what can now be seen as vague references to Jevons `testing’ his theories and helps to explain the key role that Jevons gave to metaphors in his Principles of Science (1874). Moreover, it enables Maas to show how Jevons constructed the evidence for his arguments and why his approach could result in “dogmatism.” although Maas insists that the latter had “fruitful” effects in “many cases” (p. 235). (Commentators who have identified Jevons’ work with a `fallibilist’ empiricist epistemology might become apoplectic at that point.)

It is now becoming something of a commonplace to argue that Jevons’ training, work and publications in the `natural’ sciences were crucial for the formation of his political economy. Where Maas breaks new ground is in his detailed discussion of Jevons’ experimental machine work, carefully explicating its content, context and relevance. Being familiar with the primary Jevonian sources that Maas utilizes, I very much admire the ways he has placed Jevons’ work in a perspective from which I learned a great deal.

There are, however, some difficulties. At times, the treatment of Mill and Cairnes descends into caricature, such as the claim that they “held statistics in disdain” (p. 210). This can lead to artificial divisions, such as the suggestion that Jevons’ methodology dissolved Mill’s distinction between a science and an art (p. 233), whereas Jevons actually used that distinction. I was also unhappy with the rather careless discussion of the characteristics of equilibrium in TPE (pp. 271-76). Apart from such specific points, a more general matter should be raised about the claim that Jevons’ most important analytical break lay in his `method.’ This has the unfortunate effect of making a distinction between `method’ and `content.’ Although the analysis of Jevons’ experimental practice undermines the distinction, it does play a role at some points which can be illustrated with TPE. As was noted above, Maas provides no detailed discussion of the contents of TPE, so the reader is given no means to assess the extent and significance of the theoretical break(s) that Jevons made with his predecessors. I have no doubt about the relevance of Jevons’ `method’ as Maas describes it. But the absence of any discussion of most of the contents of TPE leaves the claim about the core of the break significantly underdetermined.

A distinction between form and content is also evident in the treatment of mathematics which, for Jevons, included geometry as well as the calculus. Both components are critical for understanding and assessing the arguments in TPE. It is surprising, however, that while Maas often mentions mathematics, he pays little specific attention to its role(s) in TPE and the status it was accorded by Jevons. This exclusion, in effect, of mathematics from the domain of Jevons’ method has two results. The first is that no attention is paid to the theoretical effects of the calculus in TPE. I would suggest, however, that among those effects were a number of marked analytical breaks. It is unclear why any privilege should be granted to Maas’ `method’ in gauging their relative importance. The second result is that there is no substantive discussion of the epistemological status Jevons accorded mathematics. Linking his argument with claims that Jevons’ procedures foreshadowed the later `hypothetico-deductive method,’ Maas claims that, for Jevons, “all science is hypothetical.” So he did not treat the `laws’ of marginal utility as if they had “introspective certainty,” but rather as “hypotheses in need of verification” (p. 286). If this is difficult to reconcile with the discussion of Jevons’ experimental `dogmatism’ that was referred to above, Jevons was very clear that the utility theory was “true,” precisely because of its mathematical format and regardless of any particular statistical validity. I wish that Maas had paid the careful attention to Jevons’ mathematics that he exhibits in his discussion of those matters which are considered in this remarkable book.


1. “Charles Babbage. Died the 20th of October, 1871,” Nature 9 November 1871, pp. 28-29. Jevons was identified as the obituarist a century later [Nature, 5 November 1971, p. 2], an attribution that only recently came to my attention.

Michael White has published extensively on nineteenth-century political economy with particular reference to the work of W.S. Jevons.