At the HES meeting held at Grinnell, Iowa, June 2006, the following citation was read:
   
The 2006 Joseph J. Spengler Book Prize of the History of Economics Society is awarded to
Harro Maas of the University of Amsterdam for his monograph _William Stanley Jevons and
the Making of Modern Economics_, published by the Cambridge University Press in 2005.
  
This book is remarkable in at least three distinct ways.  First, it deals with the full
range of Jevons's varied intellectual interests, including for example his early studies
of cloud formation and his work on the theory and mechanization of logical reasoning.
Second, it demonstrates that Jevons's work in the diverse fields he chose to explore is
united by common methodological principles and a consistent vision of appropriate
scientific procedure.  Third, the broad intellectual context of nineteenth century thought
against which Jevons's work must be seen and evaluated is fully and carefully rendered.
Thus, the book is much more than a study of Jevons's economic thought, yet economics plays
a central role.  This is because the analysis of economic phenomena became in the
nineteenth century the arena in which were contested fundamental issues concerning the
mind-body distinction and the validity of intuition as a source of knowledge additional to
observation.  For Jevons (in opposition to John Stuart Mill) only observation counted.
Explanation of observed regularity was ideally obtained by proposing a coherent mechanical
analogue that accounted for this regularity in a parsimonious way.  Observational error
was of course to be expected, so that underlying functional relations could be observed
only probabilistically. Jevons did not imply that such an analogue represented absolute
truth, but it was all that could be attained by scientific observation and reasoning.
Such a methodological attitude pervaded his statistical analysis of economic time series.
Similarly, his famous analysis of the balancing of marginal disutility of labor against
the marginal utility of the product is to be regarded as analogous to the unconscious
physical balancing of a weigh scale, not something known directly by introspection or
necessarily governed by conscious calculation.  He looked to recent developments in
"psychophysiology" to provide evidence on the functional relationships involved here,
being influenced on this by the work of Richard Jennings
  
Jevons's mechanical analogues have affinity to the more recent concept of economic models
and it is perhaps here rather than in his use of marginal analysis per se that he is most
clearly a harbinger of developments in 20th century economics. Evidently there is much to
debate but Harro Maas's book will be essential reading for anyone interested in Jevons,
economic methodology, or the emergence of neoclassical economics.
   
Book Prize Committee:   
Steve Horwitz, Christina Marcuzzo, Joe Persky, John Whitaker (Chair)  
  
  
John K Whitaker