------------ EH.NET BOOK REVIEW --------------  
Published by EH.NET (June 2006)  
  
Richard van den Berg, editor, _At the Origins of Mathematical   
Economics: The Economics of A. N. Isnard (1748-1803)_. New York:   
Routledge, 2005. xvii + 461 pp. $115 (cloth), ISBN: 0-415-30649-3.  
  
Reviewed for EH.NET by Theodore M. Porter, Department of History, UCLA.  
  
  
This volume consists primarily of selections from the works of the   
French engineer and economist A. N. Isnard. Almost unknown in his own   
time, Isnard acquired a modest reputation retrospectively as a   
pioneer of mathematical economics. He was admired especially by Leon   
Walras, and William Jaffe attached great importance to Isnard's   
_Traite des richesses_ as source for the mathematical framework of   
Walras's theory of general equilibrium. Van den Berg, a lecturer at   
Kingston University in the U.K., helps to situate Isnard in relation   
to the economic thought of his own time and place, in critical   
engagement with such authors as Turgot, Rousseau, and, above all,   
Quesnay. However, Van den Berg invokes the modern style of economics   
as the reason to look back to Isnard, who stands justified before   
history as an avatar of mathematical economics, a precursor.  
  
Isnard's best-known work is the _Traite des Richesses_ (_Treatise on   
Wealth_), printed in 1781 at the author's expense, and now rare. Van   
den Berg here exhumes Isnard's other economic writings, many of them   
virtually unknown in our day and perhaps even in his. We have in this   
book only a fraction of Isnard's writings; a complete edition would   
have run to several volumes. Anyone doing serious research on Isnard   
would have to consult the works in their entirety. Nevertheless, van   
den Berg has made a good choice, performing his most valuable service   
by bringing to the attention of economists and historians Isnard's   
lesser-known writings. These include the _Social Catechism_ (1784),   
which defends human dignity and responsibility against radicals such   
as La Mettrie and the Baron d'Holbach, while at the same time   
presenting economic motives as properly linked to moral behavior and   
to sociability. There are some policy pieces from the years of the   
French Revolution, including, in March of 1789, a defense of a   
"single tax" on net revenues of agriculture, industry, and commerce   
(and not alone, as the physiocrats recommended, on land), and another   
piece on taxation in 1791. Perhaps the most interesting is his   
"Reflections on the issue of the assignats" (1790), where he   
addresses in a general way the advantages and dangers of paper money,   
with clear reference to issues of immediate importance. Isnard   
rejected any simple quantity theory, as for example that any issuance   
of paper money leads inevitably to a proportionate inflation of the   
currency. He was especially concerned with questions of trust: the   
state should introduce assignats slowly and responsibly so that the   
public will not lose confidence in them. But cautious moderation was   
not the way of the Revolution, and Isnard's worst fears were soon   
realized.  
  
What does this book tell us about the sources and the character of   
Isnard's economic mathematics? Anglophone as well as francophone   
scholars now know that French engineering corps -- such as Ponts et   
Chauss�es (responsible for transportation networks) and Mines --   
cultivated, in the nineteenth century and beyond, a quantitative form   
of economics linked to the administrative and political challenges   
faced by these powerful state agencies. Several of these engineers,   
preeminently Jules Dupuit, pursued the economic aspect of these   
problems well beyond the demands of immediate practicality. Walras's   
links to this tradition are also of interest, since he studied as an   
external student (i.e. he was not destined for service in the state   
corps) in the School of Mines. However, he chose not to take up the   
characteristic problems of French engineering economics such as   
working out a basis for deciding what transportation projects were   
economically justified and establishing a rational basis for the   
tolls.  
  
I began with hopes that this volume might reveal interconnections   
between engineering and economic quantification from before the   
French Revolution. Van den Berg presents new research in the archives   
of the Corps des Ponts et Chauss�es, the Archives Nationales, and   
French regional archives in the Department of the Rhone to   
reconstruct the trajectory of Isnard's career as a Ponts engineer.   
But the excerpted writings, at least, do not address the economics of   
public works, and the titles of Isnard's engineering writings refer   
to arches and locks, with no indication that economics is at issue.   
Van den Berg is reticent on the connections, if any. He refers often   
to Isnard as "the engineer," seeming to imply that his profession was   
relevant for his economics. For example: "The engineer's views on   
taxation are a consistent development of the central notions of his   
economic theory" (p. 41); "The surprising _Cath�chisme social_ ...   
must be considered as developing parts of the engineer's 'science of   
man'" (p. 51). But no link is shown between his profession and his   
economic beliefs or style.  
  
Van den Berg may well suppose that engineers can be expected to rely   
on mathematics in a way that literary economists would not. However,   
he does not attend to the history of engineering, and for example   
Antoine Picon's authoritative _L'Invention de l'ing�nieur moderne:   
L'Ecole des Ponts et Chauss�es, 1747-1851_ is missing from his   
bibliography, as is the extensive scholarship on French mathematics   
(and sometimes also on economics) by Ivor Grattan-Guinness. One   
readily learns from research in the history of mathematics, science,   
and technology that the creation of the Ecole Polytechnique in the   
mid-1790s was of huge importance for the formation of engineers. The   
new polytechnic school, with its highly elitist patterns of   
recruitment and curricular preoccupation with mathematics, created a   
new sort of engineer, a type that would be rare outside of France   
until the mid-nineteenth century. Eighteenth-century French   
engineering used mathematics in a more sparing and more immediately   
practical way, and it would be interesting to compare Isnard's   
economic quantification with contemporary engineering. For a   
historian, the question is not only whether mathematics was applied   
to economics, but also what sort of mathematics and how it was used.  
  
It is necessary, then, to examine the role (and not merely to note   
the presence) of mathematics in Isnard's economic writings. My   
impression is that his mathematics is often not very hospitable to   
what we might call an economic sensibility. Van den Berg refers (p.   
34) to assumptions made for "mathematical convenience," assumptions   
Isnard knew to be inaccurate. The formulation by Isnard that is   
sometimes seen as a precursor of general equilibrium mathematics   
treats the economy as a bookkeeper might. Costs of production, and   
hence values, are fixed. Economic actors divide their wares into what   
they need for themselves and what they will offer in trade, rather   
than letting this division be a function of the price structure. His   
solutions are reached arithmetically, with perhaps a rudimentary   
element of algebra. This is the sort of conception that economists   
nowadays sometimes associate with engineers, though it is far from   
clear to me that any of Isnard's contemporaries thought of the   
economy this way. In his essay on paper money (assignats), Isnard   
rejects these radical simplifications. A doubling of the quantity of   
metal, he says, will not necessarily double the value of wheat in the   
currency of metal. Instead, a "new order" will establish itself "in   
offers and bids," a "new order on which the change in value depends"   
(p. 296).  
  
Van den Berg's translations are fairly clear and free of   
anachronistic terms and concepts. Although he relies often on   
cognates when a different sort of word would be more accurate (for   
example, he renders _confiance_ too often as "confidence" rather than   
as "trust"), the volume is a real translation, whose phraseology is   
almost always idiomatic, if not arresting. It is convenient to have   
the French on facing pages for comparison. This is, in short, a   
useful introduction to a mostly unsung economist, and on an   
appropriate scale. I don't know how much more singing about Isnard is   
required.  
  
  
Theodore M. Porter teaches history of science in the Department of   
History, UCLA. His books include _Trust in Numbers: The Pursuit of   
Objectivity in Science and Public Life_; _Karl Pearson: The   
Scientific Life in a Statistical Age_; and (co-edited with Dorothy   
Ross), _The Cambridge History of Science, Volume VII: Modern Social   
Sciences_.  
  
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