**Last summer I visited the UNESCO archives in Paris. Located at the far end of the Champ de Mars, right after the Eifel Tower and the École Militaire, the organization’s headquarter is a well-known and impressive building. Place de Fontenoy, however, is a place for diplomats and government-representatives. Historians interested in the past activities of UNESCO are directed to another location in the 15th arrondissement. The documents of the Division of Ecological Sciences, the stuff I am professionally interested in, are housed in the basement of a temporary building on UNESCO’s grounds at Rue Miollis. Although the place misses the grandeur of the headquarters, the labyrinth-structure of Miollis and the dusty basement packed with unsorted files, definitely adds to the supreme experience we all love so much: immersing ourselves into bygone times by reading obscure books in obscure places.**

# Monthly Archives: March 2015

# The History of Mathematics in Economics III: Debreu, or How the Truth is in the Mathematics

*This contribution is the third post in the four-part blog series on the history of mathematics in economics. For the first post on Philip Mirowski’s account of Irving Fisher, which also introduces the series, click here. For the second post on Marcel Boumans’s study of Jan Tinbergen, click here.*

**The previous contributions in the series have made you familiar with two stories in the history of mathematics in economics that reached radically different conclusions. For Philip Mirowski, the introduction of mathematics into 19 ^{th}-century economics was the result of physics-envy: economists without a proper understanding of physical theory, but with a fascination for its rigidity, borrowed from physics without noticing that these theories did not work in the economic domain. Marcel Boumans, on the other hand, showed how Jan Tinbergen used tools from physics to clarify economic problems by restricting this transfer to domains where the structure of the problem was the same for both fields – and, consequently, without presupposing a substantive analogy between the two disciplines, as was the case for Fisher. This third instalment will introduce the third and final author on the final economist in our series, with E. Roy Weintraub’s discussion of Gerard Debreu (1921-2004).**

# WIE HAALT UIT EEN RECENT PROEFSCHRIFT OVER SIMON STEVIN EEN PRACHT-ARTIKEL?

**Ik begin deze oproep met een waar gebeurd verhaal. Op 5 juni 2013 promoveerde aan de Vrije Universiteit ir. Kees Schilt op een proefschrift met als titel Simon Stevin en het Hermetisme. De jonge doctor was toen 80 jaar oud en al zo doodziek dat de promotie bij wijze van hoge uitzondering niet op de universiteit plaats vond maar bij zijn dochter thuis in Velp. Promotoren waren mijn collegae Davids en Frijhoff, met Stamhuis als co-promotor. Ik was lid van de leescommissie die met toelating tot de promotie had ingestemd, maar doordat ik vastzat aan een lezing aan de andere kant van het land kon ik er tot mijn grote spijt niet bij zijn. Van Karel Davids hoorde ik naderhand dat het een uitermate stijlvolle, zonovergoten bijeenkomst was geweest, waarbij de mentaal nog geheel heldere promovendus zich vanuit zijn rolstoel prima tegen de oppositie weerde. Zoals toen al door iedereen werd voorzien, is hij kort erna inderdaad overleden. En dat betekent dat de verbreiding over de aardbol van wat dit proefschrift wetenschappelijk waard is, het van het begin af aan zonder de schrijver zelf heeft moeten stellen. Waarom zou ik het nu zo jammer vinden als deze studie verder in het vergeetboek zou raken?**

# The History of Mathematics in Economics II: Jan Tinbergen, Paul Ehrenfest and Formal Analogies

*This contribution is the second post in a four-part blog series on the history of mathematics in economics. For the first post, which also introduces the series, click here. *

**My previous contribution on Mirowski painted a grim picture of the role of mathematics in economics: Irving Fisher, one of the saints of neoclassical economics, had tried to apply physical methods and theories to economics because he thought there was a substantive analogy between the ontology of physics (particles, force, energy) and the ontology of economics (individuals, marginal utility, value). This translation was wrong, because Fisher did not understand the physical theories that he was invoking, and it was inadequate, because the physical theories that Fisher pressed on economic problems simply did not fit that domain. A different perspective on the use of physical analogies in economics is defended by Marcel Boumans (1993) in his treatment of the exchange between physicist Paul Ehrenfest and economist-to-be Jan Tinbergen. According to Boumans, this case is an example of ‘formal analogies’: Tinbergen drew on physics for his innovative macro-economic models because some aspects of the mathematical form of physical and economic systems were similar, not because of any underlying substantive analogy between the subject matters.**