Faran med matematik

En av den matematiska nationalekonomins frontfigurer, John von Neumann, hade dessa varningens ord att säga om faran med en långt gången, abstrakt matematisering:

As a mathematical discipline travels far from its empirical source, or still more, if it is a second and third generation only indirectly inspired by ideas coming from ”reality” it is beset with very grave dangers. It becomes more and more purely aestheticizing, more and more purely I’art pour I’art. This need not be bad, if the field is surrounded by correlated subjects, which still have closer empirical connections, or if the discipline is under the influence of men with an exceptionally well-developed taste. But there is a grave danger that the subject will develop along the line of least resistance, that the stream, so far from its source, will separate into a multitude of insignificant branches, and that the discipline will become a disorganized mass of details and complexities. In other words, at a great distance from its empirical source, or after much ”abstract” inbreeding, a mathematical subject is in danger of degeneration. …

In any event, whenever this stage is reached, the only remedy seems to me to be the rejuvenating return to the source: the re-injection of more or less directly empirical ideas. I am convinced that this was a necessary condition to conserve the freshness and the vitality of the subject and that this will remain equally true in the future.

Jag tolkar nationalekonomins utveckling som att den renodlade matematiska inriktning som dominerade på många håll för ett par decennier sedan har ersatts eller kompletterats med ny empirisk forskning, genom utvecklingen av olika metoder och tekniker och genom allmänt bättre datatillgång. Inte minst torde den experimentella revolutionen, som lanserades av bl.a. Vernon Smith, ha ändrat ämnets karaktär en hel del. För personer som inte vill att nationalekonomin främst ska vara l’art pour l’art är detta en utveckling att hälsa med glädje.