Saturday, September 03, 2005

Economics and Physics Envy

"The discipline of economics had gone the route of many social sciences. They had contracted "Physics Envy." That's the disease that gets you thinking that the only way to be respectably scientific is to do things the way the physical sciences, especially physics, do them.

As Jared Diamond has pointed out in his magnificent book, Guns, Germs, and Steel, social sciences cannot use the same experimental methodology that physical sciences use. Social sciences deal with human systems which are messy in the extreme and often not susceptible to double-blind, controlled experiments.

Diamond suggests several ways that social sciences can be scientific without succumbing to Physics Envy. We might apply them to economics, except that economics is not a science at all. Instead, it's philosophy, using mathematics to dress itself in the clothes of science.

Today's economics either regurgitates the obvious with a few equations thrown in or falls back on reasoning to replace experiment. Also with a few equations thrown in."

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Gene Expression: Physics Envy

"In my previous post on this subject, I asserted the non-applicability of higher mathematics to economic analysis, arguing that true functions (in the mathematical sense) are missing from all economic relationships.

The root of the problem lies in the belief, held by academic economists, that deep down and in some mysterious way -- maybe only statistically -- the laws of supply and demand are like the laws of physics -- as, for example, the laws governing the attraction and repulsion of electrons and protons. But consider:

In physics, the law which describes the inverse relation between distance and force between charges (or masses) is not just a rough approximation, qualitative description, or statistical generalization. Rather, it is an extremely precise description, to roughly 20 decimal places of significance, in which measurement error plays a very small part... physicists will be the first to admit that even the most powerful mathematical machinery they are able to bring to bear on a problem can deal successfully with only the very simplest situations, beyond which their equations are useless. Thus, for example, their equations can be solved for the two body problem but not the three body problem in Newtonian mechanics; they can solve the Schrödinger equation when there is only one proton and one electron interacting, but not when there are even two protons and two electrons, let alone anything more complicated than that.

Furthermore, on those occassions when physicists do make complex predictions -- such as that nuclear fission would occur en mass, before the first atom bomb was tested (to choose an historical example) -- they do so with caution, double checking all their calculations, and hoping that they haven't overlooked something, or might accidentally set the atmosphere on fire."
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