Wednesday, December 24, 2008

An Evolutionist Speaks Out About Economists' Pretensions About Science

Massimo Pigliucci, professor in the departments of Ecology and Evolution, Stony Brook, NY, contributes an important piece of work in the Blog, (‘a site devoted to positive scepticism') (HERE):

Economics learns a thing or two from evolutionary biology”

“Economics is supposed to be a solid discipline, founded on complex mathematical models (and we all know math is really, really difficult). They even give Nobel prizes to economists, for crying out loud! And yet, economics has always had to fight off the same reputation of being a “soft” science that has plagued sociology, psychology, and to some extent even some of the biological sciences, like ecology and evolutionary biology. Indeed, like practitioners in those other fields of inquiry, some economists admit of being guilty of “physics envy,” that is, of using the physical sciences as the model for what their field ought to be like. Turns out even the assumption that a good science should be modeled on physics is “flawed,” to use Greenspan’s apt phrase.

“A recent article by Chelsea Wald in Science (12 December 2008) puts things in perspective by asking how it is possible that so many smart people in the financial sector made irrational decisions over a period of years, despite clear data showing there was a problem, and eventually leading to a worldwide economic crisis that is at the least poking at, if not shaking, the foundations of capitalism itself.

Part of the answer is to be found in the persistent idea in economics that “markets” work because people are rational agents who act in their own self-interest and have perfect, instantaneous access to relevant information about the businesses they are considering investing in. Economists are not stupid, and they know very well that perfect rationality, complete information and instant access are all light years away from the reality of how markets operate. And in fact recent models have relaxed these assumptions to some extent. But it is so much more tractable to model things that way! After all, physicists do it too: remember those problems in Physics 101 that started “consider a spherical cow…”?

“Perhaps not surprisingly, there is another science that has been inspiring economists for some time now: evolutionary biology. The old “efficient markets hypothesis” underlying classical models is being replaced by the “adaptive markets hypothesis,” where Adam Smith’s invisible hand becomes more directly analogous to natural selection.”

”As evolutionary biologists have found out, natural selection is not an optimizing process, but a satisficing one, meaning that it produces whatever outcome happened to be achievable at a particular historical moment and that works “well enough” for the problem at hand. Moreover, it does so while “wasting” a lot of resources and often marching straight into dead ends (just think that over 99% of the species that ever existed went extinct). The emerging picture is much more realistic than the rationalist paradigm, but it sure is a lot more messy too.”

“There is another lesson to be learned from evolutionary biology that will not make economists, or the public at large, particularly happy: when complex systems evolve over time the paths they take is contingent on historical accidents (as opposed to being deterministic, like the laws of macro-physics, outside quantum mechanics). Sociologists, psychologists, ecologists and evolutionary biologists will readily tell their economic colleagues that it is certainly possible to explain past events (the extinction of the dinosaurs, the dot-com bubble) by the use of sufficiently complex causal-historical models. What seems to be out of reach, however, is precisely what economists want most: predicting the future, the hallmark of “good” science

The moral of the story is that all of the above is not a failure of economics, sociology, psychology, ecology or evolutionary biology. It is the predictable outcome of the fact that these sciences deal with complex, historical systems, unlike much (though not all) of physics. The real assumption we need to get rid of is the highly persistent and pernicious one that physics is the golden standard by which all other sciences ought to be measured. Now if we only could convince federal funding agencies of that...”

What a breath of fresh air from Professor Massimo Pigliucci! I wish (more in hope than expectation) that fellow economists will read all of his article. But because there are large dollops of research-grant money – and even bigger salaries from financial institutions (and government agencies) – available to smart-talking economists, who tell the grant agencies exactly what they want to hear, there is a steady demand for the services of 'future predictors' and no amount of their constant failures to do better than tossing a ten-pence coin could do, will curb the willingness to believe those in the prediction business.

It’s at least as bad as the historians of the immediate past, when they already know what has happened, who cannot agree on what caused, led to, or contributed to whatever is the latest ‘fine mess’ we’re in.

The historical precedents for this quite silly state of affairs goes back to classical times, and almost certainly farther back than that. Romans believed in ‘omens’ and fortune tellers, and even great generals, who pitted their lives against formidable foes, eagerly listened to what soothsayers and mystics had to say about the next few hours in decisive battles.

Among economists, we have bought the unscientific myth that if we spend a century creating beautiful mathematical models of an imaginary economy, without people in all their complexity and unpredictability, and our competence is judged by our understanding of the model, but not the reality of real economies!

We are a ‘hard’ science and much ‘superior’ to ‘wishy-washy sociology, psychology and history, even though it is well-known that humans are not ‘well behaved’ like physical objects. We are not like wooden pieces on a chess board, as Adam Smith put it.

It is worrying too that just as more economists begin to realise that “the old 'efficient markets hypothesis' underlying classical models is being replaced by the 'adaptive markets hypothesis,' into which realisation, the oldest nonsense in modern economics (invented as a mass myth from the 1950s), is being re-introduced into the latter, under the guise that the metaphor of “Adam Smith’s invisible hand”, such that it is to be regarded as “more directly analogous to natural selection.”

Please spare us from this spurious nonsense; it’s bad enough that the proponents of the so-called scientific basis of economics have got away with their claims that the mystical disembodied body part was the ‘most important idea’ of modern economics, which is something that they never got from the texts of Adam Smith (see my paper: 'Adam Smith and the Invisible Hand: from metaphor to myth’, 2008 and downloadable from the homer page of Lost Legacy).

The myth of the invisible hand is a fabrication to support propaganda for corporate bodies to behave with all the monopolistic spirits and protectionism of the ‘merchants and manufacturers’ of his day, against whom Adam Smith railed in Wealth Of Nations because they persuaded legislators and those who influenced them (and they ‘bought’ not a few) to assist them in narrowing the competition and raising prices.

Follow the link to read Professor Massimo Pigliucci’s short article HERE.

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Blogger michael webster said...

I have doubts that evolutionary biology is going to tell us anything about the gaming system known as the financial markets.

(I did read the article and a transcript of Wald's interview in science.)

My sense is that Kahneman/Tversky and others have directly attacked the notion of invariance in modeling decision making.

All of our natural sciences have accomplished so much by various exploitations of various invariance principles.

But if the K/T crowd is right, we cannot just presume invariance to hold in human decision-making, we might actually have to construct with good market design.

9:48 pm  
Blogger Gavin Kennedy said...


Thanks for your observations.

"All of our natural sciences have accomplished so much by various exploitations of various invariance principles."

It is most likely that human decision making is beyond modelling with the same quality of results as in the natural science.

Electrons, planets, chemicals, molecules, and such like don't have minds of their own. They may behave variably on occasion, but this usally sparks a hunt for the non-conformities (and breakthroughs in science).

But people behave under more than asserted motivations; but in economics we ignore the variance and force determinate solutions in search of determinate models.

I have no views on trying to game financial markets - the future is unknowable. Period.

The human past is vaguely knowable, with wide areas of disagreement. Humans are far more complex than can be captured in a determinate model.

That is my (provsional) view.

10:45 pm  

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