Deductivist modeling leading economics astray
from Lars Syll
To achieve explanatory success, a theory should, minimally, satisfy two criteria: it should have determinate implications for behavior, and the implied behavior should be what we actually observe. These are necessary conditions, not sufficient ones. Rational-choice theory often fails on both counts. The theory may be indeterminate, and people may be irrational.
In what was perhaps the first sustained criticism of the theory, Keynes emphasized indeterminacy, notably because of the pervasive presence of uncertainty. His criticism applied especially to cases where agents have to form expectations about the behavior of other agents or about the development of the economy in the long run. In the wake of the current economic crisis, this objection has returned to the forefront. Before the crisis, going back to the 1970s, the main objections to the theory were based on pervasive irrational behavior. Experimental psychology and behavioral economics have uncovered many mechanisms that cause people to deviate from the behavior that rational-choice theory prescribes.
Disregarding some more technical sources of indeterminacy, the most basic one is embarrassingly simple: how can one impute to the social agents the capacity to make the calculations that occupy many pages of mathematical appendixes in the leading journals of economics and political science and that can be acquired only through years of professional training? …
I believe that much work in economics and political science that is inspired by rational-choice theory is devoid of any explanatory, aesthetic or mathematical interest, which means that it has no value at all. I cannot make a quantitative assessment of the proportion of work in leading journals that fall in this category, but I am confident that it represents waste on a staggering scale.
Elster’s article is essential reading for all those who want to understand why mainstream – neoclassical – economists actively have contributed to causing todays’s economic crisis rather than to solving it.
Perhaps this becomes less perplexing to grasp when considering what one of its main proponents today – Robert Lucas – maintained already in 2003:
My thesis in this lecture is that macroeconomics in this original sense has succeeded: its central problem of depression-prevention has been solved, for all practical purposes, and has in fact been solved for many decades.
And this comes from an economist who has built his whole career on the assumption that people are hyper rational “robot imitations” with rational expectations and next to perfect ability to process information. Mirabile dictu!
So, yes, I can’t but concur with Elster — the deductivist modeling endeavour of mainstream economics is leading economics astray.