Read my lips — validity is NOT enough!

10 Jan, 2015 at 13:49 | Posted in Economics | 1 Comment

Neoclassical economic theory today is in the story-telling business whereby economic theorists create make-believe analogue models of the target system – usually conceived as the real economic system. This modeling activity is considered useful and essential. Since fully-fledged experiments on a societal scale as a rule are prohibitively expensive, ethically indefensible or unmanageable, economic theorists have to substitute experimenting with something else. To understand and explain relations between different entities in the real economy the predominant strategy is to build models and make things happen in these “analogue-economy models” rather than engineering things happening in real economies.

Formalistic deductive “Glasperlenspiel” can be very impressive and seductive. But in the realm of science it ought to be considered of little or no value to simply make claims about the model and lose sight of reality. As Julian Reiss writes:

errorineconomicsThere is a difference between having evidence for some hypothesis and having evidence for the hypothesis relevant for a given purpose. The difference is important because scientific methods tend to be good at addressing hypotheses of a certain kind and not others: scientific methods come with particular applications built into them … The advantage of mathematical modelling is that its method of deriving a result is that of mathemtical prof: the conclusion is guaranteed to hold given the assumptions. However, the evidence generated in this way is valid only in abstract model worlds while we would like to evaluate hypotheses about what happens in economies in the real world … The upshot is that valid evidence does not seem to be enough. What we also need is to evaluate the relevance of the evidence in the context of a given purpose.

Neoclassical economics has since long given up on the real world and contents itself with proving things about thought up worlds. Empirical evidence only plays a minor role in economic theory, where models largely function as a substitute for empirical evidence. Hopefully humbled by the manifest failure of its theoretical pretences, the one-sided, almost religious, insistence on axiomatic-deductivist modeling as the only scientific activity worthy of pursuing in economics will give way to methodological pluralism based on ontological considerations rather than formalistic tractability. To have valid evidence is not enough. What economics needs is sound evidence.

1 Comment

  1. The “because we can’t experiment…” is a problematical misreading of how science proceeds (Tony Lawson emphasizes this). Jane Goodall never ran an experiment (conceived in this way).

    Part of the problem lays in the goals assumed to be attainable. Jane Goodall did not set out to predict what a family of chimps would be doing 20 years after her observations. Once prediction becomes the end all, be all of a social science there is no escaping the road to crazy town. This is due to the fact that social systems, chimp and human alike, are not predictable. Full stop.


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