2011-03-28

Gilboa's View on Theory

What is theory, or what is the role of theory especially in social sciences? In his book, "Theory of Decision under Uncertainty," Professor Gilboa shows thought-provoking argument.




The following quotes are all from Chapter 7: "The Role of Theories."

Theories are never correct, and in the case of the social sciences they tend to be almost always wrong. The question is, therefore, not whether they are right or wrong, but whether they are wrong in a way that invalidates the conclusions drawn from them. In other ways, theories are tools for reasoning and rhetorical devices.
The last standpoint I think is more or less common among great Israeli theorists such as Bob Aumann and Ariel Rubinstein. In a later part, Gilboa also says as follows:
Recall that we are not hoping to obtain theories that are very accurate. We use the theories more often as reasoning aids.
Then, the author further offers philosophical argument on science, referring the key thinkers such as Friedman, Popper, and Kuhn.
It follows that the degree to which we are willing to accept an assumption does not need to be a monotone function of its degree of accuracy. The assumption is tested based not only on its direct implications, but also on its indirect implications, which may involve nontrivial theorems.

The preceding discussion brings to mind Friedman's celebrated argument that theories should not be judged based on the validity of their assumptions, but on that of their conclusions. This argument is a bit extreme, and I would be careful to accept it (because of the following two reasons).
1) It is generally hard to draw a sharp distinction between assumptions and conclusions, completely ignoring the veracity of the former and testing only the latter.
2) Justifiably or not, it (= Friedman's argument) has become a bit of an excuse not to question the theory.

The logical positivist heritage (coupled with Popper's contribution) suggests that our theories should be falsifiable. The axiomatization we saw earlier is formulated in terms of conditions that can be violated. However, a theory such as utility maximization is not always easy to falsify. [...] Only in carefully designed controlled experiments can one hope to unambiguously refute a theory, but then one faces questions of external validity: the fact that a theory fails in artificial experimental environment may not be an indication that it will also fail in natural environment, to which it was presumably intended in the first place.

It started with Kuhn (1962), who asked questions about scientific paradigms and the way they changed. Kuhn described scientific evolution as a social phenomenon that need not converge to any objective truth. Rather, it was a process involving many factors, including accumulating evidence on the one hand, but also personal interests and tastes on the other.

The postmodern critique sometimes appears to confound descriptive and normative claims. It may well be true that science will never be able to be completely objective. But this does not mean that is shouldn't try. [...] There are instances of postmodern critique that sound to me similar to the argument, "We know that wars are inevitable. Hence, let's start shooting people."

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