Doug Henwood wrote:
>
>
> At a seminar several years ago, when I tried to refute efficient
> market theory with empirical evidence, David Laibman, editor of
> Science & Society, informed me that you can't refute a theory with
> evidence, but only with another theory.
>
Since the proposition "X is an empirical fact" is meaningless except in the context of some theory, as a description of empirical reality Laibman's proposition is probably correct. As Susanne Langer pointed out back in the early '40s, major theories are not disproven, they are abandoned.
A theory will always dictate the kind of empirical 'evidence' that can disprove it.
1. "The sound wind through an aspen tree cannot be heard by anyone with defective hearing."
2. "Abigail despises pickled beets."
3. "John Adams was a president of the u.s."
4. "The wastebasket in the kitchen needs emptying."
5. "There is a Phoenix Ave. in both Normal and Bloomington, Illinois."
6. "The altitude of Santa Fe is approximately 7000 feet above sea level."
Conclusion: Propositions 1-6 demonstrate efficient market theory.
If you want to attack that conclusion you will have to advance a theory as to what kinds of empirical evidence are relevant to the confirmation or discomfirmation of efficient market theory.
Carrol