Popperism (was Chomsky -- Put up or blah blah)

Scott Martens smartens at moncourrier.com
Thu Mar 30 09:40:13 PST 2000



> I thought that the view that scientific theories had to be
> falsifiable was no longer held by most philosophers of
> science. The Lakatosian position as I recall is that there
> is a core of theory that is not regarded as falsifiable.

This is not the position generally held by scientists. There may be some portion of a theory that isn't falsifiable, but if the portion that is falsifiable is falsified, the theory is unlikely to last. For example, Newton made no effort to verify the law of conservation of mass and energy, and his theory was accepted anyway. It turns out this law isn't true. What can't be falsified now, may be falsifiable later.

Remember, you can't ever be certain that a scientific theory is true, you can only be certain that it is false.


> The theory of relativity would be a present-day example. An
> earlier paradigm would be Newtonian mechanics. As Kuhn
> points out theories are not typically rejected by being
> falsified but through paradigm shifts--as with the Ptolemaic
> and Copernican theoryes. Another problem with the Popperian
> falsification viewpoint is that there can be many
> falsifiable but competing theories but
> the theory does not give any positive reason for choosing
> one unfalsified theory over another.

The biggest boost relativity got was from predicting exactly the orbit of Mercury. This was a falsification test, Newton's theory was falsified by Mercury's failure to be where it predicted it would be, while Mercury was exactly where Einstein said it would be. Much the same story appies to Newtonian mechanics, which was accepted on the basis of it's ability to accurately predict the motion of masses.


> The theory can tell us
> when a theory is false and to be rejected but not its degree
> of confirmation. Some type of confirmation theory such as
> that of Bayes is needed. Duhem and Quine have shown as well
> that
> any theory can be saved from falsification by adjusting
> auxilliary hypotheses etc.

Yes and no. There are external criteria for determining which theories to favour. Like generality, brevity, and specificity. When a theory becomes laden with special rules and exceptions, one starts looking for an alternative.


> There is no such thing as a
> crucial experiment that makes or breaks a theory. I am not
> expert in this area but the difficulties with the view that
> scientific hypotheses must be falsifiable are well
> established. The "naturalized" approach to the philosophy of
> science recognises such charactertistics as simplicity,
> predictive success, and heuristic fertility, as
> characteristics of good scientific theories.

Yes, there are experiments that make or break a theory, but it usually isn't that simple. Generally, it takes years of repetion under different circumstances and arguing with people who want to interpret the results differently to get a theory widely accepted. However, I can cite examples of experiments that were crucial in undermining various theories and building up others. The blackbody experiment, the Michaelson-Morley experiment, Einstein's prediction of the orbit of Mercury, and more recently the Aspect experiment, or the unification of the electro-magnetic force and the strong nuclear force in the 70's.

There are other heuristic criteria scientists use to select which theories they propose and test, however, Popperian falsification remains the ultimate test of truth in science. Mostly, scientists are not strict Popperites, however, trial by falsification is pretty much part of the dogma now.


> Theories in neo-classical economics would surely fail the
> falsification test.

Yup. One of the reasons I'm trying to understand economics is because I see a lot of the same problems I see in linguistics.


> But I suppose they are supposed to have
> some of the virtues listed above and of course best of all
> the theories justify free market capitalism, the real test
> of the acceptability of economic theories within capitalism.


> Then there are the Feyerabendians who claim that even
> observations are theory-laden and so there is not even the
> conceptual possibility of confronting a theory with a simple
> falsifying observation.

Very little good has come of either Kuhn or Feyerabend. Kuhn's distinction between "revolutionary science" and "regular science" strikes me as unhistorical, and it isn't true that scientists have one method for humdrum projects and another for the ones that get in the history books. His notion of "paradigms" hasn't done any good at all. As for Feyerabend, the first time I read anything from him, I thought he was kidding.

There are problems with Popper's methods, but they are mostly in his analysis of how scientists come up with theories, not in how they verify them. I don't see how Newton's laws could be regarded as anything but falsifiable unless it was so burdened with auxiliary theories as to become useless. This leads me to think that theories are falsifiable in something very much like the Popperian method.

Scott Martens

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