Difference between revisions of "Talk:String theory"

Revision as of 02:24, February 26, 2007

Falsifiability is from Pragmatism, not Positivism

Advocates of logical positivism such as Wittgenstein, Carnap, et. al. held that scientific propositions should be verifiable, thus the name "positivism". The question became what, exactly, it meant for something to be verifiable, so the logical positivists developed a theory of logic & language to be put to use in the course of empirical investigations.

Karl Popper and W.V. Quine were the pragmatists who took issue with the positivist position of verifiability and required a falsifiability condition from empirical claims on the grounds that one could never actually verify a claim through empirical investigation, but one could most assuredly prove it wrong through experimentation.

Because of the strong mathematical content of String Theory, a positivist would be more likely to accept it as a scientific theory than a pragmatist.

Your comments here make sense to me, and were consistent with my original entry until someone else changed it. How about fixing up the entry itself with your improvements?--Aschlafly 21:20, 25 February 2007 (EST)

Completeness and Computability

This:

"However it is not yet demonstrated that the theory is insoluble (see the Incompleteness theorem): that is, while string theory is not yet provable, it has not been shown to be unprovable. As an analogy, it can be suggested that all objects become green when they are not being observed: this is a model which is unprovable in principle, and therefore unscientific."

Makes no sense whatsoever. This is confusing the mathematical notions of completeness and independence with the ability to disprove something through empirical means. One does not show by mathematical means that a potentially empirical claim is indeed falsifiable, that must be done by considering the claims of the theory and the manner in which they are phrased. If string theory were to predict certain particles in certain abundances, or something similar, then the theory would be falsifiable, in the same way that quantum field theory is rendered falsifiable by the Higgs mechanism. What's more, only the mathematics may be subjected to the incompleteness theorem. As all of physics relies on extremely rich mathematics that are, under Godel's theorem, incomplete while, at the same time, remaining falsifiable, it seems ridiculous to suggest that the completeness or incompleteness of the mathematics should have any bearing on the falsifiability of the claims in question.

What's more, it is extremely unlikely that incompleteness has any bearing on any physics anywhere in any way -- the ties between computability and completeness prevent this from happening. A physically realizable state is always computable, in any context. The system giving rise to that realization is doing the computation! Invoking Incompleteness here is pure hogwash.

In the last sentence, we've gotten confused again. The first part of the article made appeal to falsifiability, and now in the last sentence we're requiring positive establishment. For consistency with the first part of the article, the author should have said "The claim that all objects become green when they are not observed is not falsifiable". (And I doubt that even this is true, since a lack of the required mechanism to render objects green falsifies the statement).

Finally, String Theory's central claims are put in a way that are falsifiable, as long as we have the ability to probe the energies and scales required. The fact that we don't have the technology does not have any bearing on the lingual structure of the claims.

It is enough to note that, to date, no evidence has been found to support string theory. That's it.