----- Original Message ----- From: "Doug Pensinger" <[EMAIL PROTECTED]> To: "Killer Bs Discussion" <[EMAIL PROTECTED]> Sent: Thursday, July 24, 2003 12:31 AM Subject: Re: Science and knowledge
> Dan Minette wrote: > > > I think the key to reconciling this with the general description of > > physicists as mostly realists is the "shut up and calculate" statement of > > Feynman. It is an acknowledgement that there is no good realistic > > explanation for how QM works. It deliberately tables the question; tacitly > > acknowledging Feynman's inability to solve it. > > > Because today's physicists can't explain it it can't be explained? Its really significantly stronger than that, but it requires a bit of explanation to show how. Physicists have not been able to unify gravity and E&M for over 100 years, but there is still a general feeling that it is doable. Further, with two different systems to reconcile, the problem is not underdetermined. That is to say there are not a wealth of free parameters to play with: the first person or group of people to come up with a system that has both GR and QM as special cases will have made a tremendous step forward. Historically, unification of previously distinct theories has been a great source for increased understanding. Reconciling QM with realism was never the same type of thing. First of all, the mechanism for doing this has always been hidden variables. These hidden variables behave classically, they just happen to result in observables that do not. What does this mean? Classically, particles go through one slit or another; waves do not interact at a single point; objects have their properties independent of observation. This is not seen in QM. What was proposed by Einstein and others was that the lack of these properties was just temporary; when the next level was explored, it would be found to contain objects that behaved in a more classical manner. Only, many many levels have been explored since then, and nothing has been discovered. Roughly 10^15 orders of magnitude have been explored below the first quantum levels seen, and no hidden variables have been observed. This is in contrast with the neutrino, which was observed after only about 25 years after it was first postulated as the reason for the apparent non-conservation of mass in weak decays. But, that's not the only problem with hidden variables. The biggest blow came with Bell's and Wigner's work, showing that a local hidden variable theory was impossible. That is to say, that the hidden variables would have to transmit spacelike signals. At the time, it simply showed the inconsistency of local hidden variable theories with the theory of QM. Since then, there has been extensive experimental work, inconsistent with local hidden variable theories. So, the only available realistic theories are either non-local in a hidden manner, like TI, or invokes other features that really have a hard time matching common sense realism. Why? Because finding out that there really are hidden variables and observable backwards in time signals would falsify special relativity (SR) in a profound fashion: indeed in a fashion that classical mechanics has not been falsified. It would be akin to discovering that there really is a preferred reference frame and an aether, after all. Indeed, I'd state that this is one of the less revolutionary ways for scientific discovery to reconcile QM and realism. The others involve things like real backwards in time signals, allowing the possibility of a transmitter destroying itself via a signal sent after the destruction. This is the fundamental difference between our present inability to reconcile gravity with QM and our present inability to reconcile local realism with QM. With the former, we need to take a step forward. In that case, both GR and QM will be special cases of the new theory. With the later, we need to take a step backwards, since the last 100 years of physics would be proven to be a dead end. Well, that might be overstating it a bit, but it would certainly be akin to finding that there really is an aether. Dan M. _______________________________________________ http://www.mccmedia.com/mailman/listinfo/brin-l
