Monday, May 18, 2015

Bell was only partially misguided about relativity

Lubos Motl argues that John Bell actually misunderstood relativity, too:
Just a few hours ago, I believed that Bell was simply ready to abandon special relativity because "realism" (i.e. the faith that quantum mechanics must ultimately be wrong) was a more important dogma than relativity for him. But only today in the afternoon, I was led to a text that shows that it was just a part of the story. He was actually ready to abandon relativity because he was a relativity denier. To say the least, he denied that Einstein has changed anything about the content of physics. In his opinion, the previous theories based on the aether were already OK and Einstein has only changed the style, philosophy, and pedagogy!

The reason why relativity – and quantum mechanics – are taught as a "discontinuity" is that they are a "discontinuity", a radical conceptual change within the basic assumptions of physics. ...

He is frequently repeating the thesis that what Fitzgerald and the other people believed was physically equivalent to Einstein's special relativity – it only differed in "style, pedagogy, and philosophy". Those claims are clearly wrong, as I will discuss. ...

Physics just doesn't care about "style, pedagogy, and philosophy".
I cannot agree with Motl here. This blog celebrates continuity, and shown in the Latin slogan. Einstein's special relativity was equivalent to previous theories, as even Wikipedia details. If it were really true that Physics just doesn't care about "style, pedagogy, and philosophy", then Einstein would not be such a big-shot.

I do agree with Motl that Bell showed an incompatibility between quantum mechanics, relativistic locality, and what is confusingly called "realism". And that Bell foolishly preferred to keep realism instead of relativity, and that is where many of his followers go wrong also. And that the geometric view of relativity is clearly superior, and Bell is peculiar not to embrace it.
Fitzgerald and others believed in the aether – in fact, I think that he did so even after 1905 because this guy didn't understand relativity. Relativity has killed the aether.
No, relativity did not kill the aether. As Wilczek said, "the truth is more nearly the opposite". See more here.

Relativity suggests that the aether be Lorentz covariant, but does not say anything about whether it exists or not.
Bell has never explicitly "endorsed" the aether but everything about his "solutions" to the problem make it clear that he believed exactly the same crap as e.g. Fitzgerald did. That's also why he consistently talks about the "Fitzgerald contraction" – even though a sane modern physicist would talk about the "Lorentz contraction". But if he believed his claim that the Fitzgerald's and Einstein's treatments were physically equivalent, then the Fitzgerald contraction and the (relativistic) Lorentz contraction would have to be the same thing, too, right?

He seems totally unaware of this waterproof logic. Also, he never actually explains what is the difference between the effect he calls the "Fitzgerald contraction" and the actual relativistic "Lorentz contraction".
The terms FitzGerald and Lorentz contraction are used interchangeably on Wikipedia. They both (independently) proposed the contraction first as a logical consequence of the Michelson-Morley experiment, and then proposed an explanation in terms of molecular forces.

The preferred explanation since 1908 has been the non-Euclidean spacetime geometry one due to Poincare and Minkowski.

Einstein's 1905 approach was to postulate what Lorentz had proved, and to endorse Lorentz's view of the contraction. He used Lorentz transformations of space and time, but did not attribute the contraction to a purely geometrical spacetime effect, as did Poincare and Minkowski. The modern view that relativity is a about measurement, not objects, was due to Poincare and Minkowski, and Einstein never liked the geometrical view.

I guess Bell liked the molecular force explanation, and for some reason that drives Motl and other modern physicists nuts. A respected British philosopher named Harvey Brown likes the explanation, but few others today. As I say, it is not the preferred view, but it is a view that is legitimate and justifiable. Physics often has more than one explanation for a phenomenon, and that is a good thing, not bad.

1 comment:

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