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Lee Smolin & DSR: defending the indefensible

One week ago, I mentioned the renewed realization of many former DSR researchers that "doubly special relativity", "variable speed of light", and similar mental masturbations lead to contradictions with the empirical facts.

In particular, even a former German collaborator of Smolin's, "Angela", has managed to understand that the non-linear "Lorentz" transformations of the energy-momentum vector lead to non-local transformations of spacetime which make the very question about the "coincidence of two events" observer-dependent. This "ambiguity about locality" clearly doesn't occur in reality, so the theory is ruled out.

Six days ago, Lee Smolin tried to "resuscitate" the dead theories once again:

Classical paradoxes of locality and their possible quantum resolutions in deformed special relativity
Suddenly, Smolin seems to realize that this "Angela" argument has been known to him at least since 2003 when R. Schützhold and W. Unruh wrote a paper called
Large-scale non-locality in "doubly special relativity" with an energy-dependent speed of light
whose content is pretty much identical to the "new" paper by "Angela". I just learned about the paper - and it's probably older than any text I ever wrote about the topic. At any rate, how does Smolin try to avoid the conclusions by Schützhold and Unruh? His main (and only) statement is that
The paradox is an artifact of an inconsistent limit in which "hbar" is taken to zero while "l_{Planck}" is not.
That almost sounds like a physics argument. It uses similar words and symbols as proper physics arguments. Except that the airplanes don't land. Smolin's "logic" is pure gibberish. Why?

First, it is not true that a possible limiting procedure described by Smolin is inevitably inconsistent. The Planck length "l_{Planck}" is equal to "sqrt(hbar.G/c^3)". So even if "hbar" is sent to zero, "G" (and/or the speed of light "c", if we are allow to break relativity) may be sent to infinity so that the particular expression is kept fixed. In QFT and string theory, we often consider many types of limits where different things are kept fixed.




Second, the Schützhold-Unruh argument doesn't make any assumption that "hbar" is equal to zero. The argument just deduces the predictions of various "doubly special relativity" theories and compares them to the observations. Of course that the very pillars of a "doubly special relativity" assume that "hbar" is non-zero. Smolin's claim that the non-locality arguments assume that "hbar" is zero is simply untrue. More generally, the Schützhold-Unruh argument is based on actual observable physics, not a particular formalism. So one could only claim that 1) their deduced consequences of DSR are incorrect, or 2) the real-world phenomena behave differently than they claim. No other counter-argument is possible in this case. So Smolin hasn't offered any valid argument about this point, either.

Concerning the first two points, Smolin says a lot of related absurd things in the body of his text. For example, he says that the classical limit of DSR, whatever it is supposed to be, only predicts new things in the momentum space but not in the position space. That's absurd because these spaces are just Fourier transforms of each other so it's very clear that if an effect appears in one of them, the corresponding Fourier-transformed feature must occur in the other one, too.

Third, Smolin presents no evidence whatsoever for his claim that the contradiction is an artifact of the limit. In particular, he doesn't show that the paradox is resolved when the things are done "properly". Even though one major logical fallacy would be enough to make Smolin's paper invalid, Smolin's logic is actually defective at every conceivable level.

Concerning the third point, the only "similar" thing he tries to offer to resolve the paradox is to add some new and bizarre kind of "uncertainty", "spread", "chaos", or "stochastic component" (he has used the latter term to "deny" the observations by the FERMI satellite). But by doing so, he shows that he completely misunderstands - or totally denies - the very point of the contradiction between DSR and locality because his "solution" actually makes the problem worse, not better.

The problem is not that DSR predicts too little uncertainty of the position of spacetime events. The problem is just the opposite one, namely that DSR predicts too much uncertainty - via observer-dependence - about the position of spacetime events! To be viable, it shouldn't really be predicting any. You can't fix this problem by adding more chaos and incoherent stuff. You can only fix it by eliminating the source of the discrepancy and uncertainty - in this case, you must eliminate all the new pathological DSR effects.

Nevertheless, adding fog, nonsense, and additional uncertainties is Smolin's general method to "solve" any problem in the world. It's about his very character - after all, he is an inconsistent slimy piece of jellyfish himself. That's why the postmodern and feminist "anything goes" trash likes him so much.

But the goal of science and the rational criteria to judge the theories in science are exactly the opposite ones than what he seems to think. The best theory is not the theory that predicts the maximum fog and the maximum source of uncertainties and chaos, using a maximum amount of unrelated assumptions and additional effects. The best theory is the theory that correctly predicts the observed phenomena most accurately, using the minimum amount of independent assumptions.

And because we can actually measure the position of subnuclear particles with the accuracy of approximately 10^{-18} meters today, and the measurements of the relative position between two events are clearly observer-independent, we can eliminate all hypotheses that fail to reproduce this accuracy in the particles' locations.

Smolin's general method to throw junk and fog upon everything to obscure the situation and elevate the importance of the stupid people, ignorance, and illogical arguments is just no good in physics. It would be no good in any other hard science, either. When you read similar papers, you must feel that Smolin's brain is simply defective. However, he probably knows very well that what he keeps on writing is just pure trash.

But it has become his source of income and for the community, it has sadly become OK if not fashionable to tolerate this kind of dishonest freeloaders.

And that's the memo.

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reader Brian G Valentine said...

A A Michelson demonstrated the transformation correct to fourth order in (v/c), FitzGerald and Minkowski proved the transformation unique, and after 90 years or so it is time to say "Goodbye!" to the Lee Smolin's of the world and move on.

Bye Lee


reader unhealthytruthseeker said...

My god, the fact that position and momentum are Fourier duals is undergraduate quantum theory stuff. I refuse to believe that Smolin doesn't know this basic fact of quantum mechanics.


reader Luboš Motl said...

Dear truth seeker, all the evidence indicates that Smolin is ignorant about undergraduate physics, and is making a career out of it.

In the paper - first link in this blog entry - you will find explicit comments saying that e.g. his new theory has the same dynamics in momentum space but different dynamics in position space, even though these two pictures are by definition just Fourier transforms of each other (something he doesn't appreciate).

The issue is that people like Smolin abandon any rule of quantum mechanics, or any other rule, however elementary, whenever the rule is inconvenient for the preconceived conclusions they want to write and for the flow of text "arguing" in favor of such a conclusion.

So the position and momentum may easily become totally unrelated to each other and hbar may be zero in QM when Smolin needs those assumptions in order to argue that a certain theory isn't excluded by an experiment even though it clearly is.