SpaceAdmiral writes "You've likely heard of Lee Smolin's book The Trouble with Physics. It has created a lot of controversy because it argues that string theory gets far too much attention and money, despite a complete lack of evidence. It accuses string theorists of groupthink. Smolin has dabbled in string theory from time to time but he's a proponent of the alternative loop quantum gravity. Although irrelevant to this book review, he has also suggested that it is possible that universes reproduce via black holes, making them prone to pressure similar to natural selection (universes that produce a lot of black holes are more successful spawners than those that don't). In The God Delusion, Richard Dawkins quotes Nobel-winner Murray Gell-Mann as once saying, "Smolin? Is he that young guy with those crazy ideas? He may not be wrong."" Read the rest of SpaceAdmiral's review.
|The Trouble with Physics|
|publisher||Houghton Mifflin Company|
|summary||The Rise of String Theory, the Fall of a Science, and What Comes Next|
The Trouble with Physics is very unlike most pop-physics books not only in its criticism of string theory, but in its open adulation of Einstein and skepticism of the Copenhagen interpretation of quantum theory. Having said that, it does provide a very decent summary of 20th century physics (including string theory) for laypeople, not unlike more traditional pop-physics books (e.g. by Hawking and Greene).
The book's main criticisms of string theory are that it makes no testable predictions and that some things string theorists take for granted haven't been rigorously proven mathematically. Smolin is highly skeptical of many string theorists' reliance on the Anthropomorphic Principle.
The book becomes most interesting somewhere in the middle where he discuses truly controversial approaches to physics. This includes things like MOND, which, interestingly enough, Smolin is skeptical of.
In case you've forgotten your high-school physics, I'm going to use this paragraph to refresh your memory of special relativity to prepare you for the next couple paragraphs. The basic idea of special relativity is that the speed of light is constant. Pretend that I am shining a light at you while (A) standing still relative to you; (B) moving towards you at half the speed of light, and; (C) moving away from you at half the speed of light. In all three scenarios, I will accurately measure the light moving away from me at 3,000,000 km/s and you will accurately measure the light moving toward you at 3,000,000 km/s. To ensure this result, distances and times will have to be different for me than they are for you, except in case (A).
Now I'll quickly remind you of the Planck length: This is a theoretical limit on how small something can be. According to Smolin, all versions of quantum gravity seem to suggest the Planck length as a limit. But would observers moving relative to each other disagree about the Planck length?
I used to be a big fan of MOND (in a layperson sense) until Smolin introduced me to DSR (doubly special relativity) and DSR II. The basic idea is that it may be possible to modify the theories of relativity such that observers agree not only on a constant speed of light, but also on a constant Planck length. It's not unreasonable to guess that a modification of this sort could solve some of the same problems MOND does (e.g. explain astronomical observations without resorting to dark matter and dark energy). Furthermore, since DSR in its current incarnation predicts that more energetic photons are slightly faster than less energetic photons (only the speed of the least energetic photons is constant in DSR), it could also explain away, for example, inflation in the Big Bang model. (Immediately after the Big Bang, everything was hotter and more energetic, so the average speed of light would have been faster than it is now if DSR is correct.) Although I'm not qualified to judge the actual mathematics of such a theory, I find it very appealing for reasons of consilience.
I was slightly disappointed with the final chapters of Smolin's book since, despite an obvious effort to the contrary, it struck me as awfully bitter and reeked of sour grapes. Leaving physics in favor of sociology, he lambasted the current tenure and peer review systems (particularly in the United States) as favoring Master Craftspeople (like those scientists who developed the standard model of particle physics) over Seers (like Einstein, Bohr, and de Broglie) who look at the deep questions of physics that border on the philosophical rather than the latest technical problem. A few interesting things do emerge in these chapters. One such thing is that Smolin seems to have a soft spot for Paul Feyerabend as a philosopher of science (despite describing himself as a proud Popperazzo in an endnote). Another is that Smolin thinks a scientist who is hated by half his senior colleagues and loved by the other half is likely better than a scientist who is liked by all his senior colleagues. I strongly recommend this book.
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