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The Trouble with Physics
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
author
Lee Smolin
pages
392pp
publisher
Houghton Mifflin Company
rating
9
reviewer
Fane Henderson
ISBN
0618551050
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.
You can purchase The Trouble with Physics from bn.com. Slashdot welcomes readers' book reviews -- to see your own review here, read the book review guidelines, then visit the submission page.
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.
You can purchase The Trouble with Physics from bn.com. Slashdot welcomes readers' book reviews -- to see your own review here, read the book review guidelines, then visit the submission page.
A big problem amongst educated people is to think that scientists are not prone to the same illogical behavior as average people. We think that they are immune to "following the flock" or otherwise being influenced by their peers.
While scientists are in general better than average people at being objective, they still tend to have their own biases. Spending you life working on a particular theory makes it hard to give it up even when the evidence disproves it. Even an objective scientist is going to have problems throwing away their life's work.
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-- All that is necessary for the triumph of evil is that good men do nothing. -- Edmund Burke
OK, so he has a paper on M-Theory, so he probably does understand the latest stuff. But my main point still stands. This is just a thing about who gets to build the bigger empire and get more publicity, power and money. Just like the entertainment industry!
Because theres not a lot else in fundamental theoretical particle physics to spend it on. Basically we've reached the point where everything we can test right now is tested and understood and there hasnt been any significant surprises in the last 30 years. Basically the cludge that is the Standard Model works far too well and its completely theoretically worked out. And the theorists are just screwing around with silly things now because they are waiting for experiment to catch up with theory. We hope that this will happen when the Large Hadron Collider (LHC) turns on and that we will find something unexpected. This will give us the clue what to try next theoretically. And as soon as that happens, the theorists interest in string theory will disappear as they will (hopefully) have something new to work on to explain (hopefully) very strange experimental results. Particle physics is either about to go through a golden age in two years time or its going to wither and die.
On the contrary, string theory is very interesting, and has a great deal of interesting things to say. The issue is more that it is mathematics not physics. There is, of course, nothing wrong with mathematics for its own sake. Indeed, many physics theories were preceeded by the development of purely mathematical work - where would general relativity be without Riemann's work on manifolds for instance? In many ways string theory could be classified in a similar sort of category - it is a lot of very interesting mathematics that could, one day, be applied to the development of a physical theory. The dilemma comes when people act as if it is physics instead of mathematics.
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As physics progresses we seek for something that was hidden from the previous generation of physics. For example we start with observing gravity happen. 100k years ago (or 6k years ago - depending on your worldview) Ogg drops rock, ogg gets sore toe. Then more recently someone figured out it is because of mass/proximity of objects. Then someone figures out a characterising equation. Then someone else figures it is because space is bent. Then strings. No longer are we improving our observations. Now we're coming out with mathematical models of things that don't really exist.
Engineering is the art of compromise.
"Science is prediction, not explanation" - Fred Hoyle
The serious problem with string theory is that it doesn't yield falsifiable predictions. Theories which don't yield falsifiable predictions are not useful - you can't check them by experiment, you can't effectively choose between them, and you can't develop engineering based on them.
This matters. From subatomic physics we got nuclear power. From quantum electrodynamics we got semiconductors and lasers. From string theory we got nothing. If you can't make predictions, you can't do engineering design.
With string theory, you can create pretty mathematical objects, but it's not clear that there's any connection to the real world. Smolin says that's bad physics, and he's probably right.
There's real progress in physics, but it's mostly at the low-energy, low temperature end. Seemingly impossible objects like Bose-Einstein condensates and materials with negative indices of refraction have both been demonstrated. Quantum computing is hard to do, but real. That's progress. But the high energy physicists and the cosmologists have been stuck for a while.
It's possible for an entire field to take a wrong turn like this. Artificial intelligence did, back in the 1980s, when the expert systems people were claiming that strong AI was just around the corner. Then came the "AI winter". Twenty years later, AI is moving again, but with new approaches (more statistics, less formal logic) and new people.
Your idea of "real object" is very very strange. Mass?? It's just a characteristic of matter.
Agreed. We cannot tell the difference betwen a "model" and something "real" other than our model of it fitting observations. But fitting observations only tells us how accurate our model is. It says nothing directly about wether something is "real" or not. Wrong models can still fit reality. But perhaps it does not matter. Ideally we would like to have the "correct" model, but a wrong model that produces all the answers the right one does could be equally useful from a technology standpoint (assuming it is not more complicated).
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