by John Horgan, The Scientific Curmudgeon
So why has string theory persisted for more than two decades in spite of its hideous complexity, its blatant violation of Occam’s Razor, its lack of evidence, its failure even to offer testable predictions? The journalist Tom Siegfried raises this question in “A Great Unraveling,” his review of the anti-string books Not Even Wrong by Peter Woit and The Trouble With Physics by Lee Smolin in Sunday’s New York Times Book Review. (See my review of Woit on our website, and keep an eye on this space for our webcast of my interview with Woit here at Stevens.)
Siegfried notes that neither Smolin nor Woit “really confront the reason ideas in physics become majority viewpoints. When John Schwarz of Caltech and his few collaborators worked alone on string theory throughout the 1970’s, they wrote no books complaining about lack of resources. They worked until they found a striking result that mainstream physicists found worth pursuing. Physicists vote with their feet, which suggests that there is, after all, a way to prove string theory wrong — by finding a different theory and proving it right.”
I rarely agree with Siegfried, whose science journalism is too fawning for my tastes, but he makes an point here. The only way to displace a bad theory is to find a better theory. I made this point in the December 1996 Scientific American in an article titled “Why Freud Isn’t Dead,” an article for about why Freudian theories and treatments persist in spite of a century’s worth of vicious criticism.
Freudians cannot point to unambiguous evidence that psychoanalysis works, but neither can proponents of more modern treatments… The anti-Freudians argue, in effect, that psychoanalysis has no more scientific standing than phlogiston, the ethereal substance that 18th-century scientists thought gave rise to heat and fire. But the reason physicists do not still debate the phlogiston hypothesis is that advances in chemistry and thermodynamics have rendered it utterly obsolete. A century’s worth of research in psychology, neuroscience, pharmacology and other mind-related fields has not yielded a paradigm powerful enough to obviate Freud once and for all.
That is why string theory refuses to die, too. If string theory is phlogiston, so are all the other unified theories of physics.
September 20th, 2006 at 9:19 am
As you might guess, I found the Siegfried review highly annoying. Pretty much everything he had to say was either inaccurate or a fallacious argument. This wasn’t too surprising given that he is the recent author of one of the more outrageously over-hyped books about string theory, but still. One example: he writes that, unlike me, Smolin admits that string theory makes predictions, and that they’ll be tested at the LHC. If you actually read what Smolin has to say, he devotes a long section in his book to explaining exactly why string theory makes no predictions about what the LHC will see.
As for the part you quote, the problem with the question “why are these guys complaining about the dominant theory when string theorists didn’t complain back in the late 70s?” is that the dominant theory then was the standard model, which was incredibly successful, with a huge amount of experimental backing. If the standard model made no predictions and there was no experimental evidence for it, Schwarz and others would have been loudly complaining about the situation.
It’s just not true that neither of us “confront the reason ideas in physics become majority viewpoints”, both of our books are very much about why string theory became so dominant. The reasons are quite different than the usual reason a theory becomes dominant, that it works. It’s of course true that what we both would like to see is a better theory than string theory. One of the main concerns that led both of us to write about this is that we see a problem with the way research in this field is organized. For quite a while it has been difficult for people to pursue certain kinds of research unless they are connected to string theory.
You’ve written eloquently on why making progress on unification in physics is much more difficult than in the past. This is true, but the way string theory research has been pursued, with vast amounts of hype, refusal to admit failure, and ideological fervor devoted to discouraging ideas not related to string theory, has not made it any easier. If things do turn around and there’s a more balanced view of string theory, perhaps this will encourage support for the very hard work of looking for more promising ideas.
September 20th, 2006 at 11:59 am
String theory lacks observable predictions and claims immunity to empirical falsification. String theory derives the Equivalence Principle (EP): all local centers of mass vacuum freefall along identical (parallel) trajectories. String theory is killed by two lumps that reproducibly fall differently.
Earth’s day lengthens by 0.000023 sec/year causing lunar recession of 3.84 cm/year. Symmetry of the Einstein curvature tensor and contingent energy-momentum tensor prohibit exchange of spin and orbital angular momenta in General Relativity. The patch is Einstein-Cartan theory. This also creates a chiral pseudoscalar vacuum background. Space is a left foot. Metaphoric left and right shoes will not fit identically. They will violate the EP. Do they?
Organic chemical benzil is achiral in solution, molten, or as vapor (a sock). Crystal lattice forces orient benzil molecules into “infinite” homochiral helices that stack like straws. Helices are left-handed or right-handed, giving opposite parity crystals (opposite shoes). If space is chiral then one crystal parity fits with higher energy than the other (opposite shoes on a given foot). When melted into identical socks, their heats of melting/gram must be different. Are they?
Opposite parity benzil single crystals, two differential scanning calorimeters; eight paired runs over two consecutive days. Subtract paired outputs. If all eight net outputs are zero within experimental error, string theory is validated. If four net outputs are reproducibly not zero, string theory is falsified. Somebody should look.
September 20th, 2006 at 12:13 pm
Ah, John, perhaps you are on to something when you say “If string theory is phlogiston, so are all the other unified theories of the universe”.
Could it be that for there to be something rather than nothing that gravity must remain as a separate, independent actor from the three (or is it just one?) other forces identified by quantum theory? Penrose has seemed to be skirting around this position, which seems to better describe the world we live in than other alternatives.
It seems almost a religious conviction that there must be a unified theory. Does anyone ask why?
By the way Dr. Woit, I am enjoying your book. What has wrankled me most is the labeling of sophisticated philosophical speculations (which may someday prove valuable) as a “theory” when it is not even a hypothesis since for something to be an hypothesis implies the potential for testing. Using this terminology devalues the institution of science and gives credence to the “just a theory” arguments from those wedded to an explanation of reality based on some “revealed truth”. That people who call themselves scientists permit this terminology boggles my mind.
Sam Taylor
September 20th, 2006 at 9:50 pm
You say that string theory doesn’t die because there is no better theory. But there is a better theory. The Standard Model is better. It is testable, and it agrees with experiment.
September 20th, 2006 at 10:33 pm
Following on Roger Schlafly’s point, I believe the predictions of General Relativity are also testable and agree with observations.
Wouldn’t any concept that sought to replace these two powerful ideas that work, particularly one that made such extraordinary claims, require some extraordinary proof?
September 22nd, 2006 at 2:59 am
Siegfried’s comparison with Freud is an interesting one. Check out the
following (podcast) debate between a freudian and an
anti-freudian on the subject of dreams
http://www.abc.net.au/rn/philosopherszone/
The Freudian argument is, so far as I can tell, just hot air. Or
possibly poetry. But not science. However the anti-freudian lets
the freudian off the hook by really having very little in the
way of a testable alternative. I hope physics doesn’t get stuck
in such a sterile debate for the next century.
September 22nd, 2006 at 3:36 am
Your statement “The only way to displace a bad theory is to find a better theory”, combined with popular philosophical interpretations, could be misleading. Philosophers of science believe in the pessimistic induction: since theories in the past have been rejected as false, all theories, both past and future, are false. Philosophers also believe in the thesis of increasing verisimilitude: in the historically generated sequence the theories are increasing in verisimilitude; that is, in the degree to which they are approximately true. Accordingly, the theory that is the last in a sequence is the truest one so far. It is implicitly implied that the better theory can only be looked for in the future, not in the past. This may turn out to be a fatal mistake. We may have to return to some solid ground - e.g. Newton’s theory - in order to be able to replace present “bad theories”.
Pentcho Valev
pvalev@yahoo.com
June 7th, 2007 at 1:04 am
I am disinclined to be hard on present theories for the reason that Newton’s wonderful theory, while certainly elegant, was not earth-shakingly useful for a number of centuries (except for a handful of astronomers.) The old epi-cycle based celestial charts did as well for predicting tides well into the 20th century. Probably not until the USA went to the moon did Newton’s formula really show its utility, which was actually AFTER Einstein’s insight about matter and energy gave us working nuclear bombs and power plants.
Persons familiar with my blogging have heard my speculation about a race of intelligent aliens who gad about the universe with ease and seem to be far more advanced than ourselves in every way–except that they absolutely insist that their home world is not only the center of the universe, it is perfectly at rest. We try to explain to them that this view is somehow “wrong” and not only that, it must make their practical computations much too difficult. They reply that very early in their history they developed computers that had little difficulty in navigating around the universe guided by their arbitrary, absolute reference system, and they liken our different conceptual view of the cosmos to of no more real significance than the difference in our own two major systems of units, the metric and the old English units.
Somehow that just doesn’t seem right to us because it implies that having the correct “conceptual” view of anything is only a matter of semantics that doesn’t really matter. What matters is whether your civilization has sufficient mathematical and engineering skills to actually DO things. For all we know Tibetan monks long ago chanced upon the true “theory of everything” but since they lived in homes with no running water or electricity and they never traveled more than three day’s ride on a donkey from where they were born, their ideas amounted to curiosities without any real impact. For the time being, string theory may be stuck with that label.