The September issue of Physics World is out, featuring a 13 page advertising supplement for string theory which is pretty much unadulterated hype. The same issue includes an editorial which takes the point of view that the only problem with string theory is that:
String theorists need to do much more to explain their field’s genuine links to experiment
String theory’s lack of falsifiability is minimized as a problem, and the fact that it “raises several philosophical issues, such as the role of anthropic reasoning” is listed as a point in its favor. As for those who complain that string theory predicts nothing, in particular nothing about what will happen at the LHC, they are told to just shut up:
With CERN’s Large Hadron Collider (LHC) due to switch on next year, now is the wrong time to slam string theory for its lack of predictive power. While not able to prove string theory is right, the discovery of supersymmetric particles at the LHC would give it a major boost…
The fact that string theory doesn’t predict supersymmetry visible at LHC scales is actually acknowledged in the advertising supplement by Kachru and Susskind.
The few quotes from string theory skeptics allowed seem chosen to be those that put string theory in the most favorable possible light (except for Phil Anderson, who is reduced to hostile spluttering by Polchinski’s claims that string theory may explain high Tc superconductivity). This allows the editorialist to conclude:
However, the richness of string theory that has become apparent in the last decade, and its increasing contact with the real world, gives theorists something to shout about. This is why our main feature on the subject, which started with fairly modest intentions, has ballooned into the longest ever to appear in Physics World. As the views of even many non-string theorists in the article make clear, the theory still holds all the potential it ever did to revolutionize our understanding of the universe.
The critique of string theory by Smolin and myself is pretty much completely ignored or dismissed, with Susskind quoted as having come up with a new insulting term for us (to him we’re “Smoit”, evidently he likes that better than the “Swolin” favored by those in Santa Barbara). The claim is made that
few string theorists think that the sometimes negative portrayal of string theory in the popular arena recently has had much of an effect other than to irritate people.
Amidst the endless misleading hype contained in the Physics World piece, there’s some that simply is demonstrably completely untrue. The most egregious example might be the discussion of Witten’s Fields Medal which claims that it was awarded him due to his work on string theory compactification spaces:
.. with the study of 6D “Calabi–Yau” spaces making Witten in 1990 the first physicist to be awarded the prestigious Fields Medal
The quotes from Witten himself don’t include any of the hype about connections to experiment. He describes string theory as something very poorly understood, with even the fundamental equations of the theory unknown, and no good ideas about how to find them, leading to the danger that even if his vision is correct, realizing it may just be too hard:
It’s incredibly rich and mostly buried underground. People just know bits and pieces at the surface or that they’ve found by a little bit of digging, even though this so far amounts to an enormous body of knowledge… There is an incredible amount that is understood, an unfathomable number of details. I can’t think of any simple way of summarizing this that will help your readers. But despite that, what’s understood is a tiny, tiny amount of the full picture.. One of the greatest worries we face is that the theory may turn out to be too difficult to understand… [about the search for equations for string theory] This is certainly a question that interests me… but if I don’t work on it all the time, it’s because it’s difficult to know how to make progress.
Unlike Witten, many of the other string theorists quoted seem to have no problem with issuing streams of highly misleading hype claiming “predictions” of string theory. For instance, from David Gross:
String theory is full of qualitative predictions, such as the production of black holes at the LHC or cosmic strings in the sky, and this level of prediction is perfectly acceptable in almost every other field of science,” he says. “It’s only in particle physics that a theory can be thrown out if the 10th decimal place of a prediction doesn’t agree with experiment.
I don’t know how to characterize this kind of claim that string theory is as predictive as other scientific theories, just not able to get accuracy to 10 decimal places, as anything other than out-and-out dishonesty. If someone could come up with a legitimate, distinctive, testable prediction of string theory that gave even the correct order of magnitude for some experimental result, that would be a huge breakthrough.
Michael Green, while describing the landscape and its potential to allow for a small CC as “an enormous success” for string theory, is one of several string theorists characterizing the status of string theory as being just as good as that of QFT, with the landscape not a real problem at all, just a “supposed” one:
This supposed problem with a theory having many solutions has never been a problem before in science.
Several people promote the anthropic point of view, with Susskind describing it as the third superstring revolution, one that is even more of a revolution than the others. Polchinski adds
In terms of changing the way we think about the world, the anthropic landscape is certainly as big as the other revolutions
while Susskind’s colleague Shamit Kachru is described as “in the middle”, sensibly pointing out that it would have been a stupid thing for people to do, once they realized that the ratios of sizes of planetary orbits were environmental, to start claiming that “there is a deep anthropic lesson to be learned from Newtonian gravity.”
All in all, I think that the picture the Physics World article presents of the reaction of leading string theorists to the failure of the superstring unification project is a depressing one. Instead of acknowledging in any way this failure and considering what can be learned from it, on the whole they seem to prefer to abandon science for anthropic pseudo-science, to spout misleading claims of bogus “predictions” of string theory, and make indefensible claims that the lack of predictivity of string theory is not unusual for a science.
On the other hand, among string theory skeptics, I fear that the attitude of Howard Georgi is all too common:
I have been critical in the past of some of the rhetoric used by string-theory enthusiasts,” says Howard Georgi of Harvard University, who coinvented the supersymmetric extension of the Standard Model in 1981. “But I think that this problem has largely corrected itself as string theorists learned how complicated string theory really is. I am concerned about the focus of young theorists on mathematical details, rather than what I would consider the real-world physics of scattering experiments, but with any luck the LHC will take care of that by reminding people how interesting the real world can be.”
The problem with string theory is not too much mathematics and a lack of effort towards making connection to real world experiments, but that it is a wrong idea about unification, and thus cannot ever explain the standard model or predict what lies beyond it. The recent move among string theorists to hype bogus claims about connections to experiment, abandoning the search for greater mathematical insight into string theory as just “too hard”, retooling themselves as more salable “string phenomenologists” and “string cosmologists” is not a healthy trend. It is based on adopting the Susskind-Polchinski “multiverse” revolution in the received wisdom about how to do fundamental physics, slowly turning a once great subject from a science into a pseudo-science.
Update: Lubos is beside himself with glee over the Physics World article, see here and here (don’t miss the photo-shopped “Smoit” graphic of me and Lee Smolin). For something more reasoned, there’s a short piece at Wired.
They have a surprise coming to them, then. A general attitude of eye-rolling toward string theory is prevalent at the Perimeter Institute (at least, in the quarters I associated with), and almost every undergraduate I’ve spoken to at Caltech things string theory is just a “not even wrong” mess. The view seems to be “OK, maybe they have some idea what they’re talking about, but it doesn’t seem promising. I’ll let someone else work on that stuff, while I try something more likely to be correct.”
The point is, you guys have had an impact, so be sure you know that :).
The editorial contains the sentence: “String theory is guided by problems in the real world – for instance the entropy of black holes”. Who wrote this must be either a string theorist or a humorist.
Peter,
I don’t usually get involved in the string theory arguments, but since it’s a 3-day weekend (and I’ve been working all weekend):
I think ‘t Hooft is right (and now I’ll put some words in his mouth). Theoretical physicists aren’t doing science or the public any favors by arguing in public, in layman’s terms, about the merits and de-merits of string theory. It’s just too easy for people who don’t understand the technical details to get wrong ideas about speculative research.
We’ve seen this in one direction for some time now, with many laymen being quite convinced that string theory was already a done deal. (I even remember a WPI professor, not a particle physicist himself, who told me when I was 17 that grand unified theories were pretty well-verified.) And now we’re seeing it in the other direction, with for example, many slashdot denizens (and Caltech undergrads apparently) convinced the string theory is basically a fraud. This isn’t much of an improvement; we still have people with firm opinions and no understanding.
I’m personally hoping that these two public impressions will eventually cancel out, leaving people with a more or less correct impression. String theorists do have their hands on something quite interesting, maybe even a good framework for building quantum gravity models, but their research is quite premature. (So it goes: it took mathematicians 3 centuries to prove Fermat’s Last Conjecture.) Said framework has a lot of problems, but most of these problems — no vacuum selection, landscape of solutions, no preferred extension of the Standard Model, no sensible computation of the cosmological constant — are shared by the effective field theory framework we’re currently using. The string theory framework might be the correct one, or maybe not. We don’t have any way of telling without experimental data. In this sense, I thought the Physics Today article wasn’t that bad.
So, let me make a modest suggestion: Scientists have to talk to the public, and they’re obligated to give some explanation of the ideas they’re working on. But it would probably be better for everyone involved if scientists and science journalists remembered that, when we’re talking about things we have no experimental evidence for, the question is usually vastly more interesting than the proposed solution. If I’m going to read about an attempt at computing the half-life of a de Sitter geometry, I want 75% of the article to be about dark energy, the sign of the cosmological constant, and why anyone is thinking about metastability of geometries with positive cosmological constant.
Karl Rove, who famously claimed to have made the “reality-based community” irrelevant, seems to have landed his new job at Physics World, then? String theory as an analytical tool to study the quark-gluon plasma? And there is that famous E8 picture…
Gerard ’t Hooft of the University of Utrecht, who
shared the Nobel prize in 1999 for his work on electroweak
theory, thinks that discussions about the merits
of theories should be limited to professional circles.
But they already are! This must be an appeal to have the door to the ivory tower walled in from within. Or to shut down blogs?
The fact that they are resorting to calling Peter and Lee names says it all.
During the Einstein Bohr debates, I wonder if Einstein snarked “Beisenberg” or “Heisenger” or “Heisenbohr” or “Schreisenberg.”
Alas, there was a time when honor, reason, and logic ruled physics.
Hi A. J.,
I agree with ‘t Hooft that the issues here are complex, and not really appropriate for a discussion at a popular science level. On the other hand, sometimes they are the subject of inappropriate mystification: no, you don’t need to work through the details of the KKLT mechanism to understand what the landscape problem is. At this blog I do try and provide a discussion of these issues at an appropriate level, and in the book I tried also to not dumb down things past the point where a serious, accurate argument was being made.
I certainly see lots of ignorant arguments used to condemn string theory, just as I see equally ignorant arguments used by string theory partisans. Maybe they cancel each other out. But I’m actually not really that interested in the question of how good the public understanding of the string theory issue is (although I’d argue it’s much better now than a few years ago, and I hope I had some role in causing that). What I do care about is the understanding of these issues among physicists and mathematicians, and that’s who the blog and the book are both aimed at.
It certainly would be much better if this discussion was carried on at a more serious level. Unfortunately, many well-known string theorists seem to have decided not to respond to serious scientific criticisms in a serious way, but instead to dismiss them by calling Lee Smolin and me names, and going to the press with the kind of less than honest hype that dominates the Physics World piece. I don’t think blog entries by undergraduates who don’t understand these issues well are a big problem. The kind of misleading claims being put out to the public by leading physicists like Gross are.
Hi Peter,
Just wanted to say, great post.
Keep up doing your thing. 🙂
Anonymous
Hi Peter,
I, as I imagine many others, appreciate the time you take to put these issues into context and the commentary you provide on various articles/resources.
I am not at a level of understanding where I could put up novel arguments for or against string theory myself but I feel able to follow much of what yourself and others blog about. Reading the ebb and flow of ideas for and against the various theories being put forward to advance our understanding makes me feel a small part of history in the making (if only mainly at the level of spectator).
I would disagree with t’Hooft and others that it is not useful to have such discussions in public. “Layman” who can follow most of what is being said (or are even interested) are likely to be slightly above your average layman in terms of their knowledge of physics. Thus, on average, will be able judge the arguments in an appropriate way.
e..g I don’t have to be able to write an original paper concerning compactification on Calabi-Yau manifolds to appreciate the difficulties you raise in relation to the landscape – and if you did not discuss such issues I would possibly be swallowing string theory hype hook line and sinker. On the other hand I am sensible enough, as no doubt others are, not to take everything you say as gospel either, and take information from multiple sources to form my own opinion.
Theo
AJ, what is there to understand? The simple fact is that every natural string theory suggestion (supersymmetry, extra-dimensions, 496 gauge bosons, non-positive cc, …) is pretty much ruled out by experiment. Even susy with two layers of excuses (broken, and with R-parity conservation to kill dim-4 operators) is disfavored by experiments at the Tevatron and elsewhere. Surely intelligent laypersons can understand that a theory which disagrees with experiments is in trouble.
In fact, the situation for string theory is quite similar to that of ether theory. In both cases, there is one thing that should happen but did not (ether wind/supersymmetry) and one thing that could not happen but did (photoelectric effect/positive cc). And in in both cases, the strong proponents include a Nobel laureate (Lorentz/Gross) and a top mathematical physicist (Poincare/Witten).
Another similarity is that it takes a long time for a flawed theory to die. If you look at the title of Paul Ehrenfest’s inaugural speech, you will see that ether theory was still alive in 1912, 25 years after the Michelson-Morley experiment and seven years after some crackpot patent clerk discovered special relativity.
Peter,
I’m happy to leave the hype disposal to you. I’m glad that someone is doing it. But I’d rather see the science journalists doing it themselves. (My favorite posts here are your comments on mathematics.)
On a related note: that someone’s making jokes with your name and Smolin’s is normal human nature, however unfortunate. Reporting said joke in a “serious” publication, on the other hand, is odd and rather tasteless.
——–
Thomas,
If you read more carefully, you’ll notice that I said essentially nothing about string theory as source of particle physics models, except to note that it shares many of the qualitative flaws of our current framework. I said it was a barely apprehended framework for building quantum gravity models. I don’t expect useful predictions about TeV scale particle physics from it; indeed, given how much of the framework is probably missing, I don’t see much reason to take such suggestions seriously.
What makes string theory interesting, to my mind, is that it’s a good context for testing out ideas about gravity, black holes, and quantum geometry. So our theoretical intelligent layperson ought to be skeptical when she reads articles about large extra dimensions, colliding branes, and TeV scale supersymmetry. But she should also feel a little wonder maybe at the computations of black hole entropies. Even though this behavior should be fairly universal, it’s amazing to see the correct constants coming out of a microscopic accounting.
In short, it’s an interesting set of ideas. It’s probably good for something. We should keep it mind, even if we choose to work on other things, since we gain nothing by trashing it. (After all, thinking about the problems with the ether theory helped Einstein find relativity.)
I said it was a barely apprehended framework for building quantum gravity models. I don’t expect useful predictions about TeV scale particle physics from it; indeed, given how much of the framework is probably missing, I don’t see much reason to take such suggestions seriously. What makes string theory interesting, to my mind, is that it’s a good context for testing out ideas about gravity, black holes, and quantum geometry.
In your perception, is this what string theory researchers* are currently using the theory for?
Assuming for the moment that you’re right about what makes string theory important: do you think it is possible for string theory to produce useful progress and insights if, rather than attempting to attack it as a framework for testing out ideas about gravity and quantum geometry, those working on it are approaching it as a model for predictions about particle physics, or as a set of ground rules that lets you build 10^500+ configurations of Calabi-Yau manifolds [one of which is expected to describe the Standard Model], or as some other similarly literal interpretation of the theory?
* Given that I’m sure it is silly to try to think of “string theory researchers” as a homogenous bloc.
Pingback: Un poco de Teoría de Cuerdas « La Singularidad Desnuda
AJ, perhaps it is because I am a physicist that I react strongly when people ignore that every testable string theory prediction is plain wrong. However, I feel strongly about this, and something that has been suppressed for 25 years. Ether theorists didn’t just give up after the Michelson-Morley experiment neither – after all, ether theory was the best developed theory of light and arguably the only game in Newtontown.
Besides, string theory is hardly a successful theory of quantum gravity, because such a theory must explicitly involve the detector’s properties. Every physical experiment is an interaction between a system and a detector, and the result depends on the physical properties of both. Typically we want to extract only those aspects of the experiment that are independent of the detector, which means that we implicitly assume that the detector’s charge is small (so we can ignore its backreaction on the fields) and that its mass is large (so we can measure both the detector’s position and velocity to arbitrary precision). This assumption, which is built into theories like QFT and string theory, clearly breaks down for gravity where mass and charge are the same.
The Five Stages of Coping with Catastrophic News
1. Denial 2. Anger 3. Bargaining 4. Depression 5. Acceptance
http://en.wikipedia.org/wiki/K%C3%BCbler-Ross_model
Oddly, “swoit” and “swolin” both appear in the Book of Zweig, but as verbs. If I may quote:
Correction: swoit->smoit
Dear Peter
Is it really true that in writing 12,000 words about the status of string theory I have only made one mistake? That’s the best news I’ve heard all day! Perhaps you can do better after a second or third read (try the more technical 750 word text-box titled: “Why can’t string theory predict anything?” on p42 for starters).
On a more serious and hopefully constructive note, however, your post raises important issues about the role of balance (and thus objectivity) in science journalism and blogs. Journalists, who normally don’t have an axe to grind and can therefore go into a new field with an open mind, often aim to achieve balance by seeking a mixture of expert opinion (for example, by printing the quotes of 10 eminent non-string theorists alongside those of 11 string theorists in an article surveying the scientific status of string theory). Because blogs tend to be read by narrower audiences that hold similar views as the author’s, balance is presumably less of an issue.
However, I’m sure that anybody interested in the current debate surrounding string theory would still be interested to hear your reasons for deciding not to even mention RHIC in the context of the Maldacena conjecture when you “evaluate” string theory in the second half of the paperback version of Not Even Wrong, for instance. Could this be the same logic that prevented you from acknowledging the presence of three other articles in the same September issue of Physics World (pp14–19) that were written by yet more non-string theorists, in particular by philosophers of science? These pieces tackle anthropic reasoning and the issue of testability head-on, and may help your readers reconcile your own somewhat perplexing stance on string theory — i.e. if the theory is, as you routinely point out, unfalsifiable then how can you be so certain that it has already failed?
Oh, and one last thing: next time you want to make a point, get out there and find your own quotes to back it up.
Matthew
Since Matthew Chalmers is gracing this blog with his presence, maybe he could elaborate a bit on what ‘t Hooft actually said. Was it literally that “discussions about the merits of theories should be limited to professional circles”, or is this an extrapolation? It does sound dangerously close to “shut up an pay”, a position which, when taken by a public employee addressing the tax payers, has only one legitimate answer: you’re fired.
How can one be so sure that it has already failed?
Well, just because in mainstream scientific reasoning the terms “unfalsiable” and “physical theory” had been always considered as mutually exclusive.
Remarkably, after nearly 40 years, we still don’t know what string theory truly is,” exclaims Gross. “From the start, string theory was a set of rules for constructing approximate solutions in some consistent classical background – and that’s all it still is.”
How then can it be called a theory of quantum gravity?
What I quoted above is at odds with
The most important is that string theory provides a finite (i.e., non-divergent), consistent, quantum theory of gravity that reduces to general relativity at large distances and low energies.
I am somewhat worried about this hype by Physics World. It implies that this community of theoretical physicists is indeed very powerful to manage information (beside positions). This situation has no precedents in the history of physics.
It will not be a beatiful result of our generation to be remembered as the worst ever.
Jon
Matthew,
I can’t help pointing out that the mistake you made about Witten’s Fields medal indicates you didn’t bother to read my book, since there’s a whole chapter in it about the subject of Witten’s contributions to mathematics and what he won the Fields Medal for. It does appear that you skimmed it enough to notice that it doesn’t contain mention of the latest string theory hype about heavy-ion physics. There are a couple reasons for that, the most important being that the book was written in 2002, and the hype about this subject began in 2005, by which time I’d found a publisher willing to publish it, and the manuscript was being copy-edited and out of my hands. If I were writing the book today, I suppose I would discuss the subject, including the awarding of a “Pinocchio award” by a heavy-ion physics expert to string theorists for their misleading claims about this that you uncritically repeat.
As for why I didn’t discuss the other articles about string theory in the same issue of Physics World, the reason is also pretty simple: I don’t have access to them since there appears to be no online access available through my institution (Columbia) and I’m not a member of the IOP. I wrote about what I have access to, if someone is willing to send me copies of the other articles I’d be interested to see them and probably would write about them then.
“if the theory is, as you routinely point out, unfalsifiable then how can you be so certain that it has already failed?”
You’re not making any sense here. A scientific theory that can’t be falsified is a failed scientific theory. The argument, which does require getting into technicalities, and involves making informed scientific judgments, is about whether there is any hope of the current situation changing, and getting falsifiable predictions out of string theory. I’ve argued here at length why I think this is hopeless, others have different opinions.
I very much respect the large amount of work you did on this, including the many people you talked to and the large number of relevant quotes from experts that you gathered. That’s not what I do though. When I’m writing about string theory as science here on the blog, I try to stick to writing about things that I actually understand, and what I write is based on my own judgments and my own understanding. People who disagree with these often write in here to do so, and that often leads to an interesting discussion. When I write about the public perception and debate over string theory, sure, I discuss what string theorists are telling journalists. Again, thanks for all your work on getting this sort of material together.
Much of my comments on your article were aimed not at you, but at the many string theorists who talked to you. I find a lot of their claims outrageous, and their willingness to make highly misleading and overhyped claims about the state of string theory disturbing. At the same time they are doing this, other string theorists often complain that string theory has gotten a bad rap just due to the over-hyped claims made for it in the past. Anyway, it’s your job to accurately transmit what experts have to say to the public, and I have no problem with your role in doing that.
But, for some reason you decided in your article to strongly take one extreme side of a scientific controversy. That’s rather unusual, and I think it deserves a commentary like mine that points this out. You not only ignored the arguments on the other side of this controversy made by Smolin, me and others, but you adopted a framing of the issue that I think even most string theorists would find dubious. The claim that string theory is “rooted in experimental data”, and your emphasis on the LHC doesn’t reflect my impression of the opinions of most string theorists, who readily admit that the LHC can’t in any standard way “test” string theory, and that the tenuous connection of string theory to experiment is a huge problem. It appears that you didn’t bother to contact anyone who is actually an LHC expert, either the people working on the experiments or the theorists with expertise in analyzing collider data. If you asked such people what they thought of the idea of the LHC “testing string theory”, you might have gotten some strong quotes disagreeing with the thrust of your article.
“It’s only in particle physics that a theory can be thrown out if the 10th decimal place of a prediction doesn’t agree with experiment.”
A) Nobody ‘throws out’ a theory that agrees in 9 decimal places. One might want to clarify in which limit it is suitable.
B) Ever heard of General Relativity? I believe this blog has plenty of readers that would be thrilled to hear about a deviation in the nth decimal place.
The above Witten quotation about digging out knowledge leaves me wondering: if string theory is not the looked for ToE, then what is it? And should one dig it out whatever it is?
Besides this, I guess we should be grateful your name is not Peter Wirch.
-B.
Dear anon.,
About the 10^500. One thing which is known to all experts, but you will not be told on this blog, is that in the most studied case where the 10^500 means anything, and also where the number came from, (technically, this case is called IIB flux compactifications), for many (not all, but a lot of) physically relevant quantities the `10^500 different cases’ collapses into a single unknown number.
The effect of these 10^500 choices on low-energy physics then collapses into the presence of a single unknown number in the low energy theory. Big deal – you have one number you need to fix by hand, and then (for a lot of problems) your 10^500 has gone away.
So the notion that the 10^500 solutions makes the theory unpredictive is not at all true and is in fact highly misleading. Indeed, people who work on this area are currently very excited rather than depressed.
This situation is present all the time. The Standard Model has an *infinite* number of possible varieties – there are twenty or so numbers that have to be fed in by hand. Of course this doesn’t make the Standard Model not science.
Another anon.
2anon:
I’m not sure if I can answer your question completely but here is what I know. In the original KKLT construction, the integer fluxes which fix the values of the complex structure moduli enter through the so called flux superpotential W_0. Now, W_0 is indeed a very complicated function which can take on an exponentially large number of discrete values. However, if you read string phenomenology papers (by Choi et al. for example) based on the KKLT constructon you will notice immediately that the corresponding particle phenomenology always depends on the fluxes through a single parameter – W_0 and not on the individual flux contributions.
Hence, in practice, all these comlicated flux configurations, while useful to tune the cosmological constant, completely decouple from particle physics.
Note: “another anon” is responding to a comment by “anon” that I deleted. The first “anon” is someone who specializes in submitting off-topic comments here attacking string theory and string theorists, usually in an uninformed way. I have to waste a lot of my time deleting them, and I’m really, really unhappy about this. This whole business of overuse of anonymous comments is annoying. If you want to make a scientific argument here, there rarely are good reasons for you to not be willing to put your name to them.
Please, anyone who is not happy with string theory or string theorists, I ask you to not use my blog comment section as a place to vent about this. If you don’t have something well-informed and relevant to say in a comment, don’t post it. There’s more than enough very pointed criticism of string theory and string theorists going on here, adding your own adds nothing, and if it contains inaccuracies, all it achieves is to give string theory partisans a reason to dismiss the serious arguments being made here.
As for the arguments of “another anon”, they have nothing to do with the topic of this posting, and are an argument against a straw man argument I’ve never made. Yes, the situation with the landscape is far more complicated than the one specific compactification mentioned. If you look at one very specific compactification and just vary the fluxes, sure you can’t get anything you want. But you also can’t get a prediction of anything, because a different choice of Calabi-Yau, branes, other background information will give you something different.
I’m afraid I’m going to cut-off any more discussion of this right now since it has nothing to do with the topic of the posting, the Physics World article, unless you are claiming that the study of flux compactifications makes string theory testable at the LHC, in any standard usage of the term “testable”.
Also, please do me a favor and allow a few minutes after an uninformed comment by “anon” attacking string theory appears before responding to it to give me a chance to delete it. I know arguing with “anon” is a lot easier than arguing with me, but still. The line in his comment about how I was going to delete it should have been kind of a giveaway in this particular case.
Also, please consider putting your name to what you have to say, unless you have a very good reason not to.
From the editorial:
That’s pretty serious criticism actually, given the perennial shortage of resources in particle physics, and the standards of integrity expected of scientists.
Peter:”unless you are claiming that the study of flux compactifications makes string theory testable at the LHC, in any standard usage of the term “testable”.”
In Type IIB flux compactifications one can derive a reliable prediction for the pattern of the gaugino masses. See Nilles and Choi for the related work.
JD:
So you are claiming that the non-discovery of gauginos at the LHC will disprove string theory 🙂
Peter – a quick skim through the Notes pages of your book reveals that you should be awarded a Pinocchio prize yourself (e.g. you appear to have had no trouble in fitting in an Edge quote from Phil Anderson in 2005, nor in quoting from Krauss’s 2005 book, Randall’s 2005 book or Susskind’s 2005 book). Recall that the APS announcement of the RHIC result was in March 2005, with plenty of hints coming out from late 2004.
As for my not making any sense about your stance on string theory, you should consider broadening your philosophy of science slightly by reading Lakatos and others. Your entire attack on string theory seems to me to be based on a convenient but narrow and overly simplistic Popperian view of testability (i.e. falsifiablility) that is simply one interpretation of how science progresses — and certainly not the consensus view among philosophers of science.
Stringscape is not an attempt to give an overview of the “debate” surrounding string theory based on echoing yours and Smolin’s arguments while completely ignoring the views of string theorists and other theoretical physicists. That has been done to death in the last year or so, as I set out in the first few paragraphs. Rather, the article is an attempt to bring something new to the debate by giving Physics World readers a non-partisan overview of where string theory — a scientific research programme that, for better or for worse, dominates current research in fundamental theoretical physics — stands today. (As it happens, the other three more interpretive string-related articles in the September issue do address the broader anthropic etc debate, although none mention your blog or book I’m afraid).
My article could of course have turned out quite differently if all 10 of the non-string theorists I interviewed had been more critical. But they weren’t. Similarly, I could have turned up at Strings07 in Madrid to find a bunch of deluded nut-bags dealing only in abstract mathematics and talking in tongues. What I did find, however, was a bunch of mostly extremely able theoretical physicists trying their damndest to understand nature at its most basic level. The overwhelming impression I got, and which I have tried to convey in the article, is that string theory is simply not yet developed to the point where it can make the “falsifiable” predictions that physicists need before they can know for sure whether it is a viable physical theory. Rather, it is a compelling framework for unification that also happens to have all these great applications in mathematics, black-hole physics and, most importantly for physics perhaps, quantum field theory.
You still don’t seem to get my earlier point that as a journalist I have no vested interested in whether string theory is portrayed in a positive or negative light. Since you claim only to blog about the things you understand, perhaps you should find something else than science journalism to criticize — after all, it’s not that hard an approach.
“So you are claiming that the non-discovery of gauginos at the LHC will disprove string theory ”
Please point to the phrase where I made such a claim.
Matthew,
Thanks for raising the level of discussion here by calling me a liar. One of the depressing things I’ve learned during this string theory debate is how many people think the correct response to legitimate criticism of the content of something they have written is to launch a personal attack.
Some of the things you mention were among a small number of additions and changes made to the text in November 2005, after it was copy-edited, before it went to the typesetter (the manuscript was delivered to the publisher in the summer of 2005). Sure, by that time people were discussing the application of AdS/CFT to heavy-ion physics, but it only became a major talking point for string theorists starting in 2006. I made no claim in my book to deal with every overhyped claim made for string theory, doing so would have made it a much longer book.
This issue in any case has nothing to do with what I was criticizing in my book, the failure of string theory as an idea about unification. If you look at page 192 of the book you’ll see this subject referred to as
which remains an accurate description of the situation, minus the hype surrounding the attempt by many people to use rather tentative results about heavy-ion physics to deflect attention from the failure of the string theory unification program, which is something quite different.
The other thing I get a lot of from people I’ve criticized accurately is sneering put-downs about how ignorant I am (“you should consider broadening your philosophy of science slightly by reading Lakatos and others”). Actually I’ve read Lakatos (and others), and am well aware that “falsifiability” is a tricky subject. If you read my book (you really should do this, you might learn some things) you’d find a long discussion about the problems with falsifiability and a lot of evidence that I don’t have a “convenient but narrow and overly simplistic Popperian view” of this issue. What counts as a convincing test of a scientific theory is a tricky issue, but it is uncontroversial that there is no such thing possible for string theory unification at the moment, and, as I said, I’ve argued extensively that any hopes for this in the future have little to back them up other than wishful thinking.
Finally, I don’t know or care whether you have a vested interest in string theory or not. Honestly, I know nothing about you beyond having read the 13 pages that you wrote. What I wrote here was a response to claims made in those 13 pages, by you and people that you interviewed, many of which are highly misleading. I’m willing to debate those claims further if you want, but I really think you should start by stopping personal attacks on me, and informing yourself what my views on this subject actually are, rather than making up naive and uninformed ones to argue with.
Pingback: String “theory” versus physical facts (updated) « SU(2)xSU(3) for QFT
JD,
I already spent a lot of time looking into claims of “predictions” of gaugino mass ratios that refer to Nilles and Choi. These turned out to be quite misleading, see the discussion at Cosmic Variance, one of my relevant comments is
http://cosmicvariance.com/2007/03/31/string-theory-is-losing-the-public-debate/#comment-241803
As far as I can tell, the situation here is just like in anything else in “string phenomenology”: for certain specific classes of models you have constraints on what you’ll see, but there are no general constraints. If you don’t see one particular pattern, you can find another class of models that will give you what you want.
JD:
You used the phrases “LHC”, “reliable predictions”, “gaugino masses” in you previous post. But of course this does not mean that string theory reliably predict gauginos at the LHC, only that you want to create such a false impression.
Peter. You had said: “unless you are claiming that the study of flux compactifications makes string theory testable at the LHC, in any standard usage of the term “testable”.”
I’ve read the discussion you pointed to and then looked at my original post and I see no problem. I still claim that flux compactifications (discussed in Nilles and Choi) yield robust predictions for patterns of gaugino masses.
I agree that there are no general string theory constraints on how SUSY is broken but since you specifically mentioned flux compactifications, I have to say that the corresponding phenomenology has been worked out.
For Thomass Larsson: It is well known that in its current state, string phenomenology does not give a definite answer about the scale of SUSY breaking, just like the standard model without experimental input does not predict the higgs mass or the top quark mass. So what? If we are lucky and the superpartners are discovered at the LHC we may be able to identify the particular class of string compactifications by studying the pattern of gaugino masses, why is this so controversial?
another anon., this is really priceless argumentation. it reminds me of a seminar i once sat through by some few body model-builder. it involved ‘free’ quarks with pion exchange ans should explain the nucleon spectrum. this guy claimed he had no free parameters whatsoever.
finally, he had to admit, that the model contained an arbitrary function describing the interaction potential. he pulled some arguments that no, this means no free parameters and this function almost presents itself.
but he was just doing phenomenology. so i excuse him even if he needs infinitely many parameters to describe what essentially is a theory with one parameter (qcd in the massles limit). but hey, wow! the lanscape can do that too. i am seriously impressed 🙂
Chris, I think you got confused about another anon’s point. Your analogy is incorrect. Read the KKLT paper and you’ll understand what another anon meant.
Matthew, I would like to comment on your sentence: “The overwhelming impression I got, and which I have tried to convey in the article, is that string theory is simply not yet developed to the point where it can make the “falsifiable” predictions”.
String theory started with the hope that maybe quantum gravity implies testable predictions on observable low energy physics. String theory was partially developed, and a more realistic and pessimistic expectation emerged. No matter how much you develop the theory, you will never get any prediction, if no prediction exists.
Dr. Woit,
I’m not sure if this is the appropriate place for this, but I’ll post anyway. I am not a specialist on one side of the debate or the other (I’m a chemist who knows a little bit about such things as quantum mechanics, symmetry, and group representation theory). I read your book during the summer and found it to be quite an eye opener and well worth reading. I was previously under the impression that “M-Theory” was some kind of unification of several string theories and in some sense a complete theory. I enjoy looking at your blog from time to time.
Thank you.
Hi Peter:
Sorry for abusing your hospitality, but in case anybody drops in here after reading Lubos’ totally distorted summary of this comment section, I want to point out that I’ve never said David Gross is a moron (as Lubos has managed to read, I wonder if he’s taking pills to achieve that?), the comment above was addressed to Peter (you might recall – the guy who writes this blog) and the words ‘your name’ refers to ‘Peter Woit’s name’. One should have thought this is obvious.
I just want to leave that clarification here since I’m afraid Lubos will delete my comment at his post. I should add that I am pretty much pissed off by so much unjustified viciousness, and I am (eventually) going to remove links to TRF (what I should have done much earlier I guess).
Best,
B.
Bee,
Surely you should know by now that paying any attention to Lubos is virtually always a big mistake. The Chalmers article seems to have gotten him really excited, finally seeing his point of view reflected in the media, after a year of having to read much more accurately skeptical pieces about the problems of the theory.
The only surprising thing he says though is his claim that PI offered him a job. If someone who knows what’s behind that story wants to tell me about it on deep background, I wouldn’t mind…
“The problem with string theory … it is a wrong idea about unification, and thus cannot ever explain the standard model or predict what lies beyond it.”
Peter,
Would you still stand by this statement if LHC and other experiments support the idea of both theoretically and experimentally, the idea of something like a SUSY-SO(10) GUT, and as such, could be embedded within a string theory?
It is amusing to see a group of people with nearly zero knowledge in high energy physics arguing whether a group of Nobel proze winners is correct or not. Who should I believe ? 🙂
proze->prize …
A quote from Bee :
” Ever heard of General Relativity?”
Well, should we tell David that you think he has not heard of GR ?
ori,
Thanks for making it clear that Bee’s comment
“so much unjustified viciousness” is an accurate description of other string theorists besides Lubos Motl.
Besides the insults, do you have any commentary on the actual blog posting?
Dear Peter
The reason why I decided to post a comment on your blog this morning, in response to your labeling an article that I had written a dishonest and misleading advertising supplement based almost entirely on unadulterated hype, was to raise a couple of points about the differences between blogging and journalism (and how the two interact with one another). This is a topical issue for those of us who work in traditional media outlets — and presumably for those who read and write blogs too — and has already led to some interesting episodes between scientists and journalists.
A great example of this was the “bump-hunting” saga at Tevatron earlier this year, which led to an article in New Scientist magazine (see http://physicsworld.com/cws/article/print/27731). Once high-energy LHC data begin to pour in a year and a half or so from now, and blogger-members of the Higgs groups in the ATLAS and CMS collaborations start getting excited, it will be a real challenge to know when best to break the story of a possible Higgs or some other discovery. Indeed, journalists aside, these large collaborations are going to have to deal with problems of their own involving how to manage the blogging activities of physicists.
In retrospect, however, Not Even Wrong was probably not the place to try and have such a discussion, given that, for instance, you are not actually involved in string theory/high-energy physics research yourself. And since our brief exchange has turned into pointless pedantry and apparent confusion over what is personal and what is fair-game, I would guess that readers are not going to get much more from it either.
More to the point, it is late and it feels as if I have been looking at that bloody UA1 W-event all day. This stuff must tie up hours of your time!
Matthew
PS I posted a hard copy of the September issue to you last week, in which you can read the other articles that I mentioned – that is, if you’re at all interested in taking someone else’s opinion on string theory on board.
dan,
Sure, I’ll stand behind that statement until someone comes up with a plausible way of getting real predictions out of string theory. I think the great hope of some string theorists is that the LHC will see not only supersymmetry, but a pattern of supersymmetry breaking that corresponds distinctively to a certain kind of string background. Based on this they might then be able to make real testable predictions. This seems to me to be nothing but wishful thinking, we’ll find out in the next few years.
Turning the question around, do you think string theorists are willing to change their minds about string theory if no evidence of a supersymmetric GUT turns up at the LHC?