This week’s New Scientist has an article promoting the string theory multiverse, starting off with positive comments from Brian Greene, and continuing with a claim that the majority of physicists now embrace the idea:
Greene’s transformation is emblematic of a profound change among the majority of physicists. Until recently, many were reluctant to accept this idea of the “multiverse”, or were even belligerent towards it. However, recent progress in both cosmology and string theory is bringing about a major shift in thinking. Gone is the grudging acceptance or outright loathing of the multiverse. Instead, physicists are starting to look at ways of working with it, and maybe even trying to prove its existence.
In his promotional book on the subject, Susskind is able to come up with exactly one bit of information that the string theory multiverse hypothesis provides, a prediction of the sign of the spatial curvature of the universe (others don’t think that even this bit is there, see this by Steve Hsu). The New Scientist article ends:
…says Susskind. “If it turns out to be positively curved, we’d be very confused. That would be a setback for these ideas, no question about it.”
Until any such setback the smart money will remain with the multiverse and string theory. “It has the best chance of anything we know to be right,” Weinberg says of string theory. “There’s an old joke about a gambler playing a game of poker,” he adds. “His friend says, ‘Don’t you know this game is crooked, and you are bound to lose?’ The gambler says, ‘Yes, but what can I do, it’s the only game in town.’ We don’t know if we are bound to lose, but even if we suspect we may, it is the only game in town.”
The arguments for string theory have evolved over the years, with the “it’s the only game in town” one being made starting fairly early on. Weinberg seems to be willing to go for a new variant of this, that not only is it the only game in town, but it’s probably crooked (i.e. can’t possibly work, is obvious pseudo-science…), and this doesn’t matter, one should continue anyway.
It has become increasingly clear to me in recent years that there is a large cohort of people who have so much invested in string theory that they will never, ever give up on the idea of string theory unification, no matter how clear it becomes that the game is crooked and not legitimate science. They will be active and with us for a long time, but the idea that there has been “recent progress in both cosmology and string theory … bringing about a major shift in thinking”, causing the majority of physicists to sign on to this is nonsense. Quite the opposite is true, with the increasingly obvious problems with string theory causing non-string theorists to shun the subject and avoid hiring anyone who works on it.
The New Scientist article is also available here, and if you want more recent multiverse promotional material, there’s this. Finally, a panel discussion on this was held at the Origins symposium at ASU recently, and is now available on-line.
Update: The torrent of string theory hype seems to continue unabated, with claims that the Planck satellite will tell us something about string theory (see here):
The results could also offer insights into the much vaunted string theory – science’s big hope for a unified theory of everything. The idea involves a complex 11-dimensional universe, with seven ‘hidden’ dimensions on top of the four observable dimensions of space and time.
Professor Efstathiou said: “The potential for fundamental new discoveries that will change our understanding of physics is very important and that is what I’m really hoping for with Planck.
“We might find signatures of pre-Big Bang physics. We might find evidence of cosmic defects – superstrings in the sky.
“Unravelling the physical information may tell us something about the warped geometry of the hidden dimensions.”
Oh my God… You are really a sick puppy. Vitriolic, unfounded and really pathetic banter. Do us (= scientists) a favor and offer us when rejecting (whatever you do not like and that’s your perfect right) a valid – or at least interesting – alternative. This blog is really becoming the prime example of the emperor with(out) his clothes. PLEASE: publish a scientific paper and BUILD instead of destroying…
Examine the psychology of these people who are doggedly promoting string theory. They are desperate. The vast majority are over 45, the age beyond which it is extremely rare for a mathematical physicist to make significant contributions. They have devoted most of their professional careers to string theory. They need a new generation to continue the quest or they will have wasted their research lives.
Egotism, the refusal to face the consequences of their folly, and the terrifying realization that they will never be more than footnotes to science unless the next generation can make the breakthroughs building on their work is what drives them on. Worse, the failure of the past thirty years risks being held up as a model of how not to do theoretical physics. So they have to succeed.
The fact that they are sucking young talent into the same futile exercise is of no concern to them.
It’s clearly a form of fanaticism. Almost religious in nature.
Weinberg is only lukewarm, his place in history is secure.
LSD,
Sometimes I do think of giving up on trying to do anything about the endless hype and pseudo-science going on under the banner of “string theory”, mainly because it seems hopeless and there is no way to have an effect on it.
Then, I hear from people like you that I’ve managed to really upset, who seem to feel that I have great destructive powers, and I get the strength to go on. Thanks.
“Sometimes I do think of giving up on trying to do anything about the endless hype….”
Peter, One thing you could do is encourage people to actively seek alternatives (or help find one yourself).
Jo,
I do work on alternatives myself, spending far more time on that kind of work than on the blog. The whole point of the hype campaign is to convince people that they should not seek alternatives, that string theory is the “only game in town”.
That Weinberg is admitting that the game is probably crooked and unwinnable seems newsworthy, and pointing people to that news seems like a good way to encourage them to look for alternatives.
“I do work on alternatives myself, spending far more time on that kind of work than on the blog. ” I am impressed by this 15+ years of time&efforts and the results which emerged from it… http://www.slac.stanford.edu/spires/find/hep/www?rawcmd=find+find+a+p.+woit .
Thanks again LSD. Responding to criticism with anonymous personal attacks does a good job of convincing people that proponents of this particular game have neither a scientific case nor the guts to stand up publicly for it. Your destructive power is far greater than mine….
Is there an interview or something where Weinberg is more verbal on the string theory and landscape? In the NS article he is just quoted to say “We just can’t make a list of 10^500 things. That’s more than the number of atoms in the observable universe.”, and I fail to read much of an attitude out of this…
Just remembered that “Lucy” had been here before, leading to a similar exchange. He or she really doesn’t like it when I say critical things about multiverse research.
http://www.math.columbia.edu/~woit/wordpress/?p=717
SR,
For Weinberg’s views on the multiverse, probably best to read this
http://arxiv.org/abs/hep-th/0511037
Recall that he’s generally the one credited with pointing out that the size of the cosmological constant could be understood by an anthropic argument. I suspect that, like Gross and many others, to some degree he recognizes how problematic the whole string landscape subject is, but one naturally tends to think more highly of one’s children than is reasonable…
Regarding the endless hype of string theory, it seems to me that much unwarranted help is being enlisted by periodicals such as New Scientist. I subscribed to it for about a year but realized quickly that my interest in physics was not being at all well served by it. I had to actually get my credit card replaced to end their tireless automatic resubscription.
It seems to me a good plan to hit string theory where it hurts is to stop subscriptions to pseudoscience periodicals such as New Scientist. That may hit string theory harder than large amounts of well reasoned arguments against it.
Eric,
I don’t think the problem is New Scientist. They’re generally reporting reasonably accurately what physicists, often prominent ones, say to them.
Very timely post Peter as I just NOW read on the Bad Astronomy blog how the Planck mission will test string theories of cosmology.
coolstar,
Looking at that blog, it seems to me that Phil Plait avoids making the claims about string theory that you state. Perhaps Planck will see evidence for gravitational waves in the CMB, that would tell us something new about the Big Bang, and that’s what he’s excited about. Wouldn’t tell us whether strings have anything to do with anything though….
Keep up the good work Peter, thanks for let us know why string theory does not work. It is apalling how some called “(= scientists)” can’t see the objective of your blog
Thanks Peter. It’s spotlighting the hype which makes an interested non-scientist like myself want to delve deeper into the alternative material, which this post does very well.
Peter ,see this nice talk by Krauss on inflating , string theory etc.
he points out how one can/may never test inflation with CMB experiments.
http://www.stsci.edu/institute/itsd/information/streaming/archive/STScIScienceColloquiaSpring2009/
Lucy, Jo,
Your criticism of Peter’s publication record rather than his arguments only shows how little you have to offer in support of the “multiverse.” (It’s also not a self-consistent position, as you don’t offer your own publication records to be examined.)
The argument you make, which seems to be popular among string theorists, is that one should “build, not destroy.” This is not science. Poor ideas should be criticized. Proponents of ideas should be frank about their limitations — and not encourage hype, whcih was the whole point of Peter’s post. Some ideas are so poor that it is really better to give up on them and work on something else.
In fact, what Peter reported seems to go well beyond hype and into a level of serious misrepresentation — New Scientist suggesting, presumably on the basis of their interviewees’ comments, that most physicists accept the multiverse.
It’s hard to see Peter’s points there as objectionable at all.
Peter,
I am glad you’re doing this work and I believe it’s valuable. I’ve heard fm more than one researcher who believed stupor string theory was draining talent and thwarting progress in physics, e.g., “Is string theory a futile exercise as physics, as I believe it to be? … The sad thing is that, … other avenues are not being explored by the bright, imaginative young people, and that alternative career paths are blocked.” P.W. Anderson, NY Times, 4 Jan 05. So, I believe it’s important that someone takes the time to communicate flaws in SST.
As for your own attempt at an alternative to SST unification, what are you working on? I see you had pubs in lattice gauge theory, are you working on a discrete method now? Maybe this isn’t the place to discuss it based on the warning that “this is not a place for people to promote their favorite ideas about fundamental physics.” If so, please email me your answer. Thanks.
Mark,
No, I haven’t worked on lattice gauge theory in a long time, and I don’t have any particular ideas about discretization as helping with fundamental issues.
Recently I’ve been working on a variant of the BRST approach to handling gauge symmetry, using something mathematicians are calling “Dirac Cohomology”. Still sorting out some things about this that confuse me. Now that classes are almost over, I hope to devote the summer break to finishing something I’m writing on the subject.
Peter: perhaps you’re correct about Bad Astronomy, Planck, and string theory but on a second and third reading, and on following the links, I’ll still have to disagree. I’ve obviously been wrong before, but less than average about that particular blog. And of course, what you’ve said about gravitational waves and Planck is correct (I certainly didn’t mean to imply that Planck wasn’t a worthwhile mission).
Who is the greater musician–he who wins American Idol and sells a million records or he who plays from the heart, come hell or high water, whether there are three people in the audience or 30,000?
Who is the greater physicist–he who publishes millions of indecipherable, fundaemnatlly-erroneous and intenionally- misleading papers in meaningless, groupthink journals, or he who speaks the simple, honest truth regarding physics and physical reality?
Truly, many “scientific” journals have been hijacked by the same financial “geniuses” who brought us the decline of the economy, giving a bad name to mathematicians, physicists, and economists.
`Joey Ramone’, you seem to be having trouble maintaining a consistent character.
One can only hope that the new minds are steering clear of string theory. In the beggining the string people were all confident (read arogant) about how their theory will explain everything. Now they are desperately clinging at straws. Looking for any kind of confirmation even marginal ones. This is a good sign. String theory is on its death bed. The question is how long will it linger before someone gives it the final dose of painkiller. The idea that Planck will confirm some aspects of string theory is absolutely pathetic. The final nail in the string’s coffin must come from alternative theories. Otherwise all those tenured types with their lives vested in it will continue to push it forward. And their task is not hard because by definition string theory is impossible to disprove. So I agree that this blog should also describe and discuss alternate theories.
Hmmmm writes, “`Joey Ramone’, you seem to be having trouble maintaining a consistent character.”
Hey Hmmm–you try fathering/furthering/definining the American punk rock/alt.-rock movement, never selling out, getting inducted into the Rock’n’Roll Hall of Fame, and then taking up physics in the afterlife.
It are all the string theorists who have trouble maintaining a consistent character, as they have displaced and suppressed their own characters and curiosities to serve the greater goals of the group–never has physics, like rock’n’roll, been furthered by corporate-state groupthink. The String Theorists are always waiting for their marching orders from their antitheory, physicsless elders, who command them to show their loyalty by anonymously attacking Peter Woit’s blog, which makes for good entertainment. Imagine if Einstein or the Ramones had had to take dictation from seventy-year-olds going on and on about the Anthropic Principle and Multiverses–the very opposite of physics–when there were in their twenties!
Imagine if Lenny Susskind or Michio Kaku were in charge of writing the Ramones’ lyrics! Brian Greene wouldn’t be so bad–he wears cool black leather jackets in his music video for The Elegant Universe. If he grew his hair out he could definitely audition to be a roadie.
The best thing NEW did was to steer new graduate students away from string theory into other fields where they might actually do some real physics.
Peter, are you going to write a sequel?
Thomas,
No plans for a sequel. For one thing, little has changed since 2002, when most of the book was written. There would have to be something new to write about for me to get interested in thinking about a sequel. Maybe if LHC results change things dramatically.
Someday I would like to write a technical book on representation theory, QM and QFT, but that project is also a long ways off right now.
Hello Peter,
sorry, my comment is obviously a little bit off topic: String theorists tend to claim that “string theory contains all of general relativity”. As far as I understand this, this statement reduces to “string theory contains massless spin-2-particles”. It seems to me that the impression that this implies all of general relativity contains can be traced back to the Lectures on gravitation by Feynman who showed that one can indeed derive the field equations from this fact. But is general relativity not much more than just the field equations? Can a spacetime containing a black hole even be generated by gravitons? This seems to be one of the key arguments of the LQG-people, but has this question even been asked by some string theorists?
On the other hand do the field equations of general relativity enforce consistency of the energy-stress-tensor and the spacetime geometry, meaning the energy-stress-tensor generates spacetime curvature which back reacts on matter = energy etc. To postulate some spacetime and putting some strings in it that may or may not generate gravitons seems to completly ignore this point.
I would be very grateful to any link or hint to further discussions of these points,
with kind regards,
Tim (interested layman)
P.S.: Could it be that string theory is mostly popular in the US has to do with the fact that Feynman did not publish his lectures, but that they were passed around from hand to hand?
Tim,
I don’t think the availability of Feynman’s lectures had anything to do with it, the argument was well known and I believe repeated in many sources. The sociology of particle theory in the US has always been more trendy than in other countries, with a big emphasis on hiring people working on the “cutting edge”. Actually, at the moment, I think this trendiness is cutting against string theory in the US, as the perception has grown that string theory is dormant, with cosmology and phenomenology the “cutting edge”. String theory seems to me to be doing better in other countries, where there is more willingness to hire people in field perceived as “prestigious”, even if not currently very successful.
String theorists certainly do worry about the question you ask, and there have been extensive debates over the issue of “background dependence” in string theory here and elsewhere. I don’t want to get those started again, unless some commenters willing and able to provide a well-informed, balanced discussion free of hype and wishful thinking magically appear.
Perhaps the main reason I have little interest in arguing these issues is that if you can’t use the criterion of solid mathematical consistency or that of agreement with experiment, you can’t ever be shown to be wrong, So you may be doomed to a future of arguing over who has the “best” not truly consistent quantum gravity theory that can’t be tested, with no objective way to decide. I’ll leave this to others.
In addition to containing gravitons, it is possible to demonstrate that string perturbation theory makes sense precisely when the background spacetime satisfies Einstein’s field equation. The gravitons are the perturbations around the background.
Thanks Peter for the link to the Origins Conference at ASU. I did find Sheldon Glashow’s comments most interesting. What I got from it was that the cancellation of the Texas collider created a 17 year pause in experimental physics. With no real data to construct new theories it seems that the imaginations of some very bright people over the years got a bit carried away which eventually led to untestable notions like string “theory”. If the devil truly does find work for idle hands then with a nod to Occam it is the most simple and most human explanation of why ST has garnered so much attention.
The claim of “only game in town” may be exaggerated. String theory uses, as Witten says, 4 ideas: supersymmetry, higher dimensions, duality, and stringiness. If one leaves out the first two or three, which have little counterpart in experiment, another game in town pops up: to produce a unified model based on stringiness alone, but in three spatial dimensions.
I would be ready to take a long bet that this game has better chances than any one that uses 11 spatial dimensions.
Hi Peter,
thanks for your answer, I was kompletly unaware that the thing with the gravitons is common sense,
I looked at severel sources and found no reference I could follow, e.g. wikipedia or several
books on string theory. Mr. Kaku in his two books on string and M-theory e.g. does not mention
the origin of his starting point at all (I mean the axioms that any quantum theory of gravity
needs to live in Minkowskian spacetime and contain massless spin two particles aka gravitons).
Of cource since I am not affiliated with any physics department I am a little out of the loop 🙂
It is completly understandable that you do not like to repeat any extensive discussions that
obviously did take place, but one wonders if it would be possible to give a little overview over
the conclusions if there were any, or over the arguments of both sides (or a link to that), for someone who was not involved.
All I did came up with is that “background independence” for string theory seems to mean that one can choose
any spacetime one likes to start with, while the LQG idea is that a spacetime is a classical state
and a quantum state should be a wave function living on some space where each “point” is a
classical spacetime that is a valid solution of general relativity.
If this post happens to fuel any hostility on your blog please accept my apologies.
Hello Peter,
In fairness to Steven Weinberg, I believe you completely misinterpreted his little joke about the poker game, and more importantly, his attitude towards string theory. If one reads the New Scientist article, the correct interpretation becomes obvious. It’s not, as you say, that he admits string theory is ‘crooked and you are bound to lose’ and that means he thinks string theory ‘can’t possibly, work, is obvious pseudoscience’. Rather, he feels that physicists can’t win in the sense that it may well be that the fundamental values of nature cannot ever be predicted by theory because they are randomly determined in each universe of the multiverse. THAT is regarded by physicists as a ‘crooked’ game because for at least a century they operated on the assumption that a ‘fair’ universe would be one whose values had to be what they were, and it was the job of physicists to create a theory that predicted those values. It pains and sometimes infuriates them to think that that glorious undertaking may be doomed to failure.
And think about it Peter—why on earth would Steven Weinberg embrace a theory he considered obvious pseudoscience?
Christina P
christina philosina, are you saying that Steven Weinberg doesn’t recognize a false dichotomy for what it is? I find this hard to believe.
>2, your comment mystifies me.
What is the ‘false dichotomy’? There’s a real dichotomy: 1)We live in the only universe there is, whose mathematical values for the forces and constituents of nature MAY all be derivable from first principles or 2)we live in one of many (or an infinite number) of universes, whose fundamental values are randomly affixed.
Until the strong version of the anthropic principle (implying the existence of a ‘fine-tuning’ God) led atheistic physicists to propose a multiverse as a rebuttal in the 1970’s, no one ever considered the notion of other universes. The only issue was: could all quantitative aspects of the (one and only) universe be deduced? Physicists fervently hoped so, since only then could their theories have a sense of ‘completeness’. Steven Weinberg certainly shared this craving, but now he is reluctantly accepting the notion that a number of lines of argument (string theory’s 10^500 solutions is just one) suggest the unfortunate truth may very well be that we live in a multiverse. If so, any Theory of Everything will have to have deeply irritating arbitrary elements, determinable only by experiment. ‘The only game in town’ would then be ‘crooked.’
christina philosina you forgot 3), 4), 5), …
>2:
What third (or fourth—or fifth!!) option do you have in mind that is scientifically or philosophically relevant to this discussion? Or do you always just reflexively reject any Either/Or as too simplistic? While I admire the almost poetic brevity of your comment, there IS such a thing as being TOO succinct.
And I notice that Peter has been more than succinct, he’s been utterly silent in the face of my having pointed out his error in interpreting Steven Weinberg’s poker game joke as indicating that Weinberg believes that string theory is pseudoscience. Hmmm.
Christina,
Having read the NS article myself, it seems to me that Peter has a direct reading of it and you have rather an interpretation based on what you think Weinberg must have meant. (Your interpretation could well be right; the article might have misrepresented Weinberg’s meaning by juxtaposing two quotes.)
I think bringing in religious issues can only obscure the matter — if it’s hard enough to agree on objective issues, the discussion will become impossibly fragmented if you add a religious element.
It is of course possible in principle that certain things about the universe are not knowable. (Science recognized this in one precise sense when it found that the results of quantum measurements could only be predicted probabilistically.) But the aim of science is to say as much as possible, and so giving up on making predictions in an area is the very last thing a scientist should do — and it should not be done without a very strong argument for the failure of predictability even in principle for the situations considered.
The “mutliverse” ideas motivated by strings suffer from a basic misjudgment. They are predicated on the notion that string ideas are so convincing that it is preferable to consider a major retreat from the goals of science rather than to call strings into question.
This from a “theory” which is not at all a theory in the strict sense, and which has no phenomonological successes. (String-inspired mathematical tricks — which do appear to be useful — cannot count as much evidence for strings as a theory of nature.)
christina,
The reason for Peter’s silence is a bit different than you think. For the last 24 hours he has been having a life: taking advantage of the break in the weather to go on a long bike ride, going out to dinner with friends, sleeping in and having a lazy morning, and doing laundry. He just got into the office, where the main item on the agenda is to make up Monday’s final exam for his class. Tonight will be taken up with going to see Star Trek with some friends, Sunday devoted to a day-long celebration of mother’s day and to meeting up with Tommaso Dorigo.
So, there’s a short window of opportunity here to respond to your comment. Of course I understand that part of what Weinberg was doing was making the standard argument for the anthropic multiverse (“maybe we can’t calculate things we hoped to, they’re just environmental”), and couching this as “the universe has put us in a crooked game”. But unfortunately, that’s not all he was saying. He explicitly identified “the only game in town” as string theory, and is making the very popular argument for string theory that, even though it predicts nothing, it should not be abandoned as a failure. The idea seems to be that, since it provides a framework that explains why it can predict nothing, we should believe in it since we don’t know how to do better. Personally I think this is pseudo-science. I don’t think Weinberg thinks of this as pseudo-science, probably because he still has some hope that string theory will somehow lead to a legitimate scientific prediction of some kind. Some people like him still think this, lots of others, including me, think this is just wishful thinking.
While writing this, I saw the comment from Pawl come in, which I agree with.
Peter, all I said was “Hmmm”!!!
And I do admit to having a soft spot for a roguish yet gallant Highwayman-like character defying the authorities in pursuit of, not Bess, the landlord’s daughter, but, far nobler, True Science! (Remember The Highwayman, from Junior High? “Then look for me by moonlight, Watch for me by moonlight, I’ll come to thee by moonlight, though Hell should bar the way!” And isn’t it amazing how swiftly String Theory has become the dare-not-challenge Establishment, and how thoroughly dissenting views like yours have taken on the stigma of heresy?)
However, one should not let admirable zeal lead you to mischaracterize someone’s comments so that it converts (in this case) Steven Weinberg from a reluctant supporter of string theory into someone seriously impugning it. Let’s review, for the record, what you said about Weinberg in your original post:
“The arguments for string theory have evolved over the years, with the “it’s the only game in town” one being made starting fairly early on. Weinberg seems to be willing to go for a new variant of this, that not only is it the only game in town, but it’s probably crooked (i.e. can’t possibly work, is obvious pseudo-science…), and this doesn’t matter, one should continue anyway.”
You now acknowledge, in your last post, that Weinberg doesn’t actually think it’s pseudo-science; I think I gave a far more plausible interpretation of his joke in my previous posts. As for whether string theory has been prematurely crowned ‘the only game in town’ is a separate issue–you have advanced powerful arguments in support of the notion that the Physics Establishment has shown reckless haste in its embrace of it, a haste that I think would have propelled Thomas Kuhn, were he still alive, into a possible revision of his belief that theories were always accepted only long AFTER the evidence in support of them justified acceptance.
Pawl,
You fault me for introducing religion into this discussion. Religion subtly lurks at the heart of the acceptance of string theory!! Or more precisely, the antithesis of religion—the fierce materialism of most physicists. It is delightfully ironic that the very thing that makes string theory scientifically unpalatable—the prospect that the 10^500 solutions are irreducible—makes it philosophically irresistible (if you’re an atheist). Atheism, the intelligent and informed person realizes, is now untenable without a multiverse—the strong version of the anthropic principle demolished traditional atheism (one universe, without a God being necessary to explain our presence). Incidentally, one reason for the quick embrace of inflation theory was its mechanism for the spawning of other universes. Of course, string theory with 10^500 solutions doesn’t prove there IS a multiverse, it simply is consistent with one. Dark energy, as a cosmological constant, WOULD be evidence. And of course, a multiverse would not DISPROVE the existence of God, only make him unnecessary as an explanation for the existence of intelligent life in our universe. Then one would have to decide if one wants to use Occam’s Razor on God.
Christina,
You seem to have a number of premises (about what atheism or theism is and how they bear on science) which you think the rest of us share. They are certainly far enough from my understanding that I can only guess at what you have in mind.
You seem to have in mind that having a scientific perspective must mean thinking the world is so far from being god’s special creation that a multiverse is an appealing idea. I don’t know any scientist who holds that view (although perhaps there are some). Virtually all scientists (and the “virtually” is there only to do multiverse proponents the courtesy of not dismissing them, for the purposes of this discussion, as scientists), including atheists, do believe in a world of natural laws and order.
You seem to want to turn this into a theistic/atheistic debate. I decline to do so.