Finally we get to some real substance in the program! (See earlier notes, and thoughts.) Jeff actually mentions all the effort going on string theory and experiments at Brookhaven, and asks that question I keep asking everyone… “why oh why is this never mentioned by the press in these discussions?” I’ve asked this of Peter Woit on his blog a lot too, for example, and have never got much of an answer. Peter and Lee want the world to believe -by reading their books- that the entire field of string theory is just people sitting around discussing the Anthropic Principle and lots of different universes, and blah blah blah… It serves the purpose of the books in question to completely distort the view of what is actually going on in the field. They claim that there is no experimental support (true) or hope for experimental support (how can they know that?) for string theory… but they ignore the fact –they intentionally don’t tell you, dear reader– about the interesting work going on by a huge percentage of the field to use string theory to study the structure of nuclear matter. It is still in its early stages, and may not work, but it is rather interesting. As Jeff put it, about the new form of matter that is constructed in these experiments, string theory is “the only approach that I know of” that currently seems to be able to explain the observed properties….
Lee, about the omission of this huge effort in string theory research from his book: “At least it is alluded to…”
That’s just lame.
He then proceeds to rather poorly attempt to claim that such contact with experiment (if this is indeed the case we don’t know for sure yet, I should say) is essentially beside the point. Nothing to do with whether string theory is a fundamental theory of Nature.
Sigh.
Dear reader, did you think I was exaggerating when I used the words “Storm in a Teacup”, “Self Interest”, and “Counter-Hype”?
-cvj
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Dear Prof. Harvey,
Thanks, I’m glad you agree about the problem with (lack of) good objective measures. One thing that could maybe be done is to re-establish the role of journals in providing “quality stamps”. In the maths community, someone working on a less fashionable topic can still get attention and career opportunities if they can “prove” the quality of their work by getting it published in top maths journals. I don’t see any principle reason why a system like that couldn’t work in physics (including theoretical particle physics), and I think it would go a long way towards alleviating the “sociological” complaints against string theory: No reasonable person is going to complain about jobs going to the “best people”, and if these happen to be string theorists then so be it, as long as they really are seen to be the best by some reasonably objective measure(s).
Thanks very much for your kind offer for me to contact you privately. But I’ll respectfully decline this, since my purpose here has been to raise general issues and not to seek personal help or advice.
I’ve just plowed through about a hundred blogs, all-too-human stuff. I read the New Yorker review, entitled “Unstrung,” which seemed to me fair enough. I worked for Science Magazine for years and have read hundreds of scientific papers. I am now 85 years old. As a professional “discipline,” science is an epistemology that answers the question, “What do you know and how do you know it?” by the convention of repeating “experiments.” These are based upon what the experimenters see as a result of manipulating material objects in unnatural ways (not too different from tying a can on the cat’s tail to see what happens, or dissecting a frog to see what’s inside). Science depends upon consensus among the experimenters, just as religious communities depend upon a consensus of beliefs. Answering the question “Do you see what I see?” binds communities together intellectually, making (in my opinion) science and religion indistinguishable. In my view, there are just as many “scientific” worlds as there are mothers, and as many godheads. Your god is not my god, your mother is not my mother, your science is not my science, and what you call “the” world is not my world. Perhaps each of us is a unique ripple of space, time, energy, and matter. There are as many dimensions (directions) of STEM as there are radiants of light (an infinity), and just as obviously an infinity of dimensions (sizes) of STEM, just as there is an infinity of possible organisms. Whether all ripples of whatsoever size can be shown to function according to a single dynamic that also governs our own species of STEM is an open question. Lastly, I suggest that science give up the notion of nature and creation as entities that are MADE (a theological precept). STEM happens, randomly, and unpredictably, despite our incurable beliefs, e.g., that the sun rises and sets. and that apples fall as expected. Best wishes to everyone!
if everyone is so high-minded and interested in science and all, why are you all so damned mean to each other? i think you should strive to make your posts in the form of:
“Q: what is the connection between QCD and 10Mplank” (or whatever)
rather than
“Q: what is the connection between QCD and 10Mplank and by the way, stop intentionally misrepresenting my spin on your interpretation of my post to the 137th comment on your response to my explanation of your hostility about my feelings about your sneering about my dismissiveness”
really it’s like a dysfunctional family gathering or something rather than point-counterpoint!
in this respect probably trading scientific questions by physical mail, with postage stamps and having to pay for each page of paper, might’ve done science better than this insta-flame-war-promotting-blogging bs.
Stefan:- Thanks a lot for those references … they were very interesting indeed. It is such a fascinating area!
Cheers,
-cvj
I would like to point out two recent papers related to the “strongly coupled” QGP discussion and the viscosity bound which I found very interesting and readable:
The Letter "s" (and the sQGP) by Jamie Nagle (nucl-th/0608070) gives a nice discussion of all the different notions of strong interactions and strong coupling involved in the debate about the hot and dense nuclear matter created at RHIC.
On the Strongly-Interacting Low-Viscosity Matter Created in Relativistic Nuclear Collisions by Laszlo P. Csernai, Joe Kapusta, and Larry McLerran (nucl-th/0604032) presents a new and fancy way to plot the phase diagram of fluids in the vicinity of the critical point: They plot the ration of shear viscosity to entropy density as a function of temperature for different pressures. These curves seem to look quite similar for all kinds of fluids, with a kink when hitting the critical point. Moreoever, this kink corresponds to the absolute minimum of eta/s for the fluid under discussion, and it is allways higher than the AdS/CFT bound, which seem to be quite universal indeed! This paper was published as a PRL last week, and it seems to have been directly motivated by the Kovtun-Son-Starinets PRL. However, it does not (if I did not miss that point somehow) discuss whether AdS/CFT says anything more specific about RHIC matter or not.
Dear amused,
Thanks for your thoughtful and tactful response. I agree with you that we are lacking in good
(semi-) objective measures of what work should be supported, in main part because
of the absence of data. I think that applies equally to string theory, other parts of
formal particle theory, and much of what is now called “phenomenology.” And
entrenched groups whether in string theory, lattice gauge theory, brane-worlds,
perturbative QCD or what have you have a tendency to hire people who work in the same area. I think not so much because they are trying to keep the upper hand, but because they want people they can talk to and collaborate with. I really don’t have any good generic job advice (or maybe am just not in the mood), but if you want to send me email I’d be happy to discuss it in private. if you don’t want to give up your anonymity just creat an email
account on gmail or yahoo and send me an email with “amused” in the subject line.
Investment Spanker:
“I really sympathize with you.”
Gee, thanks.
“It’s difficult for great, iconoclastic geniuses like to you to succeed while being crushed down by the great String Theory Conspiracy.”
Yeah, its tough. But we’ll get our own back when the Revolution comes.
“Your inability to find a job is unquestionably because you’ve seen through the great fraud that is string theory, and because the string theorists are jealous of your great ideas.”
Ah yes, that must be it. How perceptive of you.
“It’s not at all because you’re a nitwit crackpot or anything like that.”
Certainly not. Glad we got that straight. Now let me tell you about my brilliant discovery of a Theory of Everything based on little pulsating squiggly thingies…
(Btw, despite my inability to find one, I do somehow appear to have a job in physics at the present time… at any rate, some or other university seems to be putting money into my bank account each month, and doesn’t seem to mind my occasional use of one of their offices for scribbling and blog-surfing…)
Dear Prof Harvey,
Thanks very much for your response.
As Peter mentioned, the point I was making was that it seems pretty difficult for people working on non-string topics in formal particle theory (as opposed to phenomenology) to compete with string theorists for jobs, so your advice to “go find something else you do like and work on that” might not be a very good one for a young person who wants a career in this area (although I realize that you were directing it specifically at Peter). I’m aware that finding a job is no piece of cake for string theorists either, especially in recent years. But wouldn’t you agree that in general their chances are still considerably better than than for people working on non-string formal particle theory topics? How are the latter supposed to make themselves competitive on the job market? As a grad student and young postdoc (in obscure places) I naively thought that demonstrating independence and publishing on my own (including a few in PRL, our supposedly top journal?) might do the trick. Well, maybe I just didn’t do enough, or it wasn’t that interesting, or whatever. I’m certainly not claiming to be particularly deserving, or to have been “cheated” out of a job by the “string conspiracy” (contrary to what was suggested in “Investment Spanker”‘s moronic comment). I’m also well aware that there are other, much better people than me out there who are having a tough time. But my case and others do provide some kind of lower bounds on what it takes for a non-string person to be competitive for jobs in formal particle theory, and leaves me curious about what it would really take to be successful. Can you enlighten me on this – what would it take for your group to hire, say as a postdoc, someone working on a non-string particle theory topic?
“You say that “string theorists seem to be presenting this application of AdS/CFT as more interesting and important than other work on RHIC physics.†Wouldn’t you at least like to qualify this to “some string theorists?â€
Ok, fair enough. The general impression I’ve gotten from string theorists’ presentations (those I’ve seen or read, which admittedly isn’t many, and which doesn’t include any by you) is that this is to be seen as a great triumph for string theory and vindication of it as a research program. Well, sure it’s a triumph, sure it’s interesting, and I can certainly understand people being excited about it. But these things are relative. As far as the impact on QCD physics goes, how important is this compared, e.g., to solving the chirality problem for fermions on the lattice? Or compared to other theoretical advances regarding RHIC physics or QCD in general…. What seems to be missing, at least from what I’ve seen, is a sense of proportion, a discussion or at least acknowledgement of how this development is one of many interesting ones, that it’s full significance remains to be seen, and similar stuff in that vein. If the presentations had all been as reasonable and balanced as your description above, I don’t think these hype complaints would have arisen. But unfortunately they aren’t.
“Your “you guys seem to think†tars all string theorists with a very broad brush. I don’t think as you said, and neither do many other string theorists I know. Where do you get the idea that all string theorists think
alike?”
If you can point out any string theorist or string-dominated particle theory group that would be remotely interested in hiring or supporting anyone working directly on QCD theory (i.e. not via AdS/CFT) I’ll humbly take it all back.
“As you may or may not know, my work with Curt Callan played a small role in one of these formulations involving chiral domain wall fermions”
I’m familiar enough with your work with Callan to know that your description of it as having played a “small role” is far too modest.
“…It should be possible to check these ideas using lattice gauge theory, and conversely string theory makes some interesting predictions that could be checked using lattice gauge theory….It seems to me to be quite a fun and exciting time with string theory and other parts of particle physics having something interesting to say to each other and with possible experimental tests of the whole framework.”
Sure, I agree completely. But is this going to be an arrangement where string theorists provide the theoretical brains and lattice folks are just supposed to supply the numerical brawn? The developments regarding chirality on the lattice were of a formal theory nature, and there are plenty more interesting and important things that remain to be done on that. (Hamiltonian formulation, understanding CP symmetry, anomalies and their cancellation in chiral gauge theories on the lattice,…). But working on this formal stuff pretty much is career suicide. Who is going to hire such a person? Traditional lattice groups aren’t interested (which is kind of understandable since they are heavily invested in numerical QCD). The natural home for such person would be in a formal particle theory group, but for “most” of them you have to be doing string/brane stuff.
“Regarding your proposal to measure things via PRL pages, […] in particle theory (and not just string theory) that went out as a useful measure of anything about 20 years ago.”
Really? That’s at odds with my impression. The physicists I know of seem to regard publishing there as a bit out of the ordinary, and want to publish there when they do some thing they consider a bit out of the ordinary. That includes senior physicists who definitely consider themselves particle theorists. It also seems to be the case for various string and brane folks (for starters, Randall&Sundrum…). But if PRL publications isn’t a useful measure (and I’m not insisting that it is), then what is a useful measure these days? Is there one? This brings me back to a question from the beginning, about what it takes for non-string people to make themselves competitive for jobs in formal particle theory. Without some (semi-)objective, impartial measure it’s going to be kind of difficult, right?
Jeff,
I was directly quoting your words, apologies for any misinterpretation of them, but I certainly wasn’t misrepresenting them.
Your response to “amused” gives plenty of evidence for one of the problems he is discussing, that string theory completely dominates formal particle theory. I’m sure it’s true that many institutions are trying to hire phenomenologists, but “amused” was not claiming that phenomenology is not getting enough attention.
“amused” also claims that it’s very difficult to get anyone interested in non-perturbative issues about QCD unless they can be approached via AdS/CFT. You respond by discussing AdS/CFT approaches and telling him that working on their relation to lattice gauge theory would not be career suicide, which I’m sure he’s well aware of. His question is about whether it’s possible to work on things that are not phenomenology and that have no relation to AdS/CFT.
And as for “Investment Spanker”, he provides yet a different sort of evidence for the problems with string theory and how it is being pursued.
Dear amused,
Princeton recently hired a collider phenomenologist. Chicago has an offer out to
a senior phenomenologist and is planning a search for a junior person. Other
universitites with strong string theory groups are doing similar things. I’m sure some
good people working in other areas of particle theory have lost out to string theorists.
But the job market has not been a piece of cake for string theorists either, no matter
the impression that some people try to give that working in string theory amounts
to a guaranteed job. I’ve had several students in string theory who gave up on academics
because of the tough job market and several others who perserved and eventually got
good jobs but only after many postdocs, hanging on by a thread and much personal
sacrifice. Some of my best string theory students have also contributed in significant
ways to efforts in phenomenology.
You say that “string theorists seem to be presenting this application of AdS/CFT as more
interesting and important than other work on RHIC physics.” Wouldn’t you at least like
to qualify this to “some string theorists?” If you read my earlier post I think you will see
that I was quite clear in saying that the string theory calculations are only a small part of a
large and complicated story. I recently heard Starinets, one of the founders of this topic,
talk on the application of AdS/CFT to RHIC physics. He was also extremely careful to
point out that the data is very complicated to interpret and that the string theory calculations are only one approach among many. Among the string theorists I talk to I
don’t think one of them has been responsible for “hypeing” this subject. It is not hype
to say what is true, which is that there aren’t any other methods known for doing near equilibirium calculations in a strongly
coupled thermal gauge theory. No other calculation gives the small ratio of shear viscosity
to entropy. The bulk viscosity of gauge theory is such a complicated calculation that it
was first done using AdS/CFT techniques. It gives a novel approach to calculating the drag force on massive quarks moving through the QGP. This is why not just string
theorists but also experts in QCD and finite temperature gauge theory like my old colleague
Larry Yaffe are working on this.
Regarding chirality in non-perturbative formulations of QCD (by which I assume you mean
lattice QCD) I agree this is interesting and important work. Your “you guys seem to think”
tars all string theorists with a very broad brush. I don’t think as you said, and neither do
many other string theorists I know. Where do you get the idea that all string theorists think
alike?
As you may or may not know,
my work with Curt Callan played a small role in one of these formulations involving chiral
domain wall fermions. Here also string theory via AdS/CFT is starting to play an interesting
role (although a minor one so far). The recent work of Sakai and Sugimoto incorporates
chiral symmetry breaking into a string dual of QCD (and by the way, without supersymmetry) so for the first time one can study
the problem at strong ‘t Hooft coupling. In these models one can separate the scales of
confinement and chiral symmetry breaking (see hep-th/0604017). it should be possible
to check these ideas using lattice gauge theory, and conversely string theory
makes some interesting predictions that could be checked using lattice gauge theory.
I don’t think working in this area is at all career suicide.
It seems to me to be quite a fun and exciting time with string theory and other parts of particle physics having something interesting to say to each other and with possible experimental tests of the whole framework.
Regarding your proposal to measure things via PRL pages, I know that in some fields that counts for a lot, but in particle theory (and not just string theory) that went out as a useful measure of anything about 20 years ago.
Finally, a brief note to Peter Woit. Please stop misrepresenting what I say. If I had
wanted to say “there is a bit of hype going on” I would have said that. Saying ” some
people are getting a little bit too excited” is quite a different statement.
Amused —
Do you really think the preferential weighting for string theorists in formal particle theory job searches is a good and justifiable thing? (Surely you don’t deny that it exisits?)
I really sympathize with you.
It’s difficult for great, iconoclastic geniuses like to you to succeed while being crushed down by the great String Theory Conspiracy.
Your inability to find a job is unquestionably because you’ve seen through the great fraud that is string theory, and because the string theorists are jealous of your great ideas.
It’s not at all because you’re a nitwit crackpot or anything like that.
Hi Prof. Harvey,
“If you don’t like or don’t think it is fascinating, fine, but then go find something else you do like and work on that.”
Some of us are doing exactly that. But we find it a bit difficult when competing with string theorists for jobs in formal particle theory groups. Young people working independently on non-string topics quickly discover that their single-author PRL publications count for nothing in competition against string theorists, especially when the latter in most of their papers are junior authors on papers with senior influential people.
Do you really think the preferential weighting for string theorists in formal particle theory job searches is a good and justifiable thing? (Surely you don’t deny that it exisits?) Now that string theorists are developing an interest for QCD physics, is there any prospect of string-dominated formal particle theory groups hiring (e.g. as postdocs) people who work directly on that topic? Or is it only the results that come via AdS/CFT that are of interest. Or perhaps it’s just that string theorists, thanks to their innate superiority, will always be able to do better than the practitioners of another field when they enter it. (In that case it’s kind of surprising that they haven’t been dominating the pages of PRL in the same way that they dominate on the job market, but I guess it’s just their natural modestly that restrains them from this.)
Regarding “hype”, the thing that irks some of us is the way string theorists seem to be presenting this application of AdS/CFT as more interesting and important than other work on RHIC physics (or QCD/Standard Model physics in general). An objective way to quantify its importance would be to count how many papers on it have been published in PRL, and divide this by the total number of PRL publications on theoretical RHIC physics – I suspect this would be a small fraction. More generally, you guys seem to think that AdS/CFT is the only important theoretical development in QCD in recent times. It isn’t. For example, developments regarding chirality in nonperturbative formulation of QCD are an order of magnitude more important for QCD physics than anything that has come from AdS/CFT so far. (E.g. it opens up the possibility of a first-principles investigation of spontaneous chiral symmetry breaking, and chiral phase transition at non-zero temperature. In contrast, AdS/CFT gives at most an approximate, effective theory description of chiral phase transition in finite temperature QCD. A first-principles treatment is preferable, right?) Btw, this chirality stuff has rich, interesting and subtle mathematics associated with it as well (anomalies, index theory,…) and allows to address rather interesting questions such as whether the Standard Model actually exists at the nonperturbative level. But only a career-suicidalist would work on such non-string stuff.
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Incidentally, Peter, I’d like to thank you for your timely intervention. I was almost ready to start telling my friends that string theory has been very much more successful than I had thought.
Jeff,
All I was referring to was that
“And certainly some people are getting a little bit too excited about this new possibility of making contact with experiment.”
seemed to me to be at least some acknowledgement that there was a bit of hype going on.
Peter,
What I am saying here is pretty much what Jacques and Clifford are saying. If they
disagree with this I’m sure they will speak up. 😉 When you say “You even seem to
agree with me” all I can say is that seeming is in the eye of the beholder.
Jeff,
The description you give here of the string theory/heavy ion story is perfectly reasonable, the problem is that it’s not what most string theorists are publicly saying. You even seem to agree with me that there is at least some problem of overhype here. I didn’t say this subject is “irrelevant”, I said that it’s overhyped, and I’ll stand by that.
I’d much rather be spending my time on something more positive and less contentious than trying to counter string theory hype. The day prominent string theorists start telling the public that the story about 10/11d unification that they have been promoting for so long doesn’t seem to be working, and they’re interested in thinking about what steps can be taken to encourage work on alternatives, you’ll hear a lot less from me on this topic.
Instead what I see all too much of is attempts to prop up this failed centerpiece of the string theory program with overhyped and often misleading claims, most recently the ones about heavy-ion physics. An excellent example is Jacques Distler’s comments here, with which he managed to convince at least one relatively well informed reader (Egbert) that string theorists were now able to get information about 4d quantum gravity out of heavy ion collisions. Scientists should not be engaging in this kind of behavior, and when they do, not complaining about people who point it out.
Peter, Jacques, and Jeff,
Thank you for your helpful responses. And I will definitely look at the post and discussion on Sabine’s blog.
The “string theory is the only approach I know of” “hype” was Clifford quoting me on the radio,
so if you want to accuse someone of hype, please accuse me. I was talking specifically
about the calculation of the viscosity to entropy ratio. I’m also just learning this stuff,
so it is quite possible that there is another approach that I don’t know of. But the statement
is the literal truth, it is the only approach I know of that gives this result, at least within
any well defined framework.
In case anyone doesn’t know, I’ll add that the calculation is done at large N_c and at
large ‘t Hooft coupling and we don’t yet know whether these limits give a good description
of reality. As the delightful post on Sabine’s blog makes clear, heavy ion physics is
incredibly complicated, and these string calculations are one very small part of a very
complicated story. There are many other ideas and approaches that go into trying to make
sense of the data. This whole story is also very new, and it is clear that there are other
things that can be calculated in string theory using these techniques that might be
testable. It will not be a definitive test of string theory. And yes, string theorists are
desperate, or at least they should be. 20 years without contact with experiment is much
too long. And certainly some people are getting a little bit too excited about this new
possibility of making contact with experiment. But isn’t trying to make it work and
exploring and doing new calculations that have never been done before much, much more
satisying than being negative and attacking string theory and dismissing this possible
dialog with experiment as irrelevant? If you don’t like or don’t think it is fascinating, fine,
but then go find something else you do like and work on that.
Peter, Jacues,
Thanks for both of your comments. Yes I had noticed the missing “not”, and I expect most people did. But Jacques had me convinced for a moment that it was the “4d” Planck length, meaning the actual Planck length, which had been found to be relevant for QCD calculations. This was my mistake, and of course it’s very disappointing to discover otherwise. Presumably the so-called 10d Planck length in the QCD dual is set to whatever value it must be set to in order to give the right dual to QCD. This would only be exciting if the value that it needed to be set to was the same value as the actual Planck length. But at least I have a few things to read now.
Thanks again.
Yes, it is a rather good (and funny in parts) post.
-cvj
Definitely! I like Sabine and Stefan’s post quite a lot. (Especially, the little parenthetical comments from one to the other about points on which they disagree. Very refreshing to see that.) I’ll also recommend Shuryak’s recent review of RHIC physics, for a more “insider’s” view.
Another Grad Student,
I agree that Clifford is avoiding an insulting tone, which is to be commended. However he continues to show no evidence of any interest in addressing the scientific arguments that I make. There’s a long and detailed one on my blog which I devoted most of yesterday evening to writing, and one motivation for doing that was to specifically address issues that he has raised. I don’t see what the point of rewriting and reproducing parts of it here would be. Either he wants to engage in discussing these issues or he doesn’t, and his response here I think gives the answer to that.
As for the issue of how overhyped his discussion of heavy-ion physics is, a discussion of that is likely to be both tedious and unenlightening, partly because the issue of “hype” is one where “feelings” come into play, and people can legitimately have very different views. I suggest looking at the discussion of the issue over at Sabine Hossenfelder’s blog, by people who know about heavy ion physics. From what they have to say, Clifford’s claim that
“string theory is “the only approach that I know of†that currently seems to be able to explain the observed properties”
is, well, overhyped.
Actually I was referring to two posts ago, not your latest post, when I said:
I saw a different tone in Clifford’s response to your latest post here.
Peter,
I saw a different tone in Clifford’s response to your latest post here. Even Jacques seemd a bit more restrained. Neither one of them sneered at you. Maybe, just maybe they are willing to have a discussion with you about scientific issues without condescension, sneering, misrepresentation of what you said, and implication that you are looking for personal gain.
So, are you willing to have a discussion of the issues as long as the tone maintains at least some minimum level of mutual respect? For example, I think it would be useful if you could:
1. Explain in more detail your statement that I do think that your comments on the relation of RHIC results to string theory are heavily overhyped, especially since the usefulness of string theory in understanding RHIC results is seemingly being presented as a test for string theory as a fundamental physical theory, at least on this blog.
2. Explain your last comment to Clifford, You’re continuing to ignore the scientific issues here, claiming this is all about people’s “feelingsâ€. Maybe you are right, but without elaboration your comment seems a bit general and cryptic. Maybe if you identify specific issues explicitly here (rather than just referring him to your blog post) he will respond with specifics. Hopefully his “specifics” would not merely be pointing you to a thread on some discussion a year ago at Cosmicvariance; those discussions covered a lot of ground, much of it irrelevant to a specific issue, and don’t constitute a specific answer in my opinon.)
Maybe it’s too much to hope for, but I would really like to see a (civil) discussion of issues like these.
Dear Peter,
Let’s just agree to disagree. There’s little point us going into a “yes it is” vs “no it isn’t” back and forth. I asked for proof and you have shown none. I think that the open-minded reader can make up their minds given all that we’ve said and pointed to.
In the meantime, I’d like to ask you to please stop posting strange accusations about me on your blog (as you did a day or two ago) in an attempt to tarnish my reputation. I’ve done nothing to warrant such accusations, it has nothing to do wiht the physics issues we’ve talked about, and it does not help your cause (except as a smokescreen/distraction) to engage in such silliness. Thank You.
Best,
-cvj
Clifford,
You’re continuing to ignore the scientific issues here, claiming this is all about people’s “feelings”. It’s not.
Peter,
That’s actually a smokescreen, as I think everyone knows. Furthermore, I’ve addressed the landscape issue you keep talking about several times, here and in several discussions we’ve had over the last 14 months or so (I’ve pointed to some above). So I do not understand why you keep saying I am ignoring what you say.
The issue of stabilization of moduli, although an interesting and important one, has nothing to do with a proof of whether or not having multiple solutions to string theory neccessarily implies that it is not predictive. I’ve just been asking for the proof, which you claim is well known, that the one implies the other. As I have said before:- If you have a feeling that string theory is not predictive, that is ok, and we can disagree, and you are entitled to say so. But a feeling is not a proof, and it is certainly not something upon which to base all your claims about the research in the field. To claim you have a proof is therefore a wrong thing to do, and this is what I am talking out against, as I’ve said so many times very clearly in this comment thread.
I’ve read your post, and others can too, and there is nothing in there that constitutes anything close to a proof. Just your feelings. The research is nowhere near done yet. You can’t know the outcome beforehand…
It is important in any scientific endeavour -especially when we are trying to be honest with ourselves and the public- to be clear about the difference between our feelings and opinions and what we actually know has been shown to be true by the standard standards of doing science.
-cvj
Clifford,
I gave up trying to discuss anything with you here, since you pretty much just ignore whatever I write and devote your efforts instead to insulting me. One of the obstructions at issue (stabilizing moduli) is discussed in great detail on the latest posting of my blog.
Jacques,
I agree with you that the “old quantum theory” looked very much like a Rube Goldberg machine.
I was reading Max Born’s “Mechanics of the Atom” book a few days ago, which covered the “old quantum” mechanics of doing things with the Jacobi action-angle variables and adiabatic invariants constructions. Even Heisenberg’s first few papers on quantum mechanics looked very “ad hoc” and very “Rube Goldberg”-ish. At times I wonder how modern quantum mechanics evolved from this huge mess, besides being a huge “guessing” game. (Modern formulations of quantum mechanics cover the same ground in a few lines of algebra).
Perhaps the same could be said about the present formulation of string theory as we know it today. Some day somebody may find a better formulation of doing string theory.
Ksh95…. The comments begin by addressing Navelling by name. Use the search facilityin your browser to whip through the comments. Here is one and here is another (also to Wolfgang).
I don’t actually mind whether I agree or disagree with Susskind or anyone else. Disagreement in research is healthy. This is about physics, not about being told what to think. This area is so under-developed in terms of rigourous computations so far that I don’t think that anybody knows for sure what is going to be the outcome. This is why we are still working on it. And this is why it is not right for Peter to claim to the general public that he has “well known” obstructions… which he never told us about when asked several times.
All I am asking is that we just get on with the research and stop grossly misrepresenting what each other’s reserch program is about. It does not do any good for the field at large.
Best,
-cvj
Clifford says:
Not that I would ask some one else to do my work, but could you give me the date and time of your explaination. After all, there are 133 comments here.
The reason I asked this question is because it would put you in clear and utter opposition to Susskind and the rest of the landscapeologists. They necessarily believe that multiple string theory solutions are very different than multiple Maxwell’s wave equation solutions.
PS
Not that my opinion matters, but I happen to think that the anthropic principal is an exceedingly elegant and aesthetically appealling proposition. Notice that the previous sentence stands on its own and says nothing about the valitidy or lack thereof of string theory.
Just like to say, “Bee and Stefan” offer a good education, so it is well worth the effort to follow that line of reaeach pertaining to the physics developing.
Also to include, the extension from a “layman perspective,” what I understood of the QGP as an extension of the elementary particle discernation. From experimental RHIC research to reductionistic views and what is understood of Strominger in relation to string theory.
More on name.
Stefan,
This is just great. This is all I was really asking for… I never said -as you know- that this stuff (using strings to understand properties of strongly coupled gauge theory and hence maybe some experimentally accessible phenomena) was right or wrong, or that it was going to save the world… All I asked was that it not be ignored in the discussions of what the string community is doing.
Your post has helped in this regard. It looks like physics discussion might win in this thread after all, despite all the smoke screens! I’m very pleased indeed….
Cheers!
-cvj
Dear Clifford,
what started originally as a comment in this discussion from my point of view of heavy-ion phenomenology has grown, after discussions with Bee, into a longer post on our blog. I hope you don’t mind if we link from here to there. We have also tried to explain in a little more detail the complexities involved in heavy-ion physics, which usually are not discussed in press releases.
Thanks, and best regards,
stefan
Hi Ksh95,
I think I explained carefully in the comment(s) to Navellug what I have in mind, and why I think there is notihing intrinsically wrong with a landscape of scenarios. I’ve not proven this, but nobody has proven the opposite either, which is one of my central points. I really can’t think of anything more to say on it right now (please see the comments), except to remind you that I am not wedded to this “theory of everything” perspective that seems to be tripping up a lot of the discussion, and which is really a red herring. I’m just focusing on trying to find tools to help understand the questions -and the answers to them- that we currently have about Nature. In that endeavour, landscapes have been with us since the dawn of science, and it is possible that they always will.
Best,
-cvj
I’m a little late to the party 😉
Clifford Said:
I am thoroughly confused by that statement, perhaps you are saying something deep that I am missing. Let me explain. A landscape of solutions in “the fundamental theory”, and a landscape of solutions in a “low energy theory” are two completely different animals. In the latter case a unique solution (or unique free parameters) are presumably derivable from some larger theory. In the former case there can be no such larger theory, “the fundamental theory” must fix the solution. If it is then shown that “the fundamental theory” admits many solutions we must assume that some other mechanism fixes the unique solution. In this case we have the anthropic principal.
You seem to be saying that a landscape of solutions to “the fundamental theory” is no more problematic than the infinitude of solutions to the wave equation???? Are you saying that it is natural to have parts of the universe that are inherently inexplainable???
Jeff Harvey said:
Hmmm, on one side we have the exhaustive experimental proofs of the equivilance between the path integral approach and the canonical approach. On the other side we have QFT on the boundary and ADS. Neither ADS nor the boundary exist in this universe so I have no idea what you are talking about.
No, it is obvious from the context that it is the 10D Plank length that appears on the AdS side of the duality.
Presumably, that’s because people read the following sentence
and correctly inferred that the word “not” should have been present in the preceding sentence.
But thanks for clearing this up for anyone who might possibly have missed it.
Egbert,
The references Jacques is giving you have nothing to do with your question, and the idea that QCD predictions involve the physical 4d Mplanck, while certainly exciting if it were true, is obviously nonsense. We know precisely what QCD is, and it doesn’t involve this constant.
No one seems to have noticed an obvious typo way back in this thread. About QCD, for
“So, naively, it does have an AdS dual”
read
“So, naively, it does not have and AdS dual”
Why is that “unfortunate”?
On the one hand, 3D CFTs are of vastly greater physical interest (critical phenomena) than are 4D CFTs. They’re also, generally, more calculationally tractable. On the other hand, quantum gravity in 4D AdS is doubtless of more physical interest than in 5D AdS.
So how about doing some calculations in the 2+1 boundary CFT to learn what LQG has to say about the physics of 4D AdS blackholes?
For instance, you ought to be able to do analogue of the calculations described here to determine whether or not LQG smooths the singularity of AdS blackholes. AdS/CFT turns this question into a question about the behaviour of Wightman functions of the boundary field theory, continued to complex time.
Hi everyone,
Lots of good stuff here. I am still catching up, so here are just a few quick comments
Jacques: If Lee has an alternative construction of quantum gravity in asymptotically anti de Sitter space, I invite him to use it to compute these transport properties. (On general grounds, it is clear that the observable of quantum gravity in asymptotically AdS space are the correlation functions of some QFT on the boundary). Perhaps his theory gives a better account of the physics observed at RHIC.
Thanks, this is a very good suggestion. There is such a construction, and we even know how to extend it at least to N=1 supergravity. Here are some references: gr-qc/9505028, hep-th/9808191, hepth/ 0009018. Unfortunately we only have this construction for 3+1 bulk and 2+1 boundary but perhaps there are properties of 2+1 CFTs that can be computed this way. I have long had a draft of a paper in progress on this, and perhaps it would be good to return to it. But I’d be even happier if someone else took a fresh look at this or developed the theory one dimension up.
Jeff,
Yes, I do agree that the AdS/CFT connection is fascinating and important and some of the reasons are the results you mention. The fact that I mention that there are things still to understand does not mean I fail to appreciate the great discoveries that have been made.
As I emphasized in a recent post, the issue is not just mathematical rigor, there are also ideas and results missing at a physicists level of rigor. But sometimes rigour is important. It matters that the spin foam formulation of the path integral is completely well defined, whereas the old path integrals written down in semiclassical approaches to quantum gravity were never well defined, either perturbatively or non-perturbatively. The fact that the spin foam path integrals are well defined means that real calculations can be done and real results gained, and much recent progress comes from this, including the recent calculation of Rovelli et al of the graviton propagator. The same can be said for the rigorous results in the canonical theory such as the LOST theorem. These results gives us a lot of physical understanding of the theory, but do so in a way that is rigorously based.
The issue of the relationship between canonical and path integral formulations you mention is also a crucial one for LQG. If one is willing to be sloppy and use a physicists level of rigor one can argue that spin foam amplitudes must define the same theory as canonical LQG and indeed people did so argue at first, But because each is completely well defined, it is possible to do better and examine in detail whether they are the same or not. So far the issue is unresolved, but many think they do not define the same theory. This is because there are amplitudes in the path integral for transitions that cannot be represented in a canonical theory. This comes down to technical issues about regularization, because point splitting in space and time will give different answers than point splitting in space alone.
This is of crucial importance, for example, when Nicolai et al raise old issues about the dynamics in the canonical formulation, many of us answer that the problems were resolved in the spin foam models. This would not make sense if they define the same theory.
Hence, this is a case where having completely well defined theories that have rigorous formulations lets us reach important conclusions about the physical content of theories.
So while my own work is at a theoretical physicists level or rigor, and I understand well where you are coming from, working in a community with people who are able to make rigorous constructions and arguments has taught me that sometime their tools are essential to make progress. Given that there are people in the string community who also work rigorously I woudl guess you have had the same experience.
Thanks,
Lee
I thought I addressed that point above.
On very general grounds, any theory of quantum gravity in asymptotically anti-de Sitter space is dual to some QFT on the boundary. So, if there is, indeed, more than one candidate theory or quantum gravity, we could use this duality to study (and compare) the properties of these candidate theories of quantum gravity.
We could use theoretical calculations in the respective dual quantum field theories, and perhaps even experimental input from RHIC to extract predictions about these candidate theories of quantum gravity that might help us decide between them.
So, even if you doubt that string theory is “the” theory of quantum gravity, you should be interested in AdS/CFT, as a laboratory for testing not just string theory, but any alternative theory of quantum gravity.
Dear Jacques, Egbert
Jacques said: “So I’m hard-pressed to understand how checking the predictions of AdS/CFT could fail to bolster your confidence that we are staring at a consistent theory of quantum gravity.”
I think it is fair to clarify something for egbert…I think part of his question was not so much:
`How does AdS/CFT give us confidence that string theory is A consistent theory of quantum gravity’.
but rather:
`How does AdS/CFT give us confidence that string theory is THE theory of quantum gravity that describes nature.’
I think that you have answered the first question, but maybe not the second. Is that fair? Of course, there are many reasons to think that string theory is the `right’ theory, but I just thought it was worth pointing out this distinction.
Evidently, we are really poor salesmen, if this is the first time you’ve heard that.
Probably, there are lots of other things that I am assuming are “obvious” or “well-known” that, apparently, aren’t. So this is really useful for me to hear.
If you read Hawking, he says that he was convinced by the AdS/CFT arguments (which use the fact that everything that happens in AdS, including blackhole formation and evaporation, has a dual description in the boundary gauge theory, where time evolution is manifestly unitary). However, he remained unsatisfied, because there was not a clear explanation of what was going on, in the language of the bulk degrees of freedom. So he set out to construct such an explanation.
But his conclusion that AdS/CFT demonstrated convincingly the unitarity of blackhole formation and evaporation (and, famously, his conceding his bet with Preskill) preceded (and inspired) this paper.
Explaining all the detail will take a while. You might start with this Physics Report from 1999. It is a pretty thorough review of the state of the art in AdS/CFT, circa 1999. But there have been a number of important developments since then. One is by Berenstein, Maldacena and Nastase, who found a limit in which the duality between the boundary gauge theory and bulk string theory is weakly-coupled on both sides of the duality, and so one can see the full stringy spectrum from the gauge theory.
This has been pushed much farther by subsequent authors, and there is now an emerging belief that both the large-N gauge theory and the classical string theory in the bulk of AdS are exactly-integrable systems. I’m sure you can appreciate that would be an astounding development (with striking implications for the quantum theory), if it turned out to be correct.
Clifford already linked to some posts of mine about RHIC physics. I’m sure there are quite a number of other posts of mine that would be useful to you, in this regard.
But I think that’s a plenty substantial reading list to start off with…
Jacques said:
Thank you; this is exactly the kind of thing I was looking for. So, if I have understood properly, the Planck length is actually a parameter which you use in order to make predictions about QCD. This is very good news indeed and makes string theory seem much more credible to me. I have never heard anybody say that before, though.
I thought that Hawking used a Euclidean path integral argument to convince himself that black hole evaporation was unitary and there were no strings involved.
If the numerical value of the Planck length can be used to make experimental predictions about nuclear physics which could not be made without knowing the value of the Planck length then I would be very grateful indeed if Clifford or anybody else could explain all the details. In fact, if this were widely known it would boost everybody’s confidence that string theory is the correct theory of quantum gravity and would thoroughly refute Lee’s and Peter’s criticism that string theory has made no experimental predictions.
Thanks again for your reply; this was very helpful for me. As I had previously understood it, the actual numerical value of the string scale in the bulk theory had no consequences at all for the QCD dual. Discovering that this is not the case is most enlightening and I am in your debt.
Aaron:
Thanks for your reply. I have, in fact, heard string theorists argue many times. Often about string theory.
Yes, you are missing something crucial. Back in the old days, when people thought they were working on a theory of the strong interactions, the string scale was supposed to be the QCD scale and the string was supposed to propagate in 4 dimensions. Its excitations were supposed to describe hadrons.
In AdS/CFT, that’s not what’s happening. The string propagates in a 10-dimensional spacetime (AdS_5 x S^5, for instance), and the string scale is the Planck scale. The bulk physics is that of a gravitational theory, with gravitons and blackholes and …
This is not the “QCD string” of yore.
We really are talking about a theory of quantum gravity in (asymptotically) anti-de Sitter space. We can study gnarly old problems, like blackhole formation and evaporation. And it was in this context that Hawking was finally convinced that the latter process is unitary.
So I’m hard-pressed to understand how checking the predictions of AdS/CFT could fail to bolster your confidence that we are staring at a consistent theory of quantum gravity.
Does it shed light on how to solve other (long-outstanding) problems? In many cases, no. But, in some cases, it has had an important impact.
When one studies flux compactifications (the current , where one puts a large amount of flux on some cycle, then there’s a warping of the geometry, so that locally, it looks just like the aforementioned AdS/CFT geometry. And this warping gives a new mechanism for generating a large hierarchy of scales (the same large hierarchy of scales between the Planck scale of the AdS bulk physics and the QCD scale of the boundary theory).
Clifford, among others, could give you a long disquisition on this and related phenomena, if that’s what you are really interested in. But you seem to be doing a good job of convincing them that’s not what you are actually interested in.
Somehow, I think Igor might find this amusing given how annoyingly skeptical I probably was during his string theory class.
As for the rest, if you had ever heard a group of string theorists argue, I doubt you’d be asking the questions you’re asking.
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Navellung,
Yes, it seems that we might have got some useful physics discussion to happen in the end. I do hope that it was worth it.
Cheers,
-cvj
Clifford, thanks for your answer. This thread, and the twin one at CV, have been quite
interesting. Cheers.
Jacques said:
Thanks for your reply. I would like to know if other string theorists find these arguments about tests and tracks persuasive (Clifford, Aaron, Jeff?).
To me it seems like the argument isn’t valid because I am no more confident, after seeing the relation to QCD, that string theory will pass a driving test. So it is certainly not the case that evidence is provided in favor of the conjecture that string theory will pass all tests, including driving tests. We must therefore distinguish between the tests which string theory is considered more likely to pass (in the light of the QCD success) and the tests which it is not. I may be missing something that is very clear to you, but it seems to me that when a theory which was designed to account for the strong interaction turns out to be a theory of the strong interaction then this does not provide evidence that it is a theory of physics at the Planck scale.
But I may be misinterpreting what you mean by “on the right track”. It is a metaphor and I’m not good at interpreting metaphors. If all you mean is that the mathematics of string theory is useful and interesting and relevant to some physics (even if only QCD), then I fully agree with you. On the other hand, if “on the right track” means that string theory is the correct theory of Planck scale physics, then it would seem that you have made an inference that I cannot, but of course you may know something I don’t about it, which makes the inference valid. If so, I would be grateful to know what that something is so that I can regard the inference as valid as well.
I am sorry if I said anything which could be interpreted as snide. If you show me what it was that you think was snide, I will apologize specifically and try to rephrase it in a way that you don’t consider snide. You are all very intelligent people and I am humble and respectful.
Aaron said:
Thank you; I read it many times. Unfortunately it seems that the question you addressed was not the one I raised. No doubt at the time people first make the choice to work on string theory the effect could not have altered the person’s perception, unless perhaps it is through the coverage of string theory in the popular media. In order for the effect to work the individual must have already taken a gamble and joined a community of people who have taken the same gamble. So it would only start to take effect after somebody has become a string theorist, and not at the time they choose to work on string theory. Your comment seemed to presuppose that the effect I mentioned was the reason that people start to work on string theory, but this is not the case. This was why I tried to clarify your response. I am sorry if you perceived my attempt to clarify as hostile.
Lee:- This may be progress!
Yes, get in touch.
Cheers,
-cvj
Dear Clifford,
Let me reply quickly to 2). I am happy to do anything in that direction. I also have a suggestion in this direction that I may contact you directly about.
I don’t think that my book misrepresents the field, it says at the beginning that the focus is on research aimed at the five questions, and it also says explicitly that there is much progress in the rest of physics.
But in any case, if you or anyone thinks that I leave anything open to misrepresentation I am very happy to correct it. There was a lot more about stringy applications to QCD in an earlier draft of the book, and I can put them back in case there is another edition. It won’t change the main conclusions, but if you think that is a good thing to do I am happy to do it. I am happy also to put something on my web site and add a page to the talk I am giving related to the book.
I have a lot to say about 1) but I would like to formulate it carefully to avoid further misunderstandings. More later about that and other issues you and others raise.
Thanks,
Lee
I know that you did not ask Clifford, but I have to respond to this.
Egbert:So I do not think it can be said that people who are beginning graduate students can make an informed decision about whether string theory is worth studying.
Historical reference is always imprtant to the converstaion because it can support what seems untenable for some, whilst the true process is a “gathering storm” of all the information that becomes relevant. Why would you go back and change it? Personal stories, failed attempts? It became a problem and th equestion was what are we to do?
At “one time” how decidably so then our views of the times? A Ghost Particle?
So quickly you may think of the inclusive extnesion of the standard model graviton perception in the bulk here? But wait, we are still dealing with the continued course of events revealled in how neutrinos work in line with elemental particle considerations of the microstate blackhole? Cosmic particle collisions?
How could you not be excited that any theoretical/concept/idea model would not deal with this?
Yes, as a lay person I may talk about the future of the students and what influences may be attributed by our teachers. As a “lay person” I recognized the way in which sound reason had not been appplied by making wide claims for treating the model less then the theoretical, joined the ranks as a concept(or not even) maybe just an idea?
So any collaboration to that effect is less then appealling on what we(society) want in the future? Can I be so bold to denounce in the “one way” that “the other” would denounce themselves, as to our future?
Egbert —
Since you have been so unhappy with the reading comprehension of your posts, I suggest you reread mine to see precisely what I referred to as unfalsfiable.
HTH.
It is logically possible that a theory of quantum gravity could pass some tests and, yet, fail others. But it would be stupid to say that passing one test “does not provide evidence in favor of the conjecture” that it will pass other tests.
Every test passed bolsters one’s confidence that we are on the right track.
A “background independent” theory of quantum gravity must describe quantum gravity, not just in our universe, but in asymptoticallly AdS universes as well. AdS/CFT related the properties of quantum gravity in AdS to physics that is accessible to us in other ways, either calculationally (despite your snide response to Jeff Harvey, it is a fact that we are good at calculating in QFT) or experimentally (RHIC).
So, the fact that we can test string theory, as a theory of quantum gravity in AdS space, is a nontrivial and important test of whether we are on the right track.
Dear Lee,
The Maldacena conjecture maps large N QCD into string theory in a space with a particular
asymptotic structure. This string theory involves quantum gravity. Because of the duality to a theory of quantum gravity, it seems clear to me that studying this duality and testing it experimentally does teach us about quantum gravity. For example, studying the duality at finite temperature involves the physics of black holes. While this is not quantum gravity in our particular spacetime, it is still quantum gravity.
It is also my opinion that your emphasis on mathematical rigor is misplaced. We are trying
to do physics here, not mathematics. To add to Jacques’ discussion above, one could
make exactly the same kind of criticism of a “conjectured duality” between the path
integral formulation of QFT and the canonical formalism. On the canonical side one
has a perturbation series which is divergent and clearly does not define the theory.
One the path integral side one has, well, path integrals. To my knowledge no one
has made rigorous sense of them, at least not in our physical Minkowski space. In spite
of this the duality between these two sets of calculations is taught all the time to graduate students and even undergraduates and even presented as fact in many textbooks. What
a scandal!
Without use of these mathematically ill-defined objects it is hard to imagine that we
would have made much progress in studying non-Abelian gauge theories. Neither side
is well defined, yet we calculate, and the calculations agree with experiment. It causes
distress and consternation among mathematicians, but somehow nature seems to be OK
with this shoddy state of affairs. In my opinion mathematical rigor comes after the fact, and emphasis on it during the development of new theories only slows down progress. Clearly you disagree, and in the case of quantum gravity the jury of experiment is still out. But I think history is on my side.
My sincere apologies. Of course I meant “each others’ confidence”.
Aaron,
Thank you for your reply. It is good to hear some fresh voices.
Thank you. It is good to hear somebody say “of course they can”. Jacques said that he will leave these things to his wife (and I am waiting to hear either his wife’s response or that his wife didn’t respond). Clifford said that he does not want to answer. It is very good to find somebody who is willing to answer my questions.
Will you be willing to state, as other string theorists were not, that the conjectured relation of string theory to QCD does not provide evidence in favor of the conjecture that string theory can reproduce the standard model, or is the correct theory of quantum gravity? Jacques and Clifford declined to address the question; I would be grateful if you would be more verbose.
You say that my question is unfalsifiable. What is it that you claim is unfalsifiable?
There are two possibilities:
1. You claim it is unfalsifiable that people who have taken a common gamble and who communicate with each other over a long period of time will tend to reinforce each other’s confidence that their gamble will pay off, so that their communication with each other increases each other’s assessments of the likelihood that their gamble will pay off.
I think you have a considerable amount of intelligence, certainly enough to understand that the statement 1 above is not any more unfalsifiable than the statement that people are not happy when tortured.
2. You claim that it is unfalsifiable that string theorists, on this particular issue, have reinforced each other’s beliefs.
This is unfalsifiable in the same way as evolution is unfalsifiable – it is a statement about the past, and we can never prove any statement about the past with certainty.
Thank you for your time and attention. I know that both of these are precious, because we will soon die, and it would be good if we could spend our little time alive helping each other rather than insulting and attacking each other.
Dr. Spanker,
Thank you for your statements. I agree that the availability bias may have some effect here. Certainly d-branes, t-duality, black holes, eleven-dimensional supergravity and Calabi-Yau compactification seem more like consequences of string theory than spinfoams do of LQG, rather than being an idea thought up independently which might hopefully fit together (Lee, please correct me if I am wrong). So in that sense, string theory looks more like an actual theory.
But we also have to bear in mind that d-branes, t-duality, eleven-dimensional supergravity and Calabi-Yau manifolds have no relevance for us apart from their connection to string theory. And the wonderful achievements of string theory are in a large part a consequence of the fact that there are an infinite number of conserved charges in 2d CFT. The discovery of the Virasoro algebra will most likely turn out to be important not because it is “The Universe” or any other such religious notion, but because it is an integral and indispensable part of conformal field theory.
So I would say that if we are looking for a theory with a lagrangian like the Nabu-Goto action or the Polyakov action then of course there will be an availability bias towards string theory. But most string theorists make the decision to study string theory long before they have heard of gerbes or quivers. In fact, it takes many years before a committed string theorist has any idea what a left-mover or a right-mover is, or even what heterotic means. Nobody can make an informed decision to start studying string theory.
So I do not think it can be said that people who are beginning graduate students can make an informed decision about whether string theory is worth studying. Any bias must arise after people are already string theorists, or through their interaction with the string community, including feedback through the popular media.
Aaron —
If there is a psychological bias among string theorists which leads them to misoverestimate the likelyhood of string theory being true, I think the relevant concept is not so much ‘groupthink’ but availability error.
It’s a ‘fallacy’ which leads people to misoverstimate the relevance/importance of things and concepts which they are in frequent contact.
In this case, it is a result of the fact that string theory, whether right or wrong, has a plethora of solutions, each of which makes extremely detailed predictions for scattering amplitudes, spectra, nonperturbative effects, etc., LQG has still not even managed to produce a single solution where a graviton scattering amplitude can be computed, in any approximation.
Given this, their wild claims about being ‘better’ or more ‘phenomenologically viable’ than string theory are risible at best — the bald-faced lies of a clown-car full of pathological liars who wouldn’t know a successful physical theory if they had one handed to them on a silver platter.
So it is only natural that there be some availability bias in favor of a theory which actually exists, and is capable of producing physically well-defined amplitudes over a theory which, after 20 years, is still just an airy cloud of vague promises that something might one day be computed.
Egbert —
This is silly. You ask, can people sometimes reinforce each others’ views. Of course they can. It’s an inane question. If you choose to believe that the reason most people work on string theory is this sort of ‘groupthink’, no one will be able to prove to you otherwise. It is, dare I say it, an unfalsifable assumption.
I don’t think it’s true, but, then, perhaps I’m just overly influenced by others.
Clifford,
I have an idea which may make it easier to understand my question. Let me ask instead: the critics of string theory – Peter, Lee, Glashow, Anderson, Laughlin and so on – do you think that they might possibly have taken a gamble by publicly opposing string theory? And, given that investors who have made a common gamble and form a community can reinforce one another’s confidence, do you think that it is possible that they could have emboldened each other, through their public and private communications, to believe that string theory is not the theory of everything?
Of course, you are no better qualified to judge this than anybody else, because you are not a member of their community of naysayers. But you evidently have no problem accusing them of dishonesty, which is a speculation about their state of mind, so when directed against the critics of string theory the question may be easier to understand.
Lee wrote:
Just so that everyone understands, Lee is reminding us that no one has ever rigourously proven the existence of any nontrivial 4D quantum field theory. Ergo, it is impossible to claim to have proven a duality between two 4D QFTs (let alone between a QFT on the boundary and a string theory in the bulk of AdS).
Somehow, though, in the absence of a rigourous definition of QFT, we manage to muddle through, extracting useful information from them.
Even in the absence of a rigourous definition of either side of the duality, we can still amass evidence for it, by calculating various quantities on both sides of the duality and comparing the results. When we find agreement, we build confidence that, at least some weak form of the duality must hold. Since there have been many such calculations performed, in the case of AdS/CFT, the scope for the possible points of failure of the conjecture have narrowed.
Over at CosmicVariance, I asked Lee whether he could think of a form of the conjecture, weaker than the “strong form” which would still be compatible with everything that has been checked to date.
Obviously, for the reasons stated in the first paragraph, no one can claim to have proven the Maldacena Conjecture. There are many things in Physics (and even in Mathematics) which have never been proven, but for which there is very strong reason to believe that they are true.
I think the Maldacena Conjecture falls into that class. Evidently, Lee disagrees. If so, could he, at least, outline a plausible scenario in which the Maldacena Conjecture might still fail?
See my above remark about the neccessary connection between gambling and research.
vegas, baby — VEGAS !!
Clifford,
No; what I was asking was whether string theorists reinforce one another’s confidence in the expectation that string theory is a theory of everything (a theory incorporating the standard model and gravity). Or rather, I was asking you to give your opinion on whether this is possible, bearing in mind that the analogous effect is very common in the investment community.
The ideas about lack of intelligence arise when individuals in the community of investors talk to each other about those people outside the community who have the opposite assessment to the people within the community. It is completely natural and understandable that somebody who regards an investment as wise and seeks to portray it as wise to his colleagues will say that people who think the investment is unwise are foolish. Indeed, this is what happens all of the time in the investment community.
So it is not “people not working on string theory”, but “people who explicitly think string theory is not the theory of everything”.
But I am not so interested in the question of whether string theorists think these or those people are lacking in intelligence (one only has to read Susskind’s comments about Lee to get an idea about this). What I am interested in is the question of whether string theorists reinforce one another’s expectations that string theory is a theory of everything in the sense of containing the standard model and also being a theory of quantum gravity, in the same way that people in the investment community do. If so, their perceptions of the likelihood of this being the case are distorted.
This may seem antagonistic, but try to imagine it from an honest outsider’s point of view. String theory is more of a gamble than organic chemistry; string theory might turn out not to be the theory of everything, but many people invest their careers in the hope that it will. These people, who have all taken the same gamble, form a community of hundreds and talk to each other. Do they reinforce each other’s confidence that they have made the right choice or not? If not, how do they escape the problem that affects investors? I think these are valid questions, and important ones.
As a string theorist you are more likely to have insight into this than an outsider, so I asked you.
If you do not want to express an opinion on the matter, that’s ok. I don’t want to press you on it. If I haven’t explained the question clearly, I’m sorry; I will clarify any part that you say is unclear. If you think I am rude to ask the question, then I apologize and do not wish to be rude, but I still think the question is valid and important.
Thanks again for spending so much time on this.
Egbert:- Most string theorists I know, and whose company I care to keep, do not regard people not working on string theory as lacking in intelligence. Was that all you were asking? I see now. But I cannot speak for everyone, as I said before, but that is my impression. In fact, I spend a great deal of my time talking to non-string theorists about physics… sometimes more than I do to string theorists.
Best,
-cvj
Clifford,
Please; I do not wish to be hostile. I think the question in an important one. The phenomenon is not at all unusual in investing. Members of communities who have made a common investment reinforce each other’s confidence in the wisdom of the investment and regard people who don’t share their assessment as lacking in intelligence. The string community strikes me as something which might manifest the same effect, since the same conditions are there. I don’t wish to accuse you of anything. I just wanted your opinion as a string theorist. If you don’t want to speculate about it, that’s okay – I have no desire to ask you to do anything you don’t want to.
Again, thanks for your time.
Egbert – You are asking me to speculate about what is in the minds and motivations of others…. Why would I know that sort of thing? I spoke for myself and took quite a bit of time to answwer you carefully and honestly about my own motivations. I cannot speculate about the rest. I don’t even know most of the string community.
Good Day to you.
-cvj
Lee said:
Bert Schroer, in the paper here says, beginning on page 18:
As I understand it, most string theorists regard Maldacena’s AdS/CFT as a done deal. Will they continue to believe this in the face of a rigorous proof of the contrary by a non-string theorist?
Clifford: I don’t think you were being dense at all. From my point of view, there are two possibilities – one is that my comments were very confusing and I have failed to communicate the question to you despite attempting five times and rephrasing it and clarifying it in various ways. The other is that you, as a string theorist, do not want to answer the question honestly out of a desire not to say anything disloyal about your colleagues. Whichever one of these is the case is a matter of speculation and I would not presume to make any judgement about it; anybody who reads my comments can judge their clarity for himself.
But I am grateful that I was able to ask the question to you and that we could politely discuss at least as much as we have. Let me thank you once again.
So Lee,
Now that you have considerably narrowed the scope of what you’re saying about the work of the community on string theory, will you:
(1) Re-assess your remarks about the distribution of resources (research funds, etc) in the light of them? There are very many people working on those aspects of string theory that you consider to be mere applications (even though it is in the context of potential applications to currently experimentally accesible physics), and not fundamental. In your accounting of how much resource is being misdirected to the string community, you should be sutracting that effort on the “applications” stuff, no? Or do you think that is not important in the scheme of things, and so should be just abandoned. If so, should you not also cut the program of research in condensed matter physics and several other fields as not fundamental too?
(2) Be much more careful in your public remarks and appearances to not misrepresent the work in string theory, carefully distinguishing between the two efforts? Your book right now, and the things you said in the two radio interviews I’ve heard so far (and no doubt several others) are, just like Peter’s book and remarks, a serious misrepresentation of the effort in the field. Perhaps you could add something to your website for the book, or maybe even add something to later printings of the book? Wouldn’t that be the responsible thing to do?
So will you be doing any of those things?
Thanks,
-cvj
Dear Jeff,
Sorry to have missed this your post, its been busy. Ill do my best to respond briefly and, given the pressures of time, quickly, I apologise in advance if I get something wrong, in which case I look forward to being educated.
First, as I said in the program, I strongly admire the work on using string theory to connect QCD to experiment. BUT, if the contact between string theory and experiment turns out to be entirely in the service of connecting QCD to experiment, so that the theory in question remains QCD in minkowski spacetime, and string theory plays a role entirely as a tool or a reformuation of QCD in Minkowski spacetime, then string theory will not turn out to be the fundamental unification of GR with quantum physics. This seems to me an elementary logical point. String theory will then certainly be useful, beautiful, good physics, etc, but it will not be the answer to the problem of quantum gravity.
Therefore I did not have much to say about this possibility in a book narrowly focused on the status of different attempts to solve the problem of quantum gravity (and the 4 other problems mentioned in the introduction.) I was more concerned to evaluate progress towards the hypothesis that string theory is the quantum theory of gravity.
So, the passage you mention is the only place in which a discussion of these applications are mentioned in the book. Perhaps it was bad judgment to remove the long description of applications to QCD that were there initially, if so I can accept that, the above was the reasoning.
This does not mean that I think that the applications of string theory to QCD are not worth pursuing, indeed my view is that this is a very worthy topic of study, as I said so strongly as soon as you brought the subject up.
Indeed, if it would help I would be glad to write or sign a letter to whomever it may concern emphasizing my strong support for developing applications of string theory to QCD, heavy ion physics, etc. What ever else I say, I do not anywhere say that I think that people should not continue to investigate string theory and I agree that this is one very important direction. My issues are entirely different, they are about evaluating different and perhaps competing approaches to the problem of quantum gravity.
As to my understanding of dualities beyond maximal supersymmetry, I am aware of some results but none that I know of are strong enough to prove the strong form of the Maldacena conjecture in the absence of either an explicit formulation of string theory on asymptotically AdS^5 X S^5 spacetimes or a general background independent form of string theory. I think this is a simple logical point. One cannot claim to have proven an isomorphism PHI between two mathematical structures, A and B, when there is no detailed definition of either A or PHI.
As to non-supersymmetric string theories, again I know of a number of different results, which you are alluding to. But my impression is that there is no explicit definition of string perturbation theory, with a demonstration of consistency and uv finiteness-to genus 2 as in the susy backgrounds-on any background that is not either static or conformally static. If this is incorrect please give me details.
Please remember, I am not interested in guessing what might be shown in the future. I am instead mostly concerned with stating precisely what has and not been shown, till now. The reason is that I don’t know how to think reliably about where to go in the future without a precise and correct catalogue of present results.
Thus, I do not know whether there can be a non-supersymmetric string theory without tachyons, but I want to distinguish between a situation where one has been explicitly constructed and checked for stability and consistency, and the situation where this has not yet happened.
Again, if we had a fully background independent definition of string theory, we could explicitly expand around different solutions, some stable, some unstable, and settle these questions. In its absence, we cannot reason assuming that it exists. Reaonsing based on assuming that in the background of everything is a consistent background indepednent form of string theory assumes what is to be proved. So just because in some special cases we can trace where the instability goes, does not guarantee that we can in all cases. The theory might just be unstable, in which case some tachyons might lead to good vacua, but there will be others that do not.
Am I reasoning wrong here?
Thanks,
Lee
Egbert:– Thanks for your questions. I’m sorry if I am being dense. I tried my best.
-cvj
Clifford,
I guess it was a failed exercise, then. Many thanks for answering as much as you have.
I would be grateful to anybody else who has read my comments who can explain to me how they are unclear or how it could be so difficult to understand what I am asking. To me it seems perfectly clear and straightforward, but of course it is difficult to judge how clear it may seem to others.
Plato:- I’m just as mystified as everyone else with Peter’s accusations. They are again a dstraction from answering the physics questions I asked him. I’m sticking to the physics.
Egbert:- I really don’t understand this gambling business -at the level you seem to want me to get to- at all. I’ve tried to answer it as well as I can. I am not offended. I’m just unable to answer you any more than I already have on that point. I have quite clearly explained (I think) what I think we as a field are doing in terms of the physics. I’ve explained that I do not think that it is different from any other physics endeavour. Pleasse see again my remarks about the pragmatism of the exercise. I cannot really speak for everyone else in detail, so cannot really help further on this issue.
Cheers,
-cvj
Clifford,
Thanks for your reply.
I agree that all of research involves risks, but the situation with string theory appears to be unique in all of research because it is the only area where an entire community of hundreds if not thousands of researchers appear to have taken a common gamble regarding a conjecture, and the truth or falsehood of the conjecture will not be known for the foreseeable future, and the community has been already been bound together by their common gamble for decades.
In other areas of research different researchers take different risks, and do not form communities of hundreds of people who have all dedicated their careers to the same speculative conjecture. String theorists who have taken up string theory because of its promise as a theory of everything (a theory reproducing the standard model and containing gravity) are in a very different situation to anybody in any experimental science. The former have taken much a much bigger gamble and they have all taken exactly the same gamble.
So I do think that the investment effect I mentioned in my first comment would have a greater effect on string theorists than on organic chemists, because the conditions necessary for the effect to manifest itself seem to be present in the string theory community but not in the organic chemistry community.
This was why I asked to hear the opinion of a string theorist on the issue. I am eager not to cause offense because then you would dismiss me and refuse to answer my questions and I would be left to draw my own conclusions, as Jeremy Paxman (BBC TV presenter for those who haven’t seen him), urges people to do when somebody has been asked a question several times and refuses to answer. The default conclusion is not favorable to string theorists. Please help me to draw a different conclusion.
Clifford this post may seem harsh, but it is necessary.
Investment Banker:My criticism against Prof. Clifford is not about his promotion of string, but his suspected involvement in stopping the publication of Peter Woit’s book. It is pretty hard to argue for this kind of behind-the-door censorship on moral ground. I simply pointed out the legal aspect of his action since it can be intrepreted as unduly and unfairly influencing the decision of public grants that he may receive in the future.
Censoring statements to continue to provide a fundemental view of the reality by Dr Woit as he see’s it is not the viability one might want to see expressed in society based on what is known?
So you look at Dr Woits current article of expression by his comments in regard to KC Coles’s “Strung Along” and you get to see the psychological effect of what one may think is the “onslaught of string theorists doing the damage to his credibility?”
Lets remove the cover of this situation and see what lies underneath? What is the physics involved?
For that you have to see KC’s article in light of Peter Woits article from his bloggery. His “supportive views by the tribe” as to what may be of something profoundly important that supports the view’s Dr Woit has of string theory. So you see the very happening that he himself “complains of in the group of string theory” as a redundant process to the way one may look at reality?
So what’s the jest here then?
Again we come back to KC’s article for inspection and what has been provided as an example here on this site in regards to what ICECUBE may offer of the “new physics” and the microsate blackhole as part of the evidence we may see?
He did not want you to “see this” the public? Which would have run contrary to the image and position he wants to portray for us in society.
So one mst investigate and look at this and make his own assumption as to what is happening.
The links to Peters Woits site and article by KC COle is located at Peter’s site for your preview.
What is mssiing is the information that I” pointed out” in relation to KC’s article and the points she made. This is no oversight to my opinion but of the evidence that will be thrown away to support his merry and continued view with which he has taken as a stance for society.
No thank you, if you continue to deny the model approach to experimentation.
If you wsh for me to site the example, all you have to do is ask.
Yes, it is amazing.
You seem to be arguing (correct me if I have misconstrued you) that the editor, upon receiving a manuscript about string theory, should not have sent it to any string theorists to be refereed?
I think this is the source of the problem with theoretical physics these days: unaccountability. You seem to argue that the referee can do whatever he wants in academia, while in the real world decent people are expected to recuse themselves when self-interest is involved. The mind sets are so different that it is simply amazing.
You are talking nonsense.
Editors and granting agencies are supposed to ensure that their referees do not have conflicts of interest. On many occasions, I’ve turned down a refereeing assignment, because I I had a conflict.
Evidently, however, you are of the opinion that merely being a string theorist is, in itself a conflict of interest. I’m not sure how to respond to that, except to point out that the Editor had the option of calling upon a second referee who was a non-string high energy theorist.
Whoever the referee(s) were, I think that the default assumption (in the absence of any evidence to the contrary) is that the editor did his job, and there was no conflict.
Unless you have some inside information you’re not sharing with us, your hurling charges of illegalities is utterly ludicrous.
M:- Please read the links Jacques and I gave above. it is pretty clearly explained there. I think that there also my be a review on some of these matters by Ed Shuryak.
-cvj
This blog does not work well on my browser, so posting is difficult. I apologize if I don’t get consistently involved in subsequent discussion, even if I had started it.
My criticism against Prof. Clifford is not about his promotion of string, but his suspected involvement in stopping the publication of Peter Woit’s book. It is pretty hard to argue for this kind of behind-the-door censorship on moral ground. I simply pointed out the legal aspect of his action since it can be intrepreted as unduly and unfairly influencing the decision of public grants that he may receive in the future.
It would be interesting to have a post about string results vs RHIC data. A paper on hep-ph today tells that strings predict shear viscosity to entropy = 1/4pi, that the measured value is 0.2, no uncertainty is mentioned.
Egbert:- You caused no offence whatsoever.
Thanks for your questions.
See my above remark about the neccessary connection between gambling and research.
Cheers,
-cvj
To illustrate the principle with an example:
Suppose I was receiving an NSF grant to work on string theory. And suppose I used my grant money to fly to Washington, DC and throw big parties for US senators where I would wine them and dine them and lobby them to shut down all funding for Loopy Quantum Gravity in the US.
That would probably be an unethical conflict of interest, maybe even illegal lobbying.
On the other hand, suppose I were funded by NSF and I decided to give talks and write blog posts and say, “Loop quantum gravity has been around for 2 decades and hasn’t even produced a graviton scattering amplitude, which string theory did when it was negative 2 years old. Maybe someone in authority should think about pulling the plug on LQG, not string theory.”
Would that be illegal or unethical? No, obviously not. I would have as much right to say that, legally, as would the average 40-quaffing Joe Schmoe — and I would certainly be infinitely more worth listening to.
For some reason, AnInvestmentBanker wants only complete scientific illiterates to be allowed to comment publicly on science, and he thinks that everybody else should be silenced by law.
Maybe the in-house lawyer at AnInvestmentBanker’s company told him about all the labyrinthine rules the firm has to go through to make their bribes to legislators technically legal. And maybe AnInvestmentBanker got confused, and assumed that scientists were just as crooked and cynical as himself and his banker colleagues.
Sorry, AnInvestmentBanker — I realize you’re cranky because your bank got busted for illegally lobbying the House GOP to loosen insider trading laws so you could set up some more Enron-like pyramid schemes. Better luck next time! 🙂
But that doesn’t mean scientists have to give up their right to reality-based public speech on scientific matters.
AnInvestmentBanker says:
My only question is whether prof. Clifford receives any funding of strictly public nature, such as DOE or NSF grants. If so, then his behavior is no longer a private issue but a public one, since his efforts can be seen as self-enriching at public expense. This is clearly an ethic violation and potentially illegal. Have you registered as a licensed lobbyist, prof. Clifford?
Scientists blogging, writing, public speaking and expressing their opinion on scientific matters is aquintessentially legal activity, completely regardless of what grants the speaker may or may not be receiving from whatever source.
Maybe your investment bank should hire some people who understand the basics of US law, and can tell the difference between constitutionally protected free speech and ‘self enrichment’. I suspect your investment bank will rapidly ‘self-impoverish at private expense’ (as you would put it) 🙂 if they do not have some smarter people working for them.
Not understanding the difference between blogging and lobbying — it really doesn’t get any dumber than that.
This comment
Thanks Jacques and Clifford again for replying.
Yes; that makes sense from the particle physics perspective. As you know, people who think that general relativity is more “fundamental” than particle physics are not convinced by these arguments. Thank you for the Georgi quote, by the way.
Yes, indeed, and it has already passed several tests of its relevance – counting rational curves and so on. The connection to QCD and relevance to other areas of mathematics makes any proposal to “stop doing string theory” unreasonable, even if the standard model never fits in with it.
(The claim was that VEVs in a particular string vacuum give the masses of the elementary particles.)
I may have been misinformed about how general that claim was, but it isn’t entirely relevant what mechanism is used to calculate the fundamental constants. The point is that a major selling point of string theory is the possibility of calculating the fundamental constants. That claim may be made less often now (after the landscape), but there is the residual hope among string theorists that some vacuum of string theory will be able to reproduce the standard model. As Jacques mentioned, this may or may not turn out to be true after all. This is the thing which I am asking – have some string theorists taken a gamble on this very point?
I would think that anybody who chooses to research string theory primarily because of its promise as a theory which can reproduce the standard model and still contain gravity (which is what physicists usually mean by a theory of everything) then that person has indeed taken a gamble. He may not have had much choice (there are no obvious alternatives, for example) and it may be the optimal thing to do. But he is still hoping that one thing and not another turns out to be the case, because of what he has spent his time on.
I may be wrong, of course; string theorists may not feel that they have gambled anything on the success of the theory-of-everything project. Or they may agree that they have, and be aware of the dangers of being in a community of people who have taken the same gamble, and they might consciously strive to counteract the investment effect I mentioned. This was why I asked for your views on the issue. It is clear what the critics of string theory think about this; it would be easier to understand the pro-string side of the story if a string theorist would respond with an answer more informative than “No comment”.
I did not mean to cause any offense. I just wanted to understand what you meant by the expression, and how a theory of Nature might differ from a theory of everything, as you use the terms.
Yes, I realized that would be a source of confusion, after I wrote it. I was alluding to something very specific, namely Georgi’s objection. You ought not be able to couple arbitrary matter degrees of freedom to a sensible theory of quantum gravity. String theory is a theory of that sort, to which you cannot couple other degrees of freedom.
Now, it’s perfectly possible that string theory isn’t the only theory of that sort.
It’s possible that string theory could pass all sort of tests (like, say, giving successful predictions of RHIC physics) and then, ultimately, fail to deliver the goods on other tests (like failing to yield a vacuum that reproduce the detailed features of the Standard Model). Or, maybe, we might fail to be able to calculate crucial properties of the theory (think of the long and frustrating history of the Navier-Stokes equation).
If there weren’t a possibility of failure, they wouldn’t call it “research.”
More to the point, though, I think that what we now call “string theory” looks a little like the Rube Goldberg-esque contraption known as the old quantum theory. Hopefully, this century’s Heisenberg and Schrœdinger will come along and recast it in a form bearing only a vague resemblance to what we have now.
Which is why I actually struggle to understand what the LQG people are doing. The key insight may very well come from some totally unexpected direction.
AS to your penultimate paragraph:- Nobody to my knowledge, has claimed any such thing. There are lots of suggestive models and scenarios where such things might turn out to be true, but these sorts of things are still subjects of ongoing research….. And the paragraphs before… Yes… Is QCD not a theory of Nature? There was a Nobel Prize for one of its key properties, Asymptotic Freedom, not long ago, so I think that counts, no? So if strings described the same force, but a different experimentally accessible regime, why would you not call it a theory of Nature, whether or not it described a single other phenomenon in the universe? We should not lose sight of what we are trying to achieve with science here.
-cvj
Jacques, Clifford,
Thank you for your replies.
Thanks; this clarifies the issue.
There is considerable confusion about what the word “theory” means. It seems that different people use it in different ways. Presumably by theory here you are referring to the “every theory has its lagrangian” idea of a theory and would not classify, for example, causal dynamical triangulation as a theory.
Indeed I would be very interested to hear what she has to say on the matter. But I would be even more interested in hearing a string theorist’s point of view.
It is difficult for me to understand what you mean by a “theory of Nature”. If the mathematics of string theory turned out to be useful for understanding QCD, but never had any other connection to experiment (a scenario which I agree is very unlikely), would you still regard it as a theory of Nature? Or is there another criterion?
I agree, but I am more specifically asking about the people who claim that the masses of the elementary particles are vacuum expectation values of string theory in a yet-to-be-identified vacuum. This is a rather concrete claim, and I would be very grateful to hear a string theorist’s opinion about whether those who make such a claim are taking a gamble, and whether the investment effect I mentioned could be influencing their perceptions.
Many thanks once again for taking the time to answer my questions. I think it is important, as you point out above, to hear the opinions of the scientists themselves on these issues.
gerry atric:- I’ve made that point above, indeed. A landscape of solutions is a very normal thing to have in physics. This is nothing new. See my comment to Navellung here. As regards initial conditions… we’d like to understand that better in strings too…. it is not neccessarily connected to the landscape.
egbert:- I’m really not “portraying” strings as anything other than a candidate theory of Nature. Some are interested in its potential to help understand the strong interactions, others the unification of forces and so forth, others black holes, etc….. I work on all of those.
I think that there are those who are excited about strings’ potential to answer a lot of the open questions we have in physics right now. So am I. Some people call that the “theory of everything”. I think that this is a naive term (I bet that there are a lot of questions that will surface later that we have not even concieved of asking yet), that has caught the public’s imagination a lot. If one does not like the attention, and wants people to work on other things, the reaction to this is not to publicly misrepresent the work in question, as Peter and Lee are doing.
As to risks and investments. What can I say? I don’t think that there is anything out of the ordinary in choosing to work on strinf theory. You take risk whenever you step into the unknown. Research is all about the unknown.
Cheers,
-cvj
I don’t think there’s any disagreement.
AdS/CFT has provided a rich set of examples of QCD-like theories which have critical string duals. The string dual lives in some asymptotically AdS space, whose boundary is the 4D spacetime on which the field theory lives.
The field theories all share the common properties that
1) There is a large-N limit. (This is the limit in which the dual string theory becomes classical.)
2) The theory is controlled by a nontrivial UV fixed point. (This is dual to the statement that the string theory lives in an asymptotically AdS space.)
QCD, of course, satisfies 1), but not 2). So it’s not really in this class. So, naively, it does have an AdS dual. Nevertheless, clever people have been working hard to build one. I discuss one such model here.
Any theory of quantum gravity is necessarily a theory of everything. And any good theory of everything has applications well beyond predicting the parameters of the Standard Model. Studying transport properties of strongly-coupled gauge theory plasmas (the application to RHIC physics) is one of them.
If Lee has an alternative construction of quantum gravity in asymptotically anti de Sitter space, I invite him to use it to compute these transport properties. (On general grounds, it is clear that the observable of quantum gravity in asymptotically AdS space are the correlation functions of some QFT on the boundary). Perhaps his theory gives a better account of the physics observed at RHIC.
As to the rest of your questions, I’ll leave the psychologizing to my wife. She’s a professional. And there’s nothing worse than amateur psychologizing.
Sorry; I should have mentioned that my comment above was directed to Clifford.
So it would appear that we have more or less the same opinion about string theory.
You say that you are not making any bets. From a non-string theorist’s point of view, becoming a string theorist seems to be a gamble, and you have done at least that. Presumably, by declining to portray string theory as a theory of everything, and by instead portraying it as a successful tool for understanding the mathematics of gauge theories, you can say that you have not gambled anything.
Would you agree that those who try to portray string theory as the theory of everything have gambled something? For example, there were and still are string theorists who insist that the masses of the elementary particles can, at least in theory, be calculated as vacuum expectation values of string theory, and the only task left is to find the right vacuum. Do you have colleagues who express such views, and if you do, do you think that the investment effect I mentioned above could be influencing their assessments of likelihood?
I don’t mean to be antagonistic, of course; it seems that the hostility which this issue produces seems to be centered around the way that string theory is presented to the public. It is the idea that string theory is a theory of everything which captures the public imagination, and the battle seems to be a battle for public perception. String theorists like yourself who do not emphasize the theory-of-everything claim are in the best situation to mediate the issue.
OK, I’m going to stick my neck out here and ask a dumb physics question. The principal objection of PW and LS and co to string theory seems to be the existence of the landscape. Now as other people have pointed out somewhere in these threads, even Newtonian mechanics has a “landscape”. So too does general relativity. Maybe the latter is a better example. GR admits white hole solutions. This is not controversial, the solutions do exist. Trouble is that we don’t know of any way the actual universe can make any use of those solutions — there is no way to make a white hole. Similarly for the Godel solution, it’s there but it just didn’t get used.
The analogy with string theory is pretty obvious. Clearly we expect string theory to have lots of solutions that never get used. And it does. So what?
I guess that the reason people get excited about the landscape is that the entries are “universes”. Well, the way to fix that kind of problem is to put in the initial conditions and see whether that particular solution agrees with what we see. But this is the problem: we actually have an extremely poor understanding of just what the initial conditions for our Universe actually were. But that has nothing to do with the existence of a landscape surely? Anyone want to help me out here?!
Arun:- I don’t know.
-cvj
Egbert:- Thanks for your question.
I’m not betting one way or the other. I’m just trying to understand whether strings are a good candidate for a description of the universe we live in, at least in some regime. I do not pin my hopes on “ultimate theories”. I have a gut feeing that they do not exist. It would be remarkable if such a thing existed, but whether it does or not is beside the point. I just want a good tool for understanding Nature at the next level. What is the best description of the strong interactions that can get us to grips with understanding the entire phase diagram of QCD? What is the physics beyond the standard Model? Etc. Etc. As I have explained above, I cannot see how to separate understanding the strong interactions from understanding all those other aspects that have been mentioned, since I think that they are all connected. They may not be, but we shall see.
Bottom line is this…. The Standard Model is remarkable, and is constructed from gauge theory. There are a lot of fundamental questions about guage theory that we do not udnerstand. String theory seems to be telling us -on paper- that these fundamental questions may have answers using its techniques. That’s reason enough to work on it. In addition, strings seem to be connecting those same possible answers to the same sorts of questions that are coming up in beyond-the-standard model issues. (See my earlier comments) Double or square the reason to work on it right there!
As for the ultimate scope of strings… I’ll repeat my central point:- We don’t know what it is. Nobody knows. We are still working on it. Peter and Lee certainly don’t know, and this is why it is dismaying to see them claiming such certainty that they do.
Ultimately, progress in physics is driven largely by pragmatism. What is the best tool for the job? I see a good potential and powerful tool -strings- and there are no other tools around with as much promise, in my opinion. So I’m going to pick it up and work with it until it stops giving me results, or until a better tool comes along. This is the way science has always proceeded.
Thanks again,
-cvj
Clifford, Jacques, Jeff,
It is good to hear your views on these topics, and I would be very grateful to hear what you think about the following questions. I feel it will be most productive if each side tries to honestly and charitably understand the other’s point of view, rather than engaging in hostilities.
First, whether the string dual to QCD is critical has changed from “No” in Lee’s comment to “Not exactly” in Jacques’ post to “Yes, as Jacques said” in Jeff’s post. I have not examined these matters for myself. Is it the case that I have to read the papers and decide for myself, since experts do not agree? Can you debate this matter among yourselves and come to a firm unanimous conclusion?
Second, a major complaint of Lee’s and Peter’s seems to be that there is a confusion between the claim that string theory can be useful for certain tasks (RHIC) and the claim that it is the theory of everything. String theory is proving itself useful in the same way that group theory or algebraic topology prove themselves useful when doing calculations, that is, in its role as a legitimate part of pure mathematics. Rightly or wrongly, this achievement is being confused with evidence that string theory is the unique theory of everything. It would be a breach of protocol to accuse anybody of deliberately spreading this misconception. It would be good for all parties concerned if at least some string theorists were to state publicly that this is indeed a misconception and that string theory may prove indespensible for understanding QCD without being able to reproduce the standard model.
Third, with regard to the status of string theory as the theory of everything, or as the fundamental theory of the universe, consider the following situation. It seems as though some people are betting that it is, and other people are betting that it isn’t. The situation is analogous to a long-term investment. It is a very very common phenomenon, in the investment community, for the people who have invested in a particular thing to form a community and agree with each other that they have made the right investment and they also agree that the people who share that assessment are more intelligent than the people who don’t.
A good example of this is the typical gold investor, who usually agrees with all other gold investors (called “gold bugs” – google it for more info) that gold is about to rise in value and inflation is everywhere and the people who don’t invest in gold are fools. They form a community and reinforce each other’s belief in the correctness of their choice.
So the question is: Are string theorists prone to the same psychological effect? This is not a question about whether string theory is actually the theory of everything, but rather about whether a person’s perception of the likelihood that it is can be affected by making a gamble and then interacting with a community of people who have made the same gamble. I do not, of course, mean to imply that there is anything reprehensible or contemptible about being prone to this effect – allowing other people’s confidence to boost your own is a necessary part of thinking properly.
Personally, my own opinion is that the issue which each side (the anti-string and the pro-string) is betting over is a conceptual misunderstanding. It’s as though somebody just discovered number theory and people started placing bets on whether it was the ultimate description of the Universe.
Is it true that the only practical realization of any kind of supersymmetry we have so far is in nuclear physics?
(e.g., http://aip.org/pnu/1999/split/pnu444-1.htm ) ?
Navellung:-
I don’t know the answer to your question… this is in part because I don’t think the understanding is well developed yet to answer that…. Nobody yet knows. Do have a look at the work of Mike Douglas et. al. over the last couple of years about the statistics of vacua. This sounds to be along the track of what you are looking for.
Wolfgang:- As I said before, I do not understand why anyone thinks that the existence (if it does) of the landscape is a “problem” for the reasons I stated above a couple of times. As to the “why” question you posed above…. physics has not really ever been good at answering big “why” questions like that…. I think it would be nice to just do what science does best which is find a good description that has the facility of pushing our understanding (in that limited sense of the word) to encompass more phenomena than we currently do, and tell us of new ones we have not thought of. The big “why” questions will all trasform into something else, as they always do.
Best,
-cvj
This seems to be a browser-dependent issue that I do not understand. It is not present (as far as I know) in Netscape, Safari, or Firefox. IE seems to be the one that is most afflicted. But try a simple reload first. Sorry, but I’ve not been able to spend serious time to diagnose the problem.
Cheers,
-cvj
For reasons I don’t understand, as this discussion progressed, the text wandered off the left hand side of the page. Any ideas as to why, or how it might be fixed?
As Distler is participating in this discussion, I would like to tell that it is very sad that the recent page http://www.math.columbia.edu/~woit/wordpress/?p=470 by Peter Woit about “Navier-Stokes Equation Progress?” is not included among trackbacks at arXiv. After reading the comments there, it should be obvious that his page is much more informative than the trackbacks allowed by arXiv.
I think that many readers got the impression that arXiv was used to try preventing Peter Woit from presenting his view.
Clifford’s response to the question of blocking the publication of Woit’s criticism seems a typical weaseled version of yes. To be fair, using one’s influence to further a personal agenda against public interests is a common practice in capitalist society and is absolutely protected under freedom of speech. The market mechanism does not assume nor rely upon altruistic behaviors. My only question is whether prof. Clifford receives any funding of strictly public nature, such as DOE or NSF grants. If so, then his behavior is no longer a private issue but a public one, since his efforts can be seen as self-enriching at public expense. This is clearly an ethic violation and potentially illegal. Have you registered as a licensed lobbyist, prof. Clifford?
Dear Lee,
I read your book in preparation for the radio show and have gone back and reread
some parts of it but am still having difficulty locating the passages where you
mention applications to QCD and allude to the application to heavy ion physics.
Would you mind quoting the passage and giving me the page numbers?
The closest I could find is on p. 144 where you discuss the Maldacena conjecture.
You say , in reference to N=4 SYM that “this has allowed us to calculate some
properties of the corresponding gauge theory in our three-dimensional world. This
in turn led to insights into the physics of the other gauge theories.” But these
sentences are closely followed by “After several years of intensive work, these matters remain confused.” I do not find mention of QCD or of heavy ion physics at all.
The fact that an expert on this subject read your book, or that an earlier version
had more treatment of these matters is interesting, but not really relevant to my main point which is that there is an ongoing dialog between a part of string theory and experiment
and you chose not to discuss this at all in a book which in part attacks string theory
for its lack of contact with experiment. Furthermore, as Jacques points out earlier,
the string duals of QCD _are_ critical string theories and many of the elements studied in
critical string theory (D-branes, black holes and so on) play a central role in understanding
the duality.
I also get the impression that you are unaware of the fact that these dualites extend
beyond theories with maximal supersymmetry and that you have the impression that string
theories without supersymmetry inevitably contain tachyons. For example, on p. 145
you say “String theories built without supersymmetry have instabilities; left alone, they will take off, emitting more and more tachyons in a process that has no end, until the theory breaks down. This is very unlike our world.”
First of all, not every string theory without supersymmmetry has tachyons. Second, the
tachyons, when they appear, indicate an instability, just as in QFT. In some cases one
can figure out precisely where the string theory goes to as a result of the instability. The
theory doesn’t break down, rather it finds a new, stable configuration. This is a subject
of ongoing research. Finally, to the best of our current knowledge, this i precisely like our world where the tachyonic instability of the Higgs field leads to breaking of the electroweak
symmetry and gives mass to the W and Z bosons and fermions.
> 4D gauge theories (similar to, but not precisely QCD) are dual to critical string theories, with gravitons and photons and all the rest. They’re just not 4 dimensional critical string theories.
I have a silly question about this. IF 5d (+5d) critical string theories exist in this sense (consistent and stable), would this not make the landscape problem much worse?
Why do we not live in a 5d (+5d) world, or in dual words ‘ why do we not live in a N4 SYM world?’.
Clifford,
Until the connection to experiment is made, this argument between Woit, Smolin, Richter, etc., and you all, as far as the general public is concerned, is about whom to trust. It is hard enough for ex-physicists to evaluate the various claims made. It is outside the reach of the scientifically literate public.
So it is not silly or irrelevant whether you were the alleged blocking referee for the Cambridge University Press or whether K.C. Cole wrote that stinky LA Times review of the two books with your input or not. He-who-should-not-be-named’s behavior is not irrelevant either.
-Arun
Pingback: Not Even Wrong » Blog Archive » Corrections…
His [PW’s] target audience is not high energy theorists, who might be persuaded by technical arguments, but, rather, lay people (or scientists from other fields). A technical argument would simply go over the heads of his target audience. They might, however, be persuaded of his charge that the “string theorists†are “arrogant†and out-of-touch. So he’ll consistently try to focus on atmospherics over substance and will cry foul and walk away from any debate where he has no alternative but to respond on substance.
As to AdS/QGP, and the fact that the Press seems to be quite oblivious of this application of string theory to real world physics, as you know I’ve written quite a number of semi-technical reviews on my blog. Maybe someone (you?) should post a somewhat less technical review that would be more accessible. – Jacques Distler
Dear Jacques, if he forces one of you to get deeper into explaining stringy arguments at less technical levels, that is a step forward. You can’t expect a string critic to be totally expert in every aspect of string, which is a vast enterprise. (Similarly, the restaurant critic need not sample every dish on the menu before writing a review.) 😉
Another grad student,
You’re always welcome to have a discussion here. I thought I’d say that in case you’re in doubt. I particularly hope that students of all persuasions feel welcome. Several read and comment here already. I would defend you or any other student from someone who is trying to intimidate or bully. (Incidentally, and ironically, I did that on Peter’s blog in that exchange I spoke of earlier… but never mind.)
I hear what you are saying, and have remarked upon your remarks as much as I can. I agree that it is unfortunate when anyone ends up using a less-than-polite tone in a discussion, and I think that I usually am well away from (and on the correct side of) the borderline in most of everything I say and do here and elsewhere. You may disagree, based upon your apparently selective reading of various comments, and it’s sad if you do, but there is nothing I can do about that. I am particularly careful of this in arguments when students and others who are still learning and developing are involved. I think I’ve explained why I’ve lost my patience with Peter. I’ve already pointed to discussion threads elsewhere where I’ve tried my best too be patient and listen to what he has to say and address each point. (see e.g. the thread here where you’ll find exactly the same discussion we’ve had here all over again….)
But when you’ve addressed all the points, well over a year ago, and again and again… and seen other address the same points too,… and then to see it all forgotten (conveniently or otherwise)… you begin to wonder about the motives, and lose a bit of patience. Like I said, I do not think that it is innocent. To go to the public with such a deliberate distortion is damaging to physics in general, and so I’ve lost a lot of patience. That’s why I’ve lost a civil tongue with Peter.
I’ve really nothing more to say about the topic of tone. If you like, we can talk about the physics now.
Cheers,
-cvj
Bah! Sorry, Clifford.
One of the perils of juggling too many comment threads between my Feed Aggregator and my Web Browser.
Jacques, CIP seems to be on the wrong thread so I will link your comemnt to him/her and hope that he/she will put further remarks (if any) on this thread. You need not go to the other thread.
Cheers,
-cvj
Hi Lee,
I think that we might have a fundamental disagreement about what the word “fundamental” means in the context of describing Nature. Perhaps you are using a narrower definition than I. I’ve always been hampered by the lack of ability to sharply draw a distinction between physics topics as being “fundamental” and “other”. They connect up in so many intricate and beautiful ways, in my experience and opinion. So I tend not to make any sharp distinction. If string theory turns out to be a key aspect of the description of some experimentally accessible regime of the strong interactions describing the nuclear stuff we are made of, that would be truly wonderful in my opinion. If it does so by using higher dimensions, gravity, branes, and all those same structures that are being applied elsewhere in studies of physics (the stuff you call “fundamental”), I’d say that was very promising indeed and highly suggestive that Nature may have stringy descriptions elsewhere. As I’ve said before, I don’t see how research on those matters can be excluded from a book or books that claim to be a fair assessment of whether it is worthwhile to support research in string theory. That’s what I’m trying to say, and have done a number of times earlier in the thread.
Cheers,
-cvj
CIP:
To add to Clifford’s remarks …
For a discussion of finiteness of string perturbation theory, look at this comment thread.
As to the convergence of the perturbation series, there’s no interesting QFT whose perturbation series converges. So, as far as I can tell, complaining that the string perturbation series doesn;t converge seems like a complete red herring.
Indeed, string theory would be dead in the water if its perturbation series were convergent. So it’s rather a good thing that it isn’t.
Lee wrote:
But it is precisely that expectation that we have now learned is wrong. 4D gauge theories (similar to, but not precisely QCD) are dual to critical string theories, with gravitons and photons and all the rest. They’re just not 4 dimensional critical string theories.
That’s a profound and deep observation. And the fact that it has observational consequences at RHIC strikes some of us as rather noteworthy.
(In the same breath, it can, and should be mentioned, that in the context of large-N theories, it had long been expected that the correlation functions would be determined by a “Master Field.” Indeed, that turned out to be correct, but the Master Field, again, turned out to be higher-dimensional.)
Another grad student said:
Peter Woit is not some timorous graduate student, easily intimidated, were Professor Johnson to scowl, or speak sharply to him.
In fact, he didn’t seem intimidated at all, going on to post 7 more comments after Clifford challenged him to justify his statement, “Sorry, but I do think that your comments on the relation of RHIC results to string theory are heavily overhyped.”
In those comments, he went on to accuse Clifford of engaging in “stupid sneering and ad hominem attack,” and Distlerian sneering, ending with “You are being dishonest” and “it’s obvious that trying to seriously discuss any of these issues with you is just a complete waste of time”
Finally, on his blog, he apparently makes some wild-ass (and, as far as I can tell) totally unsubstantiated accusations against Clifford.
Doesn’t seem intimidated at all…
No, this is merely a debating tactic.
Think about it: if you were arguing with one of your peers, would you suddenly turn and stomp off, if you felt he wasn’t being “sufficiently respectful”?
I kinda doubt it. In fact, if you felt you had facts and logic on your side, you’d stick around to prove a point, and show him wrong.
Dear Clifford,
I have not been following this, but just to clarify what I recall from the discussion with Jeff. When Jeff mentioned the application of string theory to QCD calculations, in particular heavy ion physics, I said something like, “I think this is great, its good physics and I’m all for it.” Jeff asked why it wasn’t mentioned in the book. I replied that applications of string theory to QCD were mentioned, mentioned that an expert in that area had read the book carefully, and said that the application to heavy ion physics was alluded to. When Jeff asked why, I pointed out that to assert that a theory was useful when applied to some particular phenomenology is very different from saying that that theory is a candidate for a fundamental theory of nature. Jeff said it still was a check of the theory and I didn’t disagree.
So I don’t see why you are excited. I do mention in the book that there are promising applications of string theory to QCD. But I would think it clear that the success or failure of string techniques in heavy ion physic would not provide evidence for or against the claim that the fundamental theory of nature is a string theory. Indeed, the idea that QCD is dual to a string theory is very old, and I would think it well understood that the dual to QCD is not going to be a critical string theory with massless gravitons and photons. It may be true that some properties of the non-critical string theory that would be a QCD dual can be calculated within string theory or supergravity duals of supersymmetric gauge theories that do have massless particles. If so this is great, and I said it was. But it does not bear directly on whether critical string theory is a fundamental theory of nature. Since my book is about the status of a search for a fundamental theory, it was not necessary to go into this application in more detail.
Unless I’m wrong, it would be precisely the same to argue that Newtonian physics should be studied and taught because it is useful when applied to engineereing. This is true and unproblematic but the fact that engineers use Newtonian mechanics does not provide evidence that Newtonian physics is the correct fundamental theory.
I can mention that there was much more about applications to QCD, and much more generally about AdS/CFT, in an earlier draft, but many thousands of words about this and other details were cut so as to come down to a reasonable length. To do this I had to focus on the main argument of the book, which is the status of attempts to solve the five key problems mentionedin chapter 1. Aspects of string theory not relevent to them were cut down.
Finally about hype etc. I am doing no more and no less than is asked of me. I worked hard on this book and it says pretty much exactly what I wanted it to. It is an argument, carefully structured. I am not at my best in debate in a live format, but if invited there I try to do my best. Since various things have been implied let me emphasize that I solicit no interviews or public appearances, and give out no press releases. I would much prefer to be home with my baby boy, working on new stuff I’m excited about. But I do think that when a journalist calls or emails we should spend the time to communicate clearly. And I have always taken time to do public outreach and continue to do so when asked.
I wrote the book to make a careful, structured and respectful argument, directed mainly to colleagues like yourself, about what we should be doing in fundamental physics going forwards. I am very interested in what you think, but I would ask that if you respond you do so not to some impressions of a radio show or some superficial review, but to the actual words and arguments that I worked hard on to get right. I also have no problem admitting if I am wrong about something, I am interested in making a constructive contribution and I would be very happy to be proved wrong about the conclusions I came to while writing the book.
Thanks,
Lee
Clifford:
>Why need the process of the dialogue between theory and
>experiment that I described above be any different within a
>string theory context? What is the proof that it must be
>different, that it fails for strings?
Good point… What I would say here is that, even at the
beginning of the seventies, it would have been relatively
easy to use known phenomenology to rule out, e.g., a
proposed electroweak gauge group different from SU(2)xU(1).
(Another example: the “uniqueness” of SU(3) as the flavor
symmetry of the strong interactions is discussed in Ch. 1 of
Coleman’s book, which was written in 1966. Flavor is not a
gauge symmetry, of course, but the elimination process is
essentially the same, i.e., selection rules.)
To understand the ST point of view, I would like to know
what kind of experimental input would be needed in order to
extract from the set of all ST vacua a much smaller subset
of (in principle) phenomenologically viable ones.
Obviously, this is not the place to start a set of lectures
on the topic, but I could use a pointer to the literature
or two.
Dear Clifford,
The tone of your comment to “Other another graduate student” and me showed no hint of sneering or condescension, and so whether or not I agree with everything you said is not important — at least I can feel comfortable carrying on a discussion here without feeling like I’m under attack. I wish you would use a similar tone when discussing issues with Peter (and anyone else) — forceful yet without undercurrents of disprespect or contempt. You said that
I’ve attempted to politely debate with Peter for a long time now….. you are seeing the end of a long series of pointless debates where I try to get firm substance from him, and to no avail.
I have seen those debates between the two of you (maybe not all of them, but I have seen the ones on Cosmicvariane, Asymptotia, and Not Even Wrong), and unfortunately, while I agree that they start out politely enough, I have felt in every case I can recall that your tone descended into condescension, sneering and mockery before Peter cut off the debate. Further, his comments conveyed a definite impression (to anyone who would notice) that he didn’t think you were treating him respectfully, again before cutting off the discussion. I don’t think this current example is any different. (I don’t think I am particularly siding with Peter here — I felt that your tone was going downhill before seeing Peter’s response, so it didn’t surprise me when Peter reacted negatively to it.) I also recall at least one case on Not Even Wrong where it was you who cut off the debate for whatever reason, so it isn’t always the “other guy’s” fault. However, Peter accused you of being dishonest, for example in a comment above, and I think that is a pretty serious accusation that shouldn’t be made lightly; clearly the mud has flown in both directions.
My perception of the debates between Jacques and Peter parallel those of your debates — the condescension and sneering by Jacques seemed to invariably presage the end of the debate, and advance warning was given about how things were heading.
So even though you and Jacques seem to say that you have repeatedly tried to carry on reasonable conversations with Peter, but that Peter is a slippery character who always manages to cut and run rather than answer the probing questions you ask, the whole context surrounding the debates seems to invariably include an atmosphere of sneering, disrespect and implication that Peter has ulterior motives. That context makes yours and Jacques’ claims about “reasonable” or “polite” attempts very questionable. In fact, I would say that neither you nor Jacques have ever actually “Done The Experiment” and debated forcefully yet without ad hominem attacks and put-downs. If you want to point to a specific counterexample that I can view, I would like to be wrong about this.
I wish you and Jacques would take Peter up on his offer:
If you ever decide to stop dealing with what I have to say with […] sneering, and are instead willing to seriously engage in a mutually respectful discussion, let me know and I’ll try and find time to participate.
Those “terms of engagement” seem quite reasonable; I would think that the level of respect and sincerity that you showed in your response to “Other another grad student” and me would be quite enough (nothing at all like Jacques’ sample “respectful” phony dialogue). Tempers would be bound to fly at times, but that can happen between people who respect each other. The main problem I see is that from all indications neither you nor Jacques do respect Peter, and both of you do very poorly at hiding it. Both of you also seem to have a similar feeling of righteousness in your behavior, that somehow sneering can be justified, e.g.,:
I make no apology for pointing out Peter’s wriggling in the manner that I did.
(At least your unapologetic attitude here is consistent with the number of times I have seen you apologize in the past!) That you think public sneering is justifiable is unfortunate, because it tends to make observers more sympathetic to the target of the sneering, especially if the target is seen as a nice guy who is standing up for what he believes. It seems like everyone would be better served by a little more mutual respect.
It seems that this is mathematical physics versus theoretical physics.
When one reads the commentaries it is easy to spot the difference between those whose primary interest is in math and those whose primary interest is in physics.
Sad.
Jacques Distler:
I think this is a good thought in regards to setting the record straight so that the subject is not tainted by “loose speculation of Peter” where even I am guilty “being lost in the struggle to make sense,” of it all to have found good explanations of value in leading any future perspective. You watch the debate.
But now you even have Lee Smolin to contend with. Who is going to explain the theoretical adventure so us lay people will undertand what the physicist is being challenged along with their maths to “possibly explain the natural” to us that we see where you are headed?
So why is it important that any researcher stays close to the forefront in terms of the work being done in regards to string theory? Keeping it real perhaps? So the points you list and encourage Jacque.
Perhaps the challenge has been put out there to sit and discuss at the table the way you would want any of society to conduct themself?? A round table? 🙂 Just make sure you have a good exposure to the laptop of real time, so the public can see what’s going on.
Thanks Jacques. Yes, I should have a go at a post like that at some point, although I don’t think it will make much of a difference to those writing articles in newspapers and the like. But we can indeed try to reach those who have begun to come directly to the scientists for news of what we are doing, rather than through intermediaries. (Although, as I am always keen to point out… some journalists do a good job.. I’m not trying to demonize the whole enterprize).
Until then, or until someone else does a post (and people should point to links if they know of any), I will place links to some of yours, which I think do a good job actually:
http://golem.ph.utexas.edu/~distler/blog/archives/000885.html
http://golem.ph.utexas.edu/~distler/blog/archives/000820.html
http://golem.ph.utexas.edu/~distler/blog/archives/000812.html
http://golem.ph.utexas.edu/~distler/blog/archives/000608.html
Cheers,
-cvj
As you well know, Clifford, I have been trying to challenge Peter Woit on these matters for far longer and gave up trying to get a meaningful response a long time ago. Sad to see that you, with your sunny disposition and seemingly infinite forebearance have given up too.
I think you need make no apology for the tone of your comments. Actual scientific debates, between actual scientists, are rarely the thoroughly genteel little affairs that PW demands as the prerequisite for answering your questions:
The real reason he won’t respond to you (or me, or — come to think of it — anyone else) on a technical level is, I think, that there’s no percentage in it for him.
a) He doesn’t have the technical arguments on his side.
b) His target audience is not high energy theorists, who might be persuaded by technical arguments, but, rather, lay people (or scientists from other fields). A technical argument would simply go over the heads of his target audience. They might, however, be persuaded of his charge that the “string theorists” are “arrogant” and out-of-touch. So he’ll consistently try to focus on atmospherics over substance and will cry foul and walk away from any debate where he has no alternative but to respond on substance.
As to AdS/QGP, and the fact that the Press seems to be quite oblivious of this application of string theory to real world physics, as you know I’ve written quite a number of semi-technical reviews on my blog. Maybe someone (you?) should post a somewhat less technical review that would be more accessible.
Dear Graduate students of comments here and here,
Thanks for your comments. I make no apology if my tone was, in this case, somewhat strong. I’ve attempted to politely debate with Peter for a long time now…. you are seeing the end of a long series of pointless debates where I try to get firm substance from him, and to no avail. What Peter has been doing in his campaign of distortion of what the field is doing is very dishonest and highly damaging to the field at large. It is shocking to anyone who cares about the field of physics that his key point about which he claims he is so sure -that string theory cannot be tested- is in fact a mirage. It is frustrating to see him – when asked directly for the evidence – be so disappointingly and disgracefully (not to mention transparently) evasive.
A cornerstone of the practice of science should be the kind of honesty that I’ve been asking Peter to display. One should have the courage to state clearly the difference between one’s gut feelings and what one knows for sure… especially if one is going to try and smear the effort of an entire field of people. When I see this honesty being so spectacularly violated -especially when part of the claim is that several others are being dishonest- I get rather firm in pressing the person in question to clean up their act, and (in what you consider to be condescending or sneeering remarks) I carefully point out where they are falling short.
I make no apology for pointing out Peter’s wriggling in the manner that I did. It really needs to be seen. If you don’t like it, I am sorry, but you’d better get used to it if you are going to work in science, since nobody likes a cheater.
Cheers,
-cvj
Which goes to the point I was making earlier, about “the substance” versus the denigration of the subject becoming?
You had to look past this regardless if it was Clifford or even Peter Woit. You take the shots, and listen for what that substance is that is being defended? Most certainly it takes awhile to remove the covers.
While I had supplied an example above, another one is here for consideration about where the physics breaks down? What use any “geometical tendency to describe” if we had thought we could arrive ever closer to the essence of what reductionism had implied on a “cosmological level” with regards to QGP?
So we make the microstate blackhole as part of that deduction about the elementary particle creations?
How did you get there?
Hi
If there have to be sides, I agree with Clifford’s side in the substance of the discussion.
But I also agree with another grad student above that Clifford’s tone is sneering and unpleasant. Maybe one can argue that’s justifiable (and most likely born of frustration in previous debates with PW), but I don’t think it’s necessary.
Frankly Clifford, reading through your comments above, I can empathize with Peter Woit’s stated reluctance to try to continue carrying on a serious conversation with you. It isn’t that your questions are unreasonable; it is the tone of your questions, your choice of phrasing and frequent appearance of posturing that convey a condescending or sneering attitude to me. For example, just within your comments related to this post:
1. Wow. You really said that. Ok.
2. But Peter… you haven’t said anything…!
3. anon:- brilliant! (This praise to ‘anon’ was in response to a phony “summary” of interaction between you and Peter, where you are the “good and reasonable” guy and Peter is the “unreasonable and evasive” guy. Apparently for you this cheap shot was priceless, but it was also a fabrication.
4. Heh, I’m sorry to have to inform you of this Peter, but you’ve been engaging in non-professional activities for quite a bit now […]
5. Gosh. Later on in that thread, when just on the cusp of having to make an actual technical statement, you punt the questions. (This phony-sounding amazement is really irritating to someone who is trying to have a rational discussion, but I suppose you know that and intentionally chose to do it.)
This list is by no means exhaustive (you appear to me to be very free with the condescension), but it gives some examples of what would convince me that you were more interested in dishing out ridicule than having a respectful discussion. I certainly wouldn’t choose to spend my time discussing in this kind of environment.
As far as your implications that Peter is trying to run away when you press him for more details (e.g., asking him to elaborate on why your RHIC claims are hype), that kind of behavior is not what I have usually seen from him in the past. Above, you pointed out past example(s) where you saw him being evasive, and he explained why he disagreed with this assessment; rather than taking his explanation at face value, you appear to interpret his actions as running rather than defending an indefensible position. However, on his blog and elsewhere over the past 2-3 years, I have repeatedly seen him correct himself or acknowledge that he overstated his position when someone has legitimately pointed it out. In fact, he seems to be much more willing to publicly admit his mistakes than most other people I have seen, including the owner of this blog. So the behavior you accuse him of does not at all fit with my perception of his usual public behavior. If you doubt my assessment about his willingness to acknowedge error, I think you should read through the comment sections of his past posts on his blog, his comments on the blogs of others, and his posts on sci.physics.research.
Finally, regarding your belief that he “ran away” from your question, you commented:
Peter:- It’s on record for everyone with an open mind to see:- In the time it took you to write the comment pointing out how busy you are -a comment that is almost 1/4 the length of the actual post that I wrote- you could have easily pointed out the sentence in my post that you consider to be an overstatement.
Perhaps you believe that it should only take him a few minutes, but if I were in his position I would probably assume that if I simply pointed out one sentence that I thought was hype in your post you would simply: respond with a defense of your statement; then explain to the “dear readers” (frankly, I find this a condescending way of referring to your readers) how I didn’t know what I was talking about. That expectation would be consistent with the behavior I have seen from you at various times in the past. I expect Peter also saw it this way, and wasn’t willing to give a more detailed argument that answered your question because probably he really didn’t want to spend the time then (especially if he believed you wouldn’t discuss it seriously with him).
I really didn’t want to spend my time writing a comment defending Peter, but distaste for some aspects of your “debating” style finally got to me enough to say something. This style is something I found disagreeable in some of your discussions at Cosmicvariance (not just about string theory topics), and now here too. It is your privelege to behave this way, but I sure wish you wouldn’t.
Navellung… that is not the process I am talking about. There is an infinite number of gauge theories. The standard model is a rather random way of putting some of them together to make a model of our world. It needed to be constructed in this particular way, not by some grand dynamical principle that we discovered, but by reference to particle physics experiments over several decades. It needs experimental input of parameters that it cannot fundamentally determine. Within its own framework, it made predictions about Nature that we have gone out and tested, with remarkable agreement. How can it make predictions? Becasue even though there are an infinite number of gauge theories, gauge theories still work in a very tightly constrained manner that allows us to say “yes this can happen”, “no this can not happen” once we have input the required parameters that need to be measured. ….At some point down the road, the framework needs to be replaced by another framework in order to understand the answers to questions that it cannot fundamentally address. This is how science proceeds. If the landscape picture of vacua of string theory is true, then string theory may give us *at least* the above procees (it may give more, and we shall see as we do more research). Why need the process of the dialogue between theory and experiment that I described above be any different within a string theory context? What is the proof that it must be different, that it fails for strings?
Let us not forget that the Standard model was not just written down all in one go! It was built up, bit by bit, by making reference to experiments. Stuff was added as we learned more about Nature. Why on earth are we not allowed to do the same process of discovery for String Theory?
Peter’s point is one of aesthetics, and little else. It is certainly not the “well known obstruction” that is the entire basis of the thesis of his book.
-cvj
I think I understand PW’s point here, though I’m obviously only
speaking for myself, and though I don’t know to what extent that point
is actually applicable to ST.
The SM model works beautifully below the EW scale. But, what would we
think of the SM if every time some experimental result came out, the
SM would have to be fixed by adding to it a few dozen additional Higgs
bosons in some weird high-dimensional representations, and another
handful of extremely heavy fermions, etc. etc.? Something like this
happens with some unification and technicolor models, and that is why
they have been virtually abandoned. It’s just that in order to avoid
conflict with experiment they have to be complicated ad infinitum.
But, of course, if it turns out that there actually are many hundred
different Higgs bosons out there, those models will then turn out to
be correct…
Peter:
But Peter, that response is not a proof of anything. It is an expression of your distaste for the idea of building models of Nature, and then steadily improving them by having to refer to Nature from time to time by doing experiments and finding out new things or measuring certain parameters, confirming some of your predictions of new phenomena, refining your models, making new predictions…. and, yes, finding totally new phenomena sometimes (in other words, maybe even if we find that strings usefully describe some significant regime of physics, something will take over from a stringy regime one day, to answer questions and describe phenomena that we have not even thought of yet). This dislike that you express for this process puzzles me since this is how science has proceeded since science was invented/disovered/whatever. Where is the “well known” proof that one cannot do this (or some of this) successfully with string theory? That is all I ask. Please answer the question, and cease trying to hide behind excuses of:
first: being busy,
second: being terribly offended by my tone/manner
third: being not convinced that I want to have a serious discussion
fourth: having to go out to do non-professional things
and now…
fifth: my not responding to your clear answers to my question of what is the well known proof that string theory cannot be tested (answers that so far I am failing to find).
Looks to me like you’ve rather blown your cover here. Again.
And once again, folks, I must point out how sad it is that nobody will hear of this in the press, since they don’t seem to be interested in the actual facts behind the distortions of Woit and Smolin’s campaign, but just the juicy “underdog vs the establishment” story.
-cvj
anon:- brilliant!
Arun:- Please please do the count. You will find that the number of people studying string theory because they want to understand phenomena like confinement, high temperature phase transitions, and other phenomena of the strong nuclear interactions –that I remind you are part of Nature!— is a large percentage of the effort in the field. Certainly not a percentage that can be ignored by prominent nay-sayings about the “failure” of the research effort in string theory and the supposedly unfair distribution of resources. In the context of this discussion therefore, the word “huge” is not hype.
Given the fact that this work has been discussed by and with the authors of the books several times, that they both acknowledge that they are aware of it, and that they both know that there is a large percentage of activity in the field in that area….. how can one conclude that they left it out of (or sidelined it in) their books’ discussions anything other than intentionally?
Peter and Lee say that string theory has failed as a theory of Nature. Peter in the comments above said that you cannot connect string theory with experiment. This has nothing to do with “theories of everything”. That whole discussion is a red herring — not everyone who works on string theory believes in the (probably) naive idea of a theory of everything. Physics carries on whether or not such a thing exists. See anon’s rather insightful Newton/apple discussion above. If theorists find powerful descriptions of fundamental phenomena in Nature that use the framework of string theory, I would say that this is an unprecendented and remarkable step in our understanding of Nature. Pretty much everything that has gone before has been in terms of field theory, I’ll remind you. How can anyone who seriously understands and cares about progress in theoretical physics and its description of Nature honestly belittle that effort? It boggles my mind.
Everyone:- Motl is irrelevant to this discussion. Let us discuss the issues of substance on the table and not the antics, child-like, and -we probably all agree- often despicable behaviour of indivuduals who have nothing to do with the discussion of the physics. I will enforce that, I’m afraid, by deleting further comments whose content are in large part about him.
Cheers,
-cvj
There are many personalities with their own “quirks of nature.”:)
Shall we assign character asassination based on “personality of the work” that is shown, or what the work shows of itself?
While we may become critical of “such behaviors,” what is lasting is the “quality of the work” I would say?
The character had to be looked past? Not saying that you cannot have your own points of view about the character, just that you recognize the work being shown. Not that you let eccentricity go unchecked, just that you recognize the quality of the work.
For the lay people we’re either just right or wrong, for the scientist you have to be right or possibly wrong with your proof?
Please correct me if I am wrong? :)Lol
Re: Lubos Motl, he’s an embarassment for all physicists, the way he carries on, not just for string theorists.
He’s also an embarassment to Harvard, but then again, Harvard seems to like having prominent public figures that embarass them….
-Rob
Lastly, I do think that if one can remain silent about Motl, one may as well
extend that silence to Woit and Smolin as well.
“..but they ignore the fact -they intentionally don’t tell you, dear reader- about the interesting work going on by a huge percentage of the field to use string theory to study the structure of nuclear matter.”
I haven’t yet read the books, but I had thought the objections raised by Smolin and
Woit were to the use of string theory as a “Theory of Everything”, in particular
something that encompasses the Standard Model and General Relativity. Maybe
string theory belongs in the math department, or in the nuclear physics department.
I thought the question was whether it belongs in the particle physics department.
The claim of “intentionally don’t tell you” is a serious one, IMO, and needs an
answer.
I also think “huge percentage of the field” in the quote above is hype.
I could try to do a count of authors in arxiv.org to establish this one way or the
other.
Of course, Peter is telling only part of the story here. In fact the scientific conspiracy is far vaster! I have made the remarkable discovery that in Newtonian mechanics there is an infinite Landscape of possible worlds! This means that, despite hundreds of years of cover-ups and indoctrination, Newtonian mechanics is fundamentally unpredictive, even in principle! Take the facile argument of the groupthink-blinded Newtonian mechanic: that he can drop an apple from his balcony and predict how it will hit the ground. This is a lie! Why, in most of the worlds allowed by Newtonian mechanics, that apple might not even exist!
For those of you too busy to keep up with this exciting intellectual debate, here’s the recap:
PW: String theory is wrong for reasons I have explained in great detail somewhere! Why will no one discuss this with me?
CVJ: OK, where did you explain in great detail?
PW: You know where! Stop being exasperating!
CVJ: Huh? Seriously, can you link to something?
PW: There you go again, with the ad hominem attacks and the evasive arguments! When will it end? See how I am mistreated?
CVJ: This is nonsense.
PW: See? Ad hominem attack! I told you! You string theorists are abusive! Whereas my rational arguments are so well-known I don’t even have to explain them.
CVJ: ??????
More on name. Hopefully this example is up to par. Notice question at bottom of this post. Sound familiar?
Scientists May Soon Have Evidence for Exotic Predictions of String Theory issued by Northeaster University
“
”
Here above is an example of what the modelling approach does and let’s see if it was warrented to take a stance on critizing “the use of” in the way it was for any future students?
Tell me, that without comprehension of RHIC and deductive methods to this research, that any attempts at future perspective would gone on without “high energy” recognition?
Do microstate blackholes exist or not? In theory. In concept, or as an idea?
Clifford,
Sorry, but after having an evening to think about it, it’s obvious that trying to seriously discuss any of these issues with you is just a complete waste of time, and your last message confirms this. You continually accuse me of not addressing issues, but whenever I do, you completely ignore what I have to say. The answer to your latest complaint that I don’t address the difference between the Landscape and QFT is in my first comment on this thread, which as far as I can tell you never bothered to read. You certainly did not respond in any way to the argument that I made there.
The behavior of you, Jacques, Lubos, Susskind, anonymous referees, “Hmm”s, “Michael”s and others in response to criticisms of string theory is a large part of the reason that your physics colleagues, journalists and the general public have now become skeptical of what has been going on in this field. The fact that you refuse to discuss the behavior of Lubos and the fact that his string theory colleagues tolerate and even encourage him, and your reaction to his calls for my death as “not to your taste” is just disgraceful. Your problem is not me, Lee, or the publicists at Houghton-Mifflin and Basic Books, it is yourselves.
Clifford: You will recall that last year I coined the term “stringevangelistâ€, and used it quite a lot in a contemporary context.
I find it easier to discern who said what if you itaclized the quote you use of the other person.
Clifford your position came through then as well now, loud and clear as to the responsibility people should have with respect to any model and putting all our eggs in one basket. As a lay person this warning was listened too.
I have been watching string theory for a few years now as a lay person and it is really serious that such a junction has been reached, that what is in essence crucial to developing perspective and means to see the deeper working of RHIC , would have been lost on the views of those who were not doing the research and homework to understand the nature of the particles and the value of the blackhole in this research.
Dismayed that they could have cast off strominger’s work without commenting on it specifically.
This is a conversation that must continue and one that Peter must respond too as you are asking. If he made as much time as he does on his own blog “promoting” then such a conversation here would be speaking directly to the demands of the scientist who is currently engaged. As lay people, watching a process that works.
Shall we return to the Solvay of 1927 methods, thought experiments presented for consideration?
Peter… sorry that your message got held up by the spam blocker. That happens sometimes.
How would I be being dishonest by pointing readers to answers that you gave if I wanted them to think that you’d not given answers? I’m puzzled by that logic. Your answers on July 7th were not very contentful answers in fact, which is why I pointed to them. They contain vague and often repeated statements about the landscape, and that’s it. I don’t understand how that even comes close to a proof that string theory cannot be conencted to Nature when we barely understand just a few scraps of the non-perturbative physics. Even if the landscape exists, we’ve discussed how to do physics within such a framework before, well over a year ago (read the comment thread in the link). There’s an infinite number of field theories, yet we make remarkable connection to Nature using them, in the form of the Standard Model of Particle physics…. etc, etc. What is your well-known evidence that we can’t do that with strings? I’d like to hear it.
I’ve re-read the 2:10am message, and the 8:48pm one on your non-data-based view of the sociology of the field, and I don’t see anything compelling there. Are those the “well known’ obstructions to making contact between nature and string theory that you’re talking about? Gosh. Later on in that thread, when just on the cusp of having to make an actual technical statement, you punt the questions.
Heh, I’m sorry to have to inform you of this Peter, but you’ve been engaging in non-professional activities for quite a bit now by deliberately distorting the public’s view of the field quite as much as you have.
Cheers,
-cvj
Clifford,
You are being dishonest. If people follow the links you give, they’ll see that I began by politely apologizing for not having a lot of time because I had to get up early for a flight to LA for a short vacation the next morning. I went on to spend some time that evening trying to respond to what you had to say, writing two messages, the second of which I finished writing at 2:10am. I didn’t get much sleep that night, and also had to fit in trying to politely respond to you with dealing with some rather nasty personal attacks from multiple anonymous string theorists.
Sorry, but I’m still having trouble believing you actually are willing to engage in serious discussion. For one thing I just don’t believe that you think there aren’t well-known problems with trying to predict anything new about particle physics using string theory. Why do you think no one has been able to do this for 22 years? If you honestly believe there are no such problems, I’m willing to try and find time tomorrow to discuss this. If you know what they are and want to play a game with me, I’m not playing. If you feel that my responses to your questions on the evening of July 7th were insufficient, let me know what was not addressed and I’m willing to try again.
But not now, it’s Friday night and I’m leaving the office in one minute to spend some time engaging in non-professional activities.
Peter,
I just remembered… the last time I asked you -on your blog- to tell me the facts as you see them, you cited how busy you are. Don’t you think that this is a bit odd for someone who is so concerned about the health of the field, and the infection that is string theory? That when given the opportunity to enlighten us clearly about why he knows string theory is wrong, he declines to state his case ?
For those interested, I’ll point them to the comments Ii made on a post of yours on the 7th of July (here and here) where I tried to have a discussion… some others joined in too (people can read by scrolling in the neighbourhood of those comments)…. on the one hand you said (again) that you were busy and did not have time to respond, while also, you seemed remarkably preoccupied with making odd remarks about your commenters, and deferring comments on technical physics content to others to answer. You never told us the “well known” obstructions there either. I’d really love to know them.
You can’t hide behind a claim that I am “sneering”. It is not fooling anyone actually. I’ve asked you some pretty straight questions and given you some pretty straight responses in this thread… and you’ve backed away again when given the chance to tell us exactly where we are going wrong.
Cheers,
-cvj
Priceless.
Thanks Clifford.
But Peter… you haven’t said anything…!
-cvj
Clifford,
“Priceless.
Thanks Peter”
If you ever decide to stop dealing with what I have to say with Distlerian sneering, and are instead willing to seriously engage in a mutually respectful discussion, let me know and I’ll try and find time to participate.
When given the floor to point out examples of the hype that he accused me of, and when given the floor to tell us the “well known” obstructions to experimental verification that illustrate why he is so certain that string theory is wrong, Peter says he is busy.
Sad thing is, folks, you’ll never read about this in the press.
-cvj
Priceless.
Thanks Peter.
-cvj
Clifford,
I have a long experience with trying to have serious discussions with Jacques Distler, all of which were a complete waste of time since he ignored what I wrote, instead divided his time between insulting me as an incompetent and making up straw man arguments he could triumphantly defeat. I’m not surprised to see he’s back in action here in his usual mode. From your response to what I wrote you seem to be intent on behaving in the same way. At other points in life I had time to try and deal with this, right now I don’t.
Please list the well known obstructions for us. I don’t think I got the memo.
-cvj
Jeff,
Nothing I have ever said or written anywhere corresponds to
“you and Lee make it seem like we just sit around working on this big ad campaign to sell string theory to the masses, or pressuring unsuspecting students into working on the latest fad”
I’m not telling you my “intuition” says you can’t connect the theory with experiment. There is a very long history now of people trying to do this, and there are well known obstructions. If you have a plausible idea about how one might get around them and are working on that I’d be interested to hear about it.
I’m quite happy to try and find time to engage in serious discussion with knowledgeable people who disagree with me about these issues. Whenever I ‘ve done that I’ve generally found that in the end we agree about much more than we disagree and it is often enlightening. I’m not interested though in wasting time by trying to have a discussion with people whose idea of a discussion is to sneer at or insult me, ignore whatever I write and instead make up straw man arguments I’ve never expressed.
“I’ve been working 14 hour days and weekends”
Yeah…so do a lot of us to! Peter, you and Lee make it seem like we just sit around working on this big ad campaign to sell string theory to the masses, or pressuring unsuspecting students into working on the latest fad and, well, this is just not true. Pretty much every string theorist I know would LOVE to be able to connect the theory with experiment but the truth is that we’re just not there yet. But most of us are trying really really hard. My intuition tells me that eventually, in some form or another, we will succeed…yours tells you that we will not. But that’s all it is. Intuition. You do not know for sure that string theory is wrong any more than I (or anyone else) know that it is correct. Lubos is an outlier.
“…as well as zero interest in trying to have a serious discussion with someone who ignores the legitimate things I have to say…”
but what would be the fun in a debate where the other side always agreed with you…
Rob:- Yes, there was a big surprise. Nobody expected the shear viscocity to entropy ratio of the QGP to be so spectacularly low. Nowhere near where standard analyses would put it, as far as I understand.
Turning to the string theory constructions, whcih models the gauge theory using branes, higher dimensions, AdS black holes, and all that stuff that we are told by Peter and Lee is irrelevant, you see quite easily that the physics of the dual black holes that controls exactly the right regime in the gauge theory tells you that you should be counting on it being incredibly low… It is quite a robust result as far as we understand so far. And really really encouraging.
Cheers,
-cvj
Peter:- It’s on record for everyone with an open mind to see:- In the time it took you to write the comment pointing out how busy you are -a comment that is almost 1/4 the length of the actual post that I wrote- you could have easily pointed out the sentence in my post that you consider to be an overstatement. That’s all I asked for… help in identifying what I said was hype.
It is this sort of inconsistency (to be polite about naming it) in your position and in Lee’s position that I’m trying to point out to the people who care to avoid the … hype… in your campaigns.
Cheers,
-cvj
Jacques: – Thanks!
-cvj
You might want to look at the papers of former string theorists, like Phil Nelson and Mark Goulian. In fact, I’d commend to you Phil’s biophysics textbook.
I wouldn’t go so far as to call any of these “applications of string theory,” only because I think the classical Nambu-Goto action (etc) is a relatively trivial part of the story we call string theory.
As to the RHIC results, I think that the attitude of the nuclear theorists speaks for itself. If one had to choose, say, between Shuryak’s and Woit’s assessment of the relevance and importance of the AdS/QGP results, one should probably take Shuryak a bit more seriously.
Unfortunately, actual expertise seems to count for very little these days.
Graduate Student:- Thanks! Yes, there’s been an awful lot of valuable work on two dimensional field theory that tracked, benefitted from, and also fed back into string theory. I’m not aware of the biological membranes aspect. Feel free to give links/references.
Cheers,
-cvj
Rob,
My point -and you agree, essentially, from what you said later- is that the whole field is highly underdeveloped, and manifestly so. So how do they know that it is wrong? How can they be so sure? So sure as to resort to publicly claiming that it is a closed shop, a cult, a religion, etc? That’s indeed my main point.
Progress stilll continues ay quite a pace, and, as everyone keeps pointing out what are the alternative ideas we are supposed to be abandoning it for in order to work on?
Cheers,
-cvj
I just don’t accept your notion that one can’t evaluate whether ideas can possibly work out or not until they are completely understood.
Wow. You really said that. Ok.
Actually, I agree with Peter on this, but not in this context.
An idea does not have to be completely, perfectly understood for us to know that it’s perhaps not a good one, or for us to have excellent suspicions that it is a great one. It just has to be understood enough.
As a straw-man example, consider Intelligent Design. I’m not sure that anybody really fully unerstands ID; certainly the ID people are claiming that we should all be doing more research to flesh the idea out. However, as scientists, I think we’re all pretty comfortable realizing that ID is an idea that odesn’t have any scientific meat behind it.
String Theory is different. From the outside, it has been frusturating, because, yes, back in the 80’s, there was much string hype in the public suqare, and since the publication of The Elegant Universe there has been a lot of string hype in the public square yet again. But as scientists who aren’t string theorists, we see a theory that most of us can’t hope to really understand (y’all are smarter than us), and that admittedly does not have any testable predictions at the moment. That’s kinda frusturating.
BUT — from what I do know, I believe that Peter is wrong in suggesting that we understand enough about String Theory at this point to be able to put it in the “crap” bin with Intelligent Design. It wouldn’t have to be completely understood for us to be able to do that — but I don’t believe that as a field we understand it enough to be able to say that yet. Lee and Peter, obviously, would disagree, but enough other people whose judgement and intelligence seems to be sound still think there is something to string theory, so I think it’s worth continuing to pursue it to see if eventually something does come out of it.
And if something RHICish connects to string theory in a concrete, testable way, that would be really cool. ‘Cause I don’t think that anybody expected RHIC to do that. (Or did they? I don’t really know. I usually work at z
Clifford,
“Won’t take too much time out from your busy day to point it out. Please…. help the cause of anti-hype and show me. Is this really lack of time? Or lack of knowledge about the state of play in this area?”
Sorry, but for a lot of reasons (including dealing with the problem of a string theorist who wants me dead), I’ve been working 14 hour days and weekends, am behind on way too much and really don’t have time for this, as well as zero interest in trying to have a serious discussion with someone who ignores the legitimate things I have to say and engages in this kind of stupid sneering and ad hominem attack. It doesn’t help your cause one bit.
Help me here then… which sentence of mine is an overstatement? Won’t take too much time out from your busy day to point it out. Please…. help the cause of anti-hype and show me. Is this really lack of time? Or lack of knowledge about the state of play in this area? It’s ok to admit to not knowing about develpments in an area…. I can comfortably list pages of topics I know nothing about… What I don’t do is publicly trash research effort on those topics on the list.
Wow. You really said that. Ok.
I made no such identification, as I’m sure you’re aware.
I did not say that you should keep your mouth shut, but I am happy to see that you seem to agree that you have no convincing alternative to offer. The current debate indeed has some interesting parts to it, amidst the noise and hype about claims that you and Lee know that string theory is wrong (how do you know that, guys, and if you are not saying that, then please explain the titles of your books and why you are letting the press run with that story?), but you don’t carry out such a debate constructively by having a public press-drive mud-slinging match. Please remember the points I made in an earlier post:
* Fighting fire with fire leads to everything burning.
-cvj
Clifford,
Sorry, but I do think that your comments on the relation of RHIC results to string theory are heavily overhyped. I really don’t have the time to enter into a long discussion about this here, there was a similar one on my blog a couple months ago.
I just don’t accept your notion that one can’t evaluate whether ideas can possibly work out or not until they are completely understood. One can properly evaluate the results of the last 22 years of attempts to connect string theory to the standard model and I claim that by an honest such evaluation the idea is a failure, with nothing but wishful thinking and recourse to pseudo-science left of it.
Your identification of the interests of string theorists with “the cause of physics” is just ridiculous. The overhyping, less than honest behavior, and willingness to engage in pseudo-science that has characterized too much of this field has done a lot damage to the credibility of the subject. You appear to be unwilling to criticize any of this in anything other than the mildest terms, while taking great exception to the fact that Lee and I are publicly raising theses issues. I’m not happy at all to have spent a lot of time on this. I really wish someone else had, and that I could have spent the time instead working on something more positive, instead of trying to stop the ongoing trashing by others of the subject that I care about. I don’t accept your argument that I should keep my mouth shut about what has been going on unless I have a convincing alternative to offer.
I think the current debate is a necessary one and that string theorists need to admit that the problems Lee and I have raised are real and and be willing to engage in serious discussion of them. It’s not just us, see the essay in the latest Physics Today by Burt Richter. Sean Carroll likes to claim that string theory deserves its dominant position because of its triumph in the “marketplace of ideas”. The situation in this marketplace has recently started to change dramatically, and what I am seeing from string theorists is much too little willingness to engage in serious debate, and much too much whining about how unfair the changed market conditions are.
Isn’t it true that string theory also inspired and helped the development of 2D field theories? Aren’t these theories relevant for describing some condensed matter systems? I have even seen applications of the stringy methods to biological membranes.
Hi Peter,
Again, you are characterizing all people who work on string theory the same way. We are individuals, not an army walking in lock-step. Some people may be overstating the promise of the stringy applications to QCD, others are not. I hope that my remarks in this post are not taken as hype. To downplay how interesting it is -and the fact that a large number of people are working on that and not the landscape and the anthropic principle- is not a fair representation of what is going on in the field. There is a great deal of diversity of effort in the field beyond that too…. they don’t seem to be ever mentioned in your public portrayal of the research going on in the field. Why is that, Peter? What about all the work on black hole physics… is that all worthless?
Now even if that was all compleltey disconnected, and separate work within string theory, it would still be remarkable that it is not commented on in the discusson of the worth of the string theory effort… but there is an additional feature…. it is all very well connnected together. So work on getting the physics of RHIC -real experiments- to fit into a stringy framework tests the entire framework since (as I hope you are aware) all that stuff that is being used in the quantitative aspects of the landscape studies and other aspects of phenomenology, and all the stuff that is being used to study the physics of black holes…etc… all of that shows up in the physics of String/RHIC studies too. Strings, branes, holography, AdS-like throats…. etc.
Should you not be encouraging us to use these possible experimental clues to sharpen our understanding of string theory more, instead of trying to make it seem irrelevant or less than significant? I thought that your goal in all of this was to advance physics? I am puzzled.
Are we trying to stop others -or our young people- from trying other approaches to understanding RHIC physics? I’m not aware of such an effort to do so.
I nowhere said that the hype about strings was confined to the 80s. You will recall that last year I coined the term “stringevangelist”, and used it quite a lot in a contemporary context.
Please keep your affair with Lubos out of our conversations and off this blog. He, his practices, and his manner are -not to put too fine a point on it- not to my tastes, and irrelevant to the substance of what we are discussing.
About poisoning the well. I was not referring to your fine BBC appearance. I was referring to the whole practice of having a tit-for-tat series of books and press appearances from one side or another of the hype camps out there confusing the general public by deceiving them into thinking that science is done in this way… In this, rather than (trying to) bring down the house of string theory, you and Lee are (trying to) bring down the house of theoretical physics (at least in this area of high energy physics). In this latter enterprise, I do hope that you will not succeed. If you want to write books and give public talks and radio appearances, write something positive about the work you are doing that is alternative to strings….. don’t just write negative and largely over-blown critical remarks. This does not help the cause of physics.
As to the other things you say again about the effort in string theory. You have no idea whether it is right or wrong, and you should not go about saying that it is wrong. you don’t know that. Neither do I. It is the subject of ongoing research. Nobody knows. Let us carry on wiht the research. If you want people to work on other ideas, please present those other ideas and convince your peers about the merits of those ideas, what promise you see for them, and people will work on them if they agree with you. This is the way science proceeds. People work on the best and most promising things they see. They don’t just stop working on a huge body of ideas, clear their desks, and then sit there hoping new ones will come to fill the void. It does not work that way. Sorry about that.
Cheers,
-cvj
Clifford,
Let’s see if I can respond a bit to some of what you have to say here that directly refers to me. While I agree with Lee about some things, there are plenty of others that I see differently, so I don’t want to even try and defend whatever he was saying on this radio program (I haven’t even had time to listen to it, don’t know if I’ll find the time anytime soon).
About overhyped argumentation: I wrote an entire, rather dense, book precisely because I think this is a complicated enough subject that it requires a long argument to do it justice. If string theorists want to have a serious discussion with me about my point of view, it is laid out there very carefully, in a form I am willing to stand behind and defend, and I don’t think there is anything overhyped at all in it.
I’m not out there trying to generate media attention on this topic. An unexpectedly large amount of it has occurred, for various reasons, including the huge effort many string theorists have put into promoting to the widest possible public a highly overhyped description of some extremely speculative and not particularly successful scientific work. Lots of journalists have been contacting me and wanting to discuss this, with all of them I do the best I can to give them an accurate, unsensationalized, description of what I think about the science and about what is going on in this field. Often they don’t know much about the subject and need to produce something very short and simplified for their audience. Whatever I tell them generally gets truncated and simplified, with caveats and complexities removed. I’m generally not completely happy with the results, but I on the whole the journalists do a reasonably good job, considering the constraints they are operating under. In a few cases I’ve participated in unedited radio interviews. One of those (the BBC one), you link to with a comment about “poisoning the well for everyone”, when you yourself acknowledge after listening to it that I was being rather reasonable. What’s up with that???
String theorists would like to characterize the problem of the overhyping of string theory as something that occurred for a little while back in the mid-eighties. That’s just not the case, it is an on-going problem, with plenty of all-too-current examples. Besides the Susskind et. al. landscape business, exaggerated claims related to cosmic superstrings, and exaggerated claims about the use of string theory to predict what RHIC sees continue to be made regularly to the general public. This stuff is not intellectually honest.
As for the overall degree of intellectual honesty and willingness to debate scientific issues in a respectful and serious fashion, I’ll gladly defend my behavior and Lee’s against that of most of those members of the string theory community willing to publicly discuss these issues. While most string theorists behave reasonably, there are some who definitely don’t, and these often have a high public profile. The worst example of course is Lubos Motl, but he’s just an extreme version of what afflicts others. Remarkably, his colleagues at Harvard promoted him and so far have been willing to tolerate his behavior (although his recent public calls for my imminent death may change that situation).
I have answered before the substantive question you raise about what the difference is between the Landscape and the fact that there are an infinite number of QFTs, but I’ll try again here. The point is that theories are rarely simply falsifiable, since you can often fix them by complicating them. The hallmark of a bad theory is that you have to keep making it more complicated every time you learn how to calculate something in it. This is what is going on in “string phenomenology”, and the “anthropic landscape” philosophy is a bizarre attempt to claim that this is really all right. The reason quantum gauge theories are such successful science is that they can reproduce correctly a huge array of physical phenomena using a very rigid structure, one of the simplest theories in a general class. If one had to use very complicated gauge groups, fermion and scalar representations, and keep adding more complexity as experimentalists discovered new things, these theories would have the same problem as string theory. But they don’t.
I’ve discussed with you too many times your claims that I don’t give AdS/CFT enough credit. One more time. I actually spent a fair amount of time as a graduate student in the early 80s trying to learn about string theory approaches to solving QCD, and I definitely acknowledge that then and now finding a string theory dual is the most promising way of getting a more useful way to calculate things in strongly coupled gauge theories like QCD. The AdS/CFT idea of nearly 10 years ago is by far the most promising advance in this area, and it has rightly gotten a lot of attention. On the other hand, despite a huge amount of effort, it hasn’t achieved the goal of being something you can use to understand QCD, and the latest claims about its usefulness in heavy-ion physics are overhyped. People should be working on AdS/CFT, but they should also be working on other ideas about solving QCD. One thing they should not be doing is refusing to admit that idea of unifying gravity and the standard model in a 10 or 11d superstring/M-theory has failed and using it to promote support for their research when there is no evidence that this research has any prospects for getting around the reasons that idea has failed.
JoseIRS:- Yes, another excellent point…(JoseIRS is referring to my remarks about Lee’s “ten years” made here.)
-cvj
The atomic theory took about 2500 years in being verified. Therefore, ten or one hundred years are an insignificant lapse of time to find the truth
No. We are still working on it. The theory is not well developed enough (as far as we know) to
yet make firm contact with Nature. There are remarkably exciting results (as I say in the post) in applying string theory ideas -the whole shebang of strings, branes, black holes, gravity, etc- to understandng the new forms of matter being discovered at Brookhaven. This may welll be a great way of testing the remarkably intricate structures that string theory puts together… and give us lots of clues about how to develop the theory better.
But it may all be a red herring. We shall see.
There may also be some clues (we hope) from the Large Hadron Collider (LHC) at CERN. Everrybody is excited about the prospects for new clues for strings and other theories from this machine. Then there are more satellites and ground based experiments to get more data about the parameters of the universe from the Cosmic Microwave Background. There’ll be exciting hints (we hope) from those…. and so on… Since we do not know how far we are from the story coming to fruition, or not, I cannot tell you what the prospects are.
But progress is continuing in the field of developing the theory further… the work continues.
-cvj
I ask in all sincerity as someone who is not even remotely near the field of string theory (or physics for that matter): Is there any experimental support for string theory and if not what is the potential?