Priority for the Landscape

The string theory anthropic landscape point of view has now become so widely accepted and entrenched in the particle theory community that various people are making their claims about having had the idea first. The standard first paper that people generally reference is Leonard Susskind’s February 2003 The Anthropic landscape of string theory, which now has 243 citations. Susskind claims credit at least for the “Landscape” terminology in his recent book.

Last month Dutch string theorist Bert Schellekens posted a paper on the arXiv entitled The Landscape “avant la lettre”, in which he claims credit to some extent for the idea. He is quite enthusiastic about the Landscape as a paradigm shift and a new way of doing physics:

… I think even today we are only in an intermediate stage of a very slow shift of opinions regarding the objectives of our field. Although landscape ideas and even the anthropic principle are now at least discussed, it seems to me that the importance of the landscape is still severely underrated. I have tried to express my enthusiasm about the recent progress during seminars, but apparently with little success.

Schellekens claims that:

My own thoughts in this direction started around 1987. The year before I had published a paper with Wolfgang Lerche and Dieter Lust. Like other authors at the time, we found large numbers of four-dimensional chiral string theories, but much more than others we made a point of strongly emphasizing the non-uniqueness of the result.

He goes on to say that already back then it was clear to him that string theory was sending the message “if we find one vacuum we are going to find a huge number of them.” He recalls that when he was working at CERN in the years before 1992 he was promoting the anthropic string theory landscape idea and encountering a lot of resistance, often from people who now tell him that they had always been saying this kind of thing.

In 1998, at the occasion of his inauguration at the University of Nijmegen he gave a speech on this subject in Dutch. In the arXiv preprint Schellekens reproduces the Dutch text of his speech, together with an English translation. He notes that he used the Dutch word “landschap” in the text, although he mostly referred to the landscape using the Dutch word for a “mountain range”.

Schellekens admits that string theory may not be correct, but he says that string theory implies the landscape, so for string theory to be correct the landscape must exist. His only comment indicating that this might be a problem for string theory is that

…the unexpectedly huge size of the landscape is making it a lot harder to convince ourselves of that.[e.g. the correctness of string theory]

He does admit that back in 1998 he expected the size of the landscape to be much smaller than it now appears to be, smaller than the 1080 vacua that, uniformly distributed, could cover all possible values of the standard model parameters to the accuracy that we can measure them. So he expected that one would be able to somehow check string theory by seeing if one of the vacua agreed with the real world. Now that the number of vacua seems to be vastly greater than this, eliminating any reasonable hope of checking string theory this way, for some unfathomable reason his enthusiasm for the idea is undiminished if not intensified.

If you just can’t get enough of landscape discussion, there are recent blog entries on the topic by Sabine Hossenfelder and Alejandro Satz.

Update: The last-gasp hope for getting a prediction out of the landscape is that there is some useful structure in the landscape, so that it doesn’t densely cover all possible standard model parameters. Washington Taylor and Michael Douglas have been looking for such a thing amongst vacua, trying to find some correlations between properties of these vacua. For more about this, see Taylor’s web-page. Lubos has a blog posting about all this, in which Taylor explains the philosophy:

If we find 5 models with features X and Y of the standard model which all have feature Z which is not yet observed it is not very definitive. If we look in different parts of the string theory landscape and find that all 1020 models we know how to construct with features X and Y of the standard model have feature Z also it begins to carry some weight as a possible prediction.

So far, as you might expect, since there is no known reason for such correlations, they haven’t found any. Lubos reports:

Wati’s result in his particular examples was that there was virtually no information in the correlations: the difference was one bit and the distributions of different quantities were essentially independent Gaussians.

and goes on to rant:

Surely the physicists have not been working for 30 years to extract 1 bit of information – whose probability of being correct is moreover 50 percent. Even if there were any correlation, I would probably find such a correlation physically uninteresting. We know for sure that some of these correlations would agree with those observed in the real world, and some of them would not.

What will you do with this probable outcome? Will you overhype the “successful” patterns as evidence that the landscape reasoning is good, while you will be silent about the “unsuccessful” ones? I would count this activity as a part of astrology or catastrophic global warming theory, not physics. It’s frustrating to see that this is what is apparently being intended.

I wonder whether the people who were producing the very convoluted microscopic theories of the luminiferous aether in the 19th century really believed that this was the way to say anything new about physics – or whether most of them did these things just to do something and keep their jobs. Einstein took over in 1905 and showed not only that the aether was a ludicrous fantasy – but moreover, the absence of the aether is one of the basic principles that underlies his relativistic revolution in physics. Today, all of us – except for those in loop quantum gravity – know that the aether is a silliness that is not realized physically and that was never well motivated.

My feeling about the random model building and random model guessing is somewhat analogous to the random construction of the aether from gears and wheels. We’re missing something and we should not fool ourselves into thinking that we’re not.

Update: The Harvard physics department seems to be having quite a few seminars on the Landscape, and one participant reports:

A funny aspect of these discussions is that one can’t quite distinguish which of the considerations are jokes and which of them are meant seriously. At least I can’t distinguish them.

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147 Responses to Priority for the Landscape

1. Mike says:

This long discussion about the landscape further emphasizes a few points,

island Says:

” Lee Smolin said:
‘I find it bizzare that people have taken the term, and used it both without proper attribution and without recognition of its connotations-which were exactly to avoid the use of the anthropic argument. ‘

Didn’t you know, Lee?… the landscape is now synonymous with the anthropic principle and has been ever since Lenny’s book came out.”

Only a few years ago, this was posted:

The Beginning of the End of the Anthropic Principle

“We argue that if string theory as an approach to the fundamental laws of physics is correct, then there is almost no room for anthropic arguments in cosmology. The quark and lepton masses and interaction strengths are determined.”

Gordon L. Kane, Malcolm J. Perry, Anna N. Zytkow
arxiv.org/abs/astro-ph/0001197

dan Says:

“Peter, I am sympathetic to your concerns, that string theory suffers from problems, such as extracting predictions, and that too much of particle physics has been engrossed in this seemingly unpromising approach, but I am curious as to what research programs particle physicists and theoretical particle physics are pursuing that go beyond the standard model, but do not involve SUSY or string theory or higher dimensions,”

Chris Oakley Says:
“Schroer’s algebraic field theory or Peter’s geometric quantization…”

BF theory has been mentioned before too,

And Mentos Says:
“QED is an effective field theory, valid at low energies, but which must be replaced by some other, better-behaved effective theory at higher energies.”

An attempt to correct QED has also been made by new work with modified Maxwell equations.

While Pauli was the critic who said “Not even wrong”, he was also a leader in searching for new physics, and made contributions regardless of age.

2. wolfgang says:

Dear Prof. Schroer,

> Since you seem to be a string theorist

I am not.
Most of my effort was on lattice gravity and I am currently not an ‘active researcher’ 😎

3. Lee Smolin says:

Since Peter asked, let me just introduce some objectivity into the discussion about the consequences of choosing to work on an approach to quantum gravity apart from string theory. In the US now there is a single research group with more than one faculty member working on non-string quantum gravity; at Penn State it has one senior and two junior faculty. Apart from Penn State, and a single person who left Penn State and got a position largely on the basis of his work in another field, the last time there was a new faculty position in the US for someone working on a non-string approach to quantum gravity was 1990. There are at most 4-5 NSF funded postdocs now in the US that a non-string quantum gravity person might apply for. The situation is slightly better in Canada, Mexico, and a few European countries, but the situation is that there is no graduate student or postdoc-even the stars with widely read and admired single authored papers-who has an easy or assured career.

The situation would be vastly improved if there were open competition on the basis of quality, originality and promise for the large number of postdoc and faculty positions controlled by string theorists. But I am unaware of a single instance of a string theory group hiring a postdoc or faculty member in any other approach to quantum gravity, in spite of the fact that this has happened in reverse several times- because the ethic in non-string quantum gravity is to choose on the basis of quality and individual promise, whereas the string theorists seem uninterested in applicants who do not work in the mainstream of string theory.

As far as someone wanting to do a Ph.D. in non-string quantum gravity, there are many and indeed the number of applicants is increasing dramatically because of the visibility of recent important results. But there are very few places in the few groups around the world where this work is done. We literally turn away good applicants weekly who apply to our group. As a result, an increasing number of very promising students are doing PhDs in non-string quantum gravity on their own without the benefit of an advisor in the field.

The only advantage of this is that the few young people who persevere against these odds have visibly much more creativity, intellectual independence and courage than their counterparts in trendy, mainstream fields. So they do better science, and indeed young people are responsible for the bulk of the new results and ideas which have driven the fast rate of progress of recent years. So it is getting increasingly evident that their exclusion from consideration for the best positions cannot be justified on any objective scientific basis.

And yes, my forthcoming book is not an attack on string theory, it is an examination of how this kind of situation can develop, which hurts not just many of the best young researchers but the progress of science itself.

4. wolfgang says:

Lee,

I am certainly not up to date and probably misunderstood your comment about the ‘only one research group’ in the US.
Without Google’s help I can name at least three groups in the US,
around Raphael Sorkin at Syracuse, Herbert Hamber at Irvine and John Baez at UC Riverside. I am sure there are more … certainly in Europe.

As for “there is no graduate student or postdoc-even the stars with widely read and admired single authored papers-who has an easy or assured career.”
This is certainly true for all students and postdocs. I doubt that string theory guarantees a career …

5. Aaron Bergman says:

“I doubt that string theory guarantees a career …”

Heh.

6. woit says:

Wolfgang and Aaron,

You’re not addressing what Lee wrote. He wasn’t discussing generic students or postdocs, but the top ones in the field:

If you fit this description in string theory you are guaranteed a career. If you fit this description in non-string quantum gravity Lee is claiming you may have problems getting a job. Argue with him about what he is saying, not straw man arguments.

7. Mentos says:

Schroer said:

” [blah blah blah]… creates inexorably something which you generically call “gravity” then you have ruined the magic which many people still expect behind Maldacena, and I wash my hands free of guilt.”

I explained why the AdS dual of a (nongravitational) QFT necessarily involves gravity in the bulk. You can wash your hands, if you wish. Won’t change a thing.

“Wilsonism to me means that … I am able to make a conceptually closed theory in the present situation of QFT … which is free of cutoffs and elementary length.”

To the contrary, in Wilson’s approach, QFTs always come equiped with a cutoff. In his framework, there is no “conceptually closed theory … which is free of cutoffs.” The point is to, nonethless, extract cutoff-independent answers from an inherently cutoff-dependent formalism.

Your AQFT approach is about as anti-Wilsonian as one can ever be.

8. Lee Smolin says:

Dear Wolfgang, I chose my words carefully. Raphael Sorkin at Syracuse, Herbert Hamber at Irvine, John Baez at UC Riverside, and a few others (Steve Carlip, Louis Crane, Ted Jacobson, Jorge Pullin, Bob Wald) are doing important work but they are single faculty members. As good as they are, by current NSF rules they are not always able to support a postdoc, as single faculty members are rarely given postdocs.

It is a bit better in a few European and Latin American countries, as I said, whose systems are structured so that there are a few good positions where the competition is in terms of individual accomplishment and promise without regard to research program or subfield.

Thanks,

Lee

9. wolfgang says:

Lee,

I see your point. But I assume that in the long run funding and interest in general will depend on results.
The results of Witten, Maldacena etc. made string theory interesting.
If Reuters et al. can demonstrate the existence of a UV fixed point, Loll et al. can show that CDT reproduces GR etc. this would certainly increase interest and funding.
Ultimately, experiments are the most interesting results. If the LHC and other experiments will not provide evidence for super particles the interest in superstrings and subsequently funding will probably decline.
If GLAST provides evidence for LQG you will probably have an easier life 😎

Unfortunately, overall the interest in theoretical physics and the willingness to fund it is declining (at least in the US), since politicians understand that the 1940s and 1950s will not repeat …

10. wolfgang says:

I am sorry: Reuter not Reuters

11. Juan R. says:

Wait a moment Wolfgang, are you claiming that string theory is more promising or may be funding before other approaches because technical points?

If yes, let me say that string theorists have proved absolutely nothing in last decades. Nobody have proved finiteness of perturbative string theory (it is claimed that solves all renormalization issues of QFT on gravity but i never saw a proof) and still today nobody has proven that string theory coincides with GR in the large scale low energy regime.

Even asuming backgrounds and large spacetimes by default, even asuming some compactification of extra dimensions, the result is a perturbative expansion over a flat metric. GR is NOT that.

About the LHC and other experiments, i can assure you that string theory hype will remain independently of the experimental results. There is historical evidence for such one attitude in the string comunity. Exactly 40 years of successive experimental failures of “predictions” of string theory. One of most recent were supposed cosmic strings…

Let me remark that problem of super partners is not if they are there (at high energies) but they are NOT here (at current energies) and string theory fails to provide a low energy regime without super partners. That is one of reasons string theory is unable to reproduce the standard model results.

Any new theory of physics may be backward compatible with experimental results known. Before to claim about it will be seen in next HLC, stringers would explain data is already known and explained by GR + SM.

Juan R.

Center for CANONICAL |SCIENCE)

12. MoveOnOrStayBehind says:

To Oakley:
“You people are missing the point, perhaps deliberately.
Neither Peter nor the majority of the silly anti-string club here
are saying that Superstring theory should be abandoned.?

What? I have read innumerable times here that string theory is
“all wrong”, “not even wrong”, must be “given up”, etc.

“… We just think that the effort expended on this quest is
disproportionate to the results obtained and it is high time that
more effort is devoted to alternatives rather than propping up this
failed project.”

I would say that the most important, fascinating results in theoretical
particle physics and mathematical physics in the last decades came
right out of string theory. Holography, AdS/CFT, insights in
non-perturbative gauge theories, quantum black holes.., even Hawking
gave up his bet. Could you name any other field with remotely as
many important results?

And what are your alternatives? This sounds like if there would
be any. How would LQG help solving non-perturbative Yang-Mills
theory? How do you describe with that flat space, anyway? It’s
an evil strategy of certain people to present things as if there
would be alternatives, such that as their own pet theories …
laymen such as you think that alternatives must be better just
because they contradict the mainstream, isn’t it? Try to build
an alternative moon rocket out of wood…that’s as silly.
Keep on trying.

“A bit more honesty from the Superstring community would help”

All the respectable collegues I know say what they think. A few
like Kaku grabbing media attention do not stand for the community.
such a distorted picture.

” If after more than 20 years of effort you cannot calculate cross
sections then either (i) you should stop calling what you are doing
physics or (ii) you should give it up.”

Well I think I can compute cross sections. And thanks for a layman’s
tip how I should call my work. What do you think brings you in the
position to make such proposals? Decades worth of hard work on your
own, or just out the arm chair?

“I doubt very much if Peter or the rest of us silly anti-stringers
would have a problem with 10% of the current Superstring community
carrying on on the basis of option (i)”

Well, I do certainly think that investigating the quantum behavior
of black holes and gauge theories is physics, isn’t it?
And do you seriously think that LQG and other “alternative” approaches
you may propose would be more physical? Did it ever occur to you
that we first need to understand the physical concepts how things
work, in simplified settings, rather than trying to make direct
contact with reality? Most of the leading figures in the field do
pursue exactly this, because they know how difficult it is to make
contact with reality. It is simply not so that everybody would work
on “realistic” model building and the landscape – actually, among
the leading people it is a minority. And how should one then call
with your permission other research in mathematical physics, like
the one magnetic monopoles, algebraic QFT, integrable systems, which
also do not have a direct experimental confirmation?

“For those that do need acceptance, the system at the moment is set
up to force them to follow directions they do not necessarily want
to go in”

Right now, the pressure everywhere is to go into particle phenomenology.
Do you know what you are talking about?

13. woit says:

“What? I have read innumerable times here that string theory is
“all wrong”, “not even wrong”, must be “given up”, etc.”

For the innumerable + 1 time: the idea of using strings in 10d (or 11d M-theory, whatever that is) to unify the standard model and gravity has failed miserably, is “all wrong”, “not even wrong”, must be “given up”, etc. More than twenty years of work by much of the theory community thinking about strings has led to interesting insights about strongly coupled gauge theory, about enumerative problems in algebraic geometry, and speculative ideas about quantum gravity. Many of these latter things are worth pursuing, but so far they have given no insight into beyond standard model particle physics. The claim that research in string theory is a promising approach to beyond standard model particle physics is not just made by Michio Kaku, it continues to be made by almost every string theorist who gives talks to a non-specialist audience on the subject. This raises serious issues of intellectual honesty.

I don’t doubt that most of the people who make these arguments are making them honestly in the sense that they believe them. I do question whether they are being intellectually honest: are they willing to actually confront the seriousness of the problems string theory faces and draw the conclusions that follow from them, even if this is painful? I don’t see many string theorists willing to do this. Instead I see them doing things like anonymously posting here attacks on me and others in which they willfully ignore points I’ve made a thousand times that they have no answer for, making up straw man arguments they prefer to deal with.

14. amused says:

Lee Smolin wrote: “…the ethic in non-string quantum gravity is to choose on the basis of quality and individual promise, whereas the string theorists seem uninterested in applicants who do not work in the mainstream of string theory.”

Facinating. Do tell us, Prof. Smolin, what are the concrete criteria you use to evaluate “quality and indvidual promise”? If a young person working independently on, say, formal aspects of gauge theories, including a certain topological gauge theory of relevance for LQG, were to apply to you for a postdoc, what would it take for you to hire him/her? How many single-author publications in Phys.Rev.Lett should this person have in order to satisfy your “quality and individual promise” criteria? (I happen to know that this number has a lower bound of 3.)

From what I have seen, postdoc applications from young people whose topic is neither strings nor LQG generate no more interest from LQG groups than they do from string groups (unless their topic happens to be a pet interest of Smolin, e.g. the so-called foundational approaches to QM etc.) Smolin’s appeals, here and elsewhere, for jobs to be awarded on the basis of quality and promise rather than research topic, strike me as little more than an amusingly disingenious attempt to help his own people in the current string-dominated environment.

If people really were serious about promoting quality and promise irregardless of research topic, here is a way to do it: Remove hiring decisions from individual research groups (who will inevitably favour people working on their own topic), and individual physics dept.s (which will inevitably favour people working on fashionable topics, or who have famous thesis advisors etc, which will make the dept. look good), and let the decisions instead be made by large national committees whose members represent the whole spectrum of theoretical physics research. Research groups or individual physics dept.s can then sponsor the applications of people they would like to hire, but with the actual hiring decisions made by the national committee after an open competition. (This is basically the way things work for the EU’s Marie Curie fellowships.) Would you be willing to hand over your individual hiring powers to a national committee in the interests of promoting quality/promise over reseach topic, Prof. Smolin?

[Apologies to Peter for continuing this discussion in an off-topic direction.]

15. Chris Oakley says:

MoveOnOrStayBehind,

I am not sure I like getting into arguments with people who refuse to identify themselves, but my experiences in the in the world of theoretical physics are described in detail on my web site (link above). I should point out that this “armchair” you refer to exists only in your imagination; I left physics because I had to and have been earning my living since then by doing financial modelling and programming. The job I have now at least gives me more time to think about other things, and when the dust settles, there is at least one significant piece of (original, as far as I know) theoretical physics work that I plan to revisit.

I would say that the most important, fascinating results in theoretical particle physics and mathematical physics in the last decades came right out of string theory. Holography, AdS/CFT, insights in non-perturbative gauge theories, quantum black holes.., even Hawking gave up his bet.

Obviously your definition of the word “physics” is not the same as mine.

As for alternatives to ST, I have my own ideas. They do admittedly put me in a “minority of one” (as helpfully pointed out by a former HEP colleague), but they are ideas nonetheless and will be pursued when I have the leisure time to do so. And no, there is no quantum gravity component. I am not interested in building models when there is no experimental data.

As regards the Anthropic Landscape, I am sure that you are right in pointing out that most have not signed up for this. But even one is too many.

Right now, the pressure everywhere is to go into particle phenomenology. Do you know what you are talking about?

Probably not … my information may well be out of date, but if many are voting with their feet then this may well be because they acknowledge that Peter has a point.

16. Aaron Bergman says:

It’s not so much a matter of voting or “acknowledg[ing] that Peter has a point”. Rather, it’s that the LHC is turning on. Faced with the prospect of having actual data, people will naturally move from speculative stuff to stuff that’s related to the incipient data. Really, Peter’s criticisms aren’t particularly new or original (see, for example, Ginsparg and Glashow), and the anthropic stuff remains a source of disagreement in the field.

I am always astounded that people are willing to declare something wrong based on metaphysical constraints. That string theory hasn’t developed into a complete theory in 25 years or that it may have a zillion or so vacua doesn’t make it wrong. Useless, at worst, but it’s entirely possible that that’s just how the universe (multiverse?) is.

And for the people disparaging the study of SUSY gauge theories and various other things that aren’t the real world, the study of toy models has a long and useful history when the real problem is (presently) intractable.

17. woit says:

Aaron,

What’s the difference between being “useless” and being wrong? This is what I cannot understand about what is going on today among string theorists. They seem willing to accept the possibility that the theory is useless in terms of predicting anything about physics, but unwilling to draw the obvious conclusion that if this is the case it is wrong.

18. Who says:

Mr. M.O.O.S. Behind wrote thusly:
“…And what are your alternatives? This sounds like if there would
be any. How would LQG help solving non-perturbative Yang-Mills
theory?
How do you describe with that flat space, anyway? It’s
an evil strategy of certain people to present things as if there
would be alternatives,..”

http://www.math.columbia.edu/~woit/wordpress/?p=392#comment-11000
Mr. Behind sir, in reply to your comment, you seem to use LQG as a convenient blanket term for alternatives. And I concede there is an identifiable LQG community (pursuing various related approaches to QG). My point is that at least one researcher in that community just posted something about the problem you mentioned “non-perturbative Yang-Mills”. In case you would like a link, here is one:
http://arxiv.org/find/grp_physics/1/au:+freidel/0/1/0/all/0/1

In the comment you ask several rhetorical questions which make it seem that you are not very familiar with what you are talking about.

Your question “How would you describe flat space anyway?” is interesting (if taken non-rhetorically). If you try that link you can see how Freidel, for one, is addressing this question. His research is not unique in this respect but you may wish to do the author-search and check out some abstracts before making further pronouncements on the subject. That would also pick up the two papers on 4D Yang-Mills, one co-written with Robert Leigh and Djordje Minic.

I believe you would also find some papers there concerned with deriving flat space and the Feynmann diagrams of usual QFT from a spinfoam version of QG that comes under the general LQG heading. Perhaps in a simplified setting from which further work can generalize.

Mr. Behind, you ask another question that may be rhetorical here:

**And do you seriously think that LQG and other “alternative” approaches you may propose would be more physical? Did it ever occur to you that we first need to understand the physical concepts how things work, in simplified settings, rather than trying to make direct contact with reality?…**

With all due respect, I do seriously think so. Yes, is the answer to your question, they would and will be more physical. Note that the alternative approaches try to get at fundamental degrees of freedom of spacetime and matter in a direct physical fashion, often in simplified settings (as you mentioned) and going light on extra baggage.
And as one who watches the research scene I would say this strategy seems to be paying off quite well lately in terms of results.

**Did it ever occur to you that we first need to understand the physical concepts how things work,..**

I would answer that Yes actually it has occurred to me.

Oh, M.O.O.S. in regard to your warning to us:
** It’s an evil strategy of certain people to present things as if there would be alternatives,..[to superstring/M theory]…**
that sounds indeed very diabolical of them. I can only express my surprise at your discovering this.

Civilly yours,

Who

19. Lee Smolin says:

Dear Amused,

In fact I do agree that some of your proposals would be helpful, for example to instutute in the US fellowships analagous to the Marie Curie or Royal Society Fellowships. My answers to others of your questions are in my Physics Today essay from June 2005, page 56. As far as consistency, I do not now, nor have I ever made postdoc hiring decisions on my own, at PI such decisions are made by a committee. But it is true that the majority of the people who hold or have held postdoc or visiting positions at PI in non-string quantum gravity work on approaches other than LQG.

Lee

20. Aaron Bergman says:

What’s the difference between being “useless” and being wrong?

Ontologically, quite a lot. Epistemologically, maybe not so much.

This is what I cannot understand about what is going on today among string theorists. They seem willing to accept the possibility that the theory is useless in terms of predicting anything about physics, but unwilling to draw the obvious conclusion that if this is the case it is wrong.

Because that simply does not follow. Regardless, you seem eager to give up on the string theory project at every turn. Your original polemic doesn’t even include the word ‘anthropic’. Others still believe that, even with the surfeit of possible vacua, it’s not at all clear that we might not be able to treat string theory like QFT wherein experiments determine a particular vacuum and it becomes predictive. I also believe that, given results like AdS/CFT and Strominger and Vafa, string theory surely is a theory of quantum gravity, even if it isn’t our particular theory of quantum gravity. As such, we can learn a lot just from studying how string theory solves the usual problems with quantum gravity, and eventually those insights may help us understand the correct theory if and when it comes around.

But, for all this bickering, data is just around the corner, and that is where the jobs are going right now. If anything, much anthropicism is motivated by the specter of the LHC.

21. woit says:

“Regardless, you seem eager to give up on the string theory project at every turn. Your original polemic doesn’t even include the word ‘anthropic’.”

I really wish you’d stop it with the ad hominem arguments, they’re just obnoxious and don’t prove anything.

Yes, for a very long time I’ve thought that string theory has failed as an idea about unification. The problems of too many compactifications and how to break supersymmetry have been around since the beginning, and by the late 90s it was clear there was very little chance they could be surmounted (non-perturbative versions of the theory had the same problems). That was the situation when I wrote my first public polemical article. Developments since then have provided even more convincing evidence that I was right that these problems can’t be surmounted, backing string theorists into the anthropic corner which I never would have believed back then they would try to take a stand in.

22. Aaron Bergman says:

I really wish you’d stop it with the ad hominem arguments, they’re just obnoxious and don’t prove anything.

I hardly think it’s unfair to point out that your opinion of string theory predates this current situation in the context of a discussion why there are people who haven’t completely abandoned the field.

And, you asked why string theorists haven’t given up. I certainly can’t answer for everyone, but I tried to explain to you some of the reasons.

23. Who says:

what I have to say has something indirectly to do with how one reacts to the whining of young string theorists that one sometimes hears, but mostly I want to give ANOTHER EXAMPLE OF RESEARCH ALTRUISM besides what Smolin mentioned.

someone, I think “amused”, suggested that Smolin was probably just as self-interested as any string theorist and would only take postdocs that work in his own type of QG, and he said not so, and gave an example of Perimeter policy

===quote===
In fact I do agree that some of your proposals would be helpful, for example to instutute in the US fellowships analagous to the Marie Curie or Royal Society Fellowships. My answers to others of your questions are in my Physics Today essay from June 2005, page 56. As far as consistency, I do not now, nor have I ever made postdoc hiring decisions on my own, at PI such decisions are made by a committee. But it is true that the majority of the people who hold or have held postdoc or visiting positions at PI in non-string quantum gravity work on approaches other than LQG.
===endquote===

My point is that this non-string QG ethos is strikingly exemplified not only at Perimeter but also in the Utrecht QG program. Loll’s group has 3 postdoc positions. The house brand QG is called CDT (a triangulations path-integral). If you are used to EXCLUSIVITY then you may be shocked by this. Actually I was last year when I learned that the 3 positions went to STAR ROOKIES OF THE COMPETITION. The postdocs of Loll’s Utrecht group are people that Dowker in London co-authors Causal Sets papers with, and Freidel at Perimenter coauthors with, and a self-starter who helped standardize canonical LQG by proving an important theorem. These people are selfdirected reseachers with impressive track records—I’m not kidding. And so what is the good of this for Loll’s particular approach to QG? It simply did not make sense to me. She controls a sizable Dutch government grant based on her own CDT work and can do as she pleases, so why does this go to support some of the best rookies of the competition? People with their own research motivation who are not likely to change direction for trivial reasons.

It seems like the ethos in non-string QG has a large element of SUPPORT THE OTHER GUY’S POSTDOC. I have wondered how a field can survive with so much altruism running amok in it?

But there may be advantages. This year Utrecht has been getting visits from e.g. Dowker and Freidel and Ashtekar. It means that more different non-string QG approaches are being worked on there at one time than probably anywhere besides Perimeter. I guess that could pay off in the long run.

============
Anyway the ethos has a strong anti-parochial streak (wherever they have enough resources gathered so they can actually HAVE postdocs). and that is in strong contrast to the string ethos in typical US department where string faculty have control of ALL the QG positions and will not share ANY. At least as far as I know. It might be amusing to get some statistics on this corresponding but contrasting with the Utrecht and Perimeter examples.

the relevance to the situation of a young string theorist would seem to me that he or she is being supported by an exclusive system that will take on no other type of young researcher, no matter how ingenious, no matter how independent, no matter how inventive, with no matter how good a track record. that is to say a totally bigoted system

24. Arun says:

I’d say some people want to know the answers, even if it means that most of their productive research years turn out to have been on the wrong path; while some people want to build empires.

25. amused says:

Dear Prof. Smolin,

Thanks for taking the time to reply. In fact I had read your Physics Today essay, and have just re-read it, but am still confused about what exactly your position is regarding supporting young researchers, and how it differs from what people or groups in other areas do. More on this below.

“But it is true that the majority of the people who hold or have held postdoc or visiting positions at PI in non-string quantum gravity work on approaches other than LQG.”

And what areas do these people work in then? As far as I can tell, most, if not all, work on topics that can be classified under “background-independent approaches to QG” or “foundational issues in quantum mechanics”. What is the position of you and your colleagues at PI regarding support for young people not working in these areas (e.g. for someone working on formal aspects of gauge theories)? I don’t see any sign that you care about such people. It seems that on the one hand you advocate supporting independent young researchers irregardless of research area, but on the other hand you have chosen certain specific (albeit broad) areas which a person has to be working in to get support from PI.

So it seems that in reality the policy of you and your colleagues is no different from that of a typical string theory group: In both cases the group has an area, or set of areas, that it wants to support, and proceeds to hire people in these areas. Presumably it happens from time to time that a string theorist working on, say, branes and ads/cft, hires a postdoc who works in another subarea of string theory, say perturbative string theory or string field theory. The string theorist would say that he/she is doing this in order to further the career of a talented young researcher, even though the person is working on a different topic. Where is the difference between this and what you do? (besides that fact that the areas you are willing to support are broader than that of a typical string theorist).

[Peter – apologies again for continuing an off-topic discussion; I’ld understand if you wanted it to stop. I guess at some point you’ll write a post on Smolin’s book after it appears, and that might be a more appropriate time to take up this topic.]

26. Lee Smolin wrote:

(…) Latin American countries, as I said, whose systems are structured so that there are a few good positions where the competition is in terms of individual accomplishment and promise without regard to research program or subfield.

No and no.

Best wishes,
Christine

27. amused says:

Who,

“If you are used to EXCLUSIVITY then you may be shocked by this. Actually I was last year when I learned that the 3 positions went to STAR ROOKIES OF THE COMPETITION.”

When I first saw this I thought you were going to say the positions went to string theorists… being under the impression that they are (percieved as) the real competition, and that the various background independent approaches to QG are all in the same broad family…

I don’t see that this is such a big deal though. As far as I’m aware, the Ambjorn-Loll group is the only one doing this CDT stuff. So, short of hiring their own students, how could they get postdocs who are already working on this? It seems they had no choice but to hire people from other subareas. Presumably Loll is hoping that these people will get interested in CDT and do some work on it (while continuing with their own stuff at the same time). And it would be natural for them to do this, seeing as CDT is one of the more exciting developments in this general area.

28. Mentos says:

Is there any actual evidence that “background independent QG” postdoc seekers fare worse, on average, than string theory postdoc seekers?

Obviously, the field is much smaller so, anecdotally, Lee is more likely to personally know good candidates who failed to get jobs. But there are plenty of top-notch string theorists who don’t get postdoc jobs either.

Are there any statistics to the effect that a higher percentage of string theory postdoc seekers obtain jobs than “background independent QG” postdoc seekers? Or is this just another “just-so” story?

29. woit says:

Mentos,

The best data out there I would guess is at the new Rumor Mill for theoretical particle physics postdoc jobs. I had kind of started believing the complaints I’ve been hearing recently from string theorists that phenomenologists are getting all the jobs until I just recently took a look at this. By my count, getting postdocs this year there are 31 string theorists, 12 phenomenologists, and 5 hard to characterize (brane-worlds, QCD amplitudes by twistor methods…). Several institutions that hire lots of postdocs still will only hire string theorists (Caltech, KITP, IAS…)

How many “top-notch” string theorists do you know who in recent years have been unable to get a post-doc position? I personally know of no such examples, but maybe it all depends on what you mean when you say “top-notch”. Can you give an example of someone from one of the top few groups in the US who has an impressive thesis but no job? Is the problem that there are more than 31 “top-notch” string theorists on the post-doc job market, or that institutions are hiring second-rate string theorists over first-rate ones?

This is a “particle physics” rumor mill, and thus may not have non-string theory QG jobs listed. Such a list may not exist, but since, as Lee points out there are very few places in the US that ever hire in this area, I would suspect there are no more than a handful such jobs.

30. Aaron Bergman says:

My count is slightly different from yours (but I might have miscounted). I’m not sure how representative that list is; there might be a bit of a selection effect (there are very few cosmologists on it, for example). I’m pretty far from the postdoc gossip this year, though. My impression is that there is a much higher proportion of phenomenologists among traditionally stringy jobs than in the past, though, but can’t offer anything quantitative.

31. anonymous says:

Where is this postdoc rumor mill? I only know of one for faculty.

Also, the IAS only hires string theory postdocs? Funny, I bet Ian Low would be surprised to learn he is a string theorist. Other counterexamples to your claim exist. I don’t know about KITP, but Caltech and the IAS do not just hire string theorists.

32. anonymous says:

Just so you don’t think I’m choosing one exception to the rule, recent phenomenology postdocs at IAS include (but are not necessarily limited to): Mishima, Dermisek, Kitano, Agashe, and Kribs.

33. woit says:

I was referring to this site (and counting postdocs hired this season)

http://www.freewebs.com/heppostdoc/

According to it, the IAS is hiring five new postdocs, and I think they can all be reasonably characterized as string theorists. I wasn’t claiming that the IAS theoretical physics group never hires anyone but string theorists, but now that you mention it, of their 18 current non-permanent members, how many are not string theorists? You mention 3 (Low, Mishima and Demirsek), and maybe there are a couple others, but its undeniable that IAS postdoc jobs overwhelmingly go to string theorists, both in the past as well as this year.

34. Mentos says:

“Several institutions that hire lots of postdocs still will only hire string theorists (Caltech, KITP, IAS…)”

That’s kinda funny.

Of Caltech’s 8 postdocs, 4 are phenomenologist, and 4 are string theorists.

At the IAS, I count 1 formal Yang-Mills person, 3 phenomenologists, 2 (Kleban and Rabadan) who started out as string theorists, but who are now doing phenomenology, and 7 string theorists.

And, of the KITP’s 5 high energy postdocs, 4 are string theorists, and one is a phenomenologist.

“The best data out there I would guess is at the new Rumor Mill for theoretical particle physics postdoc jobs. … I had kind of started believing the complaints I’ve been hearing recently from string theorists that phenomenologists are getting all the jobs until I just recently took a look at this.”

I was previously unaware of the Postdoc Jobs Rumor Mill. I’ll have to check it out.

But on the Faculty Jobs Rumor Mill, I count 10 phenomenologists, 6 cosmologists and 6 string theorists getting jobs this year.

35. Lee Smolin says:

Dear Mentos,

I have no statistics, but it is not uncommon for top level grad students and postdocs-authors of widely read and cited papers-in non-string quantum gravity to get no offers and to have to apply in succeeding years to get a postdoc. This is not new, many who are now seen as the leaders had periods when we came close to being forced out of science. I certainly did.

Dear Amused,

I think that Who gave the best answer in describing the Utrecht group: there is simply a different ethic that values the personal promise of a young researcher over working on the research program of the faculty. This is in fact an old tradition, it came to me through my mentors who were senior faculty in relativity groups. It contrasts with another attitude towards postdocs which is that they are to be chosen to further the research program of the grant holder. My view is that the former leads to faster progress in science than the latter, because it favors young scientists who are more intellectually independent, original and courageous, and these are the kind of people who make the discoveries that drive science forward.

I disagree with your drawing an equivalence between string theory and the whole field of quantum gravity. I think it is a bad idea to organize groups or departments around research programs rather than subject areas, because that gives research programs, which can succeed or fail, more institutional inertia than is good for science. I have nothing against string theory per se, so long as it is seen as one research program among several aiming towards the further unification of physics.

Hence, I would argue that commitment to string theory as a research program is different than commitment to a subject areas such as quantum gravity or post standard model particle physics. I have never myself worked within one research program; I continue to publish a paper on string theory every year or two and the bulk of my work is seen by specialists as not strictly LQG. I think science would progress faster if we built structures that discouraged rather than encouraged scientists to identify themselves with particular research programs rather than areas.

I do personally agree with you that formal aspects of gauge theories are a neglected, under supported area, which is one reason I have been following the recent work in this area with interest.

As for PI, please do not confuse my views with either policy or the experience at PI. I am one voice and vote among many, and the basic mandate and policies-including the idea that postdocs are to be hired by the whole institute as independent researchers-were set up by the founders and director before any of us faculty were hired.

Dear Christine,

Thanks for the correction.

Thanks,

Lee

36. Who says:

Amused, both Perimeter and Utrecht ITP have numerous string postdocs, as well as “background independent QG” postdocs.
I wish that major theory sites in US were more inclined to allocate support to the individual mind rather than to the camp—as I have said–and think that this would LEAD to more diversity in the research pursued at these places. QG research diversity is not a goal per se, or is only an accessory interest. It is symptomatic of ability to appreciate drive and originality in rival lines and a pragmatic philosophy of “let’s get the problem solved however the heck we do it (rather than by my pet method or my club of people)”.

If you don’t see that philosophy operating in the places I mentioned, or don’t see the results of the past couple of years as indicative that it works, then maybe my perception is wrong—I may be deceiving myself or failing to communicate here.

Oh BTW Utrecht also has a postdoc who has co-authored with Martin Reuter—-not in Loll’s immediate group—I think he does string part of the time. As does Ambjorn, whom you mentioned as a CDT associate—my impression that his research is at least half, maybe more, in string/M.

I think the style exhibited here is “ecumenical” or maybe pragmatic. There is no intrinsic merit to it—you can only judge by the results. If this does not make sense to you please let me know.

37. anonymous says:

“According to it, the IAS is hiring five new postdocs, and I think they can all be reasonably characterized as string theorists.”

The rumor mill apparently doesn’t know about Gil Paz, who is also starting a postdoc at the IAS next year, and is decidedly not a string theorist.

The IAS is largely composed of string theorists, but for an institution so dominated by string theory in terms of faculty, I think it does pretty well with hiring a more diverse group of postdocs.

38. woit says:

Mentos,

My mistake for the wording implying that IAS, KITP and Caltech in the past only hired string theorists, something I didn’t mean to claim. I was just talking about this year.

I also had only been aware of the permanent faculty hiring data, which does show more phenomenologists and cosmologists than string theorists getting jobs. I was surprised to see how different the postdoc data is. Perhaps this is because postdoc hiring is more concentrated at a few prominent institutions, and these remain dominated by string theory, whereas permanent jobs are spread out more widely, with prominent institutions doing only a small amount of permanent hiring.

39. Aaron Bergman says:

I was surprised to see how different the postdoc data is

I’d be careful assuming that page is a representative sample. Anon above already pointed out one person missed at IAS.

FWIW, I believe that Swedish ur-string theorist Lars Brink was the one responsible for me landng a 4-year postdoc, long ago. So there are counterexamples to the claim that string theorists only hire string theorists. I’m not sure that Lars likes me anymore, though.

I thought I recognized Lars in the City Hall last December 10th, but I’m not sure since it was more than a decade since we last met. Perhaps next year.

41. amused says:

Who,
Yes, I am aware that PI and Utrecht have string as well as background independent QG postdocs, that many people who work in the latter area have wide-ranging interests and also work on other topics (a positive thing, of course), and that there has been significant progress in some subareas of BIQG in recent years.

“QG research diversity is not a goal per se, or is only an accessory interest. It is symptomatic of ability to appreciate drive and originality in rival lines and a pragmatic philosophy of “let’s get the problem solved however the heck we do it (rather than by my pet method or my club of people)”.”

Sure. But can you accept that there might be people of this ilk in other areas of theoretical physics (or science in general) besides QG? Or do they all gravitate towards QG research of some sort or other? Assuming they exist, are the ones who choose non-QG topics less deserving of support than the QG’ers?

If Smolin had simply appealed for more recognition and funding for work on BIQG and fundamental aspects of QM he would have had no argument from me. But when he starts going on about how he and his colleagues support independent young researchers of quality and promise, irregardless of their research area, then the people out there who are, or were, young independent researchers, and who aren’t, or weren’t, having an easy time jobwise, are going to prick their ears up. Questions will come to mind such as “Hey, I wonder what it takes to meet Smolin’s quality and promise’ criteria?”. Then some of the older ones might get a flash of recollection along the lines of “Er, didn’t we send a postdoc application to that Smolin guy early on, when we had a couple of papers in PRL and various others in NPB, PRD etc… (all single-author of course – we’re independent, remember)… and he wasn’t exactly enthused, was he…. Well, at least that sets a lower bound on his criteria which we can compare against the people he does hire – so let’s look them up.” And later, “Hmmm, looks like we overlooked something – the quality’ part of Smolin’s criteria appears to include a `quality of choice of research area’ factor. At which point cynicism sets in, and a snide comment or two get posted on a certain accomodating webblog.

42. Lee Smolin says:

It is a bit unpleasant to have one’s motives questioned publicly by an anonymous person over past decisions. I would think that good sense would suggest several reasons why every decision of every research group a person has been a member of may not agree with policies they presently advocate, including 1) they were one vote on a committee, 2) restrictions from funding agencies, 3) their present views are the result of reflection on past experience and have evolved 4) there are so many excellent candidates that one research group in one field cannot be expected to have room for all but a small fraction of the candidates they think are deserving of support. This is why I have begun to speak out about these issues; one institute, however well supported and well meaning (and within which I am at most one vote-when I am on the committee) can only hire a fraction of those who are deserving under our criteria. And this is why I agree with the writer that more programs like the Marie Curie and Royal Society Fellowships would help.

43. woit says:

I’ve deleted a comment from “amused” responding to Smolin in order to terminate this particular off-topic discussion. Evidently the two are in e-mail contact and can pursue this privately if they wish.

44. This probably belongs more in the comments on comments thread but I’d like to amend my comment there and say it does seem bad when an anonymous heckler addresses a Lee Smolin or John Baez by first name only. At least amused seems respectful in this sense and going to email is even better.

45. amused says:

To avoid an impression of rudeness, can I just point out for the record that I hadn’t seen Prof. Smolin’s lengthy comment – the one addressed to Mentos, me, and Christine – at the time I posted my subsequent comment above (the one addressed to Who). Perhaps it was somehow delayed by Peter’s WordPress update, or maybe I just overlooked it. If I had seen it I would have addressed his points in my subsequent post, and its tone would have been different. But now it’s time to drop this, in accordance with Peter’s wishes.