# More Scenes From the Storm in a Teacup, VI

A quick update:

• There was a second installment of the discussion led by George Johnson about press coverage of string theory. He went back to look to see what exactly some of those early articles said… How much coverage was there to start with? When did it start? When did it begin get out of hand? Did it get out of hand? Is this all just part of a standard bubble that happens for any field that the press decides to cover, a sort of manufactured (my word not his) boom and bust cycle? All issues that were touched upon in the discussion. Note also that the discussion broadens out considerably -as it should, (finally!)- to talk about the broader issue of coverage of topics in physics and science in general. The positive and negative effects of press coverage on attracting the next generation of students was also discussed. The discussion (this aspect in particular) was especially interesting because of the remarks by a number of senior people in the audience who were able to talk about their experiences over the years having seen the cycles recruitment of students in their own departments. Worth a listen/look at the archive here.
• Lee Smolin has written a “Dear Friends” letter in response to some of the things that have been pointed out about his book, and about other points he’s made publicly in various discussions*. He’s given over some time to write quite a bit, which in general is a good thing to have done. You can find it here.

I’ll leave it to you to form your own opinion about Smolin’s remarks (I’ve not had time to read it in detail yet), and start a discussion here. Maybe ask him some followup questions here, for example. To help with context and build a more complete picture, do read some of the earlier comments and discussions involving him -and questions put directly to him- on the threads that share the name of this post. (e.g., Here and here.) Put those alongside the discussion with Peter Woit and of the central thesis of Woit’s book too. They are inseparable.

My set of opinions on the issue is the same as it was before. Even though I’ve said it all so many times here, since blogs seem to have no memory, I will summarize a bit:

• The bulk of the discussion is media hype, ironically, knowingly (in my humble opinion) exploited by the authors. I think this is harmful for the whole field of theoretical physics in this area. Once you take out the short term financial gain on the part of the authors and publishers, it does not help anyone. I don’t see how adding hype to hype combats hype. I’d really like someone to explain that to me.
• The picture of research into string theory that they paint -and then attack- is an unfair charaicature, my main criticism being that they’ve overblown the focus, and virtually totally ignored a lot of valuable work that is being pursued by a rather large portion of the field -it does not fit very well with the negative picture that they are trying to draw, you see, so best leave it out.
• They want to say that the discussion is really about the young people. They are being pressured and duped into working only on string theory, which they are sure (without offers of actual proof) will not succeed in saying anything about Nature. So they want to have a discussion about the distribution of resources. Very noble cause indeed, but carried out in the most manifestly ignoble way…. Why hide this admittedly interesting and valuable discussion inside the shell of a mischariacature and negative attack on the work of a huge number of people (including, for example in the case of Smolin, effectively ignoring and sidelining as essentially unimportant or irrelevant the valuable work of your colleague down the hall at the Perimeter Institute (see the exchange around here)), when the discussion is just not about string theory? The discussion is about the larger structure of academic careers and research priorities. If they really want to talk about that, why not write their books about that?
• Perhaps most importantly of all. If they want people to work on alternative ideas, why not present these ideas to everyone – develop these research programs to the point where people will work on them because they can see their merits? Theoretical physicists will work on the best or most promising tools out there that will do the job. We’re fickle. We don’t care whether they are loops, strings, or whatever. Just that they get the job done. Show us something more promising than string theory and we’ll drop string theory like a hot ton of bricks and work on that. So, Smolin and Woit: Please do some research that will help us get the job done by providing us with real alternatives through the usual channels which are available to everybody. The job won’t get done in the media-assisted way you are doing it right now.

-cvj

(*Thanks Bee!)

### 333 Responses to More Scenes From the Storm in a Teacup, VI

1. Blake Stacey says:

I look forward to seeing this thread inflate chaotically beyond all recognition. Unfortunately, I am behind my schedule of rants I promised to deliver to other people, so I won’t be able to contribute my own trademark blend of cynicism and ignorance.

2. Clifford says:

Uh… thanks Blake, but I think if we all try we can actually have a constructive discussion (on balance, at least). It is a matter of will. Some value can and has come out of these discussions…. It has happened before. I learned from last time for example that Smolin and Woit are just concerned about the welfare of the youth in the field. That’s what they really want to talk about. Lee goes as far as to claim that it was totally accidental that his book appears to be an attack on string theory. Ok. We could do this: Run with that for the sake of argument and have the actual discussion….

I’d like very much to hear what these youths think of this concern, whether they agree that they are being duped as claimed, and what their own expeiences are…do they see it as a string theory problem? a larger problem? I’d like to hear about their perceptions of the programs of research in physics in general.

A starter question – if in physics right now, what attracted you into it? If not in physics, does it seem attractive? Repulsive? This could be valuable to the discussion…. If that really is the discusssion.

Best,

-cvj

3. onymous says:

Iâ€™d like very much to hear what these youths think of this concern, whether they agree that they are being duped as claimed, and what their own expeiences areâ€¦ and their perceptions of the programs of research in physics in general

As a young person in the field, I find the “concern” of Woit and Smolin on my behalf rather amusing. The notion that beginning theoretical physicists are so stupid that they need to be “protected” from being led into misguided research is a little insulting. All of the smart young people I know are perfectly capable of deciding for themselves which research directions are interesting. I also find the monolithic picture of theory research that they paint a little odd. There is plenty of diversity in active research directions, but they seem to single out particular narrow directions that are not popular as evidence that the community is monolothic. Woit, for instance, seems to believe that the problem is that there are not enough formal approaches to particle theory outside of string theory. He thus avoids ever having to confront the fact that there are many phenomenologists in theory groups who are not string theorists; they are not “formal” enough for him. He also avoids ever mentioning the great strides that have been made in nonperturbative understanding of field theories using SUSY an example (he mentions Witten often enough, but surely Seiberg and Intriligator have done as much for formal, non-stringy particle theory as anyone in the past fifteen years?). In the end, it seems that his criticism of the narrowness of the community amounts to “why aren’t more people trying to study non-SUSY chiral gauge theories nonperturbatively?” The answer to that, of course is, “we’d love to, but it’s really hard!”

Anyway, I’ve written enough for now, but for any observers out there who are worried about the state of us poor helpless young people, rest assured we’re not so poor and helpless.

Dr. Johnson:

Actually I am beginning to be kind of skeptical of this notion that there is concern. The only thing I’ve ever come on physics blogs to do is to:

2. Read about interesting aspects of physics and mathematics that I might not have heard otherwise.

So, I think of myself as a ‘young’ person who would like some help. And I want to say I appreciate the books and the blogs for what they are.

But since I tend to be frank, I have to say that I don’t think Dr. Woit is all that worried about young people at all. I almost said as much a week or so ago when he said his site was for professionals. As apparently when he says this, he also seems to mean questions from students aren’t welcome.

I think it’s illustrative to contrast his blog to yours. You have pictures of yourself helping young people. You start threads discussing issues that affect young people. I would say you care about young people and it’s up there among your main interests.

I think maybe when Dr. Woit says he wants to help young people what he really means is something like he would like to kill string theory which might perhaps help young people.

Dr Smolin spent about a fifth of his book on problems that affect young people maybe a little less. It’s not zero but it’s not 50% either. I think that about quantifies things.

onymous:

“… rest assured weâ€™re not so poor and helpless.”

Some of us are more young than others and might not mind some help. (I have no idea what to work on.)

“All of the smart young people I know …”

Okay maybe this is my problem … well I guess if the smart people are okay then there is nothing to worry about.

5. Bee says:

Hi Clifford,

The bulk of the discussion is media hype […] I think this is harmful for the whole field of theoretical physics in this area. […] it does not help anyone. I donâ€™t see how adding hype to hype combats hype.

Sadly enough, I totally agree with you. What would you suggest for damage control?

Hi onymous,

The notion that beginning theoretical physicists are so stupid that they need to be â€œprotectedâ€ from being led into misguided research is a little insulting. All of the smart young people I know are perfectly capable of deciding for themselves which research directions are interesting.

I am not sure where you got that from, but it’s not how I understand Woit’s and Smolin’s concerns. Ask yourself: if a beginning theoretical physicist has the intention to start working in some field he is interested in, can he actually do so? How strongly is his decision necessarily subject to open positions, and how does that distort the spectrum of original interests? How much of his ‘interests’ are dictated by a supervisor, and his grant, or somebody else’s research proposal?

All the smart young people I know are perfectly capable of figuring out which move is career-wise and which isn’t. And, to add what upsets me frequently: how old does the smart young guy have to become before he can actually decide his for own research direction? Indeed, I’d think after 10 years of education one could trust a postdoc to work on his own projects. But that’s most often just not the case.

If your interests fall were positions are, you are a lucky guy, be glad about it. What do you tell those who aren’t as lucky as you? Do you tell them not to be stupid, and decide for themselves that your research direction is more interesting?

but for any observers out there who are worried about the state of us poor helpless young people, rest assured weâ€™re not so poor and helpless.

Great! Then go fight for your right to decide ‘independently’ what your research will be on. And keep in mind that you might not always be among those whose interests fall were the jobs are.

Best,

B.

6. Peter Woit says:

I’m not going to bother to respond to what Clifford has to say about me here, past efforts were a waste of time and I don’t see any reason that new efforts would get anywhere. But I would like to try and respond a bit to comments from others.

onymous,

I don’t think people getting Ph.Ds in theoretical physics are “stupid” and have never anywhere expressed any opinion anything like that. Neither have I ever not acknowledged that there are many particle phenomenologists in theory groups who are not string theorists.

I do think that many of the popular books aimed at a non-specialist audience that have been available often give a misleading view of the current state of particle theory and I tried to write one that didn’t. Many students have contacted me to thank me for doing so. I do think that most students are smart enough to make up their own minds, and if they read both books like Brian Greene’s, Lisa Randall’s and Lenny Susskind’s, together with mine and Lee Smolin’s, they will be exposed to some very different perspectives, which is a good thing.

My concern for the young which is being made so much of here is of a very specific kind. As you note about the problem of understanding non-SUSY chiral gauge theories: “it’s really hard”. Exactly. You can agree or not agree with my point of view, but it is that the fantastic success of the standard model and the lack of experimental results that disagree with it leave us in a situation such that to make any sort of progress is “really hard”. My argument is that the field needs to be thinking about what can be done to encourage ambitious young people to try and tackle these “really hard” problems.

I should also be clear about what I’m not trying to do, and this is partly in response to “TheGraduate”. The kind of outreach that Clifford and others at Cosmic Variance and other blogs are doing is great and should be encouraged, but what I’m trying to do with mine is something different (and the great thing about blogs is that they allow these different possibilities). It’s aimed at a much more limited audience and I’ve been surprised at how many people find it worth reading and take an interest in what is going on there. I hope to find time to do more in the way of writing expository posts about various topics in math and physics, but I’d like to aim at people who already have a background in the fields I’m concerned with.

The book is different than the blog, it was my one attempt to write for as wide an audience as I could while still doing justice to the topics I wanted to discuss. I mentioned above one of the main reasons for doing this, to provide a different perspective for students interested in particle theory. It’s also true that I think the public has over the years gotten a rather misleading view of the status of string theory and I felt that this should be corrected with a more accurate one. In this view I seem to be joined by Andy Strominger, who recently was quoted as saying: “I’ve felt for a long time that the general public’s impression of what string theory had accomplished and how much of it was correct was too positive”. I think it would have been much better if he and other string theorists had done something about this, and the fact that they chose not to means that they’re not in the best position to be complaining about my book and Lee Smolin’s.

7. Clifford says:

Hi Peter,

On the one hand you have cautionary remarks about the fact that research is ongoing and that the outcome is still to be determined, and that the string picture may or may not be wrong. I and many others constantly say this, and would dearly love it if the press printed more of that sort of thing in their articles covering this research. This is indeed what I suspect Andy was talking about.

On the other hand you have a declaration in a media storm that string theory is manifestly wrong, and that it has brought about the fall of a science, and other things that you and Lee Smolin have been saying.

These things are not the same. Do not equate them. For example, one (the former) is true, and the other is not.

Best,

-cvj

8. Holmes says:

Having agreed that media hype is not the way forward, what is?

I think that one of the things contributing to the lower morale among young people these days is the collapse of the citation market. [Look at the number of cites for this nearly-year-old paper for instance: http://arxiv.org/abs/hep-th/0512039 Imagine that 10 years ago!] End result is that young people slave away to get a paper on the arxiv….which promptly sinks like lead. Older folks, who can remember hitting 50 cites within a couple of months purely on the strength of getting into something early, might find it hard to imagine the dismay of a postdoc whose magnum opus never gets beyond single digits, a very common situation these days. I’d like to see everyone with a physics blog, particularly those concerned for the young, taking note of good papers they have seen lately, especially if it is by someone young or otherwise unlikely to be cited. It may not be as exciting as announcing the end of physics as we know it, but it might make a small positive contribution.

9. Clifford says:

Wait, hang on… what is the evidence of this “lower morale among young people these days” ? It’s been tough as long as I remember… is there some new malaise that I do not know about? I’m admittedly possibly out of touch.. but I’d like to hear from some more young people before I conclude that there is a crisis of morale.

Iâ€™d like to see everyone with a physics blog, particularly those concerned for the young, taking note of good papers they have seen lately, especially if it is by someone young or otherwise unlikely to be cited. It may not be as exciting as announcing the end of physics as we know it, but it might make a small positive contribution.

Thanks Holmes… This would indeed be rather constructive indeed. Peter Woit? Lee Smolin? How about it? Blogging can be a powerful tool…. How about forming a network, a forum, etc… encouranging and promoting those alternative ideas and those young people you consider to be struggling to work off the mainstream… a focused and constructive endeavour.

Best,

-cvj

10. Cynthia says:

Even though I fail to fit any description of any person (including either the young or the old) in the field, I – nevertheless – fall under the heading of outside observer.

Because outside observing and objectivity usually go hand in hand, I’ll contend that my point of view does carry a degree of worthiness. On top of this, because I’ve been following this media-driven backlash against strings from the get-go, I’ll further contend that my point of view carries added weight to this degree of worthiness.

Apparently, a central argument used by Lee@Peter,Inc. as a means to toughen their stance is this: diversity of ideas/thoughts is severely lacking in this quest to uncover quantum gravity. In my humble opinion, however, after factoring-in this crucial ingredient called “viability”, I’ve ascertained that – in both depth and breadth – more diversity of ideas/thoughts exist inside (as opposed to outside) the field of string theory.

Dr. Woit, Dr. Johson:

A big part of Woit’s and Smolin’s criticism of string theory has to do with job selection and grants. What criteria do you think are applied in how these decisions are made and why do you think string theory has been especially successful at dominating under these decision criteria? Why have LQG and other approaches not done as well?

12. Clifford says:

It is this way largely on the relative merits of each. Both are speculative, yes, so you have to look at the promise of the subject. String theorists have demonstrated its manifest promise, and its usefulnmess to a variety of physical problems. They done this by solving a number of theoretical problems, and being able to explain very clearly too their peers from other fields what they are trying to do, and what they have done so far. LQG people have done this less successfully for their subject. Correspondingly, fewer jobs, etc.

Bring along another set of tools with as much or more promise….. people will work on it, and there will be more resources for it. No question about that.

-cvj

13. Peter Woit says:

Holmes,

I regularly do exactly what you suggest, linking to new papers that I think deserve attention. I’m sorry, but I think the reason that string theory papers like the one you mention are not getting cited is that they’re not that significant. The collapse is not in the “citation market”, but in the intellectual health of string theory.

I think Smolin in his book gives an accurate portrayal of the problems with how decisions about grants and jobs are being made.

14. Clifford says:

Iâ€™m sorry, but I think the reason that string theory papers like the one you mention are not getting cited is that theyâ€™re not that significant.

As measured by you – An active and highly informed member of the string community, right?

Come on, Peter. That’s a highly loaded judgement, don’t you think?

-cvj

15. Bee says:

Hi There,

Before you start arguing about the significance of string theory papers based on the citation index, I would like to know what the citation index actually says in your opinion.

I.e. for whatever reason, it’s in some fields wide practice to cite every paper on related subjects, whereas others do consequently only cite papers from which they actually use results. Then there are those people who essentially add a sentence like: I am not going to discuss the approaches of Refs [15-33], and then cite all their former papers, related or not. Some cite friends and colleagues for political reasons. Some fields have more frequent meetings and therefore they are just better informed about whether someone else pursues a similar way. Also, with increasing numbers of coworkers, citations tends to add up faster (I guess because there are more people advertising the work). And so on, and so on. As long as peer review does not have any policy about which papers should or – more importantly – should not be cited, the cite index imo is not a very good criterion for anything. (The only policy that I am aware of is one of copyright).

Hi Holmes,

Iâ€™d like to see everyone with a physics blog, particularly those concerned for the young, taking note of good papers they have seen lately, especially if it is by someone young or otherwise unlikely to be cited. It may not be as exciting as announcing the end of physics as we know it, but it might make a small positive contribution.

The problem that I personally have with this is the short attention span in the blogosphere. It takes me some while, sometimes quite a while, to read, understand and being able to judge on somebody else’s work. I am very hesitant to advertise papers I haven’t fully understood, and I don’t want to distribute semi-knowledge. If I finally come to like somebody’s work, that might not be a paper that would fall under your criterion of ‘seen lately’. I have a long list of papers that I could tell you are NOT worth the time reading, but maybe I’m too nice a person to write that on my blog.

One way or the other, I don’t think the blogosphere is a good place to form an opinion about other people’s scientific work. That finally brings me to …

Why have LQG and other approaches not done as well?

One thing that other approaches haven’t done as good as string theory is causing excitement.

Best,

B.

16. anonymous says:

Holmes:

Your comment about high quality papers by young people *sometimes* not being highly cited is not a new
phenomenon. This happened also to people who entered the field in the late 80s and throughout
the 90s. For instance, can you imagine any paper NOT about AdS/CFT hitting a high citation meter
between 98 and 2001? (I am sure there were a few; but my point is that so many theorists were on
a certain bandwagon that it surely distracted attention from other important developments).

This is not necessarily a bad thing. In the case of AdS/CFT, this was a merited intense focus on a
truly revolutionary insight. In other cases, such bandwagon effects are perhaps driven by little
other than sociology. It seems to me that one very healthy sign for string theory research is that
there are now several interesting developments being pursued simultaneously, and that no one
subject is dominating the “marketplace” of ideas within string theory. AdS/QCD is being developed,
string compactification (and…dare I say it…study of the landscape) is being developed, study of singularities is proceeding, string cosmology is getting ever closer to realistic models…to me this is much healthier than a situation where everyone works on non-commutative QFT for 1 year, or whatever.

If you are going to succeed in this field, you need to have a thick enough skin to persevere when
papers of your own that are of high quality, seem to fall on deaf ears. This happened to many theorists early on, and many of them are quite successful now. In fact, it is hard to find anyone who doesnt feel
that his/her papers are always falling on deaf ears (even if widely cited; many citations tend to miss
the point of the works they cite almost completely, in my experience). Keep in mind that experienced theorists who will be judging job applications, at least at the best places, can tell the difference between
a third rate “trendy” paper that is cited 100 times and a quality piece of work that is less well known.
You are better served (both for your own sanity, and your future prospects) by writing the latter.

17. Peter Woit says:

Clifford,

The discussion is about why recent string theory papers by well-known string theorists are not being cited by other string theorists. I think this is the most objective measure available of string theorist’s evaluation of the significance of each other’s work.

18. spacepig says:

Peter:

seem to be frequently appearing on the arXiv and citing each other. A comparison of citations
of some of the latter works shows a similar hit rate to e.g. Strominger/Vafa on black holes, or
the other duality revolution papers. (It is early to do this for AdS/CFT and RHIC since it just took off).
Of course none of these matches the original AdS/CFT paper, but that means that was an
exception, not that the field is quiet when no paper is cited at that rate,.

Actually, if you watch hep-ph, what you say is more true. It is a bit quiet. The model builders are
taking a collective break from model building, by and large, it seems.

The reason is actually quite clear in that case: there is going to be data soon, and a lot of the
relevant ideas that will need to be combined to explain it, are already (many people think) out there.
So it makes more sense to invest in other research directions for a bit, and wait for the data to come.

Your perverse attack on string theory (and Smolin’s) was cynically timed just right: two years before
LHC turn on. No one can say that experiment has confirmed the ideas inspired by strings (or worked
on by people who also understand and support string research), and for two years, people can debate
your book instead of focusing on the real, exciting physics to come. It is hilarious that you have
managed to make this, the most exciting time in particle theory/cosmology in the past 25 years (due
to data!), seem like a low period. Congratulations. Thats a real intellectual service.

19. Peter Woit says:

pig,

Look at the numbers of citations that recent string theory papers are getting, and compare to the numbers that string theory papers of similar age were getting before 5-6 years ago. Among the very few recent string theory papers getting a lot of citations is the KKLT paper, and that’s a sign of the sickness of the field, not its health.

“the most exciting time in particle theory/cosmology in the past 25 years”

I virtually never comment on cosmology, other than to say that it has been an exciting time for cosmology in recent years. As for particle theory, the only thing exciting about the current time is that there’s a hope that because of the LHC it will be over in the not too distant future.

“cynically timed just right: two years before LHC turn on”

My book was mostly written in 2002, cynically timed to appear in 2003, 5 years before LHC turn on. The actual timing of its appearance was determined by the fact that this was stopped by string theorist referees.

And what is it with string theory partisans, do you really think it is professional or ethical behavior to publicly attack people from behind the cover of anonymity?

20. Blake Stacey says:

Clifford wrote:

Wait, hang onâ€¦ what is the evidence of this â€œlower morale among young people these daysâ€ ? Itâ€™s been tough as long as I rememberâ€¦ is there some new malaise that I do not know about? Iâ€™m admittedly possibly out of touch.. but Iâ€™d like to hear from some more young people before I conclude that there is a crisis of morale.

I’m a young person who’s traveled around meeting other people, young and old (the Wandering Physics Student, as it were). I haven’t noticed a real malaise among my coevals — not among the string people, the neutrino people, the nanoparticle people or the biophysics people. Maybe I’m living in my shell too much?

21. Clifford says:

Peter,

Even as someone who has been active in string theory for [14] 16 years, I would not have the gall to claim that the papers currently being written are not significant. First, I can’t read all of them, and second, I’m not qualified to make that determination, and third…. It is very well known that the significance of a huge number of papers is not often not recognized until very many years later. Sometimes decades. You have some idea of how science proceeds, I think, so I’m pretty sure you must know that. So why would you -especially as someone who is outside the field- feel able to say such a bizarrely unsubstantiated sweeping statement? It would be like me claiming that about the analogous papers in theoretical condensed matter physics!

On the other hand, it’s not dissimilar to your claim that there is “well known proof” that string theory can make no contact with experiment… proof that we’re all still waiting for you to supply for us. So maybe your statement is in keeping with that level of rigour?

So (1) How do you know that these papers are not significant? and (2) How are you defining “significant”?…. since maybe that is the source of my misunderstanding/incredulity.

Cheers,

-cvj

Dr Johnson:

You pointed out that string theory had been judged on its Merit. But in part you seem to have acknowledged something of a popularity contest in that string theorists have been able to win over people from other fields to their side. How do you reconcile these ideas?

Secondly, the idea of “solving a number of theoretical problems” has been a huge bone of contention in these debates. How would you define ‘solving’ ?

Dr. Woit:

You said that you agreed with Dr. Smolin’s view. Luckily I have read Dr. Smolin’s book carefully.

I would summarize Dr. Smolin as saying that string theorists are quite established on funding boards and they also are quite powerful in many of the most prominent physics departments. They also naturally have a tendency to promote people like them. Therefore, other quantum gravity approaches are locked out.

I am trying to picture what kind of system you would like to replace this. My question is whether you would replace this with another kind of monopoly where scientists like yourself are more empowered? You can imagine that you might consider some approaches as idiotic and not want to include them in your more diverse area. Similarly, string theorists might have a low opinion of your ideas and not want to include you. In other words, would you replace the string theory monopoly with a ‘quantum gravity’ monopoly where quantum gravity means a group of fields acknowledged by you or Smolin or people like you.

Bee:

So you think string theory is simply more popular. Do you think there is anything wrong with this system? And if so, how would you change it?

23. Peter Woit says:

Clifford,

You’re not responding in any way to what I wrote, did you read it?

“The discussion is about why recent string theory papers by well-known string theorists are not being cited by other string theorists. I think this is the most objective measure available of string theoristâ€™s evaluation of the significance of each otherâ€™s work.”

If you know of a better objective measure of what string theorists think of the significance of each other’s work other than how often they use it and cite it, let us know. What I’m quoting to you here is not my judgment, but that of the community of string theorists. Maybe you think they’re kind of slow and unable to recognize significant work by well-known people in their own community.

I’ve never said anything about “proof” that string theory can make no contact with experiment, that’s not a word I would ever use in this context. You completely ignore what I do write, and make up something I never said to argue with. It’s a complete waste of time to try and have a discussion about any of these issues with you.

24. Clifford says:

Peter,

I *did* read what you wrote, and I still question your or anyone’s ability to claim so broadly that papers in a field (whoever they are written by) are not significant. Could you tell us who some of this “community of string theorists” you cite might be?

If you know of a better objective measure of what string theorists think of the significance of each otherâ€™s work other than how often they use it and cite it, let us know.

Using that single measure -which is affected by so many obvious variables- without taking account of other variables is incredibly naive, Peter. Consider for example the fact that the field has changed its working practices quite a bit.. there are several more topics being worked on by more people, and the details of previous breakthroughs are being worked out … all of this takes hits away from papers in terms of citations. Peter, this represents a *healthier* state of the field than if everyone is just all working on the same thign and citing the same few people. Come on, you *know* this. It is precisely the non-fad-driven behaviour you claim that you want to see more of!! Why are you using evidence of that diversity to claim tht the field is dead? This is a poorly constructed arguemtn that’s falling apart before you’ve even set it upright.

And on the other thing… I did not make that up. We spend an entire thread trying to get you to back up your claim that it was “well known”… but instead of telling us what it was, all you did was throw a hissy fit and retreat to your own blog to hurl insults, accuse me of doing things, etc. Not good.

Please let’s stay on topic. Every time I try to press you on something you said – to back it up with further argument, or some actual facts – you decide to claim that I am ignoring what you say or being impolite, etc, and that it is a waste of time to argue with me…. Why is that?

-cvj

25. Peter Woit says:

What I’m trying to do is to publicly put forward arguments about what the current state of particle theory is, get people to take them seriously, and see if I can convince them that the current situation is problematic and something should be done. It’s then up to them to take appropriate actions . What’s really upsetting string theorists these days is that they’re not happy at all with how much success Smolin and I have had at getting people to agree with our points of view (which are not the same, for one thing, my interest is in particle theory, not especially in quantum gravity).

26. Clifford says:

Peter,

Additionally, for the record, you might not have used the word “proof”, but i think you implied the physcist’s equivalent of it in your October 6th 2006 statement here:

Iâ€™m not telling you my â€œintuitionâ€ says you canâ€™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.

… and is the entire thesis of your book, from the title “Not Even Wrong” onwards, not an implication of your certainty? I still want to know the basis for your certainty about this…. (even though, I remind everyone, the theory is still being worked on.. is not even satisfactorily formulated, etc, etc.) Once again… I don’t mind you claiming that you have a feeling that it might be wrong…. but to claim that you know, that the reasona are well known, that an entire field continues working nevertheless – especially to the general public… That’s a lie. That is why I press you on this point, and why you collapse every time under this pressure.

Best,

-cvj

27. spacepig says:

Peter:

My limited understanding is the following. The KKLT paper and other related ones (both earlier and later) are well cited for what seems to me a good reason: the data supports a positive cosmological constant and absence of massless scalar fields. Solutions with these properties were not known before, and the KKLT paper (and the others) argue for their existence. That seems like good physics to me and that is why the papers are well cited. It is hardly a sickness of the field, to realize what remaining problems in making contact with real world physics are, and move aggressively to try and solve them.

It is of a course a goal distinct from your interests in mathematical physics of Dirac operators, but that is neither here nor there. The subject will not revert to the 1970s regardless of what happens to string theory.

Some smaller subgroup of these papers also describe the so-called “anthropic principle.”
I am no lover of anthropic principles, but that is a different story, and finding good solutions of string theory with more realistic properties seems to me one of the major goals of the subject. Or if its not, I would really like to know why, since to an outsider it seems like it should be one of the main goals! (Also, as Sean always points out, dislike of the anthropic principle does not necessarily make it incorrect — so even those papers, may really have value in the end).

28. M says:

spacepig,

can you tell what is exciting in particle theory in this period?

I think that it is preferable to say that, despite some good attempts in doing theory without data, particle physics will become really interesting only in 2009/2010 when first LHC data will be released.

29. Peter Woit says:

Clifford,

For about the 100th time, I described in detail what some of these obstructions are here:

http://www.math.columbia.edu/~woit/wordpress/?p=473

and I referred you to Michael Dine’s talk where he goes over the same obstructions, see

http://online.itp.ucsb.edu/online/bblunch/dine/

There’s also a more recent talk by Wati Taylor explaining the same issues:

http://www.phys.hawaii.edu/indico/contributionDisplay.py?contribId=96&sessionId=168&confId=3

If you have any idea other than invoking wishful thinking about what to do about these problems, which I’m claiming are deadly for attempts to connect string theory to experiment (and explain why no one has been able to do this), let’s hear it.

About the validity of the number of citations by people in the same field as a measure of how significant they think a paper is. Yes, it’s an imperfect measure, but I don’t know of a better objective one, and you don’t seem to either. If you do, let’s hear it, and see what it says in this case.

Pig,

As discussed in the above places, the problem with “finding good solutions of string theory with more realistic properties” is that people have found that as they try and do this they are forced into more and more complicated constructions, ending up with a framework that can’t be used to make predictions.

If you actually want to have a serious discussion, you should stop hiding behind anonymity, and from that protection saying stupid things about how how I want to “revert to the 1970s”.

30. spacepig says:

M,

I really meant what you say: the excitement is anticipation of what will be measured soon.

But I note that really exciting new ideas (large extra dimensions, randall/sundrum, little higgs models,…)
were developed in the past few years. None have the 20+ years of development time of SUSY and all seem more problematic, but one may well turn out to be correct.

And of course, the evidence for neutrino masses is exciting; as are the developments in understanding the phase diagram of high density QCD at RHIC. I would call both of those developments in particle theory.

If you also include “real” cosmology, the list of interesting developments grows, since inflation has become almost a precision science with more constraints soon to come. And many of the particle theorists (arkani-hamed, dimopoulos, randall, etc) also work on those models. Along with string theorists (kachru, maldacena, polchinski, silverstein, tye…).

31. spacepig says:

Peter,

The error dine and taylor make in their thinking, is that one should “derive” the low energy world
from string theory. No one “derived” the low energy world from QFT, and it is a tremendous success.
The fact that dine and taylor see obstructions to their goal does not mean there is an obstruction to
connecting string theory with reality, it means they have chosen a bad goal. Almost any physicist with moderate common sense would immediately see this distinction. Branding string theory a failure because of this, would be like calling optical physics a failure because we cannot make lasers that make the “Star
Wars” missile defense program practical, or calling nuclear physics a failure for not attaining “cold fusion.”
Failure to attain impractical goals (however desirable) is never surprising, and more practical goals are
often within reach.

In that spirit, there is plenty of progress in string theory now, and the obstructions you cite are red
herrings, obstructions to attaining a goal that few serious physicists would think possible anyway.

Dr. Woit:

Would it be fair summarize your approach as an attempt to reduce the influence of string theory by political means?

Dr. Johnson:

Sorry to be repetitive but when you broke down the idea of merit, one of your points was that string theory had garnered the respect and enthusiasm of people outside the field and that other approaches had not done so. Isn’t this in a way a popularity contest and how do you reconcile that state of affairs with the idea of Merit.

Your second point was that string theory had solved theoretical issues in other fields. This notion of solving has been higly contentious. How do you define ‘solve’ in this instance? Has there been an instance where a whole field has adopted a string theory approach to something and has progressed in their own goals as a field because of this?

33. Clifford says:

You pointed out that string theory had been judged on its Merit. But in part you seem to have acknowledged something of a popularity contest in that string theorists have been able to win over people from other fields to their side. How do you reconcile these ideas?

You did not have to repeat.. I was writing a long response for you…. see below:

Call it a popularity contest if you like. I call it “making your case”.. this is how things work. You are trying to get someone to give you some money…. you make the case for it, and someone else makes their case. The money-giver makes up their mind on the basis of the case….. This is what everyone reasonably calls “the merits of the case”. I don’t see any other way of doing it. Call it a popularity contest if you will, but that’s just obscuring the realiteis of the situation.

Secondly, the idea of â€œsolving a number of theoretical problemsâ€ has been a huge bone of contention in these debates. How would you define â€™solvingâ€™ ?

A huge bone of contention? Really? I’d challenge anyone to dispute even the rough list I compile below:

Before string theory as an idea or as an approach to some problems, there were all sorts of remarkably interesting questions that were posed about a huge variety of theoretical problems. After work in string theory work so far, we have so many new insights, new tools for computing things we could not compute before… in other words, answers to those questions. This is how I define “solving”. (E.g.1 black holes behave like thermodynamical objects… what is the underlying microscopic reason for this, analogous to what happenes in the rest of physics? The answer is well known in string theory for a large class of black holes. Solved. Lots more to do.. but solved in terms of giving totally new insigths and mechanisms for a theoretical physics problem. E.g.2 At strong coupling, some gauge theories exhibit confinement….flux tubes might form with a certain tension… what are the criteria for this? Why does it happen? This is important. How to describe this directly, and get numbers out? String theory gives you a very good set of techniques for doing this for a wide class of gauge theories… tells you how to make the flux tubes out of string.. tells you how to compute their tension…. get real numbers out…… etc etc…. Solved. Lots more to do.. but solved in terms of giving totally new insigths and mechanisms for a theoretical physics problem.)

Quite long list continues here, and it is just a start:

• Providing a quantum theory of gravity that is *actually recognizable* as one (i..e, you can find spacetime, gravitons, the weak field limit, etc….)
• Providing a very specific way in which quantum gravity works in conjuction with the other forces.
• Providing a microscopic underpininng to the remarkable fact that when you add gravity and QM, black holes behave thermodynamically.. for a large class of black holes….(see above’s breakdown)
• Providing several ways of understanding and computing properties of strongly coupled gauge theories ….. there is a huge list of facts just on this point alone…..(see above for one aspect)
• Providing several qualitative and quantitative hints about the non-fundamental nature of spacetime in a theory of quantum gravity (somethign that had been speculated about a lot long before strings came along)….. this starts as far back as the conformal field theory approach to strings, early phenomena like T-duality, and continues wtih matrix models, mirror symmetry, S-duality, matrix theory, AdS/CFT, etc…. Another huge list of specific questions and answers can be inserted here….
• Providing a remarkably efficient computational framework for scattering amplitudes in gauge theory.. with direct applications for the theories we use to currently address experiments… (another long list of things here)
• Long list of remarkable and beautiful mathematical applications can be inserted here…

I could go on. Now, let me stress here:

(1) I am not saying that there are other approaches that do not address some of the above questions here. You asked me about strings, and this is what I know and have addressed.

(2) We do not know whether any of these things have anything to do with our world…. that succesful quantum gravity conceivably might not turn out to be *our* quantum gravity for example…. but as a list of things where significant progress has been made in so many theoreticsal physics topics by a single framework….. you must agree it is very impressive. This is why it is regarded as “promising”. This is also largely why young people flock to it (rather than being purely about pressure as is claimed by Woit and Smolin)… and lastly, and to get at your question: This long list all contributes to demonstrating “merits” when making the case for funding….. or , if you prefer, the “popularity contest”.

Cheers,

-cvj

34. Clifford says:

Peter,

Once again, let me point out that your blog post does not constitute a demonstration of firm knowledge on your part or anyone’s that the far from unfinished research into the poorly understood thing called string theory will result in no experimental contact with nature. Not even close. And see spacepig’s points about Dine and Taylor.

Saying that you are sure of a result does not make it a result.

Let’s just set this out clearly:

(1) Your position is that you -having never worked in the field- know absolutely for sure, before the research is done (even though the research program is remarkably healthy…. despite your awfully shaky and naive argument abotu citations to the contrary) and so research should stop.

(2) My position is that I do not know one way or the other (and I actually *work* in the field)… I’d dearly love to know the answer…. I’m letting people get on with their research (which has had so many great spinoffs in the meantime).

Don’t you see something odd here?

Best,

-cvj

35. Plato says:

Clifford:Once again, let me point out that your blog post[Peter Woit’s site] does not constitute a demonstration of firm knowledge on your part or anyoneâ€™s that the far from unfinished research into the poorly understood thing called string theory will result in no experimental contact with nature.

In brackets, my addition and reason why, in bold. The very exercise has not be “without it’s science” in relation?

Before the onslaught of this “opposing views and string wars,” presented by Peter I was looking for those who could help, “negative or otherwise” paint some kind of picture of this “theoretical view” which would have “some possible relation” to reality.

How are the physics in relation?

Instead, “the tone itself” arose above the reasons why? Does a disservice to the “critical analysis” of why this model may not be good model of approach?

Regardless of the view I may portray, it has been fun learning, and by going to the leaders in this research, how else could us poor lay persons learn without having the insults dominate the reason, that this may not be a good avenue for research?

So by Bee and yours example, those who stand and face this kind of thing I appreciate the learning that has been placed before us, and do find, “blogging of extreme value,” where some may not think so. Even in light of, Peter’s bloggery work.

We are all entitled to our opinion even at Peter’s Site? The “string evangelistic war” is working itself out. 🙂

36. Holmes says:

A lot of interesting points raised…..
CVJ: OK, maybe morale is better in your neck of the woods. Hereabouts there is a bit of a feeling that there is not much happening *now* that is very exciting. Clever ideas come up and then seem to sink with disturbing rapidity. People don’t like the feeling that if they work on something for a year, by that time the whole approach has died out. In that sense I have never agreed with the idea that [adequately long-lived] bandwagons are a bad thing. Well, like life, they seem bad until you consider the alternative. Anyway I do feel that it is the young people who are most affected, particularly those who are in small groups. Seeing their paper discussed on prominent blogs [like this one…] might be helpful, even if the discussion is critical [but civil]. Most people would rather be criticized than ignored.

Bee said:

Hi Holmes,

The problem that I personally have with this is the short attention span in the blogosphere. It takes me some while, sometimes quite a while, to read, understand and being able to judge on somebody elseâ€™s work. I am very hesitant to advertise papers I havenâ€™t fully understood, and I donâ€™t want to distribute semi-knowledge.

And you call yourself a blogger? 🙂 I think it’s ok to post something like, “Last week Dr Frankenstein posted this really interesting paper where he claims that the theory of left-pseudo-heaps permits a calculation of the cosmological constant. I don’t understand that, because I thought that only right-pseudo-heaps can be paraholomorphic. Anyone know what he was talking about?” You never know, Dr Frank might write in to explain. And surely Dr Frank, working alone in the University of Outer Boratistan, will be delighted to be reassured that somebody looked at his paper.

If I finally come to like somebodyâ€™s work, that might not be a paper that would fall under your criterion of â€™seen latelyâ€™.

Better late than never.

I have a long list of papers that I could tell you are NOT worth the time reading, but maybe Iâ€™m too nice a person to write that on my blog.

Maybe. 🙂 But let’s leave such judgements to referees, we all know what a good job they do of it……….

One way or the other, I donâ€™t think the blogosphere is a good place to form an opinion about other peopleâ€™s scientific work.

No indeed. But it might be a good place to find out what people are *thinking* [rightly or wrongly] about other people’s work. Dr Frankenstein will suddenly realize that he was mistaken in thinking that everyone is familiar with pseudoparaholomorphicity. Somebody else will be relieved to find that he is not alone in secretly believing that the anthropic principle is closely related to certain functions of the mammalian alimentary canal, and that his words to that effect in his recent preprint will not instantly brand him as a crackpot. And so on.

Dr. Woit:

I assume you agree with the process by which string theory attained dominance that Dr. Clifford outlined. He points out that this is a normal way to do things in academic circles. Would you agree that alternative views have thus far simply done a bad job of promoting themselves?

38. Clifford says:

Holmes,

Stop what you’re doing right now and write up that paper on pseudoparaholomorphicity! It sounds *great*!

-cvj

39. Clifford says:

TheGraduate… Be sure to realise that it is not that researchers in string theory are better promoters to their peers deciding on funding, jobs, etc…… it is that they seem to have had rather a lot or good results to promote, as you can see by looking at the partial list I gave. I’m sure if alternative approaches had a list like the one I gave above, they’d have a lot more people working on them.

That’s the point. Ideas followed up and supported on the merits of the idea… a list of convincing results, and credible promise of more to come. If others do that with their ideas, they will get support. The claim that this is all about peer and other pressure and nepotism, as is trying to be claimed by Woit and Smolin, is vastly inaccurate.

-cvj

Dr Johnson:

I am curious to hear your opinion about what the output of theoretical work is.

I would consider the the ideal output to be explanatory power and the verification of explanatory power via verified predictions.

I have started to sort of hear other criteria such as consistency of the theory (I have my doubts about this. After all, “Lord of Rings” is pretty consistent but not very useful as a theory of physics. Alternatively, quantum mechanics and relativity are not consistent and yet make for good predictive physics.)

I guess what I am trying to do here is understand the epistemological basis for how you would rate and categorize the achievements of string theory rather than specific achievements which are a bit hard for me to digest as they are completely out of my realm to judge.

41. Clifford says:

Hi,

I would consider the the ideal output to be explanatory power and the verification of explanatory power via verified predictions.

I have started to sort of hear other criteria such as consistency of the theory (I have my doubts about this. After all, â€œLord of Ringsâ€ is pretty consistent but not very useful as a theory of physics. Alternatively, quantum mechanics and relativity are not consistent and yet make for good predictive physics.)

Wait. I am not aware of any inconsistent theories which are predictive. The two you list are not in that category. They are consistent in all places when deployed correctly in their realm of applicability. When they break down is a different issue… In my opinion that is not an issue of inconsistency.

I guess what I am trying to do here is understand the epistemological basis for how you would rate and categorize the achievements of string theory rather than specific achievements which are a bit hard for me to digest as they are completely out of my realm to judge.

I’m going to stick with the specifics, if you don’t mind. You asked me what things were used by people working on strings to convince a peer review panel, etc, to send financial support their way. I told you. I want to stick to that issue this time. I addressed the issue in the terms that would be used in that context. To use other terms would have been mistleading. I have neer seen the phrase “epist….cal basis” (I can’t even spell it) used in the context of deciding who gets research money in *physics*, and frankly, I hope I *never* see it in that context. Concrete pragmatism is what applies here, and rightly so.

As to the meaning of the thigns I talked about. You need to learn about them to understand the debate. There is no getting away from it. My best advice is to read up on the things I mentioned, and then form your own opinion that way. It is by *not* sticking to specifics that the substance gets lost in the rhetoric. Woit and Smolin’s campaigns have been able to seed and sustain this media storm largely by engaging in rhetoric, and staying away from the substance. If the public knew more of the substance, they’d see this all for what it is…. nonesense. But as they are largely not in a position to asses the actual facts, such as the merits of the research programs under discussion, it just sounds like people arguing technical details over their heads and then the “outsider vs the establishment” darling aspect can get a foothold, as it is the only thing they can relate to. So I’m not going to play with phrases like “epist….cal basis”. I’m just going to offer the raw facts and hope that you’ll see the sense in trying to do a bit of research on the ideas and successes I talked about in detail, and judge for yourself why people consider string theory such a promising theoretical framework.

Once again… if someone wants to get more research done on other frameworks, they should supply their own list of reasons why those frameworks are more compelling… not write books publicly attacking made up pictures of the research of others.

Best Wishes.
-cvj

42. Holmes says:

I have spectacular new results on pseudoparaholomorphicity and its application to the decay of metastable DeSitter into *exact* Minkowski, but the margins of this blog are too large to contain them.

Hello Dr. Johnson,

I hope I am not being too difficult.

Perhaps I should clarify that I am asking my questions from a journalistic stand point of getting to the bottom of the story. As a science student, I would of course want to read the specifics if I eventually decide to go into quantum gravity or particle theory. Though to be honest, as you said, pragmatism should be primary and given the job situation and the current nastiness, it seems a bit unpragmatic to go into a field that might get severely defunded over the next few years. But of course, there is nothing that stops me from reading and thinking about string theory on my own time.

I should also add that I am curious about the sociology as well as the science, what people think is important, what people value etc. I think it might be helpful in graduate school.

45. Clifford says:

TheGraduate:- Thanks. I think I’ve answered. What people think is important, and the end of the day is “what is the best tool to do the job?”. They then take the tool and do the job. That’s allwe are looking for:- the best tool for the job. The strings approach seems to be the most promising tool so far. That may change, with further research. Or it may well be fashioned into a powerful tool for studying nature when we understand it better. Nobody knows. It is *so* exciting to be part of the quest to find out.

Best,

-cvj

46. M says:

Clifford,

you should not write that Peter and Smolin have success only among outsiders who cannot understand the substance. And why do you want that Peter makes a formal proof that string theory is useless? If you want to pursue strings (or any other approach), it’s you who has to show that it can be interesting.

String theory seemed intersting many years ago, but nowadays the main hope seems that not-well-defined landscape statistical distributions, when restricted by not-well-defined anthropic considerations, might turn out to be so peaked that observing a single event (our vacuum) is enough to test string theory. At this point somebody has to try this, altough it seems a desperate attempt, not a promising approach.

If you or “spacepig” think that this is not the only game in the string town, it will be interesting to hear your better concrete proposals for making connection with physics.

(As an aside remark, I guess that the “efficient computational framework…” you mention among successes of string theory is twistors. However, it is not used in practical applications because techniques previously developed by QCD people turned out to be computationally more efficient, despite being less famous).

Dr Johnson,

You said “Thatâ€™s all we are looking for:- the best tool for the job.”

Would agree that this is all that Drs. Woit and Smolin are doing also?

48. Clifford says:

M:- Feel free to go on and on about the landscape. In the meantime, the field works on many many aspects of string theory in addition to that, making lots of progress, as I’ve said before. Also, see my earlier remarks in detail about why Peter’s claims need to be backed by actual substance, as opposed to words. I’ve made all the points rather clearly by now. As to your last paragraph… you are entirely missing the point of the list that TheGraduate asked me for.

Thanks.

-cvj

49. Drei Bein says:

The error dine and taylor make in their thinking, is that one should â€œderiveâ€ the low energy world from string theory. No one â€œderivedâ€ the low energy world from QFT, and it is a tremendous success. The fact that dine and taylor see obstructions to their goal does not mean there is an obstruction to connecting string theory with reality,

I do not quite understand this, doubtlessly because I’m ignorant.

I would say that the connection between QFT (in particular, the SM) and the “low energy world” is pretty well understood, though not always in a fully quantitative way. In some cases the relation between the SM and low energy physics is fully quantitative, for instance in the computation of relativistic corrections in atomic and solid state physics, weak processes in atomic and nuclear physics, and some strong processes in nuclear physics.

If, on the other hand, relating string theory to the low energy theory is not considered a realistic goal by string theorists, or if there are obstructions of principle, then I don’t see how we can hope it will ever make contact with experimental data.

50. onymous says:

M wrote:

(As an aside remark, I guess that the â€œefficient computational frameworkâ€¦â€ you mention among successes of string theory is twistors. However, it is not used in practical applications because techniques previously developed by QCD people turned out to be computationally more efficient, despite being less famous).

This might be a “depends who you ask” issue, but given that Zvi Bern and Lance Dixon have been doing QCD calculations for many years and seem enthusiastic about the twistor stuff, I wouldn’t be so quick to dismiss it. It’s true that there were computationally useful recursion relations already in existence (hence codes like Alpgen), but I’m pretty sure the Britto–Cachazo–Feng on-shell recursion relation is currently the most efficient way to compute tree diagrams. There was an existing on-shell recursion / unitarity method from Bern et.al. for loops, but the tree diagrams with many particles are much easier now. This has fed back into the loop-level stuff. Now, it’s true that the BCF recursion relation doesn’t really involve twistors, but it did emerge from the milieu of string theorists focusing on perturbative techniques after Witten’s twistor paper. Anyway, while it certainly can’t be claimed that the technique has revolutionized the way people are calculating collider backgrounds, for instance (though it might help Bern et.al. or other groups with certain difficult NLO predictions that have not yet been computed), I think it’s clear that it’s produced interesting insights. The fact that amplitudes are supported on simple curves in twistor space is pretty cool regardless, no? It seems like the recent work on perturbative QCD is leading to lots of odd and poorly-understood observations, which hint at deeper underlying structures. I do think the utility of these things for the LHC was initially blown out of proportion a bit, but nonetheless it’s interesting, and it is certainly possible to imagine that in the future techniques like this will dominate the way we calculate.

51. M says:

onymus: table 1 of hep-ph/0602204 shows the speed of the old (1988) Berends Giele recursion, compared to recent alternatives: when things get tough it is faster than everything else, including BCF. Furthermore, I believe that present tools are already enough for understanding LHC data.

Clifford: I don’t go on and on about the landscape because I am a fanatic, but because it seems to me that whatever you do in the meantime, at the end you will have to deal with it, and it will be the problem.

Dr Johnson,

Well, thanks for answering my questions. The only thing left to do now is to study hard so I can join you and the other physicists and be part of the quest. It’s kind of scary though, the idea of spending so much time and money only to find out there are no jobs. It weighs on my mind.

I do agree with you that when figuring out good science, only the specifics can really matter and clearly nobody likes the current disconnect with experiment.

53. Bee says:

Bee:

So you think string theory is simply more popular. Do you think there is anything wrong with this system? And if so, how would you change it?

No, its not that simple. But there’s no doubt that string theorists have done a better job getting their work across to a broader public than other Theory-of-Everything-Related-Program-Activities. I think communicating what we do is an important part of our job and shouldn’t be neglected. For this reason, I like Peter Woit’s and Lee Smolin’s books very much. However, from the scientific side, writing a book and causing excitement isn’t sufficient. And I don’t think it’s the right way to lead this discussion.

But leaving aside the String/Anti-String issue, yes, I think there’s something wrong with ‘the system’ – not exclusively with string theory though. I’ve extensively commented about that elsewhere, and I’m currently not in the mood to repeat it. See e.g.

or some recent comments on NEW. In big parts I agree with what is written in Lee Smolin’s book, last part.

@Holmes

And you call yourself a blogger?

I like to call myself a scientist who happens to write a blog.

I think itâ€™s ok to post something like, â€œLast week Dr Frankenstein posted this really interesting paper where he claims that the theory of left-pseudo-heaps permits a calculation of the cosmological constant. I donâ€™t understand that, because I thought that only right-pseudo-heaps can be paraholomorphic. Anyone know what he was talking about?â€ You never know, Dr Frank might write in to explain. And surely Dr Frank, working alone in the University of Outer Boratistan, will be delighted to be reassured that somebody looked at his paper.

If that’s the case I don’t put it on my blog, I send an email to Dr. Frankenstein asking him to explain what I didn’t understand.

I have a long list of papers that I could tell you are NOT worth the time reading, but maybe Iâ€™m too nice a person to write that on my blog.

Maybe. But letâ€™s leave such judgements to referees, we all know what a good job they do of itâ€¦â€¦â€¦.

well… yes… actually a considerable fraction of these papers are papers I had to referee at some point… and again, I wouldn’t put that on the blog…

One way or the other, I donâ€™t think the blogosphere is a good place to form an opinion about other peopleâ€™s scientific work.

No indeed. But it might be a good place to find out what people are *thinking* [rightly or wrongly] about other peopleâ€™s work. Dr Frankenstein will suddenly realize that he was mistaken in thinking that everyone is familiar with pseudoparaholomorphicity. Somebody else will be relieved to find that he is not alone in secretly believing that the anthropic principle is closely related to certain functions of the mammalian alimentary canal, and that his words to that effect in his recent preprint will not instantly brand him as a crackpot. And so on.

No. I don’t think scientists should distribute publicly what they are *thinking* [rightly or wrongly] before they have really thought it through. That’s okay if you do it in a discussion with your colleagues who know that you are just trying to sort out your thoughts. But it’s not okay to babble around in front of an audience who is likely to respect your opinion because it considers you an expert. Worse, without doubt, the blogosphere triggers fast judgements that get easily amplified by being echoed back and forth. This is NOT a good way to do science. If you want to convince me that your work is interesting, you’ll have to come up with something better than a praising blog piece.

There are cases though in which online discussion can work very nicely, e.g. in some cases a blogs or a forum can be very useful to discuss a paper, and clarify its content. If moderated wisely, I think that’s a good development.

Best,

B.

Bee:

Thanks. I will read the threads you’ve pointed me to. It’s hard to read someone’s whole blog to get an idea of what they think about specific things but when they point you to a page or two, in my book, that’s good enough.

55. Plato says:

Bee,

Us “lay people” always find it interesting, and some will ask, “what use any of this stuff?”

Well, I think all you have to do is ask them if they like to eat, “Campbell’s tomato soup?”

More on name. More on the experimental science? 🙂

56. Lee Smolin says:

Dear Clifford,

Thanks for discussing this. Let me respond to your main challenge, which comes at the end of your piece. â€œIf they want people to work on alternative ideas, why not present these ideas to everyone – develop these research programs to the point where people will work on them because they can see their merits?â€¦ do some research that will help us get the job done by providing us with real alternatives through the usual channels which are available to everybody.â€

Of course, I agree, what we seem to disagree about is whether the work that has been done till date on manifestly background independent approaches to quantum gravity doesnâ€™t pass the threshold of â€œproviding us with real alternatives.â€

In fact, there is a lot of work in this area with a number of key results in the last few years.
Among them are: 1) the derivation of the graviton propagator in 4d spin foam models by Rovelli et al, 2) the derivation of an effective field theory on a non-commutative manifold from a 3d spin foam model with matter, 3) the evidence for the emergence of 3+1 spacetime from a causal dynamical triangulation model by Ambjorn, Loll et al, 4) the discovery of emergent matter degrees of freedom in quantum gravity models by Markopoulou et al. 5) the removal of cosmological and black hole singularities in models of quantum cosmologies and black hole interiors, 6) predictions of possibly observable order L_Pl corrections to CMB spectra from such models (Hoffman and Winkler) 7) the LOST uniqueness theorem, and others.

I would very much like the chance to try to convince you and others on the merits that these and other results are very much worth paying attention to. (As I emphasize in my note they are significant even if the world is ultimately stringy, because string theory itself needs a manifestly background independent formulation.) If you would agree to be open to being convinced I would make a few suggestions that might help you to better evaluate these developments:

-Study the papers referenced in my article in the current Physics Today-which was written to communicate with colleagues about the recent results-just what you asked for. If you want background references (as they have a strict limit on references) I’d be glad to supply them.

-Invite several of the key people responsible for these recent developments to give a seminar. I’d be happy to make suggestions of good speakers, here is a very incomplete list: Alexander, Amjorn, Ashtekar, Bojowald, Dreyer, Freidel, Husain, Livine, Loll, Markopoulou, Rovelli, Sing, Speciale, Wen, Winkler.

-Invite someone working in this area as a visitor, or consider people in this area as potential postdocs or colleagues.

Finally, let me respond to your, â€œâ€œThe job wonâ€™t get done in the media-assisted way you are doing it right now.â€ You seem to think that Peter and I orchestrated a media campaign. That is absolutely not the case. Nor did I hope to cause some effect by manipulating the media. Instead, I hoped to communicate with colleagues like yourself through the straightforward means of writing a book that, I hoped, would be serious and constructive.

The amount of media interest is actually of no importance for the questions of whether the arguments made in my book are true or useful, that can only be settled by a discussion based on the actual content of the book. I would be very grateful to know what you think in response to the actual arguments made in my book.

The fact that there was a lot of interest from the media was not something that I particularly wanted, and I did nothing to instigate it-I made not a single call or email to a journalist that was not in response to an inquiry from them, nor did I put out a press release etc. The publishers did do the standard things to publicize a book, but that certainly does not account for the interest that was generated, because in the majority of cases they do the same-and in some cases much more- and there is no such response. It is you and not me who keeps making the issue the media response, when I want-for example, in my letter that is the subject of this post- to discuss the actual scientific issues that are the content of the book.

Thanks,

Lee

57. Aaron Bergman says:

Finally, let me respond to your, â€œâ€œThe job wonâ€™t get done in the media-assisted way you are doing it right now.â€ You seem to think that Peter and I orchestrated a media campaign. That is absolutely not the case. Nor did I hope to cause some effect by manipulating the media. Instead, I hoped to communicate with colleagues like yourself through the straightforward means of writing a book that, I hoped, would be serious and constructive.

And you thought that the best way to do that was to write a book called, The Trouble with Physics: The Rise of String Theory, The Fall of a Science and What Comes Next?

And then, in that book, instead of simply dealing with scientifc questions, you to essentially accuse an entire field of being enthralled to “groupthink”.

And there’s this from Sabine’s blog:

One was from Houghton Mifflin, and contained the long awaited copy of Lee’s book. But more interestingly, it came with an information sheet. Actually, it’s not so much information but advertisement for some book that reveals allegedly shocking details about faith based science that penalized young physicists. It seems, I’ve read a different book. At least that explains the contents of many reviews I’ve seen since September, which basically repeat what’s written on these accompanying pages. Well, the publisher know their job: ”In the coming months a heated debate raging on the Internet and at physics conferences is poised to break wide open, and THE TROUBLE WITH PHYSICS will serve as a rallying cry.”

Or, have you bothered searching the internet for what the reactions to your book has been outside of the scientific community?

This was all really unexpected to you? What exactly did you expect the reaction to your book to be?

58. onymous says:

M:

Interesting link, thanks, I didn’t notice that before.

It seems Berends-Giele becomes more efficient for large numbers (>~ 9) of external gluons, because the helicity patterns that are far from MHV become more complicated in BCF. Interesting. (On the other hand, when do you need to calculate nine-gluon scattering?)

Regardless, I think BCF is serious and interesting work. I’m not sure whether you meant to denigrate it or if you just wanted to point out the older techniques. I think both are worth knowing about. It’s a different point of view: Berends-Giele is a very field-theoretic, Schwinger-Dyson-esque sort of technique, while BCF has a more 60s bootstrap / S-matrix flavor. And BCF generalizes simply to things with mass and spin (e.g. hep-th/0507161), which is worth noting. All this talk of many-gluon scattering amplitudes doesn’t really address the most interesting things for experiment, but the techniques can be applied to those too.

As for whether current tools are enough for understanding LHC data, I think it depends on what we mean by “understand.” We certainly don’t know, say, W or Z + n jets cross sections at NLO for n=4,5,…. We probably don’t really need to, but it would definitely be nice, no? Granted, if we have to pull a new physics signal out of background where the NLO corrections are as large as the new physics, we’re probably screwed no matter what. But nonetheless it’s nice to have a somewhat reliable error bar on SM predictions. And talking to some of the people who work on these NLO calculations, it seems they take the new techniques seriously.

Anyway, I’m no expert on these things, just an interested observer, and perhaps you know much more than I do, but I think what Clifford said originally was pretty reasonable. He didn’t say these were the only efficient techniques or the most efficient, just that they are remarkably efficient. I don’t see how one can argue with that.

59. spacepig says:

M and others:

I actually think the string landscape is clearly part of the theory and needs to be thought about. But remember, the field theory landscape is even bigger!! In string theory, the vacua are part of one structure, and connected by dynamics.

Now peter (and dine, taylor, indirectly) take the hopeless point of view that we need to find a priori theoretical conditions that pick the one true vacuum, and then develop the power to compute everything to required accuracy (for the cc, this is of order 100 loops!).

That is what I call a red herring. In qft, qualitative hints (neutral currents, deep inelastic scattering, etc) brought people a long way towards the right class of models.

So I think the right thing to do is look for qualitative phenomena in parts of string theory — eventually one will show up in nature, if the theory is right, and this will give the needed hint about which vacua are relevant. The phenomenon could be webs of cosmic strings, or split supersymmetry, or large dimensions, or…

Again, it is a huge red herring to think one needs to find the right vacuum by a priori considerations. It would be nice, so would world peace, neither is coming anytime soon (sigh).

60. Bee says:

Aaron:

The point of the above cited paragraph from my blog is that the ‘information sheet’ which came with the book is clearly a completely over-hyped advertisement written with the sole intention to cause as much controversy as possible — written by someone who doesn’t have any idea of theoretical physics, and who didn’t care whether or not the description accurately reflects the books content.

In case it was left unclear that my blog piece (titled: bubbles of nothing) was meant as a criticism on advertisement tactics in general, and those used for Lee’s book in particular, I apologize. I am reasonably sure this form of cheap advertisement was not in the author’s intention. If you have to blame somebody, then blame those who blindly distribute other people’s opinion, and just echo what they have heard or read elsewhere.

Speaking of apologies, reading your comment I have a strong sense of deja vue, and I really wish we could move on from the subtitle-issue towards a more constructive discussion, how to proceed from here on. I hate to point it out, but it seems our world has an arrow of time, and what has happened, won’t be undone by blaming each other.

B.

PS: I don’t like the sub-title either, but taking off the cover helps also in this regard.

61. Lee Smolin says:

Aaron,

What did I expect the reaction to be? I expected that colleagues would read the book and respond to what is written in the text. When I read books, for example, by Brian Greene, Lisa Randall, Lenny Susskind and Alex Vilenkin I did not care what the advertising copy said, I expected it would be imprecise and exaggerated as it was written by people whose goal is to sell books. I have enough respect for them to ignore that and to pay attention only to what they actually write in their books. I was, perhaps naively, expecting this in return.

If you want to continue to discuss the role of media and advertising in the marketing of all these books then that is course fine, but I only ask that when you do that be fair and consider all the books on the topic. I am myself not too interested in that topic, so I will spend my time doing physics and discussing where physics is going with those people whose interest is in the substantial issues.

Thanks,

Lee

62. Hmm says:

Ha! Thats really funny Lee! You’re interested in talking with people who want to discuss the serious issues? Thats a good one–you’re not much of a physicist, but you have quite a future as a comedian. For twenty years, you have tried–woefully unsuccessfully–to convince most theorists that there is something to LQG. Having failed so miserably at this, you write a popular book to take the “debate” straight to the people, a little like the intelligent designers who can’t convinice scientists but “teach the controversy” to the general public. Then you have the nerve to say you care about the scientific issues! You lost any credibility you ever had with your colleagues, both inside and outside string theory, with this book.

63. onymous says:

Lee wrote:

“When I read books, for example, by Brian Greene, Lisa Randall, Lenny Susskind and Alex Vilenkin I did not care what the advertising copy said”

Their advertising copy and subtitles didn’t accuse people who disagreed with them of causing “The Fall of a Science.” See the difference?

64. Aaron Bergman says:

The point of the above cited paragraph from my blog is that the â€˜information sheetâ€™ which came with the book is clearly a completely over-hyped advertisement written with the sole intention to cause as much controversy as possible â€” written by someone who doesnâ€™t have any idea of theoretical physics, and who didnâ€™t care whether or not the description accurately reflects the books content.

Of course it was. It is also something completely expected for a publicist to do.

As for Lee, why do you expect anyone to spend $20-30 and a few hours of their spare time to read a book with that title, especially given that you’ve written any number of articles and blog posts on similar subjects? People have better things to do than to listen to yet another discussion of background independence. If you want people to read your book, give them a good reason to do so. Instead, you’ve given them plenty of reason not to. If you wanted this to be some interscientific discourse, you could have written an article on the arXiv as you’ve done in the past. You chose to write a book for the public. You chose to release it with that title. The result of these choicees should hardly have been a surprise. 65. Gina says: I read quite carefully Woit’s book and I think it is overall a nice book and Peter can regard it as a nice personal achievement. I did have some rather detailed criticism of various aspects of the book, as well as of Peter’s overall argument, that I posted in Peter’s weblog. I am also a little puzzled why Peter, (unlike Lee) rather than relax and let his ideas as expressed in his book (for what they worth) work for him, is getting into some sort of a crusade with little or even negative marginal gains. He almost comes across as the little Dutch boy who with his own finger try to prevent the universe to fold into undesired additional dimensions. (I only read a small portion of Lee’s book. One chapter about the main problems in physics was very nice. Another chapter gave me the impression of unsuccessfully trying to juggle too many balls at the same time.) The issue raised in these books as many other books about the relations between science and philosophy of science are very interesting. The issues concerning social aspects of science – jobs, grants, credits, – are also of interest but I do not think it is correct to study them together with the actual physics issues. Peter’s and Lee’s (similar) ideas on this front seem rather naive as I tried to argue on Peter’s weblog. Overall, I think the emerging discussion can be valuable as the issue has many interesting facets. The new concept of weblog discussion of scientific issues, even by non-experts, looks very interesting by itself. I am curious what is Clifford’s overview about this discussion and such discussions in general. (E.g., is it also a Dutch-boy effort to confront the vicious recent attacks on string theory or rather a discussion that can be of some value (and fun) on its own.) To the extent my thoughtful yet naive and not-always-fully-informed comments are welcomed I will be quite happy to contribute occasionally. 66. TheGraduate says: Dr Smolin, I do hope that some people here will eventually calm down enough to understand that it is not unusual for an author to have absolutely no control over the cover of the book and sometimes even the title. Of course each contract is unique and so only you and your publisher can report on the details of your particular contract. Anyway, I should say that I really enjoyed your book. It had quite a bit of style to it! The sbozo-the-clownino remark has become a running joke with me and some of my more physics inclined friends. (I have no opinion about supersymmetry but it was just an amusing thing to say.) I wanted to ask you some questions if you were amenable to it. A lot of your criticisms about what is wrong with theoretical physics seem to have been interpreted as a blatant bid to increase the status of LQG. What do you say in response? Do you see LQG benefiting if the things you want changed about how theoretical physics is done actually get implemented. 67. Lee Smolin says: Hi, Look, the more you guys focus on the issue of the cover and advertising copy, and the more you reply to attempts to reason with personal insults, the more you give the impression that you have nothing substantial to say in reply to the actual arguments made in the book. As to why I wrote a book rather than papers, I did as pointed out write papers on much of what is covered in the book. But sometimes it is useful to make a book length argument. The point is that this book is not a popularization, it is not intended mainly “for the public”. It is a serious piece of scholarship, and has been taken so by most unprejudiced readers. There is in fact a literature of serious books about open issues in science which are written for colleagues, but in a way that anyone else who is interested can, as it were, look over our shoulders as we discuss. Some of the most successful of these advanced debates in biology, for example the books by Dawkins, Dennett, Gould, Margoulis, and others. All three of my books have been in this tradition. When the issue of the cover copy, subtitle etc was first brought up I did agree that they were provacative and indicated that had they been completely in my control they would have been less so. This was an attempt to be conciliatory but it clearly has fallen on deaf ears. If you want to have a discussion about advertising we can find lots of statements or impressions that went beyond the evidence in advertising for various books, TV programs etc. But I insist this is not a very interesting discussion, compared to a discussion of the actual science. Aaron, I don’t need to give you a reason to read the book, there is no reason you should, unless you comment on it publically. Once you have made a public comment about a publication of a colleague, it seems to me you are obliged to either read it or withdraw your comment. Lee 68. young string worker says: Iâ€™d like very much to hear what these youths think of this concern, whether they agree that they are being duped as claimed, and what their own expeiences areâ€¦do they see it as a string theory problem? I come from small village in Mexico — no have green card — I pay$500 to sneak across border and come to United States. I am 14 year old.

They bring me to New Jersey — all day long I sit in room, work out MHV diagrams — me have no windows — no breaks — no holidays. They no pay me overtime.

I dont understand why the pheesicists, they so mean to me, make me do string theory. I ask them about some ‘alternatives’ like loop quantum gravity, and they beat me and tell me not to ask so many questions.

Sen~or Witten, he tell me to work faster on twistor string theory. He ask me why I no decouple conformal supergravity yet.

I just want to get my green card, send money to my family, but the physicists, they dupe me and make me do string theory.

I want to work on ‘alternatives’ not string theory. I weesh Sen~or Smolin he would help me and save me from the mean string theorists.

69. Aaron Bergman says:

Aaron, I donâ€™t need to give you a reason to read the book, there is no reason you should, unless you comment on it publically. Once you have made a public comment about a publication of a colleague, it seems to me you are obliged to either read it or withdraw your comment.

I have skimmed the entire book and closely read the releveant parts, Lee. I’ve even explained to you why I felt that your premise was seriously misguided.

But above, you say “I expected that colleagues would read the book and respond to what is written in the text.” Given all that has been mentioned, why did you expect people to spend the time and money to read your book? What reason did you give them? Regardless, your book wasn’t published by an academic press, and it’s clearly being marketed to the public as “the string theory emperor has no clothes”. Are you saying that you had no control over this and that it was completely unexpected to you? Contrary to TheGraduate, contracts are negotiable. You’ve written two, I’d guess reasonably successful, popular science books prior to this one. I find it hard to believe that you didn’t have any leverage over anything. You make your bed, you get to lie in it.

70. Peter Woit says:

One thing I don’t think string theorists seem to understand is how much their own case is being damaged by the behavior of some of their own partisans. I’ve had more than a few people tell me that they were initially dubious about my criticisms of string theory, but became convinced I might be right after reading some of the reponses to these criticisms, on my blog and elsewhere. People see the kind of behavior represented here by “Hmm”, and quickly get the idea that words like “group-think” may be a much too kind way to characterize what is going on. The scientific arguments are complex and understandable to relatively few people, but almost anyone can recognize the significance of some of the adolescent behavior on display, as well as the way it is being tolerated.

As for jacket copy etc., a couple more data points:

1. On the whole, no one at my two publishers bothered to even show me much of the copy written to promote the book, and some of it I’ve probably to this day never seen. The subtitle was my own effort, in collaboration with the editor, and the jacket copy was sent to me for my approval. I strongly objected to the original US jacket copy, and returned my own rewritten version. This went back and forth a few times, converging on something that both the editor and I could live with. The end result is not my words and not the way I think about the book or would want to present it, but it’s also not something I find seriously objectionable.

2. Cambridge University Press is putting out in January a new book by Michael Dine entitled “Supersymmetry and String Theory”. The promotional materials on the CUP web-site and on Amazon feature blurbs from three prominent people, one of them a well-known assistant professor at Harvard. Anyone want to speculate on whether the author is aware of this and if so why he thinks this is a good idea for how to promote his book?

71. Lee Smolin says:

What I believe is that a premature consensus has formed around the inevitability of string theory being right which has hurt support for good work being done on a whole range of potentially correct approaches to unification and quantum gravity. LQG is one of these, but even in the quantum gravity world it is just one. I would increase support for the whole range of approaches under conditions in which support went to those people doing the best work, or those with the most interesting new ideas. When I argue for rewarding intellectual independence over following established research programs I apply this every bit as much to LQG as I do to string theory. If you look at the work I champion, for example in my Physics Today article, you will see that much of it falls outside of LQG, having to do with CDT, quantum gravity phenomenology, or new approaches based on quantum information theory and condensed matter physics.

Will LQG benefit? Under the conditions I propose it would benefit only if it could continue to attract interest by young people coming into the field. To ensure this is true, my own responsibility as a senior scientist is to support the best people no matter whether they work on what I work on or not. I do try personally to do this where I can, my argument is that our field as a whole would be stronger and would progress faster if this ethic were generally followed.

Thanks,

Lee

72. Aaron Bergman says:

I believe is that a premature consensus has formed around the inevitability of string theory being right

Who believes that?

73. Gina says:

There is nothing wrong with the cover of Smolin’s book, in fact it is nice. (There was also nothing wrong with Lubos Motl’s Amazon review of Smolin’s book.) There is nothing wrong with the naked emperor metaphor either. And there is nothing wrong with the provocative name “not even wrong”, in fact it is also nice. Exact-science guys are simply not used to practicing and maintaining debates and controversies. (Either being extremely puritan or occasionally unreasonably aggressive.) Try to consult your colleagues from the humanities!

Dr Smolin,

I know you quite extensively outlined the type of person you think is most likely to make a difference. One of the characteristics you considered most important, was originality. You also acknowledge that creativity was a subjective value.

I am aware that you addressed the subjectivity by saying that while it was an obstacle, that the fact that senior scientists were witholding their support of younger candidates was bigger obstacle. I think you put it something like, work in exchange for a career.

However, wouldn’t it be fair to say that the issue of subjectivity would still persist even if the problem of self interest were overcome?

Also, suppose some of scientists took your advice and supported whomever they thought was the best person. Suppose other scientists persisted with the old game of work in exchange for a career. Would one not expect the scientists who basically have free labor to exceed in influence the other scientists, thus replicating the current system. My question in essence is whether ethics is enough to get your system to work without some policing of the scientists who aren’t so ethical?

75. Holmes says:

Frankly, I think that *everyone* should give writing books a rest. I cringe every time I see a new one come out. Most of them are really badly written, as well as being misleading. Bee doesn’t believe that blogs are good places to discuss what people think. Maybe she has a point. But books sure as hell aren’t doing much better. In fact the book by the *other* LS looks very much like a book-length blog entry. But minus the comments telling the author how evil/foolish/whatever he is.

Can everyone please stop writing books and go back to writing papers?!

76. Drei Bein says:

Can everyone please stop writing books and go back to writing papers?!

Well, at some of your career you just have to write a book. Nothing personal, though…

77. Clifford says:

All,

spacepig made a comment quite a bit earlier, but it got held up by the automatic system, and I did not notice until now. I’ve released it now, but so that it does not get lost, I give you the link here.

Best,

-cvj

78. Umm says:

>Can everyone please stop writing books and go back to writing papers?!

Not everyone is able to do so, so we can expect to see more books.

79. Elliot says:

the bonsai master
prunes for the sake of the tree
not his reflection

80. Drei Bein says:

spacepig

So I think the right thing to do is look for qualitative phenomena in parts of string theory â€” eventually one will show up in nature, if the theory is right, and this will give the needed hint about which vacua are relevant. The phenomenon could be webs of cosmic strings, or split supersymmetry, or large dimensions, orâ€¦

But, I think the question Douglas & Taylor are asking is exactly that. Given that we know what the low energy theory is (split SUSY, universal extra dimensions, whatever), what does that tell us about the vacuum? And I think it’s not clear (yet) whether there actually is an answer.

You seem to prefer the top to bottom approach, others may like the other way around, but both ends must meet at some point. The question is, do they?

81. spacepig says:

Drei Bein,

No, the questions currently being asked are much simpler.
They are questions like: is the gauge group of the SM statistically more likely than other gauge groups? Given the gauge group is three generations likely? Etc.

I would call this the top to bottom approach, and I am advocating the other. My suspicion is that the more valuable work in making contact with data,will be to build specific classes of models with interesting signatures, because from the bottom up, one of these will eventually be observed. By definition an interesting signature is going to remove a large portion of the landscape from consideration. For instance, observation of cosmic superstrings would immediately put us in the corner of string theory that has D1-branes, while
observation of E8 gauge bosons would lead everyone to
believe we are in the heterotic theory (however the latter
could happen 🙂 since no low energy models show the
E8 at foreseeable energies).

Another way to say it is : the classification programs tend
to work based on kinematics, and it is more interesting
to look for characteristic dynamical phenomena that
distinguish between low energy vacua. Specially when we know the classifications are very incomplete.

To illustrate the distinction, given SU(3) color, you could
focus on the fact that the group is SU(3) and go down a
list of models with various groups; or you could focus on
the phenomenon of asymptotic freedom. I think one of these
is more educational than the other.

82. Drei Bein says:

spacepig, thanks for the detailed answer. Now I understand your point of view much better.

83. Lee Smolin says:

There are presently ethical standards which most people follow because they improve science overall even if they go against your own interests in the short term, for example do not hire your own graduate students as postdocs, do not publish other people’s work, do not organize a conference and invite only your students and personal friends to speak. So there is nothing new, ethical standards persist from a combination of individual agreement combined with the community enforcing them by taking them into account when evaluating people for grants or positions.

“Would one not expect the scientists who basically have free labor to exceed in influence the other scientists, thus replicating the current system. My question in essence is whether ethics is enough to get your system to work without some policing of the scientists who arenâ€™t so ethical?”

Perhaps yes, in the short term, but in the long term a field or research program that supports its strongest, most original and intellectually independent scientists will do better than a program that supports yes-people who just do “me-too” science. I would offer LQG as an example, how is it that we have made a lot of progress in the last few years in spite of having very few resources? Because in a situation in which every person and every position counts it is a matter of survival of the field to make sure that the young people who have opportunities are those who have the most added-value to contribute-these are the ones who have brought in new ideas and new directions, which have led to important new results.

Thanks,

Lee

84. [I]n the long term a field or research program that supports its strongest, most original and intellectually independent scientists will do better than a program that supports yes-people who just do â€œme-tooâ€ science. I would offer LQG as an example, …[We] make sure that the young people who have opportunities are those who have the most added-value to contribute-these are the ones who have brought in new ideas and new directions, which have led to important new results.

In other (unnamed) fields, hiring is governed by nepotism, and log-rolling. Unoriginal, “me-too” science is given preference over innovative ideas. Oh yeah, and they’re shallow, flitting from one unoriginal ideal to another, instead of taking the time to painstakingly prove tough theorems, like we do.

Is it any wonder that they have nothing substantive to show, for all their efforts?

85. gina says:

Lee, If the LQG community has such superior hiring policies and yet the scientific outcomes are not impressive, maybe LQG is a bad approach towards quantum gravity? Or maybe this “how to fight sociology” issue that you talk about is not really of much importance, and the real issue is how to fight these damm scientific questions?

86. nc says:

Gina, fight scientific questions with consensus and bigotry; claim using a new version of Bohr’s complementarity principle (or do I mean correspondence principle?) that there is no need for quantum gravity because the Lambda-CDM of GR can be modified endlessly to fit gravity, while the Higgs mechanism can be endless modified to explain mass (gravitational charge) and electroweak symmetry breaking.

Then fight all new ideas by calling the authors crackpots, cranks, egotists, megalomaniacs, etc. Have fun!

87. Gina says:

nc, i do not fight anybody or anything. I really want to understand a little. I never called anybody a crackpot, (as a matter of fact, it is me who is jumping over my head and talk about things I only partially understand.) I do not expect to understand about Higgs ect. but I can understand matters of academic sociology. And I really do not understand Lee’s argument about sociology. Yes, there are different attitudes of individual scientists as of scientific communities about pluralism, publicity, attitudes towards young scientists, conservatism, controversies, rigor etc etc but I do not understand what is Lee’s idea to revolutionize universities and academic life and I think it is a bad idea to discuss specific scientific issues along with issues of scientific sociology. These two (while connected) are better studied separately before we try to grandly unify them.

88. nc says:

Gina, I’m sorry, but I just thought you wanted to fight off scientific questions.

89. Gina says:

Dear NC, It is combination of my bad English and all these war metaphores for human activities like science. (are these metaphores necessary?)

What I wanted to say is that when you see how individual scientists struggle with scientific problems what mainly counts at the end is their actual achievements and not if they are humble, or arogant, of careful or careless or peaceful or tend to argue or tend to quarel, or nice or badly behave etc. (Although we cannot deny that the various seemingly unrelated individual merits may have to do, in a subtle way, with success.) The same may apply to different scientific communities.

90. Gina says:

Let me try, nc, to elaborate a little.

It was claimed in these discussions that string theory is over-hyped and perhaps it is. But let me argue that this hype served not only string theory but also, to a large extent, physics, mathematics, and science as a whole. Society’s exposure to sometimes bold (but sincere and serious) claims about science can serve science. (And maybe even the controversy and anti-string little hype, will be of service.)

One the other hand, hype cannot change a little bit, I think, the factual scientific reality and ease even slightly the immense difficulty in exploring it.

When we carefully assess people, as whole disciplines, we are able to factor out to a large extent irrelevant factors like hype.

For example, in the first lecture about string theory that I heard many years ago the speaker (a dear and brilliant person) claimed that the universe is 26-dimensional and this is “nonnegotiable”. I was not sure how negotiations about the dimension of the universe are carried out and I am not a good negotiator anyway, but I understood that this means that the universe has definitely 26 dimensions. A few years later apparently after some further negotiations the number was down to 10 give and take 1-2. So my new picture was that these exciting issues are still on the drawing board and we should wait and see.

91. Lee Smolin says:

Dear Gina,

“Lee, If the LQG community has such superior hiring policies and yet the scientific outcomes are not impressive, maybe LQG is a bad approach towards quantum gravity?:

But my point, Gina, is that the results are impressive. Look at my first post above in response to Clifford, in which I list 7 recent results, all of which we in the field think of as important, and all of which are from the last several years. I think any unbiased observer would agree that evidence for the correctness of this approach is increasing steadily and is now much stronger than it was 5 years ago. Consequently, there should I argue, be a strong shift of interest towards the ideas and methods that lead to these results.

Notice that no one comes back and criticizes or attacks these results directly. As in many previous blog conversations about the scientific merits of LQG the response is never an acknowledgement of progress, it is either to change the subject or to engage in personal attacks. Or sometimes it is to raise an objection that turns out to be wrong as in the many posts about “how could there be a uniqueness theorem relevant for LQG if Carlip says there is not a unique quantization of 2+1 gravity.” When this was tracked down in turned out Carlip was referring to operator ordering issues in operator products common to all quantum theories.

Notice also that it would not cost proponents of string theory anything to acknowledge progress in other approaches when it occurs, and indeed we have no trouble doing this when string theory makes progress. So while I completely agree with you that we must always clearly separate scientific from sociological discussions, if I am asked why string theorists are rarely willing to acknowledge genuine progress when it occurs in other approaches, there seems little recourse but to sociology.

Now, Clifford and others will claim that if there is progress in a direction they would be happy to drop string theory and work on it. But what is being asked is much less, it is just to take an objective interest and look into and follow in some technical detail what is going on in other directions. Now, I am one of the few people who has actually switched my interest and activity among the different approaches, so unlike most people I can talk about what is involved from personal experience. I can report it is not that hard technically to switch between string theory and LQG and back again, but it does take a fair amount of honest soul searching. What helped me was to every few years make a list of precisely what had been and what had not been achieved in each of the different directions and to cleanly separate results achieved from hopes and conjectures. On the basis of this evaluation I have already switched several times back and forth, depending on the relative progress in different areas. So I know what it means to put everything on the table and be willing to put aside, at least temperarily, a direction of research I used to believe in, if another looks at the time more promising. What I hoped to do with my book and review articles leading up to it was to encourage other people to do also put everything on the table and have an objective discussion, as scientists, on the merits and issues in each direction.

Thanks,

Lee

92. Clifford says:

On the basis of this evaluation I have already switched several times back and forth, depending on the relative progress in different areas.

On the one hand, the quoted remark above seems like a good and wise thing… on another hand, a hop-and-skip-here-and-there approach one’s to research can lead to being a “Jack of All Trades, Master of None”. (I am not saying that this is the case for you, Lee.) Does this produce better results than dedicating a research program to really understanding a problem for several years? This is not clear to me, so I would say beware… it is not for everybody… in fact, it is probably not for most people, given the complexities of the problems involved – definitely not early in one’s career. This is the luxury of the established and experienced researcher.

-cvj

93. [I]f Carlip says there is not a unique quantization of 2+1 gravity.â€ When this was tracked down in turned out Carlip was referring to operator ordering issues in operator products common to all quantum theories.

None of the various quantizations, that Carlip discusses, involve the polymer representation that the LOST Theorem tells us is unique. I don’t see why it matters whether the various quantizations differ by operator-ordering, or a really distinct from each other. They are all clearly distinct from the LQG quantization.

Similarly, AdS/CFT provides a nonperturbative, background-independent quantization of gravity in asymptotically AdS spacetimes, by constructing directly to the physical observables, without recourse to a “kinematical Hilbert space.”

We’ve had numerous discussion of other purported results of the LQG program. For instance, the “prediction” of Lorentz violation at GLAST or the claim that

LQG easily incorporates most proposals for beyond the standard model unification including supersymmetry.

If I thought the discussion would go any better, I’d be happy to discuss Rovelli’s “graviton propagator” (or anything else on your list).

Unfortunately …

94. Aaron Bergman says:

Notice that no one comes back and criticizes or attacks these results directly. As in many previous blog conversations about the scientific merits of LQG the response is never an acknowledgement of progress, it is either to change the subject or to engage in personal attacks.

It doesn’t look that way on this end. I can think of any number of discussions on the merit of various ideas on LQG. In fact, the lack of a response to honest queries on various subjects has been a source of frustration.

When this was tracked down in turned out Carlip was referring to operator ordering issues in operator products common to all quantum theories.

No, it didn’t turn out that way at all. Carlip speculated that the inequivalent quantizations might be related to operator ordering issues, but he didn’t know. Regardless, operator ordering ambiguities aren’t somehow less nonunique than some other sort of nonuniqueness; you still get physically distinct predictions.

So while I completely agree with you that we must always clearly separate scientific from sociological discussions, if I am asked why string theorists are rarely willing to acknowledge genuine progress when it occurs in other approaches, there seems little recourse but to sociology.

Perhaps people just happen to disagree with you on the merits?

95. Lee Smolin says:

Disagreements on the merits is usual among experts. You will find substantial disagreement among experts about the interpretation of detailed results in any field including LQG. But when someone dismisses a whole field of resarch, making only negative criticisms, and never recognizes or acknowledges any of the successes that are broadly acknowledged by experts, then that suggests either lack of good faith and objectiveity or a lack of expertise.

This is something none of the “critics” of string theory do. Our comments are detailed and nuanced, we recognize and admire the achievements and our criticisms are based on a precise understanding of the results and how they are achieved. This is what makes the critique hard to answer, and indeed the substantial points that Peter Woit, Penrose, myself and others make are generally conceded by experts (except in rare cases where we are happy to acknowledge mistakes.) What is coming from the other side has none of these qualities of carefulness, expertise or evenhandedness, it is so one sided that it is hard to take seriously.

On 2+1 operator ordering differences are unaviodable, but do not indicate different quantizations, for they require a single Hilbert space to even formulate.

Nonetheless, if you feel there are have been honest inquiries that were not responded to, please point them out and we will answer. I ask only that you be willing to acknowledge publically when you turn out to be wrong, as we always have been.

Thanks,

Lee

96. Aaron Bergman says:

Let’s just stick to the science rather than how string theorists are evil and LQG types are pure and even-handed.

On 2+1 operator ordering differences are unaviodable, but do not indicate different quantizations, for they require a single Hilbert space to even formulate.

In what sense are operator ordering ambiguities not “different quantizations”?

And, I reiterate that it’s not at all a settled point whether the inequivalent quantizations in 2+1D are related to operator ordering or not.

97. Clifford says:

Lee Smolin:

This is something none of the â€œcriticsâ€ of string theory do. Our comments are detailed and nuanced, we recognize and admire the achievements and our criticisms are based on a precise understanding of the results and how they are achieved.

Lee. Come on. You really can’t be saying this with a straight face, even after all the discussion everyone has read here, on related posts, and on blogs elsewhere…. Including the discussions that Jacques pointed to in his comments above where there has been considerable effort made to try to understand some of the things you claim (positively) about the work in LQG, and some of the things you claim (negatively) about strings….

Let’s keep the discussion honest.

Cheers,

-cvj

98. gina says:

Dear Lee,
Many thanks for your reply. Of course, I did not mean to challenge the results of LQG and their significance but to point out a difficulty when one trys to interprate scientific and sociel effects together.

99. huh says:

Lee:

Many of us find it very hard to take LQG seriously, because we have simple questions like this.

“If you cannot get a smooth macroscopic spacetime geometry in your approach, how do you
know what a black hole is? A black hole is a solution of gravity with such an asymptotic
geometry. And without this, how can you possibly claim to compute the entropy?”

Or

“Many of us think there is a cosmological constant problem. Where in your approach is it
apparent? Is it the physical reason you cannot get a smooth continuum spacetime (because
you need to do the careful tuning to get rid of the Planck-scale CC that would typically
result in the continuum version of a given discrete approximation?)”

I discussed these questions extensively with Ashtekar years ago, after the claims about
entropy (or resolving big bang singularites, or whatever else you now claim) had been
in some ridiculous unphysical way, however rigorous you think it is, don’t think other
theorists will then congratulate you on computing the formal entropy of an object that
doesn’t exist in a macroscopic spacetime.

Perhaps this has changed by now; at the time, I found his claims in talks, compared to his answers to my questions, to be essentially false advertising.

String theorists have very clear answers to these questions. Most cleanly, they study
supersymmetric backgrounds where very precise formulations are available, and
macroscopic BPS black holes therein, which in many key respects resemble the more physical Kerr solutions, though of course not all. (Now considerable progress is being
made with less supersymmetry as well, but that is a work in progress).

100. Lee Smolin says:

Dear Clifford,

I meant that completely straight. I had missed Jacques comments above, but they are easy to address. Some of his assertions are just false. For example he says, â€œ None of the various quantizations, that Carlip discusses, involve the polymer representation that the LOST Theorem tells us is unique.â€

This is just not true. Very shortly after Wittenâ€™s 89 papers on Chern-Simons quantization of 2+1 gravity we showed that the LQG method gave the same Hilbert space and physical observables algebra after solution of the quantum constraints

2+1 quantum gravity as a toy model for the 3+1 theory, Abhay Ashtekar, Viqar Husain, Carlo Rovelli, Joseph Samuel and L. Smolin, Class. Quant. Grav. 6 (1989) L185-L193.

L. Smolin Loop representation for quantum gravity in 2+1 dimensionsin the proceedings of the Johnâ€™s Hopkins Conference on Knots, Tolopoly and Quantum Field Theory, ed. L. Lusanna (World Scientific,Singapore,1989)

Carlip refers to this explicitly on p 23 of his 2004 review and references the above first paper, as do 110 other authors. Now the Ashtekar-Lewandowski measure was not formally defined till later so one has to look at a later paper to make the explicit connection, but that the Ashtekar-Lewandowski measure formalizes precisely what is done in this early paper was easy to confirm. Also, to be precise, the papers above show the equivalence to Wittenâ€™s Chern-Simons quantization for the Euclidean case where the gauge group is compact, but the Lorentzian case (which is subtler because the gauge group is non-compact) was later carried out on both sides and shown to agree.

So what am I to do? Jacques makes an outright false statement and you use that to question my credibility. What would be nice is if Jacque and you could check the literature and confirm that what I am saying here is reliable.

Clifford I can assure you that I can do the same with every statement Jacques makes. For example he takes my statement that LQG can be extended to coupling to matter fields and supergravity and takes that in a completely different direction. Lets just take the statement that LQG has been extended to N =1 supergravity, in papers by Ling and others. This is a significant statement. Jacques never once in this long series of exchanges says, yes thatâ€™s right, and credits it.

The issue that Jacques does raise in that discussion has to do with the fate of anomalies in couplings to chiral fermions in LQG. We have thoroughly discussed this. I have said that my guess is that the issue is resolved by fermion doubling but that needs to be checked. It seems to me this was both a complete answer to the issue Jacques raised as well as an open answer, i.e. I am happy to admit when I donâ€™t know something.

It would in turn be only fair of Jacques to acknowledge when he has been wrong. Then we could begin to have a genuinely productive conversation.

OK, lets go on to address Mr/Ms Huh

Dear Huh

I canâ€™t comment on your conversations with Ashtekar years ago, but these are of course are good questions. They have straightforward answers.

â€œIf you cannot get a smooth macroscopic spacetime geometry in your approach, how do you know what a black hole is? A black hole is a solution of gravity with such an asymptotic geometry. And without this, how can you possibly claim to compute the entropy?â€

Classically a black hole spacetime is one with an horizon in it. We proceed by the following steps: 1) characterize the classical geometry of an horizon locally, in a way that makes no reference to asymptotic properties-thus answering directly your query. The result is known as an isolated horizon. 2) Define a dynamical system which is a region of spacetime with a boundary on which the definition just mentioned of an horizon is satisfied. It is a non-trivial fact that this can be done in classical GR using an appropriate boundary action and boundary condition. This directly addresses your concern because it tells us that a horizon can be identified in a background independent way as a property of a whole phase space-defined by the fixed boundary conditions rather than as a property of a particular classical solution. That is, the non-trivial fact is that a whole set of solutions which have horizons can be incorporated in a single phase space whose definition involves the isolated horizon boundary conditions and boundary action. 3) Quantize that dynamical system. 4) Discover that the Hilbert space factors into a sum over products of a bulk hilbert space times a boundary Hilbert space, where the sum is over the spectrum of the area operator. 4) For a given eigenvalue in the spectrum of the operator which is the area of the horizon compute the entropy by taking the log of the dimension of the boundary Hilbert space.

It seems to us this is a satisfactory definition of what a black hole is, which is suitable for the case at hand. It gives the right answers for the entropy and reasonable estimates for the radiation spectrum. It even gives the N-bound of Banks and Fischler for cosmological horizons. Of course, you might want to do it in another order, by first quantizing the geometry and then identifying a surface as a horizon in the quantum geometry, identifying a subspace of states associated with that quantum surface and then computing a) its entropy and b) the radiation which is produced when it interacts with the rest of the quantum geometry. If you prefer to see it this way you can read the last two papers of Ansari which do exactly this.

â€œMany of us think there is a cosmological constant problem. Where in your approach is it apparent? Is it the physical reason you cannot get a smooth continuum spacetime (because you need to do the careful tuning to get rid of the Planck-scale CC that would typically
result in the continuum version of a given discrete approximation?)â€

We do not claim to have a solution to the problem of why the cosmological constant is so small in Planck units. In LQG and other background independent approaches such as causal dynamical triangulations the cosmological constant is a free parameter which can be chosen to be very small in planck units. If you study the recent work of Amborn, Jurkiewicz and Loll you will see in detail how it is tuned to get evidence for a macroscopic geometry to emerge. This is in accordance with the general expectations you mention. In LQG less is known about exactly how a semiclassical state emerges dynamically but it is likely that similar tunings will have to be applied in spin foam models. When there are results they will be published, there is not much point in my speculating about how it will turn out.

But note, the issue is not that we â€œcannot get a smooth continuum spacetimeâ€. We know how to identify semiclassical states and study their excitations. But we have not proven that the ground state in 3+1 is such a state.

There are a few intriguing hints about the cosmological constant problem worth mentioning. One of them is that the cosmological constant induces a quantum deformation of the observables algebra of the theory. In the Euclidean case in 3 and 4 dimensions this results in a quantization of the inverse cosmological constant, thus it is no longer a continuous parameter. This is also related to the emergence of the kappa Poincare algebra as the low energy symmetry in 2+1. Some people have speculated that both phenomena could be relevant for how the cosmological constant may be solved, but if you are interested in results and not speculations than there is not more to say about this.

Finally, as to Aaronâ€™s query, â€œin what sense are ordering ambiguities not different quantizations?â€ the answer is that what is meant by distinct quantizations is those that lead to unitarily inequivalent Hilbert spaces. Once the Hilbert space is fixed, whether we are talking about the Harmonic oscillator or a QFT one can always modify the Hamiltonian by an operator ordering term, but that is not considered to be a distinct quantum theory. Or-and this is the point-it is different in a way that is very different than the way that unitarily inquivalent Hilbert spaces are different. Operator ordering terms are generally considered less serious ambiguities, because a) they arise for all quantum systems and b) they can be easily compensated for during any quantization process. Unitarily inequivalent representations of the observables algebra or representations of distinct observables algebra that are unitarily inequivalent are much more serious as they cannot be trivially made equivalent by adding a term to the quantum Hamiltonian.

I hope this suffices.

Thanks,

Lee

101. Aaron Bergman says:

what is meant by distinct quantizations is those that lead to unitarily inequivalent Hilbert spaces.

In standard quantum theory, we deal with separable Hilbert spaces (I’m aware that one does not in LQG), and there is only one infinite dimensional separable Hilbert space.

Perhaps you could state precisely what you mean by a unique quantization as in the LOST theorem? My impression (from conversations with people who work in LQG) is that it doesn’t say anything about the physical Hilbert space. Do you agree or disagree with that statement? Is the physical 2+1D LQG Hilbert space separable?

102. I wrote

None of the various quantizations, that Carlip discusses, involve the polymer representation that the LOST Theorem tells us is unique.â€

to which Lee responded

This is just not true. Very shortly after Wittenâ€™s 89 papers on Chern-Simons quantization of 2+1 gravity we showed that the LQG method gave the same Hilbert space and physical observables algebra after solution of the quantum constraints…
Carlip refers to this explicitly on p 23 of his 2004 review and references the above first paper

Carlip refers to Ashtekar variables (in which the connection coefficients are the “position” variables, and the dreibein are the “momenta”). Nowhere is the polymer representation (that bizarre non-separable kinematical Hilbert space, which is the subject of the LOST theorem) mentioned.

If there’s a paper where it is shown how to proceed from the non-separable polymer representation to the finite-dimensional physical Hilbert space, please tell me where I can find it. Carlip discusses no such thing.

So I think I have been falsely accused of “mak[ing] an outright false statement”

Lets just take the statement that LQG has been extended to N =1 supergravity, in papers by Ling and others. This is a significant statement. Jacques never once in this long series of exchanges says, yes thatâ€™s right, and credits it.

Because there is no instance where anyone has shown that there is a limit in which any of these constructions reduce to (semi)classical supergravity.

Do you want to have a detailed discussion of hep-th/9904016 (or are you referring to some other paper(s)?) ? We can do that, if you want, but probably someplace else, like my blog, where we can write equations.

We have thoroughly discussed this. I have said that my guess is that the issue is resolved by fermion doubling but that needs to be checked.

If the spin network theories in question have fermion doubling then it is … umh … a wee bit deceptive to characterize them as containing chiral fermions, is it not?

And if you don’t have chiral fermions, theny you haven’t “incorporated” the Standard Model, let alone “most proposals for beyond the standard model unification including supersymmetry.”

(In general, N=1 supergravity theories coupled to matter are chiral, which plays into the discussion of the previous paragraph.)

As to blackhole entropy,

It gives the right answers for the entropy and reasonable estimates for the radiation spectrum.

I will leave it to “huh” to read up on the construction in question.

However I will point out that, since you assume that the relevant degrees of freedom to be traced over are concentrated on the horizon, it is a strapped-down chicken test that the resulting entropy scales with the area. The coefficient of the area is the only nontrivial check, and that turns out to be a free parameter in LQG. Oh well…

103. Lee wrote:

If you prefer to see it this way you can read the last two papers of Ansari which do exactly this.

Are you referring to this paper of Ansari?

Am I to understand, now, that LQG makes definitive predictions for deviations from the Hawking spectrum of radiation from a blackhole?

(I haven’t read the paper, yet — just the abstract, but that’s the unambiguous claim of the abstract.)

104. Also, to be precise, the papers above show the equivalence to Wittenâ€™s Chern-Simons quantization for the Euclidean case where the gauge group is compact, but the Lorentzian case (which is subtler because the gauge group is non-compact) was later carried out on both sides and shown to agree.

Is there a reference for this?

(It’s not mentioned in Carlip’s 2004 review.)

105. Lee Smolin says:

Jacques:

What is done in the second of the 2+1 papers I mentioned is to start with the representation in terms of non-seperable states and define and solve the contraint equations to arrive at the state space given in the first paper and Wittenâ€™s paper on which there are only topological observables.

If you want to see the detailed reduction from the kinematical Hilbert space to the physical Hilbert space in 2+1, for the Euclidean case, done both by Hamiltonian and path integral methods, read gr-qc/0402110 by Noui and Perez. Here is the abstract:

“In this paper, we address the problem of the dynamics in three dimensional loop quantum gravity with zero cosmological constant. We construct a rigorous definition of Rovelli’s generalized projection operator from the kinematical Hilbert space–corresponding to the quantization of the infinite dimensional kinematical configuration space of the theory–to the physical Hilbert space. In particular, we provide the definition of the physical scalar product which can be represented in terms of a sum over (finite) spin-foam amplitudes. Therefore, we establish a clear-cut connection between the canonical quantization of three dimensional gravity and spin-foam models. We emphasize two main properties of the result: first that no cut-off in the kinematical degrees of freedom of the theory is introduced (in contrast to standard lattice’ methods), and second that no ill-defined sum over spins (bubble’ divergences) are present in the spin foam representation.”

More precisely, the representation theory of the Wilson loop observables is the path to the LQG quantization. If one quantizes the algebra before imposing the constraints one is working on the non-seperable kinematical Hilbert space. One can then impose the quantum constraints and find, in 2+1 the same Hilbert space as Witten found. Alternatively one can solve the constraints classically and then find the reduced Wilson loop observables on the physical phase space and quantize their algebra-which gives again the Hilbert space a la Witten. So in the case of 2+1 you can constrain and then quantize or do it in the other order and get to the same place. So here the use of the kinematical non-seperable Hilbert space as an intermediate step is optional. In 3+1 of course we donâ€™t know how to solve the constraints classically on the whole space of solutions and then quantize so we have no choice but to use the kinematical Hilbert space and solve the quantum constraints on its
dual. The fact that in cases where one can do it both ways the results agree is supportive of the correctness of the method.

-Some papers on 2+1 gravity in the Lorentzian case addressing the issue of the non-compact gauge group: gr-qc/9405031, gr-qc/9408007, gr-qc/0607121, gr-qc/9910010.

As to Ansariâ€™s papers, yes, the second paper does what the abstract says, it gives computable small corrections to the thermal Hawking spectrum. These are new papers and there are open issues regarding them, but they show one can make progress without imposing the isolated horizon boundary condition classically.

Thanks,

Lee

106. What is done in the second of the 2+1 papers I mentioned is to start with the representation in terms of non-seperable states and define and solve the contraint equations to arrive at the state space given in the first paper and Wittenâ€™s paper on which there are only topological observables.

Ah. Well, you can understand my confusion.

Neither Carlip’s comprehensive review, nor Ashtekar, Husain, Rovelli, Samuel and Smolin (which I also read) invoke the polymer representation for 2+1 gravity (proving, at least, that invoking the polymer representation is a truly dispensable step, in 2+1 dimensions). No, the paper which quantizes 2+1 gravity via the polymer representation is in an obscure conference proceedings, which is not to be found in our library.

If you want to see the detailed reduction from the kinematical Hilbert space to the physical Hilbert space in 2+1, for the Euclidean case, done both by Hamiltonian and path integral methods, read gr-qc/0402110 by Noui and Perez.

Thank you. I will take a look at that.

As to Ansariâ€™s papers, yes, the second paper does what the abstract says, it gives computable small corrections to the thermal Hawking spectrum. These are new papers and there are open issues regarding them…

…issues ?

I guess what I was asking was: is Ansari’s result considered to be correct? conjectural? incorrect?

It’s fine to point people to a paper, whose results one doesn’t completely believe. But, in doing so, one ought to state whatever caveats or reservations one has about the results.

107. observer says:

“… the argument Iâ€™m making against string theory is not that the problem is elitism. Iâ€™m actually all in favor of elitism myself.” — Peter Woit

Kinda hypocritical, huh?

http://www.math.columbia.edu/~woit/wordpress/?p=489#comment-19507

108. Cynthia says:

observer,

Regarding Woit’s response that he’s “in favor of elitism”, one ought to realize that elitism comes in two distinct “flavors”. Perhaps Woit sees Witten as practicing a more orthodox flavor of elitism. Woit, on the other hand, prides himself on practicing a more iconoclastic flavor of elitism. Just a hunch…

109. Peter Woit says:

My problems with string theorists are with the science they are doing, not with the question of “elitism”.

I think the problems particle physics is facing are extremely difficult, and to make progress on them will require the best minds around, working together under optimal conditions, with very high intellectual standards. In other words, it is kind of an elite activity, and conventional elite academic institutions are probably the most promising environments for it.

If I didn’t believe this, I wouldn’t be bothering to be doing what I’m doing, instead I’d just adopt the attitude that the best thing to do is just to ignore string theory.

110. Gina says:

Troubles with “The Trouble”, (part I)

The Trouble with Physics; the rise of string theory, the fall of science and what comes next, by Lee Smolin, A review

My review is planned to have 7 sections: 1. Introduction, 2. writing and erasing, 3. Lee’s case against string theory, 4. Lee’s case for pluralism, 5. The overuse and misuse of the notion “revolution”, 6. Lee’s ideas on fighting sociology and revolutionizing academia, 7. Should young scientists be encouraged to study, head-on, the fundamental questions of physics. (My answer: no!)

Part I (sections 1-2):

1. Introduction

String theory which has been dominating the area of high energy physics for the last
two decades is one of the most amazing intellectual and scientific endeavors of our time. In the last few months, two interesting books claiming the failure of string theory appeared. Perhaps the most surprising aspects of these two books, one by Lee Smolin and the other by Peter Woit is that they are non-technical and their main arguments can be understood and to some extent examined by non experts.
Peter Woit’s book (that I reviewed in Peter’s weblog) is clear. The chapters about physics (pp. 1-137), require some mathematics background, but are otherwise remarkably clear, and quite inspiring. The parts about string theory are more sketchy and the polemic is also very clear. Some of Woit’s central claims are outrages: Saying that string theory is an intellectual failure is ridiculous, in fact ST is a great intellectual achievement. Woit’s claims against string theorists are also wrong and are highly inappropriate. In fact, the brilliance, devotion, and integrity of the string theory community have made many string theorists leaders in the academic community as a whole, and not just in the high energy physics community. Woit’s claim that string theory failed as a viable physics theory is legitimate but he does not supply a convincing case for this claim. He does present a strong and clear opinion.

Lee’s claims are more comprehensive but are not so clear and at times are even incoherent. Lee’s book contains three (related) issues. The first is the case against string theory, the second is the case for pluralism in the high energy physics community, and the third can be referred to as “fighting sociology and revolutionizing academia”. I intend to comment on each of these topics separately.

2. Writing and erasing

A not-so-famous writer was surprised to meet on the train a famous writer and was happy to chat with him and tell him, as a writer to a writer,about the way he practice writing:

“I have these magical two hours 5:00-7:00 AM” he said, “everything is quiet, and I am fully alert and inspired. I sit at my favorite desk, I pick up my favorite pencil, and I write.”

“My own experience is quite similar,” said the famous author, “except that I write all the time, in the mornings in the evenings, when I am alert and when I am tired. “But” he continued, “just as you described, there are these two magical hours between 5-7 AM when it is quiet, I am fully alert and inspired. I sit in my favorite desk and I pick by favorite eraser, and I erase.”

Lee’s book could have used some erasing. Here is a little example: Take the story on page 275 referred to in the index as “Connes and the narrowness of string theory” (!). Does this academic urban legend really belongs in this book (or any book)? What precisely do we learn from this tale? Other examples are repetitive claims about string theory and string theorists with various quotes “supporting” them. Just like in court, “excessive repetitions”, “hearsay” and evidence which is presented in an over-argumentative manner weaken the quality of the argument.

My review is a critical look at Lee’s book based essentially on the description in the book itself. Of course, I cannot make a judgment on substantive matters regarding physics. For part 3) I plan to look at two items which are central to Lee’s case, but please have a look too. The first is: does the story related to Mandelstram and string theory finiteness, supports Lee’s claim or rather support string theory? The second is does Lee’s interpretation of what Maldacena’s conjectures tells us about this debate, reasonable? A food for thought is: would Lee’s case been stronger without Maldacena’s conjectures (which were discovered rather recently) being around?

Of course, closer to my heart, are the fascinating matters of pluralism in general and in science, sociology, and the right incentives for progress in science, what should the young do, etc. etc. I hope we get there.

Let me make two comments to conclude this part of my review. First I would like to point out that Lee is juggling several heavy balls together. Take, for example, the claim that string theory failed (or more precisely – “we all failed, in addressing the main problems of physics, on which we do not know more now than three decades ago – but mainly it is string theory that failed being the dominant theory” ),
and Lee’s call for pluralism. It is a delicate task to juggle these two issues together. One interpretation of what Lee is saying is that since string theory failed string theorists should pay (and should have payed) more attention to, say, loop quantum gravity. But another interpretation which cannot be avoided (especially, in view of a few “cheap shots” that had better been erased, like the above story) is that the signal given by Lee is essentially : “Pay more attention to the successes of LQG, or else…”,

Second, as interesting these discussions are, it is worth reminding ourselves that string theory as other similar scientific issues, will not be decided by polemic or by references to philosophy of science. It will be decided by scientific evidence that can be mathematical/theoretical (including applications to other areas of physics) or empirical. (The large-audience polemic/philosophical part is a lot of fun, though, and for that Lee and Peter should be thanked.)

111. nc says:

“… Saying that string theory is an intellectual failure is ridiculous, in fact ST is a great intellectual achievement. Woitâ€™s claims against string theorists are also wrong and are highly inappropriate. In fact, the brilliance, devotion, and integrity of the string theory community have made many string theorists leaders in the academic community as a whole, and not just in the high energy physics community. Woitâ€™s claim that string theory failed as a viable physics theory is legitimate ….” – Gina.

Thanks! I deplore Dr Woit’s elitism (I am of the sorry opinion that factual evidence and physics are central), I think your comment is right in the elitist sense if you replace the term “string theory” with previous elitist endeavours like “flat earth”, “Ptolemic epicycles” or “phlogiston”, “caloric”, “vortex atom”, or “aether”.

“… Saying that flat earth is an intellectual failure is ridiculous, in fact flat earth is a great intellectual achievement. Woitâ€™s claims against flat earthers are also wrong and are highly inappropriate. In fact, the brilliance, devotion, and integrity of the flat earther community have made many flat earthers leaders in the academic community as a whole, and not just in the earth sciences community. Woitâ€™s claim that flat earth failed as a viable physics theory is legitimate ….” – Gina.

I think you are right as long as no viable, predictive, checked alternative to string theory comes along, because that would change the sound of your comment to absurd, and the leadership would change. Kelvin clung on to the vortex atom even though radioactivity discredited it; he simply went to sleep during Rutherford’s lecture. Rutherford not to annoy him, so there was no great conflict. Rutherford claimed at first that x-rays etc would turn out to be a hoax. There is an elitism problem in the sense that some of us have been at the receiving end of patronising high handed behaviour since childhood and simply hate this kind of snobbery.

I had a conversation with Dr. Johnson above where he pointed out that the specifics of the physics was a very large part of the argument and couldn’t be left out of the conversation. I have to agree that he is probably overwhelmingly right.

I also think Dr Johnson had a very good point when he said that string theory as a subfield succeeds because of the merits of the string theory argument. In the sense that other physicists like the message and support it. Who else is supposed to care enough or be more qualified to judge than actual physicists?

The only thing a member of the public or anybody outside theoretical physics is qualified to judge is whether there is something undemocratic, unmeritocratic or both going on and whether they want their tax dollars to support it. This information is usually ferreted out by the media. But in order to make this determination, more and more invasive and personal information is required. In politics I think they call this ‘accountability’. So it’s not really a surprise that, having made all this public, things have been turning nasty.

However, this process described above is not about doing what is best for ‘science’. It’s about doing what is most desired by society.

I do find Woit’s claim extraordinary. Professional scientists at top institutions with numerous honors are not doing ‘science’. He says this from the position of quite being a professional scientist himself.

His further extraordinary claim is that he supports elitism and yet he is ‘jumping the queue’ so to speak. He published his book to be read by a huge public. It has been written about in several rather public magazines and newspapers. Was this an accident. Hardly. It was of course widely marketed … this seems a populist’s approach to argument …

I do wish he’d address the deep contradictions in his approach. What makes him feel he has the right to challenge, and more importantly damage the reputation of those, who by his own account are his intellectual betters? He has done this by publishing to a wide audience who can not possibly make an informed decision.

113. nc says:

This information is usually ferreted out by the media. – The Graduate.

Dr Woit came up with the following response to my work:

http://www.math.columbia.edu/~woit/wordpress/?p=215#comment-4081

“Iâ€™m tempted to delete the previous comment, but am leaving it since I think that, if accurate, it is interesting to see that the editor of PRL is resorting to an indefensible argument in dealing with nonsense submitted to him (although the â€œâ€¦â€ may hide a more defensible argument). Please discuss this with the author of this comment on his weblog, not here. Iâ€™ll be deleting any further comments about this.”

This is certainly elitist and high-handed (he is supposing that my work is “nonsense”). However if I was in his position, I’d behave the same way I suppose. I’m fortunate to have had the opportunity to see a lot of suppressed ideas, find where they are wrong, and find a workable predictive technique. The problem is well stated by Edward Witten in his recent letter in Nature:

â€˜The critics feel passionately that they are right, and that their viewpoints have been unfairly neglected by the establishment. … They bring into the public arena technical claims that few can properly evaluate. … Responding to this kind of criticism can be very difficult. It is hard to answer unfair charges of Ã©litism without sounding Ã©litist to non-experts. A direct response may just add fuel to controversies.â€™ – Dr Edward Witten, M-theory originator, Nature, Vol 444, 16 November 2006.

Dr Witten isn’t responding to Dr Woit so much as Smolin and others with quantum gravity alternatives. Dr Woit feels insulated – and probably is insulated – by the fact that his own work is in understanding the Standard Model better, not tackling quantum gravity. Dr Witten wants to ignore critics completely, damp controversy, and “explain” to “non-experts” what the elite are doing. You have to admire the fact that he has put it in writing!

114. nc says:

(Controversies in mathematical physics are a storm in a teacup as far as most journalists are concerned, so Dr Woit deserves credit for stirring up any interest at all.)

115. M says:

nc,

experts largely agree on the existence of something like 10^500 different string compactifications, and non-experts can see that it is a huge problem. So, it seems to me that the “elitism” issue does not have much practical relevance.

116. nc says:

M,

No, elitism is central in deciding whether the “huge problem” of the 10^500 Standard Models in string theory are a blessing or a curse. If I had even a much smaller problem, it would be seen to debunk me. But if the elite have such a problem, it is seen quite to be quite the opposite: a reason to give them more money and time to tackle it.

This problem reminds me of the saying attributed to captured pirate Dyonides, when he was brought before before Alexander the Great and asked to explain himself:

“I use a small boat, so I am called a pirate. But you do exactly the same using a navy, so you are called Emperor!”

117. Peter Woit says:

As I’ve repeatedly pointed out, my book was originally submitted to a university press, and my intention was that it was not designed for a very large audience. If I had wanted to write a book designed to reach as large an audience as possible, I would have written a very different one. The fact that it was not published by a university press but by a publisher that marketed it to a wider audience is the result of the fact that two string theorist referees stopped it from being published by Cambridge, and Lubos Motl stopped it from being published by Princeton.

My book contains scientific arguments about string theory, not personal attacks on string theorists. I, and anyone else, has every right to argue that some members of an elite are wrong about something. The claim that certain members of a scientific elite are promoting research that is not science is not some bizarre idea special to me. A large fraction of the elite of the physics community has similar opinions about this, in particular about Susskind’s claims concerning the anthropic landscape.

Undoubtedly some people whose ideas I criticize are my intellectual betters, and some aren’t. Witten certainly is a lot smarter and harder working than I am, this doesn’t mean he isn’t sometimes wrong in his judgements. When I say that I’m an “elitist” I’m not saying that members of elites are always right, and that non-members of an elite don’t deserve to be paid attention to. I’m just saying that, in this particular field, elite institutions and their members play a very important role and the health of the field very much depends on them.

118. M says:

nc, Dyonides also said: “sed si circa me fortuna mansuesceret, fierem melior; e converso tu quanto fortunatior, tanto eris deterior”.

119. nc says:

Was Dyonides there warning Alexander not to suffer his misfortune by being caught, or was he saying that it would have been a graver misfortune for him (Dyonides) to follow in Alexander’s footsteps and become an Emperor? (Never studied much Latin and a cousin who did A-level Latin is away in the army so can’t help out. Online translation is little use.)

120. M says:

maybe I misunderstand this decadent-age Latin, but apparently Dyonides warned that stopping at 10^120 vacua would be fine, while the huge luck of 10^500 vacua might deteriorate physics.

121. Gina says:

Just to clarify, the part of Peter’s argument that I found inappropriate are pages 223-225 on Chapter 16. I do not think it is a large or especially important part of Peter’s overall argument, which was all the more reason to keep it out. In fact, this is precisely the justified concern Peter himself (somewhat) had as described on the last paragraph of p. 225.

122. huh says:

Peter:

The funny thing is, you assume people “stopped” the book from being published out of
unjustified hostility, or defensiveness. Having looked through it, I am surprising it was
published, simply because it isn’t very interesting. A non-expert on scientific field
X takes the experts to task because he doesn’t like what they’re doing. Such books,
mocking workers in field X, could be written about ANY field at ANY time. Your
qualifications and achievements in science, which sound impressive when misreported
(“a professor at Columbia! Wow, he must be at the top of his field”) are in fact
dwarfed by those of essentially everyone you criticize. It should occur to you that
negative reviews of your book by experts, and general neglect of your criticism, occurs more
for this reason than because anyone is being defensive.

123. gina says:

Huh, Peter’s book is actually quite interesting.

124. Peter Woit says:

Huh,

Since you think it’s a good idea to attack me from behind the cover of anonymity (what’s up with that, do you have a clue how unprofessional this kind of behavior is?) I don’t have any idea what your background is and thus whether or not you should find the book “interesting”. On the whole I’ve been extremely pleased by how the book has been received and by how many people, experts and non-experts, have found it interesting (and it seems to be selling quite well, thank you). In particular, several ex-string theorists have privately written to tell me they thought very highly of the book. The Cambridge referees did not complain that the book was uninteresting, they just objected to the idea of this kind of criticism of string theory appearing publicly, backed by CUP. Lubos Motl’s referee report was, well, Motlesque, not about the book being uninteresting.

125. Clifford says:

“In particular, several ex-string theorists have privately written to tell me they thought very highly of the book. ”

Just thought I’d highlight that.

-cvj

126. Peter Woit says:

Thanks for highlighting that Clifford. Interesting that you seem to have no problem at all with string theory partisans engaging in anonymous attacks on me, but appear to object to my keeping anonymous the names of people who have written supportively to me in private.

By now there are quite a lot of people around who have worked on string theory at one point or another during the last twenty-some years, but stopped doing so and decided to do other things. I suggest you try contacting some random selection of them and asking them what they think. You might find this very enlightening.

127. Clifford says:

but appear to object to my keeping anonymous the names of people who have written supportively to me in private

Wrong again Peter. It’s the “ex-” part that I found interesting.

-cvj

128. Charles says:

Dear Peter Woit,

I haven’t read your book, but regardless of the tone of huh’s mail, he does have a point in that you are not an expert on string theory. Despite your academic credentials giving you authority in your own field it would be wrong to assume that this authority is transferred to another field such as string theory.

Actually, because you aren’t an expert in this field is the reason I don’t own your book whereas I do own books by e.g. Greene and Randall. How would you convince me that you have the authority to say something about the subject?

As an analogy, If an air crash survivor wrote a highly popular book criticising air-safety, I would not be surprised that the human interest element would make it very popular, but I wouldn’t buy it. Nor would I find it an especially convincing argument to hear that the author received private messages of support from other air crash survivors.

129. Lee Smolin says:

Dear Charles,

You seem to have a mistaken idea about the expertise needed to evaluate research in string theory. String theory is an outgrowth of quantum field theory and the expertise needed to work in it is a thorough background in quantum field theory, general relativity and some associated topics in mathematical physics, particularly conformal field theory and a bit of complex manifold theory. This is the same expertise needed to evaluate claims made within and about the theory. Peter Woit has these qualifications and, indeed the technical statements made in his book are for the most part correct. The same goes for most of the other physicists who write about string theory, whatever our point of view. Indeed, I would say that on some issues Woit has a more detailed and accurate knowledge of the literature than some working string theorists.

Let me make a better analogy than your air-crash victim analogy. Suppose there are 5 approaches to treating a particular cancer. Each has its proponents. Judgments about how each one succeeds are not reserved for those working in each approach, it is accepted that the community of people who work on cancer generally has the expertise to objectivity evaluate the claims made by proponents of different approaches. Progress is conceded to occur when the evidence convinces this larger group of experts, and not just those working in that particular area.

The point is that the measure of success of any scientific research program is not the degree of agreement there may be among those who work exclusively on that program. There is, in each general research field, a larger community of people with the expertise to evaluate claims made by different research programs in that field. With respect to string theory that larger field includes all those trained in theoretical and experimental physics who work in quantum gravity, cosmology and/or elementary particle physics. To succeed, each of us who has a research program in the area has to amass enough evidence to convince all those that do not work on our research program that our approach is correct.

The books by Peter Woit, Laurence Krauss, Roger Penrose, Lisa Randall, Lenny Susskind, Alex Villenkin, myself and others are part of the conversations going on among this larger group of experts in which we are assessing claims made by different research programs. Each of us has the expertise, and is part of the larger community of experts that proponents of any one research program must convince. What is clear is that no research program within fundamental physics has reached the stage where it has gained consensus among the broader community of experts. What we are then discussing is what to do from this point on. In my view, there are interesting and important things we all could and should be discussing, and attacking the expertise of people who are in fact experts is a barrier to moving on to those substantive discussions.

If there are proponents of any particular approach, string theory or something else, who insist that they alone should be the judges of progress in their research program, they misunderstand how science works. First because in fact anyone with a training in quantum field theory and general relativity can learn enough to read the papers for themselves and evaluate the field. Second, because the ethics of science requires that the community of people with this larger expertise are the court in which the claims of any research program are to be judged. From this point of view, the subclass of people who have worked sometimes, but not exclusively on a research program have a useful role, because they have done the hard work needed to learn the details of a field, but either never had or have given up a personal commitment to it that might cloud their judgment.

Thanks,

Lee

130. Clifford says:

Lee, as regards your last paragraph, I repeat my last point in the post (and written several times elsewhere). In short, we should onvince our peers to engage in (or recommend support of) a research program by providing ideas that have great promise, and a track record of promising results, and so …

If they [Smolin and Woit]] want people to work on alternative ideas, why not present these ideas to everyone – develop these research programs to the point where people will work on them because they can see their merits? Theoretical physicists will work on the best or most promising tools out there that will do the job. Weâ€™re fickle. We donâ€™t care whether they are loops, strings, or whatever. Just that they get the job done. Show us something more promising than string theory and weâ€™ll drop string theory like a hot ton of bricks and work on that. So, Smolin and Woit: Please do some research that will help us get the job done by providing us with real alternatives through the usual channels which are available to everybody. The job wonâ€™t get done in the media-assisted way you are doing it right now.

Cheers,

-cvj

131. Peter Woit says:

Charles,

What I’ve always found to be one of the most attractive features of science is that it’s not about appeals to authority. The reason you should believe a scientific statement is not that the person who said it is a professor at Harvard, but that it can be backed up with logical argument and experimental evidence. I’ve spent all my adult life working at universities in math and physics departments, learning about math and physics related to particle physics. In my book I tried hard to make scientifically accurate statements, to explain what backs them up, and to provide references to where one can go to learn more details. I was assuming most people reading my book would have previously read Brian Greene’s or otherwise know the material he covers. I think if you look carefully at Brian’s book and at mine, you’ll find that we really don’t disagree on many if any matters of fact. He’s an enthusiast for string theory and in his book is trying hard to transmit that enthusiasm. From him, you’ll learn the facts that have made some people enthusiastic about string theory. What, on the whole, isn’t in his book are the facts that make many physicists dubious about the theory’s prospects, and I thought it would be a good idea to explain those.

If you’re interested in getting a full and accurate view of the achievements, prospects and problems of string theory, I think you’re not going to get it by just reading Brian’s book. I’d suggest you really should also read my book or Lee Smolin’s, then think for yourself, and try and learn more from other sources about the issues that strike you as critical. That’s what science is all about.

132. gina says:

Dear all,

Concerning Peter’s book, as I said, I found it interesting and the part all the way to the standard model, gave me a lot, Lubos, although I did not know this physics yet. If you are aware of a better popular book on particle physics, which does try to explain some of the mathematics, please let me know.

As far as I know, books appearing in a university press should present a novel academic contribution. In the case of Peter’s book, I do not think there is a claim, even by Peter, that the book contains new physics research, so the novelty must be in the evaluation of string theory which is roughly related to the areas of philosophy, history and sociology of science. Of course, a sound description of the physics itself is a necessary condition, but far from being sufficient. Lee is correct that an evaluation of string theory does not require the author to be a string theory expert. But to make an evaluation of academic quality of string theory as any other field, some relevant academic experience in academic writing ABOUT science (not writing physics papers) that Peter does have can be helpful. Lee and many prominent physicists who write popular books (that are published by commercial publishers) about physics do not have such academic experience as well.

My interpretation of the rejection by university presses is that the book does not contain a novel academic contributions in these areas. (And Peter is not an expert in these areas; this is more relevant than his physics credentials.) This appears to be a reasonable assessment by the publishers.
In particular, Tte arguments of Peter against string theory appears to be largely known. Maybe it is important to collect and popularize theses arguments and maybe it is not, but this cannot be considered as a novel academic contribution. In addition, the rhetorics, and choice of material make the book very different from the academic style of university press books. (Maybe the book is “too interesting” in this respect.)

This matter can be examined empirically. Peter, look at the handful of books that appeared in recent years in Cambridge, Princeton and Harvard university press, on major scientific controversies. Then compare the novelty of the argument, the academic contribution, the style and rhetorics, and the credential of the authors (NOT necessarily in the controversial scientific area itself) to your book.

(But I also do not see what is the big deal about the publisher.)

133. Gina says:

among other annying typing mistake, there was a missing NOT, it should be:

But to make an evaluation of academic quality of string theory as any other field, some relevant academic experience in academic writing ABOUT science (not writing physics papers) that Peter does NOT have can be helpful.

134. huh says:

Science is not about appeals to authority. But we all know that many scientific fields do
require years of experience (even post PhD) to get anything like a global view of the
goals, results, and outstanding problems. Accomplished theorists like Susskind and Randall
(who have great achievements that have nothing to do with string theory, as well as
amazing results in string related research) clearly have perspective. Less accomplished but
active workers, or even people who have done essentially no research, are accordingly
less likely (or at least, less proven) to have this kind of perspective. It is reasonable
to question whether a book by someone without the achievements in science that indicate
this kind of perspective, should be take seriously.

Anyone can write a book attacking anything. For many it is perhaps the only route to their
15 minutes of fame. I don’t guess that such books would generally be very valuable.

135. Gina says:

“Anyone can write a book attacking anything. For many it is perhaps the only route to their 15 minutes of fame. I donâ€™t guess that such books would generally be very valuable.”

Huh: It is quite difficult to write a paragraph, or a section and it is probably very very difficult to write a book. Certainly not anyone can write a book, and certainly not anyone can write a book attacking anything; it is difficult. And when you write a book, it is far from being guaranteed that you will be able to publish it at all, even without being picky about the publisher. So this is not an easy path to fame.

Perhaps some of you can help me with an informative question: among high energy theoretical physicists, say in North America, how many roughly belong to the main parts of high-energy physics. (And what are the main parts?) Thanks!!

136. Lee Smolin says:

Dear Clifford,

Thanks, and in reply I mentioned six recent results that I believe will, if you study them, convince you that the manifestly background independent approaches to quantum gravity are doing just what you ask for. After this there was a long diversion about 2+1 gravity to discuss the issue, â€œhow can there be a uniqueness theorem when Carlip says the quantization of 2+1 gravity is non-uniqueâ€ in which I gave the answer (I wonâ€™t repeat it, it is above.) So my point remains, the LOST uniqueness theorem and the other results I mentioned are very worthy of study and I believe will convince an objective expert that the conditions you mention for being taken seriously are satisfied.

Indeed, in the recent past interest in these approaches is growing significantly as a result of these results. So the process you suggest should happen is happening.

Dear Huh,

If you want to play that game, we can line up accomplished people on every side of this debate. This is what makes it interesting. Having achieved great things is not determinate of what side of these debates someone will take. Anderson, Connes, Feynman, Glashow, Gross, Laughlin, Penrose, Polyakov, Randall, Susskind, â€˜t Hooft, Weinberg, Wilczek, Witten, are all esteemed theorists who have the highest honors, yet they have among them diverse and divergent views on the issues under discussion. So no form of appeal to authority will do. Luckily this is science which means that we believe in the power of logical arguments from the public evidence. Evidence includes experimental evidence and the record of which calculations have and have not been done by which theories.

The books that have been written on different sides of the debates about physics are built around arguments. These arguments are there to be criticized and weighed, which is indeed why they were published. If you want to participate in the debate you have also to make arguments. Insulting people or appealing to authority in one form or another just wastes our time, and we do not have infinite time.

If there were errors of fact or interpretation of technical results in these books someone would certainly have pointed them out by now. In fact, as Peter says, on all the major technical issues there is no disagreement of facts between Peter and myself and proponents of string theory. It is natural and good that there is a range of views about what to do among experts, given that the situation is genuinely mixed, that is it containts strong evidence to support both optimism and pessimism about the ultimate success of the major existing research programs. What this means is that we each have an opportunity to think for ourselves and place bets, where what we bet is mainly the efforts we put into working in different directions. In my book I tried to argue for a particular placement of bets, one that is not easily characterized as pro or anti string theory, but which mainly favors diversifying the bets across a range of approaches including string theory.

What has impressed me in the debates around my book and the other books is the large amount of time spent on peripheral issues such as who has the right to discuss what, compared to the very small number of times when someone has actually engaged with the actual arguments in my book, or those of Woit, Krauss or Penrose. I can count on one hand the number of times someone has made in print or online an argument of the form, â€œSmolin, or Penrose or â€¦ makes the following argumentâ€¦.. leading to the following conclusionâ€¦., but it is wrong because he makes the following mistake in reasoningâ€¦..â€ I expected disagreement but I never expected that the disagreement would so rarely engage the actual arguments which make up the content of the book.

Thanks,

Lee

137. Clifford says:

Indeed, in the recent past interest in these approaches is growing significantly as a result of these results. So the process you suggest should happen is happening.

Great. So what is the problem then? I still just don’t get what the fuss is about with you and Peter when it comes to string theory. This speaks again to the last part of what you say:

I expected disagreement but I never expected that the disagreement would so rarely engage the actual arguments which make up the content of the book.

I expect that is largely because people are confused as to what the fuss is all about. The points about career paths, recognition of ideas, and apportioning of resources and the like have *nothing* to do with string theory…. they are points that can be made anywhere in academia. So I think people are confused as to this whole strategy of attacking string theory when the main thesis seems to be about the standard structures of academia. *That* might be why. Frankly, I can’t see why you are surprised, for all the reasons mentioned before. You’ve written an attack-book, in most people’s minds, and one which paints a picture that many do not really recognise. This is not how you start a reasonable discussion. I’ve said this before as well.

-cvj

138. M says:

Huh, do you know that personal attacks and “ipse dixit” arguments reinforce the view that the field is ill?

Answering to your point, I think that the books by Smolin and Woit raised simple concrete issues. It is not something new that requires deep expertise and that all string theorists missed, but it something that nobody liked or dared to openly discuss, and the current atmosphere explains why.

139. Gina says:

“I can count on one hand the number of times someone has made in print or online an argument of the form, ‘Smolin, or Penrose or â€¦ makes the following argumentâ€¦.. leading to the following conclusionâ€¦., but it is wrong because he makes the following mistake in reasoningâ€¦..’ ”

Here are a baker’s 15 points, some central, where, in my opinion, Lee’s argument is incorrect, or at least problematic.

Dear Lee, I truly (perhaps naively) think that I am doing you a service by trying to attack your argument; there are, of course, things I liked in the book. I will be happy to elaborate on each of these points.

1. Asserting that there was no progress on the five major problems of Chapter 1 is incorrect or at least very problematic.

2. (Even ignoring 1.) Interpretation of the lack of progress or the small progress in answering the five major problems as a definite failure is very problematic.

3. The interpretation of the ” Mandelstram story” as mainly damaging to string theory is incorrect.

4. The interpretation of Maldacena’s conjecture is biased. Lee’s interpretation is not sufficiently positive towards the ST endeavor even unreasonably so.

5. The substantial reliance of Lee’s case on how to interpret Maldacena’s conjecture is by itself damaging to his case.

6. The issue of plurality should be studied from a wider perspective.

7. Lee overlooks (or neglects) a more serious concern about plurality in the high energy physics community (which is potentially problematic to his other claims, though.)

8. It is strongly implied by Lee but not explained that it is not reasonable that string theory and drastically different quantum gravity approaches will develop separately. E.g., that string theorists should be on top of development in LQG. As a matter of fact, it seems quite reasonable that (,e.g.,) ST and LQG will develop separately.

9. Many claims, stories and quotes against the string theory community are not really damaging to the ST community and and bringing them weakens the quality of Lee’s argument.

10. Talking together about the scientific and social issues including funding is by itself very problematic. Not being sufficiently aware of this difficulty is a mistake.

11. (Conjectural) Although a substantial part of Lee’s argument is about sociology there appears to be no real interactions with social scientists.

12. Contrary to Lee’s suggestion young scientists should not be encouraged to attack head on fundamental physics problems.

13. The reactions portrayed negatively to sporadic bold theories and ideas (like ‘t Hooft’s) are, in fact, very reasonable. Scientists current attitude is essentially the correct attitude.

14. Lee’s ideas on revolutionizing universities is not detailed and the hints we get are not promising.

15. Some natural or even positive social processes in academia (regarding academic judgment and decision making) are portrayed negatively. This is a mistake.

16. Lees sais that science clearly calls for a revolution. Maybe the opposite is true. Lee sais that science is now more conservative (anti revolutions) than ever. This is incorrect. The whole “revolution” terminology is crooked.

140. Lee Smolin says:

Dear Gina,

Thanks very much. I’d be very interested if you expanded some of these points. To make it easier to manage, shall we take one at a time. If you expand on one and explain why you disagree I will respond accordingly.

Thanks,

Lee

141. nc says:

Lee, I’d like to raise the issue of public perception of what Loop Quantum Gravity (LQG) is about. Anyone can understand what string theory is about: string.

“Loops” is ambiguous because most people think of either the loops of pair production charges which occur above the IR cutoff and annihilate to radiation which undergoes pair production, and so on in a cycle of rapid transformations.

The loops of quantum gravity are clearly a physical representation of the curvature of spacetime. Woit explains this clearly in his book: the rotation of vectors as exchange radiation travels between two masses gives rise to the loop quantum gravity representation of GR.

The mathematics you describe Perimeter Institute lectures is summing the interaction graphs for a Penrose spin network to get a QFT path integral which gives GR with background independence (without metric).

If the Penrose spin network nodes in spacetime for gravity are real masses, what you are modelling mathematically in LQG is a Yang-Mills exchange radiation scheme between masses? Will expansion of universe redshif the exchange radiation, killing off gravity attraction over large distances?

(Hence, no need for dark energy, because the distant galaxies simply aren’t being decelerated; so the apparent acceleration which is needed when you falsely use GR with distant-independent G, is not real because GR is simply wrong for neglecting this redshift effect on quantum gravity.)

142. nc says:

{Above para 2: I meant “Loops” is meaningless; most people think perhaps you mean that particles are like loops, or they think you are talking of the annihilation-creation loops above IR cutoff energies. Actually, it seems you are dealing with loops in which gauge bosons are exchanged between gravitational charges (masses).}

143. Gina says:

Thank you very much, Lee, for your willingness to discuss this matter with me, and thank you very much Clifford for your willingness (I hope ) to host it in the back yard of this old post.

As you suggested, Lee, let’s take it one at a time. I will elaborate on each one of my points in my free time, you are most welcomed to reply, as you see right. Unless emergency occur I will not reply to your replies; Here, we do need to converge. Points 3-5 are furthest away to my own interests in this debate so let’s start with them.

3. The interpretation of the ” Mandelstram story” as mainly damaging to string theory is incorrect.

Here the story is about “finiteness of string theory” that was claimed by string theorists based on the work of Mandelstram. There was some mathematical evidence to that effect before Mandelstram. However, as Lee pointed out, Mandelstram did not present a proof but rather a partial mathematical evidence and it took 17 (!) years until further stronger mathematical evidence were presented. (I will use quotation marks referring to technical terms like in “finiteness of string theory” when I want to emphasize that I am not on top of the technical issue; of course, this does not mean that when I do not use them I am.)

This story is overall not damaging to string theory. Theoretical works are at best only mathematical evidence. Even if there is a mathematically rigorous proof, it is only evidence as there are always questions about the relevance and interpretations. As Lee explains, what physicists refer to as “proofs” usually does not qualify as a mathematical proof. In this case Mandelstram work was not a full “physics-quality proof” but something less. Still it gave some evidence in the expected direction. It did not make sense to put string theory on hold and to wait 17 years for a stronger evidence that indeed came.

Mandelstram’ story is brought by Lee in the context of string theorists optimism (or excessive optimism). The meaning and nature of optimism in science is probably a subject to a whole separate discussion. This is a case that as far as I can judge, both the overall optimism and the mode of operation of “moving on” were justified. The excessive claims about Mandelstram’s result and their “foggy” status for many years were not justified and unnecessary.

144. Peter Woit says:

Gina,

It seems to me you completely mischaracterize and misunderstand Smolin’s argument here, including even getting the name of the relevant physicist wrong (it’s Mandelstam, not Mandelstram). Why do you think it is a good idea to publicly criticize Smolin over an issue you admit that you don’t understand?

Smolin was not saying string theorists should not have “moved on” and conducted research under the assumption that the conjectured multi-loop finiteness would work out, he was just saying that he was surprised to find that almost all string theorists he asked thought that this conjecture had been proven by Mandelstam, when it hadn’t been.

An interesting example of this phenomenon that is now getting a lot more attention is kind of the opposite of the finiteness claims, it is the conjecture that N=8 supergravity is not finite. The standard claim of string theorists has been that you can’t have a finite quantum field theory of gravity, since the best hope for this, N=8 supergravity, has potential divergences at high enough order. So, the conjecture has been that N=8 supergravity is not finite, and many people until recently might have told you that, at a physicist’s level of rigor, N=8 supergravity was known to not be finite. However, recently people have found arguments that indicate the opposite, that the theory might actually be finite.

Dr Woit,

“… at a physicistâ€™s level of rigor … ”

Could you elaborate on this part? I have a post touching on this on your site. It went like this:

I have one question however. I have been wondering about the way theoretical physicists argue mathematics. I understand the mathematical way of proving statements. But Iâ€™ve been confused by the way physicists argue in mathematical sketches. How does one decide which of the debaters has â€˜wonâ€™ ? It seems to me entirely possible to string together plausible conjectures and get several contradictory statements. And that indeed seems to happen often. I would appreciate some insight into this aspect of theoretical physics culture.

(This is just a question for my personal education, to help me follow the arguments being made.)

146. gina says:

Hi Peter,

I apology for the mispelling Mandelstam’s name. It should not have happened.

I raised 16 points that I felt Lee’s arguments were not correct or problematic. This is an academic discussion and not a public criticism, and I truly think that such critique can be useful, even if I am wrong on all the 16 points.

Three of my 16 points were on more technical issues, but I feel that I can understand Lee’s logical argument even without understanding the precise technical nature of “finiteness of string theory” (I do have a vague impression of what it is.) I think that my interpretation of this issue is reasonable and my critique stands.

To the best of my judgement, I do not mischaracterize or misunderstand Lee’s argument. (Even if I do, since the book was meant for people without technical skills, my misunderstanding may still suggest that the presentation could be improved.)

This was an example which was suppose to have shown that string theorists were over optimistic. But in this case the optimism appears to have prevailed. A much better example would have been a central case where string theorist have claimed one thing and eventually the opposite was proven.

(Now, again without understanding the technical details, your N=8 story, is of some interest, and I suppose that we will have to wait and see how things will develop and what is their meaning.)

147. Gina says:

Peter, let me just add that I feel that it is you who mischaracterized Lee’s argument on this matter. How can you say “he was just saying that he was surprised to find that almost all string theorists he asked thought that this conjecture had been proven by Mandelstam, when it hadnâ€™t been” when the discussion of Mandelstam results spans 4 pages of Lee’s book?

Also when you talk about “this phenomenon” it seems that you have a certain difficulty in the understanding of how science is practiced. At the end (in best of cases) all pieces fit together and it all looks wonderful. But a long the way there are many misunderstandings and conflicting pieces of information and sometimes even mistakes.

148. Plato says:

Gina,

Please let Lee Smolin respond. I am finding this very interesting. I think this is a good way that is being handled with Lee Smolin and he is in agreement to answer you.

149. Lee Smolin says:

Dear Gina,

Thanks. The issue has a scientific component and a sociological component. Science first:

-Perturbative finiteness is a major element of the claim of string theory as a potential theory of nature. If it is not true then the case for string theory being a theory of nature would not be very strong.

-Perturbative finiteness has not been proven. There is evidence for it, but that evidence is partial. There is a complete proof only to genus two, which is the second non-trivial term in an infinite power series, each term of which has to be finite. The obstacles to a complete proof are technical and formidable; otherwise we would certainly have either a proof or a counterexample by now. There is some progress in an alternative formulation, which has not yet been shown to be equivalent to the standard definition of string theory.

-This is not an issue of theoretical physicists rigor vrs mathematical rigor. There is no proof at either level. There is an intuitive argument, but that is far from persuasive as the issue is what happens at the boundaries of super-moduli space where the assumption of that argument breaks down. In the formulation in which there is a genus two result it is not clear if there is an unambiguous definition of the higher order terms.

Is string theory in fact perturbatively finite? Many experts think so. I worry that if there were a clear way to a proof it would have been found and published, so I find it difficult to have a strong expectation, either way, on this issue.

The sociological issue is not that most string theorists chose to continue to work on other problems in the hope that someone would eventually resolve it. This is fine, we all do what we can do and many of us theoretical physicists do not have the inclination or talent to work on such a difficult and subtle mathematical problem.

The problem is that many presentations of string theory, for the public as well as for colleagues, seem to have been misleading on this issue. Many people I spoke to were under the impression that perturbative finiteness was an established fact. To find out why I looked at many review papers for physicists and popular books and only a few of them correctly characterized this issue. Most gave the impression that perturbative finiteness of string theory is a fact. There were a few, including textbooks, that did characterize the situation correctly and I mentioned this in the book.

Was this a problem? I think it was. I donâ€™t believe anyone was deliberately dishonest about this, but there was an atmosphere in which belief in the theory went beyond the evidence in the published papers. Did this contribute to many, in and out of physics, having the impression that the problem of quantum gravity was already solved by string theory? I am not an historian or sociologist, but I worry that this might have been the case.

You claim that my discussion of this issue is â€œdamaging to string theoryâ€. I donâ€™t think it is if by â€œstring theoryâ€ you mean that string theory is of interest as one of several interesting approaches. It is damaging if by â€œstring theoryâ€ you mean not the theory itself but the claim that the evidence for string theory is so compelling that it alone deserves a special place as the only direction worthy of intensive investigation; “the only game in town”, as some proponents continue to insist.

Thanks,

Lee

150. Tell me something, Lee. Have you read Atick Moore and Sen’s two papers on the subject (190 pages, total) that you dismissively characterize as “an intuitive argument.”

151. Plato says:

Jacques Distler,

Just wondering if you can “link” articles.

“The Trouble With Physics,” by Lee Smolin, Index page 382, Mandelstam, Stanley, and string theory finiteness, pages 117,187, 278-79, 280, 281, 367n14,15

152. Peter Woit says:

Tell me something, Jacques. Have you read any of the post-1980’s literature on this subject (e.g. d’Hoker and Phong, more than 190 pages, total), that you dismissively ignore when you characterize Atick Moore and Sen as providing a proof of multiloop finiteness?

153. Not only have I read d’Hoker and Phong (have you?), I have taught about it in my course.

I think their work is a tour-de-force.

But, actually being familiar with the existing literature (in which Atick, Moore and Sen is merely the culmination of a long series of papers by various authors) is something of a prerequisite, in order to properly understand what d’Hoker and Phong achieved.

154. And, since we had an extensive discussion of the status of superstring perturbation theory, including a detailed discussion of d’Hoker and Phong’s work, can I assume, by your question, that none of my explanations had any impact on you?

No wonder these blogospheric “String Wars” discussions never achieve anything.

155. Plato,

Using SPIRES to search for the papers in question would be a handy skill to learn.

156. Peter Woit says:

Jacques,

Yes, your “explanations”, together with some time spent learning more about this by reading and talking to experts, did have an impact on me. It helped to demonstrate to me that one can discuss scientific issues seriously with many string theorists and learn a lot from them, but that trying to do this with certain of the more fanatical ones is just a waste of time.

157. Tell me, again, what this comment was about, then?

A subtle reminder to me to link to my blog posts about d’Hoker and Phong’s work (I,II,III,IV)?

Or just gratuitous nastiness?

158. Peter Woit says:

“gratuitous nastiness”?

No, it was simply a commentary on this comment.

159. Plato says:
160. Gina says:

Dear Lee, Thank you for your reply and good spirit. I will elaborate on my comment 4 and 5 that are both related to Maldacena’s conjecture and will take the simpler and more important point 5 first. (If you find fit to reply please indicate the number of the comment.)

My basic understanding of Lee’s book is that his argument is asserting the failure of string theory to reach any progress in the basic questions of physics in the last three decades. (This is what Lee says and this is my point 1 of disagreement.) If Lee’s argument regarding string theory (as a scientific theory) is just that string theory did not succeed yet, or that there are some concerns about specific results, as well as the whole endeavor, then this is a different matter. I do not think what Lee writes in his book supports such a mild interpretation. (But in this case, my objections 3,4 do not apply, 5 stands but is weaker, while the other objections still stand.)

5. The substantial reliance of Lee’s case on how to interpret Maldacena’s conjecture is by itself damaging to his case.

The fact that such a major part of Lee’s argument is dealing with the validity and interpretation of Maldacena’s conjecture speaks for the viability of string theory. Maldacena’s conjecture is not a 19th century conjecture that failed proofs for centuries, but something that had happened less than 10 years ago. Lee’s argument against string theory without Maldacena’s works around would have been stronger.

The issue of proofs and precise interpretation of Maldacens’s conjecture is secondary to the issue if string theory is viable enough to produce developments of such magnitude in the future. I do not see any argument why we cannot expect further such development.

161. gina says:

4. The interpretation of Maldacena’s conjecture is biased. Lee’s interpretation is not sufficiently positive towards the ST endeavor.

In addition to a very nice and non technical description of the conjectures and relations to earlier physics discussion, Lee’s assertions on this matter can be summarized by:

1) Even if true, the strong Maldacena conjecture does not bring the theory to where I would like it to be.

2) There is only strong support to a weak form of the conjecture with much less consequences.

3) These are not conjectures in the strict sense of mathematics as the objects themselves are not mathematically defined.

4) Because of the excessive optimism, the strong conjectures are assumed to be true and very few people are working towards a proof.

I was somewhat confused by Lee’s comments to my point 3. If the main issue at hand is that “…many, in and out of physics, have the impression that the problem of quantum gravity was already solved by string theory”, then Lee’s points are certainly reasonable to shed doubts concerning such an impression. But if Lee claims that no progress have been made, or that string theory failed, then his points do not seem to support such claims.

Also, regarding the third point, there is nothing special about this case. The third point reflects a certain “divorce” between mathematics and physics which occurred long before, and was a consequence of physics earlier spectacular successes. (Which show you that successes carry with them problems too.) The excessive optimism of point 4) is not a sociological issue but rather is a bold scientific methodology taken in string theory for better or for worse.

Two remarks:
a) One issue which is relevant to all the previous items and to the whole discussion is the matter of “how to measure progress” and “how to measure partial success”. This is an important question here as in other areas of science (and life). If we are too quick to declare progress we may end up nowhere or with self illusion and self deception. If we are too slow we may not get even started. I suggest to keep in mind the issue of “how to measure progress” for the discussion of other points of disagreement.

b) Following Peter’s criticism for my first item, I did try to learn more about ADS/CFT issue and looked at Penrose’ book. I did not make much progress but this was a delightful experience. Penrose discusses the technical details of string theory with affection and even enthusiasm, like talking about a beloved child, even if he does not subscribe to the theory at all. His skepticism is also charming, and he is also skeptical about his own skepticism. For example, look at what Penrose says about the high dimension idea – “My own reaction to this was basically: ‘there ought to be a different way around this'” – how simple, how nice! You do not need more, and it is such a good line for many purposes – “There ought to be a different way around this”. My heart goes to Roger! (And according to the pictures in Penrose’ book the universe is simply a sort of amoeba or an octopus.)

Reading Penrose on top of what I already learned from Lee and others popular sources I got the following mental picture on this ADS/CFT: You have this solid Octopus and you hit it on it’s head and hear a (wonderful) music, say, a Mozart sonata. Now, you take just the very thin outside skin (called the boundary) and you hit on that. And you hear precisely the same wonderful music. precisely the same!

162. Plato says:

I just wanted to interject with this post, and then back to regular programming.

How do you fight sociology

Because this by any of the leaders of string theory. it was left to someone like me, as a quasi “insider” who had the technical knowledge but not the sociological commitment, to take on that responsibility. And I had done so because of my own interest in string theory, which I was working on almost exclusively at the time. Nevertheless, some string theorists regarded the review as a hostile act.

The trouble with Physics, by Lee Smolin, Page 281

I have discovered one of Lee Smolin’s objection to a string theorist? They are only craftsman, and not seers. :)But truly, should we judge a book by it’s cover?:)

I like the fact that Lee went to the heart of the question about an assumption that was prevailing at the time. By finding the supporting data, the contacting of Mandelstam, about what all may have presumed to be true.

If such a conclusive statement is made about the level to which finiteness was calculated, “past genus 2,” then having moved beyond the limitations of Lee’s point’s
may indeed be a needed correction? His point about the responsibility of moving past the “sociological standards” was and is still important, so I give him credit for that.

163. I’m sorry, but I don’t understand the “sociological” argument either.

For over a decade, it was believed that the Atick-Moore-Sen (nonconstructive, “recursive”) proof of finiteness was the best that could be achieved. Then d’Hoker and Phong came along and gave a constructive proof at g=2, 3. This was a surprising, and quite marvellous result, but no one knows how to generalize it above g=3.

So I think we are in exactly the same situation as before. No one has found a flaw in Atick-Moore-Sen, and no one has found a way to improve upon it (say, by giving a constructive proof) at arbitrary g.

Lee’s “bravery” notwithstanding, how should things have proceeded differently?

164. Plato says:

Jacques Distler:Iâ€™m sorry, but I donâ€™t understand the â€œsociologicalâ€ argument either.

It is as if, “one piece of knowledge” is being transferred from person to person, as if it were true? If, “the assumption” is passed as well, and then having spent time studiously looking from where this arose from, then in fact sociologically you are attacking the basis of what has been transferred. Call it sociological at this point then?

Jacque Distler:Leeâ€™s â€œbraveryâ€ notwithstanding, how should things have proceeded differently?

In “retrospect” the argument was being handled? So by doing this, we may look forward next time? I have been studying you scientists. Mathematically you attack each situation and either refute the basis of argument by your proofs, and falsify, or you have evidence mathematically that is true?

If having sufficiently shown that you can move forward, then any reference backwards would be consistent. In the case above, there was a flaw in the reasoning based on a sociological assumption. Such “generalization” has been past mouth to mouth, hence has become part of the society.

I applaud Lee for that, while recognizing you may have shown the method has been further extended, even in face of Mandelstam response? Good for you to drawn attention this point, so we move forward.

165. nc says:

Mathematically you attack each situation and either refute the basis of argument by your proofs, and falsify, or you have evidence mathematically that is true? – Plato.

Plato, yes – in an ideal world. Unfortunately that hasn’t been identified by Prof. Susskind in the cosmic landscape.

166. Gina says:

Let us move, for a while, to the other end of the issue – to general matters of universities and academia.

15. Some natural or even positive social processes in academia (regarding academic judgment and decision making) are portrayed negatively. This is a mistake.

Here, I refer to Chapter 19.

Let me quote a few sentences with brief comments:

1. “The idea of changing the way science is done in universities is no doubt appeal to some, while horrifying others. But it’s probably in no danger of happening. To understand why we need to inspect the dark underbelly of academic life. Because as the sociologists tell us it is not just about wisdom, it is about power; who has it and how it is used.”

I find it impossible, even after reading the whole chapter, to understand what is said in these sentences which open the chapter and draw a dark and gloomy picture of universities, the way science is done in universities, and their inability to change.

2. “In academic world, with few exceptions, the people who evaluate you are older than you and more powerful.”

This may look bad at first sight, but it is not. Overall, I think that it is very reasonable that older people will have more influence.

I do not see anything wrong with old people. My perception is that old people are simply young people that have turned old along the years.

Curiously, part of the reason for this observation by Lee is not sociological at all but purely statistical. If you are young the people who evaluate you will tend to be older and if you are old the people who evaluate you will tend to be younger. This is referred to as “regression to the mean”. In academia, there are more old/senior people than young, those older guys have a larger burden of evaluation (and other administrative jobs), and when you are young you are evaluated more often than when you are old.

3. “… a process of enforced consensus in which older scientists ensure that younger scientists follow their directions”

When there is a need to make collective decisions the notions of power and influence automatically emerge. It is overall positive rather than negative that the amount of influence is positively correlated with age and with prominence. I am not aware of any mechanism which will lead to making the optimal decisions or eliminate the possibility of abuse of power. If Lee has ideas in this direction it will be great to hear them.

4. “A professor will shamelessly write letters slanted towards his or her own students”

Yes, many people do various things (usually fully legitimate but sometimes a little dubious,) to promote their points of view, and many are biased towards their own opinions, style, direction of research, and even students. Again, overall, this is a positive rather than a negative fact of life. But yes, it is a delicate and complicated issue and there are cases of abuse.

Finally, let me say that reading a book is always an intellectual experience and, even more than that, an emotional experience. My critique on the first sentences of Chapter 19 was that they do not give a clear massage. But, on the other hand, these sentences do deliver a very clear mood of disappointment, and, to some extent, despair from universities, the way they do science, and their ability to change. Similarly, while there are some few nice insights and good concerns in this chapter the discussion is overall emotional (which is welcomed), but not too rational, not to say academic.

167. Gina says:

Unlike the previous four items where I could not understand Lee’s argument in this item I can understand and appreciate what Lee is suggesting. still I would beg to disagree, and I think a discussion can be fruitful and interesting.

12. Contrary to Lee’s suggestion young scientists should not be encouraged to attack head on fundamental physics problems.

Here are three reasons. The first is the main one.

1) They will fail

Young scientists should learn the taste of failure but they should also learn the taste of success. And they have to be able to identify success. Real and definite success. This you do not learn by attacking head on fundamental problems or by engaging in very high risk projects.

2) Thinking “big” is the natural tendency

Everybody would prefer to find a substitute to quantum mechanics rather than compute a complicated integral. Going “big” is a natural tendency of scientists especially unexperienced ones. In science, like in surfacing, or skiing, or in learning to play the piano you have first to learn to suppress the natural tendencies in order to do things right. (And then you can try to express them again.)

Young scientist should learn the great difficulty of doing a small problem right and the great satisfaction and value of craftsmanship.

3) The fractal nature of science

While the danger of looking too much at the big picture is that you will see nothing, in science it sometimes happens that you look at your small little problem and discover something which affect the whole picture. A film located at the wrong place in the wrong time, and get ruined, can put the whole of physics on its head. Innocent experiments in iterating simple functions on a hand calculator may have immense effect. Young (and old) scientist should be pre-encouraged that when such an opportunity occurs – to take it (and to be prepared also for an unpleasant crash).

This issue is related to Lee’s distinction between seers and craftspeople. While the point he is trying to make is interesting while bold, the terminology is problematic: It proposes a clear hierarchy, two clear casts of scientists where seers are portrayed as superior. This is against the spirit of Lee’s overall approach which is towards openness and equality. Maybe better talk, Lee, about “dreamers” and “builders”.
But if you want to have more “dreamers” or more “dreaming” you must also have “spoilers” that you can call also “joykillers”. People who will look very carefully at these wild ideas of others, learn them and tell them why they cannot work. One idea at a time. There are many dreamers and many dreams, but where will you find the spoilers?

168. gina says:

Let me interupt the flow of elaborations on my points (5 down 11 to go) with a few remarks. The first is obvious. Lee’s book contains many nice, interesting and even moving parts and I am specifically trying to attack some of his arguments. Of course, the physics descriptions are very interesting. Several far-reaching ideas about physics are described and, while not remotely in a position to judge them, I am in a position to appreciate them and be impressed.

Lee also presents a bold and far-reaching view of how science should be practiced which can be regarded as a practical road-map based on Kuhn’s (revolutionary at its time) philosophy of science. (Kuhn gave a prominent role to scientific revolutions.) I will try to argue with this approach but at the same time I find it a beautiful line of thought.

Look what we have here beside physics and mathematics: The issues of pluralism, measures for progress, optimism, and risk-taking, especially in science; philosophy of science – scientific revolutions and scientific conservatism; incentives for progress in science, sociology of science – scientific communities, power and influence in academia. Great stuff! (But I know that the minute one good piece of mathematics comes along, and nobody will be left to talk about optimism and pluralism and philosophy…)

169. Lee Smolin says:

Hi Everyone

Sorry to have fallen behind. Here are some replies to recent posts:

To nc: (141-2). The meaning of loops in LQG is unambiguous. It refers to Wilson loops which are used in the construction of the algebra of observables for a gauge theory, including gravitational theories. Please see a review paper or Rovelliâ€™s book for details.

To Jacques (150,163): I donâ€™t anywhere dismiss Atick, Moore and Sen as anything, I am not referring to them when I referred to an intuitive argument. No where do I claim that there has not been good work on this issue, these papers are among them. Nor do I claim or believe that there are not good reasons to believe in perturbative finiteness of string theory on appropriate backgrounds. But good reasons are not the same as proof; my main point is that we should be clear about which is which. If you think that the statement has been proved than please publish the proof because it does not exist in the literature. In particular, if the claim is that Atick, Moore and Senâ€™s results comprise a â€œnon-constructiveâ€ proof then please point to or write a paper in which that statement is clearly explained and justified.

To Gina (160)

First, â€œIf Leeâ€™s argument regarding string theory (as a scientific theory) is just that string theory did not succeed yet, or that there are some concerns about specific results, as well as the whole endeavor, then this is a different matter.â€ Yes of course this is the basics of my argument. The conclusion I draw from this is that since there are other very well motivated directions about which the same could be said, string theory should be considered and treated as one of a number of important approaches to quantum gravity and unification that are pursued. I also argue that it would be best for the progress of science if all those who work on these different approaches consider themselves as a single research community, within which we try to mix people doing different things, as well as vary our own research interests, because presently different questions are best approaches with different approaches. My major argument is not â€œagainstâ€ string theory, it is against the idea that string theory is â€œthe only game in townâ€ or the â€œmodern paradigmâ€, so that it alone of the approaches deserves intensive investigation within a community specialized to work only on it.

With respect to Maldacena, I donâ€™t want to repeat the arguments in my book and papers on this, but I want to make clear that I believe that at whatever level it is true the AdS/CFT conjecture is a major result in mathematical physics. But I do not think it is a good thing to treat the strong form of the conjecture as essentially true, given that it posits the existence of an isomorphism between two structures which have not even been written down.

To Gina,

I agree that the key question is what to do about research programs where we have presently partial but not total success. I suspect that what is confusing you is that my view of what is wise in these circumstances does have a tension in it. I do think that we must at all times be aware of high risk these research programs are, and therefore be prepared that partial success may be the best that we do. We live in an unfortunate period in which there are many research programs in theoretical physics that, in spite of being well motivated, achieve only some partial success but never go beyond that. So I believe that individuals should of course continue to develop programs that are partially successful but that we should do everything we can to leave room for someone to invent a new program that may be more successful.

This raises issues you discuss below, Iâ€™ll come to those shortly.

Thanks,

Lee

170. Lee Smolin says:

Dear Gina (167)

With respect to â€œyoung scientists should not be encouraged to attack head on fundamental physics problemsâ€ I agree with the dangers you point out. And I absolutely agree that the training of scientists must include problem solving skills and experience in solving doable problems. But, in spite of everything we do to try to steer young scientists to do incremental work by which they may advance their career, there remain a few who insist on breaking away and inventing and developing original ideas to attack head on fundamental problems. My question is, what do we do about these? In my experience, two things are true:

1) such people often have difficult careers,

2) in the long run, they contribute a great deal to the progress of science. To mention some examples, they invent string theory, or the idea of quantum computation, or spin foam models, they find the correct physical interpretation of general relativity or invent new approaches to the interpretation of quantum theory (the many worlds interpretation was proposed in a Ph.d thesis by someone who never got an academic position in spite of how influential it became.)

I think given that these are not many people, and they are easy to identify, that we can do much better by them, and by doing so speed the progress of science.

To Gina (166),

â€œI am not aware of any mechanism which will lead to making the optimal decisions or eliminate the possibility of abuse of power. If Lee has ideas in this direction it will be great to hear them.â€

I made a number of suggestions in my Physics Today article as well as in the book. But these are standard issues that concern business, as well as academia. My impression is that we in academic science are behind the curve in several of them. For example, in investment banking, when considering the promotion of X, they tell me they do a â€œ360â€ which means they seek the views of all who work with her, both less and more senior. In law firms, banks, newspapers, and other businesses people who hire and manage other people are required to go through training aimed at combating these problems. In investment banks and successfully managed endowments they deliberately choose fund managers with a diversity of approaches and views of the market, in order to guarantee a diversified portfolio.

Another thing to note is how widely practices vary when it comes to academic hiring. In some countries and universities one would never put junior faculty or students on a hiring committee. In others it is mandated. In some the hiring committee is mainly or only people in the department and field, in others it is mainly outsiders to both. It is not surprising that the results vary and that as a result there are distinct characteristics to different countries academic environments. For example, when hiring committees are dominated by people outside the field being considered, candidates who are broader and who can synthesize ideas from different fields have an advantage. When hiring committees are dominated by people in the field specialists have the advantage over generalists. And so on.

My point is that we should never regard the â€œsociologyâ€ of a field as something we just have to live with, it is the result of concrete choices about the practices that guide hiring and promotion. So if people perceive problems with the sociology of their field, rather than complaining about it over lunch, as one commonly hears, one should work within ones department or university to change the practices. One might even take a comparative approach and consider the different practices around the world as experiments, whose results are to be evaluated.

Thanks,

Lee

171. Lee wrote:

I donâ€™t anywhere dismiss Atick, Moore and Sen as anything, I am not referring to them when I referred to an intuitive argument.

Oh? So I should have written “ignore” instead of “dismiss”? You did write:

There is no proof at either level. There is an intuitive argument, but that is far from persuasive

(emphasis added). This either ignores AMS’s proof, or dismisses it as a mere “intuitive argument.” Take your pick.

If you think that the statement has been proved than please publish the proof because it does not exist in the literature. In particular, if the claim is that Atick, Moore and Senâ€™s results comprise a â€œnon-constructiveâ€ proof then please point to or write a paper in which that statement is clearly explained and justified.

They already did that. If you think there is an error (or gap) in their proof, then the onus is on you to write a paper pointing out the flaw.

I will quote for you, verbatim, the abstract to the first of their papers:

Fermionic string perturbation theory is known to suffer from an ambiguity in the form of a total derivative in the moduli space. For a class of backgrounds (including R10, orbifolds and theories with no U(1) factors in gauge group) we show that these ambiguities for the partition function of heterotic string theory at any genus are proportional to massless physical tadpoles in the theory at lower genera and hence vanish in stable vacua. We also find that in R10 the cosmological constant at a given genus is proportional to the cosmological constant at lower genera. This enables us to give an inductive argument for the vanishing of the cosmological constant in R10 to all orders in string perturbation theory. We also address the ambiguity and finiteness of n-point functions. Our results indicate that in R10 the ambiguity can be absorbed by a renormalization of the string coupling constant and the string tension. The expected sources of divergence in the n-point function in arbitrary tachyon-free backgrounds, besides the usual infrared divergences for d â‰¤ 4, are shown to be proportional to tadpoles of physical massless fields. For type II strings in arbitrary backgrounds, we show by explicit calculations that the ambiguity vanishes at g = 2.

Again, if you think they’re wrong, you should write a paper explaining why, rather than going around pretending that their result doesn’t exist.

But I do not think it is a good thing to treat the strong form of the conjecture as essentially true, …

We have discussed this many times before, and I have yet to hear a satisfactory answer.

Is there a form of the conjecture, which is weaker than the strong form, but which is compatible with all of the known evidence?

None of the weaker forms that you discuss satisfy this requirement.

… given that it posits the existence of an isomorphism between two structures which have not even been written down.

Yes, I know you will continue to doubt that N=4 Super Yang Mills exists as a QFT, until such time as someone provides a rigourous existence proof. Since no one has provided such a proof for any nontrivial 4D QFT, you are surely safe for many decades to come.

On the gravity side, however, you have simply misconstrued the statement of the conjecture. There is not an independent definition of the quantum gravity theory that is supposed to be shown to be isomorphic to the CFT. Rather, the CFT is taken as the definition of the quantum gravity theory.

The conjecture is that, in appropriate limits, this definition reduces to the expected bulk gravitational physics. That is, in the large-N, large-‘t Hooft coupling limit, we should recover semiclassical supergravity. In the Penrose limit, we should recover a weakly-coupled string theory in a gravitational plane-wave background, etc., etc.

All of these limits have been subject to numerous calculational checks. Unlike LQG, there is no doubt that we recover the correct semiclassical gravitational physics from AdS/CFT.

172. Plato says:

I am glad this discussion has opened up too. This is what I had hope for for some time as well. Can’t learn anything from “same ole same ole.”

Lee Smolin:There is no proof at either level. There is an intuitive argument, but that is far from persuasive

I notice the same points Jacques did, and while reading Joseph’s response I became a little confused.

Joe Polchinski:Physicists work by calculation, physical reasoning, modeling and cross-checking more than by proof, and what they can understand is generally much greater than what can be rigorously demonstrated.

I thought “the proof” was in the mathematics? Anything less then that tends toward a sociological discussion and not a mathematical one?

So while one is dismissing the level at which genus 2 is being/has been solved then the basis of the sociological argument is also being conducted at a intuitive level.

Help! 🙂

173. Gina says:

Dear Lee,

I continued the elaboration of my critical points on your book in the more recent post on this matter – “masterclass”.

174. Lee Smolin says:

Dear Jacques,

With regard to Atick, Moore and Sen, I donâ€™t claim to be an expert, as you know, so perhaps I have misunderstood something here. My understanding is that they gave a sketch of a proof (as you put it a non-constructive proof) that rested on certain assumptions about supermoduli space that remained to be demonstrated. Among them is the requirement that integrals over supermoduli space are independent of choices of gauge slices. My understanding is that dâ€™Hoker and Phong have verified this only up to genus two. This appears to imply that the proof is incomplete because a condition required by AMS has not been established above genus two. See p3 of hep-th/0512197 where d’Hooker and Phong appear to take credit for demonstrating that condition required by AMS up to genus two. See also p 2 of hep-th/0110247 where, immediatelhy after referring to AMS as well as other approaches dâ€™Hoker and Phong say, â€œHowever, the basic problem was that gauge-fixing required a local gauge slice, and the prescriptions ended up depending on the choice of such slices, violating gauge invariance.â€

Let me know if this is not the right understanding. I might add that while I have discussed this issue in person, in email and on line with many people, you are the only one who makes a claim that Atick, Moore and Senâ€™s papers can be considered a proof of perturbative finiteness to any genus. Even people who claimed to me that there was a proof always referred either to Mandelstam or to unpublished work of their own, no one else who claimed that the proof existed also claimed it was to be found in AMS. So I naturally came to understand that AMS was incomplete in the sense that dHP seem to indicate in their papers.

With regard to AdS/CFT, you claim that, â€œThere is not an independent definition of the quantum gravity theory that is supposed to be shown to be isomorphic to the CFT. Rather, the CFT is taken as the definition of the quantum gravity theory.â€ This is I agree appears different than my characterization in TTWP of the strong Maldacena conjecture, but I discussed it in hep-th/0303185. But this puzzles me: is there or is there not still expected to be an M theory, that is a background independent formulation that unifies all string theories? If there is not then something big is being given up. If there is then shouldnâ€™t that M theory lead to a specialization which is string theory on asymptotically AdS^5 X S^5 spacetimes?

Thanks,

Lee

175. Let me know if this is not the right understanding.

It is almost a complete mischaracterization of the situation. But don’t rely on me. Why don’t you actually read their paper(s) and see for yourself?

AMS gave a proof. But their proof was non-constructive. They showed that, at arbitrary genus, the integrand (for the vacuum amplitude) is a total derivative which integrates to zero.

d’Hoker and Phong gave a constructive proof at genus 2. In fact, they proved something stronger, namely that the integrand vanishes pointwise on the moduli space (not merely integrates to zero). This is a big improvement. And it holds out the hope that one might also be able to improve upon AMS at higher genus as well.

But, beyond genus-3, their methods no longer work, so we are, in practice, little better off than we were before.

But this puzzles me: is there or is there not still expected to be an M theory, that is a background independent formulation that unifies all string theories?

This gets back to what one means by background independence. One of the things I have tried to emphasize to you is that, when you have asymptotia (either asymptotically flat or asymptotically AdS spacetimes), part of the prescription for what you mean by quantum gravity in such a spacetime involves specifying the asymptotics of the fields (including the metric).

And one of the things we have learned is that the observables are different in the two cases. In the former, the observables are the elements of an S-Matrix. In the latter, they are the correlations functions of a QFT on the conformal boundary of the spacetime.

(In the latter case, I have a great deal of confidence in the statement, since Maldacena has handed us a successful nonperturbative formulation of the theory. In the former case, since we don’t have such a formulation, at least not a complete one, perhaps one should take the above as a provisional statement of faith.)

We certainly hope for a nonperturbative formulation for asymptotically flat spacetimes (and for other spatial topologies). What such a formulation should look like, and how it should connect with quantum gravity in asymptotically AdS spacetimes is a fascinating question. But, given the different nature of the observables in the two cases, the connection is not going to be a straightforward one.

Even in the limit where semiclassical supergravity is valid, the mapping of observables is not nearly as straightforward as you might think.

I am as eager as anyone for a thorough nonperturbative formulation of string theory (or M-Theory, or whatever you want to call it). But it’s not up to us to make a-priori demands about what form that formulation should take.

176. Peter Woit says:

Jacques,

Your claim that the AMS paper gives a proof of multi-loop finiteness is a complete mischaracterization of the situation. As Lee correctly explained to you, the AMS prescription for amplitudes is not invariant under the choice of gauge slice. They are therefore working with ill-defined amplitudes, and cannot have a finiteness proof. Lee has pointed you to places in their papers where d’Hoker and Phong explain this. If you are having trouble understanding the technical details of this problem, you might want to consult one of them for an explanation.

177. As Lee correctly explained to you, the AMS prescription for amplitudes is not invariant under the choice of gauge slice.

The integrand is never independent of gauge slice. The difference between two choices of gauge slice is a total derivative on the moduli space. Proving that that total derivative integrates to zero is the entire business of showing the absence of an “integration ambiguity” (as it used to be called).

Every word of the above paragraph holds true for d’Hoker and Phong as well. But what they found was a “nice” gauge slice, where the integrand for the vacuum amplitude vanishes pointwise on the moduli space.

It would really help lift the level of conversation if you read (and understood) the goddamned papers before injecting your ill-informed commentaries into the discussion.

Is that really too much to ask?

178. anon says:

This is a bizarre discussion. I’m no expert on the issues involved, but I decided to take a quick look at some of the papers to try to get a sense of what is going on. Looking at the paper of which Lee says “See p3 of hep-th/0512197 where dâ€™Hooker and Phong appear to take credit for demonstrating that condition required by AMS up to genus two,” it doesn’t appear to me that they are claiming they are demonstrating a prerequisite of the AMS proof. Looking at the Atick/Moore/Sen paper, on page 6 they spell out some of the assumptions their proof depends on, e.g. a “factorization hypothesis.” For this they cite some work of Friedan and Shenker, and it seems this is the hypothesis that a partition function on a space with a node is the product of the partition functions on the two spaces left when the node is removed. Seems completely reasonable. It’s also obvious that the things that Lee and Peter seem to be worried about are precisely the issues Atick, Moore, and Sen were discussing: what sort of ambiguities can exist in their definitions of perturbative amplitudes, and whether these ambiguities can creep into physical answers in a nasty way.

Jacques, while some of the participants in this discussion seem intent on catching you in a mistake, some of us reading are genuinely interested in learning something here. What’s the status of the issues that Atick, Moore, and Sen mention as unproven assumptions on page 6 (the factorization hypothesis, something about contact terms in moduli space)?

179. Peter Woit says:

Jacques,

The only ill-informed commentary going on here is yours. d’Hoker and Phong’s argument is quite clear, and in the paper that Lee quotes they use italics at exactly two points to emphasize what they are claiming (unlike you, they rarely use italics for emphasis). They go to the trouble to make their point about gauge-slice independence twice, first in the lines that Lee quotes, and again later on the same page:

“We obtain a gauge-fixed formula … for the contribution to the superstring measure of each even spin structure \delta, which is independent of the choice of gauge slice. In particular, the ambiguities plaguing the earlier prescriptions have now disappeared.”

They later go on to claim:

“The superstring measure, when summed over all \delta, vanishes point by point on moduli space, and not just up to a total derivative, as in earlier prescriptions.”

Their claim here is unambiguous. It’s not just that they have found a “nice” gauge slice that gives point by point vanishing, but that, unlike AMS, they have a formula that is independent of the choice of gauge slice. Again, if you’re having trouble understanding the technical details of how this works, you might want to try consulting d’Hoker or Phong for an explanation.

180. young string worker says:

Peter —

Jacques has no “trouble understanding the technical details of how this works” — he understands the point quite clearly.

Whether the measure vanishes at two loops for all gauge choices or for some, the only important point is that: a change of gauge alters the integrand by at most a total derivative. This is the AMS theorem, and nothing D’Hoker and Phong say is in the least at variance with the AMS result.

What D’Hoker and Phong make is a stronger statement than AMS, containing extra information.

But that extra information is completely irrelevant to resolving the finiteness of string perturbation theory. At most, it’s a convenience for doing detailed calculations at two loops.

The question of the finiteness and gauge invariance of string perturbation theory is completely established by AMS’s proof. There is no reason whatsoever why the moduli-space integrand of an amplitude needs to be independent of the gauge choice.

The only thing you need to know is that the integrated moduli space amplitude is independent of gauge slice.

Even a 14-year old illegal immigrant like me can understand that.

181. I’m sorry Peter. Changing the gauge slice (in the BRST formulation of any gauge theory, not just this one) changes the integrand by a total derivative.

d’Hoker and Phong found a very special gauge slice, with very nice properties, not the least of which is that the vacuum amplitude, after summing over spin structures, vanishes pointwise on the moduli space. This means, in particular, that they do not have to do the delicate calculation that AMS have to perform, in order to show that the total derivative (which is what one would get for any gauge slice other than theirs) integrates to zero.

This is a huge simplification. But it does not, somehow render AMS’s work incorrect (nor, if one’s reading comprehension is up-to-snuff, do d’Hoker and Phong claim that it does).

the factorization hypothesis, something about contact terms in moduli space

The factorization hypothesis is, as far as i am aware, in good shape. (It’s a crucial ingredient in d’Hoker and Phong’s work, too.)

The question of contact terms is a little trickier. In some topological field theories (see the WDVV equation of Gromov-Witten theory), there’s a choice of gauge slice, where the entire answer is given by contact terms on the boundary of moduli space.

I think that the correct philosophy, vis-a-vis contact terms is that these are things that you add to your theory, in order to restore Ward identities which would, otherwise, be violated. In the case at hand, if AMS have done everything correctly, all the desired Ward identities hold, without adding any contact terms at the boundary of moduli space.

I could regale you with interesting tales about the so-called Green-Seiberg contact terms in fermionic string perturbation theory. But they play no role in the discussion at hand. So, perhaps we should leave that for another day.

182. Peter Woit says:

I don’t think the problem is my “reading comprehension”, partly since my reading is informed by a lot of time spent listening to experts on this and asking them questions, an experience that dramatically helps to improve one’s reading comprehension. What these experts have repeatedly emphasized to me is that d’Hoker and Phong’s breakthrough was the realization that the projection from supermoduli to moduli being used up until then violated local supersymmetry, and it was this that was leading to the ambiguities people were having trouble with. This is explained clearly in section 5.2 of hep-th/0211111, and they lead into their explanation of this breakthrough by characterizing previous prescriptions for multi-loop amplitudes as follows:

“This situation spells disaster. If an analogy were sought with the quantization of Yang-Mills theory, the present situation would be as if the perturbative evaluation of a gauge-invariant correlation function of gauge-invariant operators in \xi – gauge were to yield a result that is not independent of \xi. In Yang-Mills theory, it is clear that this situation signals a faulty gauge fixing procedure. So it does for superstring theory.”

It seems to me that d’Hoker and Phong are being quite clear here in their claim that AMS are using a “faulty gauge fixing procedure”, one that generates inherently ambiguous results, and so can’t claim to have a “theorem” and a “proof” of the properties of these. They are not simply claiming to be able to avoid a “delicate calculation”, and they are very explicitly claiming (despite what bold-face misusing “Young String Theorist” would like to believe) that it is not true that “The question of the finiteness and gauge invariance of string perturbation theory is completely established by AMSâ€™s proof.”

183. Sorry, but what AMS (and others, before them) had was not, in fact, a projection from supermoduli space to moduli space. This was well-understood at the time (and was the subject of numerous papers). It was not a “discovery” of d’Hoker and Phong’s.

I will repeat that the integrand in a BRST-quantization of a gauge theory is not invariant under a change of gauge slice. It changes by a total derivative. It is only the integral that is slice-independent (ξ-independent in the “analogy” you cite). In the case of the fermionic string, it is the slice independence of the integral that AMS went to considerable pains to verify.

d’Hoker and Phong found a clever choice of coordinates on the supermoduli space, which lead to a natural projection from supermoduli space to moduli space. And this lead to their nice gauge slice, where the integrand has the very nice properties that I do not feel it necessary to repeat.

In sum, “Young String Theorist” has it precisely right, and you are … still … confused.

184. young string worker says:

Peter —

If you go back and read the section in D’Hoker and Phong which you are quoting, you will see that they are explaining the result of a paper by Verlinde and Verlinde, in which they discover the gauge dependence of the modular integranD of the multiloop amplitude.

You are quoting this result as if it is somehow in contradiction with AMS’s result.

No, it is not.

Were AMS unaware of the Verlinde-Verlinde reference?

No, they were not.

AMS cited the Verlinde-Verlinde paper in order to explain what the issue was — the issue AMS resolved in their paper, by showing that the gauge-dependence of the modular integrand never contributes to the integrated amplitude, because it is a total derivative.

In fact, if you actually go so far as to read the AMS paper, you will see this explained quite thoroughly in the first few paragraphs, in which the paper by Verlinde-Verlinde raising the issue of this ‘ambiguity’ is prominently cited.

This is the ‘problem’ D’Hoker and Phong are referring to. Perhaps in their introductory remarks they should have been clearer that the issue was completely settled in general in other work, and that their own work was by way of elaboration and detailed working out of a concrete example. But I don’t think there’s any doubt about the matter of the consistency and gauge invariance of superstring theory to all loops.

The AMS result has never been demonstrated to be incorrect, by anyone (or even claimed to be incorrect, as far as I know).

What aspect of this point do you not understand?

185. Mark J says:

Peter, Lee, Clifford, and Jacques,

Your conversation concerning AMS is fascinating and I hope you each find time to continue it. As a non-physicist it is always difficult to discern the truth of these matters as they either get too quickly into levels of math that are beyond me or devolve into a he-said-he said form of discussion.

I have to say that Peter’s argument above especially in reference to hep-th/0211111 is particularly persuasive. But took Jacques’ suggestion to read AMS to heart and I have a question and a comment/question.

My question is: is this the AMS paper to which you are referring?

“Some Global Issues in String Perturbation Theory”
http://www.slac.stanford.edu/cgi-wrap/getdoc/slac-pub-4463.pdf

If so then on page 98-99 in the conclusion I read:

“Thus the cosmological constant may be expressed purely in terms of boundary integrals. The final answer is independent of how we choose the slice away from the boundary, but does, in general, depend on the choice of slice at the boundary.”

and

“In short, although we can express the partition function as a sum of boundary terms, these depend on the choice of the slice at the boundary , and hence are ambiguous.”

This appears to support Peter and Lee’s argument . But I would be interested in Clifford and/or Jacques POV and how I am mis-reading AMS. Or perhaps our young 14 year old could point out the “obvious” to this 40 year old.

186. No, I was referring to the first of their two papers, “Catoptric Tadpoles,” which I linked to, and whose abstract I reproduced above.

The second paper is about extending their results to compactified backgrounds with 4 unbroken supersymmetries (instead of 16 or 32). This is a much more complicated subject. Consequently, their second paper is correspondingly much longer, and its results somewhat weaker.

The subject of discussion (comparing with d’Hoker and Phong) has to do with the contents of the first paper.

187. Peter Woit says:

I understand the argument that the slice dependence corresponds (locally) to ambiguity of a total derivative term, but this term is still a very serious problem. I don’t believe that AMS have completely dealt with this and it seems to me that d’Hoker and Phong make very clear in their papers their opinion about this. Note that they refer to the problem as a “disaster”, and nowhere say anything about it not being a problem because it’s a total derivative. From everything they write, it is clear that they see the slice dependence as a major conceptual problem that has kept these amplitudes from being properly defined before their own work.

Before publicly (and anonymously, what’s that about?) making claims like “they should have been clearer that the issue was completely settled in general in other work, and that their own work was by way of elaboration and detailed working out of a concrete example” I strongly suggest that you discuss this with d’Hoker or Phong and find out from them what they have to say about this issue. I suspect that you would find this enlightening.

188. I donâ€™t believe that AMS have completely dealt with this

Please please read the “Catoptric Tadpoles” paper (which, despite being published earlier, was written after the “Global Issues” paper, and closes some gaps in the arguments of the latter paper). I don’t see how we can get past this stupid

“Yes they did.”
“No they didn’t.”

crap, if you are unwilling or unable to read and digest the paper that is the subject of discussion.

Step 1 was showing that the integrand was a total derivative. Step 2 was showing that the total derivative integrates to zero at arbitrary genus. This, indeed, is what AMS do (through a recursive argument) in the “Catoptric Tadpoles” paper.

and it seems to me that dâ€™Hoker and Phong make very clear in their papers their opinion about this. Note that they refer to the problem as a â€œdisasterâ€, and nowhere say anything about it not being a problem because itâ€™s a total derivative.

As has been pointed out to you, the “disaster” dâ€™Hoker and Phong are referring to is the slice-dependence first pointed out by Verlinde and Verlinde. Nowhere do they dispute the fact that Atick, Moore and Sen resolved the issue.

189. Peter Woit says:

Jacques,

The controversial question here is whether d’Hoker and Phong would acknowledge that “Atick, Moore and Sen resolved the issue” of slice-dependence, or whether they would claim that you need to do the sort of thing they have been able to do in the two-loop case in order to resolve the issue. Nowhere in their papers do they say anything about this issue having been resolved previously, and I and Lee have quoted you sections of their papers where they strongly imply the opposite.

If you really care about this issue, there’s something simple you can do: talk to d’Hoker and Phong about it. If you’re not willing to do this and find out what they have to say, you should at least stop making public statements claiming that they agree with you about this, when there is strong textual evidence to the contrary.

190. 1) I’ve had many conversations with d’Hoker or Phong on the subject of fermionic string perturbation theory. Most recently, I shared an office with Phong at Stony Brook this past summer.
2) You are simply incorrect in stating that their paper claims that AMS are wrong. If you had a better understanding of what AMS actually did, perhaps this would be clear to you.
3) If d’Hoker or Phong want to join the conversation here, and point out a flaw in AMS’s proof, then we could have a useful conversation. But it is pointless to continue discussing your (mis)understanding of d’Hoker and Phong.

(Whether it’s a misunderstanding of their published papers, or a misunderstanding of something Phong told you while y’all were waiting for your Lattés at Starbucks, I can’t say. But it really doesn’t matter.)

191. Gina says:

The issue of Mandesltam’s results and the subsequent developments is indeed interesting, but probably studying it in more depth is beyond the scope of a weblog discussion. I would guess that part of the disagreement is that unlike a “mathematical proof” which is essentially a clear notion, the standards for a “physics proof” are less clear and there are various levels of what can be called “proofs” in physics. This is why I would prefer to use the term “mathematical evidence”.

Returning to my main point in raising this issue, I think Lee agreed with me that the whole point of the finiteness issue was to support his central claim that ST is not a definite or a guaranteed success as a quantum gravity theory. More precisely quoting him (largely quoting me) reads:

” ‘ If Leeâ€™s argument regarding string theory (as a scientific theory) is just that string theory did not succeed yet, or that there are some concerns about specific results, as well as the whole endeavor, then this is a different matter.’ Yes of course this is the basics of my argument.”

In contrast, I do not see how this issue remotely supports Peter Woit’s central claim of “ST failed”, “it is all just a joke”. In fact, this was my point 3.

While entering a long loop of “yes!” “no!” “Yes! “no!” is a difficulty of weblog discussions, we can take advantage of the “free association” weblog spirit, so I would be interested to know: What is the source of the name “Mandelstam” and is the well-known physicist Mandelstam related to the famous Russian poet with the same name?

192. Peter Woit says:

Jacques,

I have very good reason to believe I am not misunderstanding d’Hoker and Phong on this point, and, again, before you keep making misleading public comments about their work, I suggest you contact them and discuss this point with them.

193. If d’Hoker and Phong thought there was a flaw in the proof presented by AMS in “Catoptric Tadpoles”, they would have written a paper (or devoted a section of one of their papers) to point out the flaw.

They didn’t. (And, to repeat, the passages you cited refer to the Verlinde-Verlinde integration ambiguity, not to a flaw in AMS’s resolution of that ambiguity.) There’s a very good reason why they didn’t.

If you think there’s a flaw in AMS’s proof, why don’t you just tell us what it is? Or, better yet, write a paper explaining the flaw.

Failing that, you are just blowing smoke and spreading FUD. Which is par for the course, coming from you.

194. Plato says:

While the points have been made clear between Lee, Petter, and Jacques, the views I think of that issue has been resolved?

While a “Interlude” was injected of historical significance, I thought I would just add to the Mandelstam individual by adding others here

These are layman views of course.

I would like to acknowledge the “idea of latex” to such imageries and Clifford’s excitement in asking of Carl to see what unfolds. I would like to learn how to do that, and it had been on my mind, shown in the link provided.

This lack of knowledge did not stop me from seeing what Jacques was saying.

Back to the other points of Gina.

195. Peter Woit says:

Jacques,

“If dâ€™Hoker and Phong thought there was a flaw in the proof presented by AMS in â€œCatoptric Tadpolesâ€, they would have written a paper (or devoted a section of one of their papers) to point out the flaw.”

How do you know this, did they tell you this?

Again, you are making misleading claims and spreading misinformation about someone else’s scientific work, in a very unprofessional manner. I strongly suggest that you stop doing this until you have consulted with d’Hoker and Phong to check that what you are saying about them and their work is accurate.

196. I have talked to them. And, unlike you, I have actually read and digested their papers.

The make no claim to have found a flaw in Atick, Moore and Sen’s proof.

Which means that you are the one making inaccurate claims (both about their work and — by extension — about Atick, Moore and Sen). If you don’t have any evidence of a flaw in AMS, then you should stop going around claiming that their proof is flawed.

197. Peter Woit says:

Jacques,

I understand that you have talked to them. Have you directly asked them whether they believe that the Atick, Moore, Sen “proof” settles the question of the finiteness of superstring amplitudes? If you haven’t done this, I suggest that you do so before publicly posting claims about this question.

198. Mark J says:

Jacques,

thanks for pointing out the correct AMS paper. I am still (if ever I can) reading it and trying to understand it. But in reading the (is it the one you and Peter have been discussing?) the dâ€™Hoker and Phong paper, LECTURES ON TWO-LOOP SUPERSTRINGS, hep-th/0211111 I read on page 3 they say:

“Considerable efforts were made by many authors to overcome the obstacles identified in [10] in terms of alternative prescriptions. These drew from a variety of fundamental principles, such as modular invariance [12], the lightcone gauge [13], the global geometry of Teichmuller space [14], the unitary gauge [15, 16, 17], the operator formalism [18, 19], group theoretic methods [20], factorization [21], and algebraic geometry [22]. The basic problem, however, that gauge-fixing required a local gauge slice and that any consistent prescription must be independent of the choice of such slice, remained unsolved. In fact, this state of affairs raised the undesirable possibility that the definition of higher loop superstring amplitudes could be inherently ambiguous [23, 24] and that it may be necessary to consider other options, such as the Fischler-Susskind mechanism [25].”

Here [10] is the Verlinde-Verlinde paper in question I believe and [14] are the two AMS papers including the â€œCatoptric Tadpolesâ€ one.

This appears to say that dâ€™Hoker and Phong found the situation in 2002 “remained unsolved” and “could be “inherently ambiguous”. That is they are not only focusing their attention on [10] but also on all previous attempts including AMS. Am I mis-reading this? If so can you or Peter point out where I have gone wrong. Thanks.

199. This is bull$%#@, Peter. No one, not d’Hoker and Phong, nor anyone else, has published a flaw in AMS’s proof. If, as you claim, d’Hoker and Phong have their private doubts about some aspect of AMS’s proof, they have not seen fit to publish those doubts, and subject them to the public scrutiny of other physicists. That would be the normal process of science, and being good scientists, their silence on the correctness of AMS’s proof should be interpreted accordingly. You, of course, have no such scruples, and continue to claim — without a shred of supporting evidence — that AMS’s proof is erroneous. And you cite ‘private conversations’ with d’Hoker and Phong in support of your claim. This is unscrupulous, dishonest and — if I were d’Hoker and Phong — I would be extremely pissed off to see my name used in such a fashion. 200. Mark J, The literature on the subject, from the Verlinde-Verlinde paper (which pointed out the problem), up to the AMS “Catoptric Tadpoles” paper (which finally, definitively, resolved the problem) was filled with attempts, by various authors, to resolve the problem. Someone would propose a solution, and someone else would find a flaw in the argument. I can probably name 20 papers (there were, surely many more) in the space of less than a year. This very active, and heated subject of research and debate came to a screeching halt after the “Catoptric Tadpoles” paper. There were no followup papers (pretty much until d’Hoker and Phong’s work 15 years later) Why? Because no one could find a flaw in the argument. It was the consensus of all the experts that the ambiguity had been successfully resolved. And, you will note, d’Hoker and Phong don’t claim to have found a flaw in AMS’s argument, either. To get a flavour of what such a claim would look like, you can look at AMS’s discussion of some previous attempts at a solution. Or, for that matter, you can trace back through the literature on the subject for other examples. When someone claims that a previously-published argument is incorrect, they spell out precisely where the flaw lies. If d’Hoker and Phong had found such a flaw, they would have spelled it out. That’s what good scientists do. That Peter Woit would persist in claiming that AMS’s proof is erroneous, without offering a shred of supporting evidence, should tell you something. 201. Peter Woit says: Jacques, I notice that you refused to answer my question, but instead choose to get hysterical and abusive. I’ll take that as a “no”, that you have not discussed this particular issue with d’Hoker and Phong. MarkJ has no problem understanding d’Hoker and Phong’s clearly expressed opinion about this in the passage he quotes, why do you? I’m not claiming anything about what they may or may not have privately said about this, it’s not my business to speak for them. I do however again suggest that you discuss this matter with them before making further public claims about this issue. 202. anon says: Peter: who is being “abusive” here? Jacques has been (repeatedly) explaining what anyone can read in the published papers, while you keep telling him he should refrain from talking about them until he talks to d’Hoker and Phong. It’s a bit ridiculous. What if I went over to your blog when you’re talking about, I don’t know, Freed-Hopkins-Teleman or something, and posted comments telling you that their result might be wrong and that you shouldn’t talk about any more without speaking to some particular person? It would be a bit crazy, right? If you really think something is wrong with the Atick, Moore, and Sen proof, you should explain what. 203. Peter Woit says: anon (and why don’t you dare put your real name to what you write?), d’Hoker and Phong were clear in their papers in claiming that their techniques are required in order to get unambiguous amplitudes. Most people who read their papers have no trouble understanding this. For another, very clear, statement of the state of affairs here, see the end of section 3.5 in Marshakov’s hep-th/0212114 (which Smolin quotes in his book). If you came to my blog, and claimed that what I was saying about the work of two physicists was incorrect and that I should check with them about the issue, I would not respond abusively, I’d check with them to see if I was describing their work correctly or not. 204. Too funny. If you took Marshakov’s statement at face value, it would be in direct contradiction with d’Hoker and Phong. He says that the problem has nothing to do with the choice of coordinates on supermoduli space and hence cannot be solved by finding a clever choice of coordinates (which is what d’Hoker and Phong did at genus 2). Of course, you don’t really want to take Marshakov seriously; you’d like to pretend his remarks apply to everyone else’s work, but magically not to d’Hoker and Phong. That, of course, would be silly. Much as I love Andrei, I’m afraid that paragraph (fittingly set in much smaller type than the rest of his manuscript) is simply incorrect. 205. Gina says: Let me import my elaborated points to this cozy thread where they belong. Then I will add one additional item. It is great to see you guys keeping this discussion alive, at all costs! [Here are the links to them… no need to reproduce them all again, so I’ve removed all that. -cvj] Here and Here. 206. Gina says: C) The string theory community 9. Many claims, stories and quotes against the string theory community are not really damaging to the ST community and and bringing them weakens the quality of Lee’s argument. Let’s look about some specific claims (mainly from Chapter 16) against the string theory community: “Group thinking”: Lee talks a lot about “group thinking” and the need “to fight” group thinking. It is not clear what precisely he means. Research based on large collective pools of idea and results is a very positive phenomenon which characterizes string theory and other prominent research areas. When precisely this positive, in fact, crucial practice becomes the negative “group thinking”? There is also a related claim that string theory works by fashions, so a large amount of efforts is geared towards directions which looks promising. Again, I see nothing wrong with it and it is compatible with string theory’s methodology to try to send long and thin sensors very very deep and have some picture how the emergent big theory looks like, while neglecting or being delayed due to technical difficulties at other directions. A related issue which I do not find convincing is that the “few fashionable directions” are determined by the leaders of the community who are usually (with a few exceptions) not so young. The “few fashions” claim is related to what is called the “narrowness of string theory”. I already mentioned that the supporting story (tale?) about Connes and the Chicago physicists is, in my opinion, rather weak. “Arrogance.” Lee talks quite a bit about “arrogance” of string theorists, although not as individuals. (Lee makes it clear that he does not claim that string theorists are arrogant individually.) Of course, the issue is not the the string theory’s research agenda itself is arrogant, you bet it is! This is supposed to be (and may well be) the final theory of everything, and Lee supports studying even bolder theories. So Lee’s claim refers to something somewhere in the middle between the individual daily matters (where string theorists are overall nice and pleasant) and the highly ambitious (welcomed) research agenda itself. But again the question is what precisely is this alleged arrogance? The arrogance claim is supported by various quotes and anecdotes. A few makes sense, but most are quite weak. For example, it does not really support to the claim of arrogance to quote a specific physicist (among thousands of physicists) who made a similar claim in her weblog. Beside these specific points that are not very clear and not convincing there are too many repetitions. We hear too much about “group thinking” (in more than one chapter), and the “arrogance/immense self confidence” issue is mentioned in too many places, to my taste. I did not like the “worrying” if not “one-to-one” analogies at the end of Chapter 16 concerning “group thinking” in the cases of NASA’s failure to prevent the Challenger’s disaster, and the current Iraq war, and related similar cases. Overall, the feeling I got reading this chapter and other related comments in other parts of the book was that Lee’s description of the string theory community is fundamentally unfair and his approach here is, to a large extent, incorrect. I can see how it could have been written in the heat of writing and debating mood, but a good editor or, even better, a good friend should have raised second thoughts about it. 207. Moveon says: @Gina: “Arenâ€™t there any interesting research areas closer to QED/QCD/ the standard model? Isnâ€™t there too much emphasis on fundamental problems? and not enough effort to identify interesting â€œsecond lineâ€ problems based on progress already achieved on fundamental problems?” Yes there are plenty of those more convervative areas of research and very many people work in more phenomenological directions. It may be that the situation at certain US universities is not always so balanced, but there happen to exist also other countries and especially in Europe there exist more phenomenologists than string theorists. So as for theoretical particle physics as a whole it is just nonsense to say that most efforts in particle physics would go into string theory. And people don’t tend to complain as there is not much to complain in this respect. But now there seems to be a new trend, namely to write a book to complain about the lack of support to alternative approaches, if one feels that one’s own field of research doesn’t get enough recognition. That’s a cheap way to try to bypass the battle in the marketplace of ideas, where it is the peers that need to be convinced, not the clueless public. If everyone who thinks that his own pet theory is not sufficiently recognized would write a book, the market would be inundated. 208. Gina says: Dear Moveon Writing books and papers and weblog comments and talking and discussing these matters on technical and on non-technical levels IS part of the “market place of ideas”. (I am, to some extent, part of the cluless public when it comes to high energy physics and I think even people who are uninformed on technical matters can have some judgement. And it is a lovely way to learn.) I think the current controversy and discussions are of value. The more books be written the higher the quality of the books that will be published. I do not see a real danger of fludding. 209. Peter Woit says: Jacques, Marshakov’s statement simply does not contradict d’Hoker and Phong. Read it again. It’s a short and imprecise summary of a complicated situation, but he makes completely clear that he believes the Atick-Moore-Sen argument does not work for general multiloop amplitudes. He does not claim there is a problem with the argument of d’Hoker and Phong. From your lack of response, I gather that you never have asked d’Hoker and Phong about the issue under discussion here, and that you don’t intend to, but intend to keep spreading misrepresentations of their work. This is not scientifically ethical behavior. 210. Gina says: Peter: “From your lack of response, I gather that you never have asked dâ€™Hoker and Phong about the issue under discussion here, and that you donâ€™t intend to, but intend to keep spreading misrepresentations of their work. This is not scientifically ethical behavior.” Peter, Jacques wrote that he talked with them. And also that he read their work. And also that he read AMS work. I suppose Jacque expressed his views on these works to the best of his judgements. I also think Jacque expressed his thoughts on what d’Hoker and Phong think on AMS work to the best of his judgement. You are entitled to have different thoughts about the quality of these works and about what d’H&P think about AMS, and even about what J thinks about what d’H&P think about AMS work. The whole issue of what “scientist X thinks about scientists Y’s thoughts on work Z” is unusual in the scientific dialogue and it looks that this new direction was introduced by you. I am not sure this new line of discussion is so fruitful (but it open a whole new horizons of questions, we can add scientist W and U and V and …) but certainly your claims about ethical scientific behavior are baseless. Since you introduced this line of thoughts about thoughts about thoughts, let me just mention that it is not a priori clear that d’Hoker and Phong have the same thoughts on this matter. The nice thing about coauthorship and collaboration is the joint effort of two different minds with different thoughts. Also as Jacque noted there is a difference between people’s private concerns and what the same people are sure and committed enough to express publically. You also raise interesting questions about weblog ethics. I think in the weblog environment there is no sense to say to a person : “you refuse to answer me” people ask questions and it is legitimate not to answer them. 211. Arun says: In my opinion: The discussion between Woit and Distler now verges on the ridiculous. We have to do philology on statements in papers to decipher e.g., whether D’Hoker and Phong believe AMS does or does not provide the remedy to ambiguities in multi-loop string amplitudes. Or we have to ascertain their unpublished, private opinion. Or to go by (inaccessible to us) consensus of experts that is not published. Here is my take: is there an unambiguous statement one way or the other in a published paper or textbook? If there is not, then as far as the non-expert community goes, the answer is that the question is open. That AMS is adequate or AMS is inadequate is not decided. If it is decided one way or the other, some non-controversial paper published in a reputable journal or some accepted textbook or summer school proceedings should have a statement that can be pointed to by Woit or Distler. Since the discussion has gone on unproductively so far, I take it that there is no such statement available. Please note that this does not mean, e.g., that Distler is wrong. It merely means that the non-string-theory community has no reliable source in the literature on which to base a conclusion. The alternative to what I’ve written, I fear, is to accept that physics lacks objectivity and is a sociological construct. 212. Itâ€™s a short and imprecise summary of a complicated situation, but he makes completely clear that he believes the Atick-Moore-Sen argument does not work for general multiloop amplitudes. No. He says that the problem is a fundamental one that cannot be solved by a smarter choice of coordinates on supermoduli space (d’Hoker and Phong’s solution): In the superstring case one runs into more serious problems since the very notion of the â€boundary of moduli spaceâ€ is not defined. Indeed the integral over the Grassmann odd variables does not â€knowâ€ what is the boundary term. This is the fundamental reason why the integration measure in fermionic string is not well-defined and depends on the â€gauge choiceâ€ … Moreover, these are not problems of the formalism … This is a) in flat contradition with d’Hoker and Phong. b) incorrect. Sorry, but only someone who has no understanding of the issues involved would adduce Marshakov’s quote as supporting the position that d’Hoker and Phong solved the problem that Atick Moore and Sen tried, but failed to solve. He is claiming, in this passage, that no such solution is possible. From your lack of response, I gather that you never have asked dâ€™Hoker and Phong about the issue under discussion here I most certainly have spoken to them (on more than one occasion) about these issues. So let’s put that piece of nonsense to rest. … but intend to keep spreading misrepresentations of their work. This is not scientifically ethical behavior. On the contrary, it is you who are misrepresenting the status of Atick Moore and Sen’s work and that of d’Hoker and Phong. You should have a conversation with them, rather than continuing to spread misinformation. 213. Here is my take: is there an unambiguous statement one way or the other in a published paper or textbook? If there is not, then as far as the non-expert community goes, the answer is that the question is open. That AMS is adequate or AMS is inadequate is not decided. If it is decided one way or the other, some non-controversial paper published in a reputable journal or some accepted textbook or summer school proceedings should have a statement that can be pointed to by Woit or Distler. Arun, this is not hard. (Tedious, perhaps, but not hard.) If someone published a flaw in AMS’s proof, they (surely) would have cited AMS’s paper when they published that flaw. Go to SPIRES. AMS’s paper is cited some 60 times. If their proof had been found to be incorrect, one of those papers would contain an explanation of the flaw. None of them do. 214. Peter Woit says: Jacques, You are now compounding your misrepresentation of d’Hoker and Phong’s work and their writings with a misrepresentation of those of Marshakov. Marshakov does not write what you claim, that d’Hoker and Phong must be wrong because the problem involved can’t be solved the way they did it. You know this very well, and your attempt to paint him as some kind of idiot writing things that make no sense in lower font size is just pathetic. You appear also to be claiming that, in private discussions with d’Hoker and Phong, they have told you that they believe the AMS argument to be a valid proof of multiloop finiteness to all orders. I find this very hard to believe, and if it is not true, it is exceedingly unethical for you to be implying that it is. “You should have a conversation with them, rather than continuing to spread misinformation.” I have done this. Again, I strongly suggest that you contact them and discuss the matter with them before repeating your misrepresentations of the significance of their work. 215. MoveOn says: Gina: I appreciate your continued efforts to get an unbiased and objective judgement of those matters. “I think the current controversy and discussions are of value. The more books be written the higher the quality of the books that will be published. ” I think this is manifestly not true, judging from two recent books. Just from the comment of yours I alluded to before, namely that one should “also” do research also on more down-to-earth matters, I see that you didn’t get an objective picture of how things actually are: as if such research wouldn’t be done anyway, by a large number of people (more than there are string theorists). And I guess this is the picture you got by reading the books and what people claim in blogs; it simply does not reflect reality. Books and blogs with mailicious intentions can do great damage to the “clueless” public who have no means to decide on what is true or not. The relevant marketplace of ideas is indeed among the experts, and not the general public. The recent attempts to move the battle off the scientific ground to the public and the internet, just reflects the failure of certain people to leave their marks on the academic battleground; claiming sociological rather than scientific reasons for that. 216. Marshakov does not write what you claim. That was a direct quote from Marshakov (whose review, of course, predated d’Hoker and Phong’s work). Marshakov states (correctly) that the superstring integrand changes by a total derivative when you change gauge slice. This is simply a fact of life in BRST quantization (of any gauge theory, including the fermionic string). It applies equally well in d’Hoker and Phong’s choice of coordinates for supermoduli space. This does not, however, mean that the integral is necessarily ambiguous, ill-defined, or non-gauge-invariant. It simply means that sufficient care needs to be taken to ensure that the integral does not pick up unwanted boundary contributions. That is what Atick, Moore and Sen did (at arbitrary genus). But, of course, I am merely repeating things I’ve said umpteen times already in this thread. If you want to move the discussion forward, why don’t you just tell us what the flaw in AMS’s proof is? Then we can discuss that, instead of repeating dark allusions to “private conversations with d’Hoker and Phong.” The few people who haven’t grown sick of this thread are eagerly awaiting your unveiling of the flaw in AMS’s proof. Please don’t disappoint them … 217. Peter Woit says: Jacques, You are a veritable fount of misinformation about Marshakov as well as about d’Hoker and Phong. “whose review, of course, predated dâ€™Hoker and Phongâ€™s work” His review postdates their series of papers on this subject, and he explicitly refers to them in his reference 22. You should stop repeatedly publicly making more and more misrepresentations of other people’s work and writing. 218. We’re still waiting for you to reveal the flaw in AMS’s proof … Any chance of that happening this before the end of 2006? 219. Plato says: Moveon: The recent attempts to move the battle off the scientific ground to the public and the internet, just reflects the failure of certain people to leave their marks on the academic battleground; claiming sociological rather than scientific reasons for that. The discussion I would hate to think was based on another agenda? It’s almost as if this sew saw was planned? Can’t help it. A “conspiracy theorist” at heart? 🙂 As a scientist, why “write books” if you did not want to take this to the public? Why would a scientist care to get it right? So most certainly they summarize the latest. Was it the latest? I would hate to think that any scientist would think to cut themselves off from the public. Then we would know how marketing should be affected too:) 220. Clifford says: Jacques, Maybe there’s a small chance it will be in our Christmas stockings, alongside the “well known” (Peter’s words) obstructions to string theory making contact with experiment that I tried to get him to reveal to us in a long thread eerily similar to the latter part of this one. (For those unfamiliar, you can read it starting about here.) Now that you’ve asked him for a specific technical point -in his own words and not just quoting and misquoting papers he’s not always understood very well- I wonder how long it will be before he tells us he’s busy, in a rush to a meeting, offended by our tone, it’s a waste of time, or some other thing that will prevent him from sharing a simple answer to a simple technical question. This happens every time he’s pressed to answer a detailed question. Why is that? -cvj 221. Peter Woit says: As for the AMS question, no, I’m not claiming to be an expert on this subject who can easily explicitly show you precisely at which points in the AMS paper their argument runs into trouble. Perhaps I could if I wanted to spend a significant of time looking into this, but it’s a complicated business, life is short, and the views of experts I trust about this issue are unambiguous. I really don’t see what the point would be anyway since I can’t get Jacques even to agree that 2001 is earlier than 2002. What I am claiming is that Jacques is unethically misrepresenting the views on this subject, expressed clearly in their refereed papers, of people who, unlike him, actually are genuine experts on this issue. I think this is shameful behavior, and adding to it the attacks on Marshakov’s competence and ad hominem attacks on me doesn’t help. And Clifford: you know, it’s really sad to see what you have descended to in your behavior on this blog. Trying to defend string theory against legitimate scientific criticism by personally attacking people as incompetent doesn’t help your case at all. Lubos Motl tried this extensively, making a fool of himself and in the process convincing large numbers of people that Smolin and I must have a real point. Lubos has calmed down and is sticking to science these days, I don’t think the way that you have adopted his old tactics is in either your interest or that of string theory in general. 222. As for the AMS question, no, Iâ€™m not claiming to be an expert on this subject who can easily explicitly show you precisely at which points in the AMS paper their argument runs into trouble. But you have no compunction going around claiming that their proof is erroneous, without offering a shred of evidence in support of that claim? And you call me unethical? If the “experts [you] trust” have told you about such a flaw, why don’t you get them to explain it to you? Then you can back up your claims with actual evidence. (What a quaint notion…) There’s still time to get this done in 2006. We eagerly await your debunking of AMS’s proof. 223. Clifford says: Peter, I’m not attacking you as incompetent, and I am in fact sticking to the physics much more than you have. This is the frustrating thing…. when the argument comes down to detailed arguments -to try to understand what you are really saying- you are reluctant to offer substance such as a calculation from start to finish (even in clear outline), and instead start worrying about other non-physics issues, raising irrelevant stuff about other bloggers, tone, pointing vaguely to other references, debating whether 2001 came before or after 2002, etc etc. I do not know why you do this, but there’s nothing wrong with pointing it out. It might fool the non-experts reading, trying to learn what the basis of your attacks on an entire field might be…. It is my duty to point out to those who do not workk in the field that you have gut feelings (which you are entitled to) against this line of research, but no actual technically substantial arguments to back up your strong public claims that the line of research has failed. That’s all. If pointing that simple fact out is considered unfair “tactics”, then ok. But the people reading should know it. -cvj 224. Peter Woit says: Jacques, The claim I am making is simple and straight-forward: people much more expert than you about this have, in writing, in refereed papers, made the claim that all prescriptions being used before theirs (including the AMS one) led to ambiguous results. I trust the opinions of these people and their many years of serious, dedicated work on the subject. You’re the only person who is claiming that the AMS prescription is unambiguous and that these experts agree with you about this. I certainly could go, consult experts, and spend a lot of time understanding the details of the AMS arguments and what its problems are, then come here and try and discuss those with you. It’s obvious to me that this would be a huge waste of time. You refuse to even acknowledge that your absurd claims about Marshakov’s paper were complete nonsense, so I doubt you’d ever agree that any subtle problem I pointed out with AMS was really a problem. Again, I strongly urge you to get in contact with d’Hoker and Phong, and discuss with them what they think of the AMS “proof”, and stop publicly misrepresenting their views on this matter. 225. Clifford says: Peter… you can prove me wrong right now by just answering Jacques’ question directly. Please note that you now have at your disposal on this blog the full power of LaTeX in order to make a clear argument. If you want to claim you’re interested in talking about the physics, please please show us. Now. Please. -cvj P.S. No time like the present. 226. Arun says: Reference 169 of http://arxiv.org/abs/hep-th/9212006 is to AMS. [169] J. Atick, G. Moore and A. Sen, Nucl. Phys. B307 (1988) 221; B308 (1988) 1. Excerpt, emphasis added. It would appear that these authors do not consider the proof to be complete. 4.4 Is string theory finite? A very attractive feature of String Theory is that it has a real possibility of being an ultraviolet finite quantum theory of gravity. In the previous chapter we learned that in the bosonic strings the more dangerous infinities came from the boundary of moduli space (surfaces with nodes) and they were due to the presence of tachyons in the spectrum. The integration measure is finite and well behaved except near the boundary of Mg. Since for the superstring and the heterotic string the tachyon is projected out after GSO proyection, one would intuitively expect that no further divergences should arise. This is not completely correct, since the massless states may also contribute some subleading divergences. We now however that for one-loop amplitudes there are no divergences [2, 3]. For higher loops we still lack a complete proof, but many exploratory computations has been carried out. For the bosonic string we have two-loop computations [164] as well for the superstring [165]. For the heterotic string there are several computations of the two-loop cosmological constant [166]. It was finally shown in [167] that there is an explicit modular invariant expression for the two-loop cosmological constant of the heterotic string. The result as one might expect from supersymmetry equals zero, after we sum over all spin structures. There are several general arguments [168] based on space-time supersymmetry which indicate the finiteness of superstring perturbation theory. A detailed analysis of the many technical issues involved in the analysis to all order can be found in [169, 104] and references therein. 227. Peter Woit says: Clifford, Eric d’Hoker is your colleague at a nearby institution. I’m sure you know him and can easily get in contact with him. He’s an expert on this technical issue and I’m not. If you actually care about the scientific question at issue here, and not just about using it to try and personally attack and discredit me, I suggest you consult with him. 228. Clifford says: Peter, Your earlier position on this in your comments above in this very thread (here, here, here, etc) would have caused people to believe that you were an expert. When pressed for substance, you back off and say you’re not an expert. This is the puzzling thing about all this…. and in the larger scenario of your whole campaign. You take something that you are not an expert in, and take signs that there is something yet to be shown or understood with more research and turn that into a proof that string theory is wrong, doomed, a sham, has failed, etc, etc. It is just a dishonest and downright underhand practice… and you use it to successfully manipulate journalists, non-experts, and a general audience. This is just not right. Not an honest nor a professional way of doing things at all. -cvj 229. Gina says: Dear MoveOn, I do not have obvious biases but I do not think it is possible to be completely objective or even close. (E.g. I am fairly biased by the (partially uninformed) judgments I already made, in these discussions, by my tendency to argue, and possibly by other things.) As I said, my points regarding Lee’s book were intentionally picking the places I find the book unconvincing. So it was intentionally biased. I think overall Peter’s and Lee’s book are nice. I did learn a lot from reading them. Of course, my picture on high energy physics the science and the community is very partial. I do not understand the first paragraph after my quote in your remark. I still do not really understand how the high energy physics community is built. (But I cannot blame it on the book I read.) E.g. I do not understand what “phenomenological directions” precisely (or vaguely) mean. (OK, just looked at Wikipedia and got a very vague picture). I will be thankful to learn in nontechnical (comment or link) what are the areas of high energy physics and what people are doing. I completely disagree with your last paragraph: M: “Books and blogs with malicious intentions can do great damage to the â€œcluelessâ€ public who have no means to decide on what is true or not. ” The “general public” who is interested in this stuff are overall quite restricted. It is a small circle of people in and around academic life. I do not see here people with “malicious intentions”. There is no real chance for great damage or even moderate damage. In this respect, the tea cup metaphor is OK. The discussion and debate can be also healthy and somewhat fruitful. M: “The relevant marketplace of ideas is indeed among the experts, and not the general public.” There are several marketplaces and each one has its own problems. As I said, the “general public” is not really involved it is all people here are quite close to the little academic swamp. (E.g. most enjoy Latex) M: “The recent attempts to move the battle off the scientific ground to the public and the internet, just reflects the failure of certain people to leave their marks on the academic battleground; claiming sociological rather than scientific reasons for that.” It is not really battlegrounds. It is legitimate (and sometimes welcomed) to try to influence and promote ideas in various ways. We cannot argue matters on very general principles when we discuss a specific claim we need to discuss details. I do not think the “just reflect the failure…” statement is fair or correct. 230. Clifford says: Now, the next thing you usually do at this point of the ever-repeating cycle is retreat to your lair (your own blog) and then write a blog post which includes accusing me of some terrible sin – (shooting JFK, hiding the Iraq WMDs, taking the Christ out of Christmas, starting the Great Fire of London, etc*) – and then linking here to send your hordes of yes-men over to further cloud the issue. I’m looking forward to it. -cvj * Your logic:- Since I cannot prove for sure I did not do them, it must be true that I did them. QED. 231. Plato says: Can my post be put in now? It was not put to advance my position but to point out what Lee’s thought may have been when he wrote his book. Two traditions in the search for fundamental physics 232. Peter Woit says: Clifford, I have never claimed to be an expert on the highly technical issue of multi-loop string amplitudes, have just claimed that I have gotten people who are experts to explain some of this to me, and I have based what I have to say on what I understood of what they told me. The question of multi-loop string amplitudes has little or nothing to do with what you are upset about, which is my claims about the prospects for string-based unification of particle physics and gravity, a topic I have spent a lot of time learning about. The multi-loop question is most likely a purely technical one. I happily admit that the most probable outcome of work in this area will be that the one can properly define such amplitudes for each term in the loop expansion. It’s perfectly reasonable for most string theorists to ignore the problem and operate under the assumption that it will be solved some day. It’s not all right though for them to denigrate the significance of the work of those of their colleagues who have expertise in this issue and made progress on it. Since you don’t mention being interested in asking Eric about this, I’ll take that as an admission that your motives in bringing this up did not have to do with wanting to know about the science. 233. Clifford says: The question of multi-loop string amplitudes has little or nothing to do with what you are upset about, which is my claims about the prospects for string-based unification of particle physics and gravity Really?! Since you donâ€™t mention being interested in asking Eric about this, Iâ€™ll take that as an admission that your motives in bringing this up did not have to do with wanting to know about the science. But why would you take it that way? I also did not mention that I was curious as to whether it is sunny outside. Do you take that to mean that I’ve no interest in going for a walk outside ever again? Come on, Peter. I think I’m going to go for a walk, in fact. -cvj 234. Peter Woit says: “Really?!” You know Clifford, some of your comments make as much sense as Plato’s. Pretty much all of my claims about the failure of string-based unification have been based on granting the existence of the terms in the perturbative string expansion. As I wrote, I don’t expect that this will fail, but if it does, and these terms turn out to be inherently ill-defined, that will just add to the failure. Do let us know what you learn from Eric… 235. Clifford says: “Do let us know what you learn from Ericâ€¦” I’m confused here. I believe it was you, Jacques and Lee who were talking about that issue. Knowing that I have no expertise in that particular area, I had the good sense to shut up about it and stay out of the argument*. I am still not in the argument. Eric knows about the blog, and (I suspect) your discussion (or whatever) above. He is perfectly capable of joining in if he sees fit. But you realy must learn to make arguments under your own steam, and not rely on mutterings about private conversations you’ve had, or appealing to someone to go and talk to some other person, etc. It just does not look good. Just make your argument and stand by it, or say at the outset that you are not sure, or not an expert, etc. That is the honest way to proceed. Best, -cvj (* You would do well to learn from that example.) 236. Peter Woit says: “I had the good sense to shut up about it and stay out of the argument” Right, until you found it convenient to use it as an excuse to personally attack me. 237. Clifford says: No Peter. It was until I saw that you were being evasive and not answering a direct physics question. Then I came in and asked you to address the physics question with a specific answer. Then, as usual, you folded up, made your excuses, and have still not given this answer. I’m simply trying to give you the chance, in a public forum, to make clear scientific arguments to support your case. It is not a personal attack… I’m just trying to cut through the bluster and understand (and help everyone reading understand) where the substance is. I don’t even have a position on the AMS issue, not having studied it. But that is besides the point. In the larger scheme of things, given tht you’ve written an entire book for the public arguing that an entire research program is wrong, a sham, and akin to a religion or a cult, etc, etc, your presentation of scientific arguements and general approach to avoiding substantial issues is certainly something to hold up to scrutiny. How is anyone to give weight to anything you say (which such certainty) on any issue to do with this research program if they cannot tell when you are an expert on a paper or result you are discussing and when you are not? The exchange (and rapid reversal when pressed) shown in this comment thread is a fine example, and should raise some concerns for the non-expert that maybe several (if not all) of the things you express so much certainty about elsewhere (with similar lack of substance in your argument) are full of holes as well. That is the actual subject of this entire post, and its cousins, and so it is entirely approrpiate that I point these t things out. You were, once again, given the chance to make a clear and substantial scientific statement, on your own terms. Again you failed. -cvj 238. nc says: â€˜â€¦ youâ€™ve written an entire book for the public arguing that an entire research program is wrong, a sham, and akin to a religion or a cult, etc, etc, your presentation of scientific arguements and general approach to avoiding substantial issues is certainly something to hold up to scrutiny. How is anyone to give weight to anything you say (which such certainty) on any issue to do with this research program if they cannot tell when you are an expert on a paper or result you are discussing and when you are not? â€¦ .â€™ – Clifford Hi Clifford, the ‘entire’ book he wrote is not a polemic, it’s mainly (more than half) a discussion of the development of the Standard Model and the experimental facts known in physics which come without help of superstring. Maybe Woit can write a ‘revisionist’ version which will explain how superstring theory led to the Standard Model and gravity, and is the basis of the universe? Then he might be taken seriously? You did comment recently on anothe post that string theory will be a failure when it is developed so far that it makes a falsifiable prediction and is tested and found to fail. Ptolemy could have defended the earth centred universe endlessly with that claim, adding epicycles to make it interact better with reality all the time. It could be that string won’t do that, and will be discarded when an alternative comes along. Then you have a basis for launching conspiracies to stamp out alternatives… 239. Peter Woit says: Clifford, You really should stop the attack dog tactics, it doesn’t help your case one bit. It never ceases to amaze me how people like you, Lubos, Jacques, and your various anonymous allies don’t seem to realize that if you want to have any credibility you have to answer the criticisms leveled at your field by me and Smolin with serious arguments, not personal attacks. But if you want to behave like this, don’t let me stop you. Competition in the market-place of ideas is a breeze when the people one is competing with make it clear to everyone that they can’t defend theirs. 240. if you want to have any credibility you have to answer the criticisms leveled at your field by me and Smolin with serious arguments, not personal attacks How can anyone respond with a serious argument, if you won’t tell us what the alleged flaw in AMS’s proof is? 241. Plato says: Peter you have to answer the criticisms leveled at your field….. Smolin with serious arguments, You have never been to kind in your criticisms, and imagine when there is a whole tribe of you? 🙂 But that’s beside the point. I had tried to move past this “road block” currently being debated. I am glad Arun step in above. Yet there is more that has to be done. This is the thing about experts, that they can reply as Clifford said. This is a “good thing” for clarification. I tried to reply with something Lee Smolin posts on his “book site” to show what his motivations might be for taking his position, and you call it nonsensical, and a attack. It was I who came out seeking you to learn. 242. Pingback: Lubos Motl\'s Reference Frame 243. lame says: Peter– We are begging, BEGGING you to give us an actual technical argument here; why do you ALWAYS rely on authority when any physics issue comes up? Much easier playing pretend physicist on your blog huh? Sure impresses all your fans, particularly convenient that it requires NO INTELLECTUAL EFFORT OR SKILL on your part! Nice deal. You remind me of those annoying undergraduates who talk a big game but don’t actually KNOW anything. How about backing up your words with some content for once? Can you do that without running away to Mommy/Daddy/d’Hoker and Phong to bail you out when the discussion requires actual knowledge? Tell us what is wrong with AMS with an argument other than “people who know tell me there is something wrong with AMS”. Lousy science journalists will fall for your act Peter, but you don’t fool a single decent theorist. 244. Glandlands correspondence says: Distler’s demand for alleged problems in the alleged proof by Atick et al is a stupid cheap shot inasmuch as it tries to parlay his apparently higher-than-Woit but lesser-than-expert(e.g. d’H or P) understanding of the technicalities into an acceptance of the correctness of the proof. Obviously if Woit has heard expert testimony on the matter he is not necessarily in a position to relay it or to argue it secondhand should a debate arise on the technicalities. Assuming that Woit is correctly reporting the substance of his communications on the matter, while Distler has the option to treat the AMS paper as correct until proven otherwise, it is not honest for him to operate as though Woit is publishing lunacy on this matter, either. That is, Distler should admit his own limitations in assessing the answer to this question, even if they may be less than Woit’s limitations. That would require some humility from Distler, something I haven’t yet seen. 245. young_string_worker says: Why don’t we just work it out here, using Clifford’s BlogLaTeX system? Let’s do an example, for heaven’s sake, and see if we can figure out whether the total derivative on moduli space has a finite boundary contribution or not. How hard can it be? Correct me if I’m wrong, but all these words about whether the modular integrand is ‘independent of the gauge slice’ or not are really just questions about whether they’re independent of the positions of the PCO’s, in concrete terms? So let’s write down a partition function and see what happens when we move one of the PCO’s. Assuming we do everything right, we’ll probably just be reproducing some special case of AMS’s result… but then at least we won’t have to listen to Peter wanking about how AMS is this mysterious, murky paper which may or may not have some sinister, never-specified logical flaw. 246. Gina says: Dear Jacques, Congratulations on the new medal for patience. Let me try a little to stretch your patience and ask you six little questions: 1. Is it correct to say that neither AMS nor even d ‘Hoker and Phong can be regarded as solid proofs in the mathematics sense of the word. 2. What is your take concerning this “divorce” from mathematics. (I learned this term from a paper by David Corfield posted on the n-category cafe.) Is it something physicists should worry about at all? 3. According to your explanation, the new proof (just for the second term) is “constructive” while AMS proof is not. Can you explain in non-technical terms what is the difference and why it is of important to find constructive proofs. I.e. given that AMS proof is sound why d ‘Hooker and Phong work is at all important. 4. Smolin concerns on this issue was that string theorists were too optimistic to interpret partial evidence (Mandelstam’s) as definite and this is a tendency (or methodology) raises concerns about the ST endeavor itself. In other words Smolin claims there is not enough self skepticism in the ST mode of work. Do you think he has a point and there is a bold methodology of “moving on”. If yes, is it a good methodology? 5. Do you agree with Smolin at least on the little point that regarding Mandelstam evidence as a solid “proof” for many years was unjustified? 6. Is there some merit to the claim that there is a tendency in string theory to overplay positive evidence and ignore negative evidence. (Clifford, the entire post became bold face since post 226 maybe you can do something about it?) 247. Clifford says: Thanks Gina.. I use Netscape, and it seems to fix it so that I do not see the run over, which explains why I did not fix it. Fixed it now. What browser are you using? Safari? -cvj 248. M says: High-energy divergences would give Planck-suppressed operators, i.e. experimentally negligible effects. The reason why theorists addressed this conceptual issue was the hope that an ultraviolet-finite theory of quantum gravity could be predictive also at low-energy. If instead, even in string theory, one finds 10^500 low-energy ambiguities, why should one care about high-energy ambiguities? I think that, at the level of physics rigor, the answer to the question that you are debating is that it is irrelevant. 249. young string worker says: $$c^2 – d = 0 \\ e^2 + f – 2^g = 9$$ 250. young string worker says: OK, let’s suppose you have partition function for 10 free real multiplets of (1,1) worldsheet SUSY, on a Riemann surface of genus g. And I suppose let’s take the simplest possible amplitude — the vacuum amplitude. That seems to be the one all the fuss is about anyway. So what we’re really talking about here is the invariance properties of the amplitude $$\left\langle {\bf X}(z_1) \cdots {\bf X}(z_{2g-2}) \right\rangle$$ under changing the positions $$z_i$$ of the PCO’s $${\bf X}(z_i) ,~$$ si? 251. young string worker says: I suppse you’ll also need ordinary b-ghost insertions too. $$\left\langle {\bf X}(z_1) \cdots {\bf X}(z_{2g-2}) ~b(y_1)\cdots b(y_{3 g – 3})\right\rangle$$ Jacques, this is right, isn’t it? (Sorry I forgot to put in the left-moving ghosts, but you know what I mean). 252. Warren says: You use Netscape?! Wasn’t that made obsolete by Firefox eons ago? I strongly suggest someone contact d’Hoker and Phong to find out what browsers they use. 253. Gina says: Clifford, I used to use IE but mainly for this blog moved to Firefox. 254. Is it correct to say that neither AMS nor even d â€˜Hoker and Phong can be regarded as solid proofs in the mathematics sense of the word. I don’t think physicists strive for (nor should they) a level of rigour appropriate to Mathematicians. Nevertheless, with a finite (but sometimes very large) amount of effort, it is usually the case that a “Physicist’s Proof” can be turned into one that would satisfy a Mathematician. What level of rigour physicists do strive for really depends on the problem. When the problem (such as this one) turns out to have all kinds of hidden subtleties, the level of rigour required goes up. Can you explain in non-technical terms what is the difference and why it is of important to find constructive proofs. I.e. given that AMS proof is sound why d â€˜Hooker and Phong work is at all important. A non-constructive proof says: even though we cannot write down the answer explicitly, we can prove that it has properties A, B and C. And this is sufficient to show that desired outcomes X, Y and Z are achieved. A constructive proof says: Look! We can write down the answer explicitly and you can see, by inspecting it, that it has the desired properties. Constructive proofs are always preferable in Mathematics, but even moreso in Physics, where we would like to use the answer to calculate stuff. Moreover, d’Hoker and Phong did more than merely give a constructive proof (at genus-2). Their answer has better properties than those strictly required by AMS. And these properties make it even more useful for calculations. Having said that, I will point out that AMS did write out explicit formulæ for genus-2. Their formuæ are not as nice as those of d’Hoker and Phong. But they are explicit. Smolin concerns on this issue was that string theorists were too optimistic to interpret partial evidence (Mandelstamâ€™s) as definite… I really don’t understand Smolin’s account. I remember Mandelstam going around announcing that he had a light-cone gauge proof of finiteness. This generated a lot of excitement (because, as a calculational tool, this would have been even more useful than the covariant gauge treatment that d’Hoker and Phong came up with many years later). But, when he never wrote a paper about it, everyone figured that he had found a fatal flaw in his method, and gave up on it. I have never met anyone who believes “Mandelstam proved finiteness” so Lee’s recounting of this tale completely baffles me. As to the larger point, there are many things in physics that we “know” are true, because we have amassed a lot of computational evidence to support them, but which have never been formally proven. And I think Lee is completely off the mark on this. I suggest you read my post on this subject, for a fuller account of why I think that. Young String Worker wrote: Jacques, this is right, isnâ€™t it? The issue noticed by Verlinde and Verlinde (though they didn’t quite phrase it this way) is that, in the naivest version of this class of gauge choices (inserting PCO’s at points on the RS), the gauge choice fails to be everywhere transverse to the gauge orbits. In their computation, this led to poles of the integrand in the interior of moduli space. In a more sophisticated choice of gauge that problem is fixed, but you still need to think carefully about the behaviour of your gauge slice as you approach the boundary of moduli space. Taking sufficient care, in dealing with these issues, is why AMS’s papers run to a total of 190 pages. 255. John G says: Isn’t Peter’s arguement against string theory more a business case than a technical merit case? Peter actually likes Witten’s math and Greene’s enthusiasm. The business case against string theory is not overly difficult to see. Lots of resources tied up for a long time without many Nobel Prize-like results. A CEO can cancel a research program without knowing the technical details. The CEO though does look at high level bullets covering the technical aspects. One bullet could be Lack of a developed GUT. If there was a nicely developed E6 GUT, one would not have needed to start the anthropic landscape mess. Peter actually does not like GUT models cause they don’t handle electroweak symmetry breaking well so a sub-bullet might be Good electroweak symmetry breaking. Another good sub-bullet for your GUT might be Nice emergent spacetime. Another main bullet might be Why SUSY? If you aren’t seeing SUSY yet, maybe a bunch of people should go back and think bosonic string (in general more of the workforce should be working on more things). Susskind and Smolin could actually work together and develop their bosonic M-theory ideas more. Another main bullet might be Number Theory. People like Wolfram and Finkelstein have ideas that relate to Feynman paths/information theory/number theory and Urs Schreiber once mentioned there being a deep connection between the Feynman path and string theory worldsheets, maybe string theory needs more people working on more Number theory related ideas (again the more of the workforce working on more things general theme). Requiring Peter to know all the technical details in order to make a business case against string theory just does not make sense, that’s not the way real businesses work. 256. amused string worker says: I didn’t think this thread could possible get any funnier or any more absurd but I was wrong. Peter Woit as the CEO of Strings Inc. is priceless. Maybe with a$10M golden parachute and some stock options we can get him to take early
retirement before he drives the stock price down any further.

257. Hi Clifford,

You ask what to do and what more to say, and it is difficult to dismiss such questions, even though I have tried hard to. I warn you and the readers that what follows may induce sleeping to some.

Given the state of affairs, that is, fundamental misunderstandings among debaters, some kind of convergence seem to be very far from obvious. But is it really a storm in a teacup? What is really happening?

Mostly, these misunderstandings are clearly related to the vision of science that people have.

In my opinion, there should be some effort in order that debaters attempt to at least first recognize the naturalness of the existence of different visions and interpretations in any scientific work, specially when it is under development, and exercise to leave quick temper somewhere else.

I do not mean here that wrong interpretations are acceptable just for the well being of everyone, that is evidently against what science is all about. What I mean is that a fundamental attitude a scientist should care about is to doubt and this should be seen very naturally, if not a technique to be exercised. To first doubt herself on whether she is right or wrong, since although being confident is generally a positive attitude, too much confidence in science is not necessarily a productive thing anyway. Nature does not care about human confidence at all.

We should doubt others as well, of course. To doubt each other should be seen as a natural process in science, nothing to take personally. We should doubt because there is no way for a human being to understand Nature straighforwardly. Otherwise, every assertion of a human being could be taken as true by principle. We would know for sure and science would be a trivial activity.

But that is not the way it is, although Nature has been kind to us on certain matters and at certain levels. Our only signposts to guide us through the right path is mathematics, experiements, observations, collaborations, inspiration, hard work, and they all come eventually in different proportions. Now we are at quantum gravity and more than in any other time in science, doubt should be spoken more frequently in our vocabulary.

Differences in interpretation are welcomed and have proven many times in the past as being fundamental ingredients for the scientific advance. Unfortunately, science today is a highly competitive field, and people became highly competitive even with themselves, because they just forgot the fact that humbleness is the first prerequisite towards understanding Nature. The final goal, whatever that means, will not be achieved through competition, but through wisdom.

The current system does not encourage such a view, so it is a difficult crash between utopy and reality, something I am really tired of.

In any case, the main message I want to express here is that, given the challenging endeavor of quantum gravity as a formidable example, scientists should see each other as colleagues, not competitors. Fundamentally, we are indeed just like humble creatures looking for pretty peebles in the beach, whereas the vast ocean of undiscovered truth lay before us. Old sentence, but I cannot disregard it even if I tried very hard. In my opinion, if scientists do not recognize themselves as such creatures, then what are they?

I do not have any advice on how to solve the current disputes, since it possibly involves a very personal process on how one increasingly attempts to enhance his/her view of the world and how to conduct his/her own life, even before we talk about a view of science and a scientific life. So my long comment here might be completely useless in a practical sense and perhaps seen as extremely naive to some.

Scientifically speaking, nothing more is needed than civilized discussion (be it in a blog or at a conference), collaboration, and hard work.

If people reach the conclusion that indeed the scientific activity as practiced today must be somehow reviewed (a fact many would agree), that revision will lead nowhere if scientists do not start thinking deeply about themselves as well.

That has been my very general interpretation of Smolin’s underlying intention in his recent book, whatever the string theory controversy it carries with. He doubts and he tries to recall all of us that we should doubt.

So you also are free to doubt. Is it a a storm in a teacup, first of all?

We need cooperation to understand and, mainly, to understand our main doubts. Only then we will give a step towards understanding our certainties.

Best wishes,
Christine

258. Clifford says:

Christine, Thanks!

If you read what I’ve said in my several posts on the subject, and also the main points I try to drive home in the several comments I make on the threads of those posts, you will see that we are more or less in agreement on everything you say. And I certainly agree that we should regard each other as colleagues first and foremost, and not competitors. This is why I do not agree with the practice of writing books presenting a distorted picture of a field of an entire field of research, the sole purpose being to devalue and undermine the work of very many people, and represent them as marching in lock step to some religious or sociological ideology. All presented to a readership who is not in a position to determine whether this is true or not. That is not the way to proceed. That is not the way to express doubts, or start a constructive discussion amongst your colleague, as Lee Smolin claims he is doing. This is a way lower (and more poisonous to the whole field) rung on the ladder than books that sometimes are overly positive about an area of research, in my opinion. Naive enthusiasm and positivity about something is not equivalent to catch-all negativity about the work of hundreds -maybe thousands- of people, especially when all that work is misrepresented, oversimplified, or simply poorly understood by the persons writing.

This is not a good way to proceed. In fact, it is unprofessional and dishonest. People should know that the work is being misreported and chariacatured, and that the people writing do not have complete command of many of the actual results that they criticise. Hence these posts, and comments, on this blog.

Best,

-cvj

259. Moshe says:

There is one more lesson in this thread (from which I actually learned some things, thanks Jacques…): the problem with string perturbation theory, the one that would spell a disaster for the whole enterprise, was pointed out by the Verlinde brothers, two young string theorists. Somehow this is relevant to the oft-repeated story of the unreflective community that needs to be challenged by “informed outsiders”…

260. Moshe says:

Also, 258 comments is a new record, we must keep this thread going!

261. Plato says:

In any case, the main message I want to express here is that, given the challenging endeavor of quantum gravity as a formidable example, scientists should see each other as colleagues, not competitors.

That might have been my mistake here.
I could not help but interpret the exchange between the “two traditions” as competitive, yet, I should be more respectful if it was agreed that such dialogues would go beyond “the conflict” was important.

But digging deeper for the information, regardless of the tone, that if one could move past it, if one is willing to do the dialogue. Stand corrected?

Isn’t the issue deeper then what is acknowledge by presenting the book? I am thinking this. Background/background independence? It became disguised in all the issues around it. All the verbal exchanges that hinted of…..?

Just resting on the “latest assumption” of the book written. How would you know if you didn’t write one? So each book undergoes updates and we are all the wiser for it. That’s okay, isn’t it?

262. Hi Clifford,

What you write is quite understandable, and I am sure Smolin knew he was writting a difficult and polemic book.

For what is worth, the “debate” will continue as long as it is fed, like an ever growing beast that is always hungry for more and more, reaching nowhere, except its own larger fat. The issues involved are deep and complicated, and I am happy to be out of this. Nevertheless, I wish good luck to all involved.

Cheers,
Christine

263. Gina says:

Dear Clifford,

Did you read the books by Peter Woit and Lee Smolin? Sure, there are various aspects and details of these books that can be criticized, but what you wrote is a grand oversimplification and a mischaracterization of these books and, even more than that, of the many interesting issues involved in this discussion.

Look how nice was the way Polchinski responded on the issues (those he felt are most important). Learn one more thing from the master!

264. Clifford says:

Hi Gina,

About what Joe Polchinski said in his review: Joe has his take on things, and I have mine. I am not Joe. Joe is not me. I don’t want to be Joe. Joe does not want to be me. We are separate individuals. I am free make to my own independent objections to their publicly expressed views, and I have made them. I did not write any book reviews, which would be wrong, since I have not read their books.

(By the way, contrast that statement with the fact that Woit made up out of whole cloth the public statement/accusation that I negatively reviewed his book for CUP. Not the way to carry out a discussion among colleagues, I’d say. If he makes up stuff like that at random, how can a non-expert trust what he has to say about the host of other things he says, about research in the field of string theory? That’s one of the points I’m trying to make here:- I’m just asking for a bit more honesty from him about what he knows and what he does not know, vs what he may have a strong feeling about, or dislike of. You don’t make up things to cast a bad light on someone’s professional reputation (he also accused me of somehow influencing KC Cole to write her LA Times review!) and put them on a blog. See here.)

Best,

-cvj

265. anon on the hudson says:

Gina

you are really stinking this blog up with your troll-like behavior. The experts are discussing very serious technical points. Your posts are superficial and annoying.

Questions for the experts:

Does the string theory finite perturbation problem have anything to do with problem of millions or billions string vacua?

Which one of these two problems is more fundamental?

QED and QCD make predictions even though there are serious questions about the mathematical rigor and foundations of these theories. Lubos claims that string theory already makes predictions. Do you agree with this Professor Johnson?

If the LHC discovers supersymmetry, would superstring theory be vindicated to some degree?

Does superstring theory make specific,nontrivial predictions about supersymmetry?

I think an answer to these questions would help give the civilian population a better road map of this great scientific debate.

One last question, one sting theorist claimed that string theory subsumes noncommutative geometry. What could this possibly mean? Is this true?

266. young string worker says:

In a more sophisticated choice of gauge that problem is fixed, but you still need to think carefully about the behaviour of your gauge slice as you approach the boundary of moduli space.

What is the simplest way to understand their choice of gauge?

267. young string worker says:

blockquote

what is the simplest way to understand their choice of gauge?

268. Clifford says:

anon on the hudson:-

Briefly, the general picture right now with regards predictions of string theory is that the theory is not yet well enough developed to claim anything like a definite prediction. It has made some strong suggestions of a number of scenarios, such as extra dimensions, supersymmetry, etc, but I think it would be too strong to claim those as experimental predictions. If we found signs that Nature has extra dimensions or supersymmetry, etc, that would be exciting, and encourage us that we were maybe on the right track, and would help in constraining our understanding of the theory, if it is indeed correct, since it would supply us with measurements that can help constrain things… (But it might be that this is not the way things might go…. although it would not be dissimilar to how things worked historically with the development of the Standard Model of particle physics to date.) We may also get powerful clues from unexpected directions, such as cosmology, or even in the applications of string theory to heavy ion collider physics at RHIC or some of the work to be done at LHC in that arena. It is all connected to the same story, despite what Smolin says about it being an irrelevant issue (see discussion on that in More Scenes… IV).

We have a lot to do. The framework and phenomena we see from the studies are very exciting looking – but on paper only so far. I gave a list in an earlier thread of this sort (or maybe earlier in this thread… not sure! Oh, here…) of some of the reasons people find the framework extremely exciting and promising, but there is a lot to do before we understand the theory well enough to have a tight enough framework.

That’s my opinion. Others may differ. They are entitled to do so. What they cannot claim, however, as Woit does (and Smolin to maybe a lesser extent) is that they know the answer in advance. That is untrue. The theory is nowhere near well enough developed to know that yet.

We can go into the old “how long do we have to wait?” routine, but I can’t do it again. I do not know. Nobody does. You cannot put time limits on research ideas in this field. We are not runing a business, despite the bizarre suggestion of a commenter some comments above. Progress continues, and that is good. There is a huge diversity of effort within the field (we are not all marching in lock-step on the same one or two ideas, despite the impression given by Smolin and Woit) where people are applying the ideas to a variety of problems, as well as in trying to understand the theory better overall at a fundamental level, with results coming in all the time. Please read all the threads of discussion on the posts with similar titles to this one for a lot of discussion about that.

People are also free to work on alternative approaches. Nobody is stopping them from doing so, despite what you are told by Smolin and Woit. The problems we are all trying to solve is simply a very hard one. Snarling at each other over each other’s preferred distribution of resources and effort (in book form and appealing to the press) is not productive. It is the ideas that should lead the way.

Present good, promising and successful ideas, and people will work on them, strings or not. We wait for Smolin and Woit to do so, rather than writing books attacking what we are doing.

Cheers,

-cvj

269. nc says:

“… It is the ideas that should lead the way.
“Present good, promising and successful ideas, and people will work on them, strings or not. We wait for Smolin and Woit to do so, rather than writing books attacking what we are doing.”

This argument is irrefutable, very good. …. Unless you, Smolin and Woit disagree about what is a “good, promising and successful” alternative, of course.

A little from the editorial on p5 of the 9 Dec 06 issue of New Scientist: “[Unorthodox approaches] now seem the antithesis of modern science, with consensus and peer review at its very heart. … The sheer number of ideas in circulation means we need tough, sometimes crude ways of sorting…. The principle that new ideas should be verified and reinforced by an intellectual community is one of the pillars of scientific endeavour, but it comes at a cost.”

Far easier to say anything else is crackpot. String isn’t, because it’s mainstream, has more people working on it, and has a large number of ideas connecting one another. No “lone genius” can ever come up with anything more mathematically complex, and amazingly technical than string theory ideas, which are the result of decades of research by hundreds of people. So it is unlikely that elite geniuses like Smolin and Woit will come up with ideas impressive enough to make media headlines. Stringers are safe.

270. Clifford wrote:

I have not read their books, but it is well known that those views are also represented in their books. (…) I am arguing against the larger arc within which the books fit.

Hi Clifford,

This is an interesting detail, thanks for making this clear, specially the last sentence that I quote above from you.

I did not read Woit’s book, but read Smolin’s and reviewed it positively. My review focused on the topics which appeared to me to be quite general, namely: his view on how science works. I believe that he could have written a completely independent book on this matter without mentioning string theory whatsoever, but I could be mistaken.

So you see, in my interpretation, he also offers some other kind of “larger arc” concerning science that it is interesting by itself. However, as I previously wrote, it is quite understandable that the book would find a strong opposition due to the polemics it carries. At the end of the day, it is a pity that this implies a missing opportunity for some to learn about interesting and important issues that deserve attention, thought, action.

Best regards,
Christine

271. Plato says:

While the discussion is an “open debate” about the effects it has on those delving into the frameworks of the two traditions there is a “definite line up.” Smolin used his book and then his book site to demonstrate a continued effort to speak from his position, his lectures, his letter etc.

So he uses his book.

His last summation on “exploratory avenues.” AS if, one contentious issue in Jacques and Lee’s and Peter’s debate. While this is only one, and was being corrected, I see what you are saying about the overall idea, and of course he had to know about what he was writing, whilst making that summation.

It is hard not to inject these ideas about “the industry of the traditions” and this is what Peter had done. About schools and such. Who is being supported. I didn’t like seeing this either. It was always about learning the foundational perspectives and model approaches?

Of course I am watching this discussion at a higher level of expertise debate amongst the experts. Why Lee Smolin or Joeseph Polchinski might choose to speak to one in Brane developmental understanding?

272. Peter Woit says:

Clifford,

Thanks for making it clear that you were not the CUP referee, had nothing to do with the KC Cole “review”, as well as acknowledging that you haven’t even read my book or Lee Smolin’s. My apology for having made mistaken suggestions in my posting, and misinterpreting your later comments about it. I will update that posting to include this apology.

273. Gina says:

Dear Clifford,
What I meant to say rather than “Learn one more thing from the master!” was “Let’s learn one more thing from the master!” so it was not meant to be personal, but was based on your characterization of Polchinski as a master and your statement about how much we have learned from him. In this case, I do not ask, of course, to adopt Joe’s specific opinions but rather his approach to discuss specific issues that Woit or Smolin raised, issues that he found interesting, explain clearly and fairly what they say, and then explain clearly his own take on these issues.

You wrote: “Iâ€™ve written thousands of words about the issues that both Smolin and Woit have raised.” and also “Please read what Iâ€™ve been saying in discussions with Smolin and Woit -in great detail- for the last year and a half on this issue”. And also “I have not read their books, but it is well known that those views are also represented in their books”.

Dear Jacques,

Many thanks to your answers to my questions. I am familiar with your post “the role of rigor” that your mentioned in your reply, and, in fact, I posted there a remark with my opinion on this issue of rigour. (This is my only remark on your weblog.)

274. Clifford says:

Christine Dantas:-

I’ve also addressed the larger arc of careers and ideas in science that has come up in the discussions. As I said -also several times- if that is what they wanted to talk about, why did they not talk about that, instead of attacking string theory?

I’ve addressed that, and that issue is yet another contributor to why this is a storm in a teacup. It is clear that the fuss over these books… this “controversy” … is a media-generated whim. Standard Outsider Vs The Esptablishment…. one of the few and well-known hooks the media use for a science story. They do not care about the issue of careers, or how ideas come forth, in science.

I can’t sit here and type out everything I have already clearly said umpteen times all over again. Sorry. Please have a look at the things I’ve said. I’ve carefully linked and crosslinked, and made a great effort to give the principal posts similar titles to make it easy to search, etc, etc.

It’s all been said.

Gina:- “I am puzzled by your choice not to read the book themselves until now”. Did you read my long comment about the fact that I’ve been debating the authors directly for almost a year and a half now? That would seem to me to be a better source of what they think than the books. We’re not talking about checking detailed calculations here, we’re talking about a fairly simple set of assertions that can be quite readily conveyed (and have) in a series of conversations.

Best,

-cvj

275. Clifford says:

Peter Woit:- The standard practice in academia is not to force people to violate the rules of anonymous refereeing for journals and publishers by publicly accusing them of things such as you did, and then requiring them to deny it. This is not good behaviour. In fact, even outside academia, you don’t make up random things about someone and then make it their duty to deny it, interpreting their silence as proof. That’s just nuts. Hiding your apology and correction at the bottom of a months-old blog post is not really much of either, in my opinion.

-cvj

276. In fact, even outside academia, you donâ€™t make up random things about someone and then make it their duty to deny it, interpreting their silence as proof.

When running for Governor of Texas in 1948, LBJ instructed his aide to circulate a rumour that his opponent had been caught having sex with farm animals. “But Lyndon,” the aide said, “you can’t just call the man a pig-f@#%er.” “Maybe not,” LBJ replied, “but I sure as hell can make him deny it

277. Peter Woit says:

Clifford,

I acknowledge that this was something I should not have done and apologize for it. Besides doing so here, the other location was chosen not for its obscurity, but because it is the place of the original misguided suggestion, and what anyone looking into where it came from is most likely to read.

That said, I should also point out that your behavior towards me has all too often been execrable and highly unprofessional. The kind of less than honest ad hominem attacks that you have indulged in here have no legitimate place in discussions of a scientific research program. It goes way beyond the bounds of acceptable academic behavior to attack serious books that you have not even read. I’ve certainly made my share of mistakes in how I have responded to this behavior and I apologize for those, but I think you need to take a serious look at the nature of your own over-reaction to legitimate scientific criticism.

278. Hi Clifford,

Right, in fact I did not read the other posts of the “Scenes From the Storm in a Teacup” series. Certainly there is a lot that has been said many and many times, and I should have considered taking some time going through some older posts.

Sorry about that, but thanks anyway for the replies.

Christine

279. Gina says:

Peter, It is nice that you start to apologize on your old misinterpretations and not very conventional/ethical referee’s identity public-speculations. But it does not make sense to add new misinterpretations and imaginary “denials” to the “apology”.

Clifford, I beg to disagree. It is not complicated calculations, but still there are arguments and thoughts and ideas which represent several years of efforts by the authors. Many of the arguments and ideas expressed in the books are not conveyed in your lengthy debates with the authors. (And also, Woit and Smolin approaches are different on various matters and this is not reflected in your comments.) As a matter of fact, Lee Smolin made (above) precisely the complaint that rarely were the points he was making in the book addressed by its critiques. Given the small amount of effort required by you to read the books compared to your overall efforts on this matter I am still quite puzzled. In any case, I would recommend spending the few hours needed (especially that you can skip most of the physics) to read the books.

280. Clifford says:

Gina, Thanks. I have talked directly and publicly to the authors, at length. That is the quickest and most direct way of getting the substance of what they are saying, and that is what I am arguing against. I am not interested in discussing the details of exactly how they put things in their sentences. The discussions I have had are more than enough for me to know what they are saying and to disagree and put my own points. You and I can agree to disagree on that, and I see no point in discussing it further. And yes, I do equate Smolin and Woit’s approaches in this. I am clear on the differences in what they say, but their approaches are the same, and a lot of what I am talking abotu is the whole logic of writing attack books as a means of having a discussion like this. They both do it, they are both taking advantage of each other’s presence for press coverage, adn so they both get to be lumped together in this discussion. It is both of them that contribute to the storm in the teacup.

Peter Woit, Scientific criticism is welcome. I keep giving you the opportunity to make some, and you back off when asked for details. That’s a fact. You can’t claim that an area of research cannot make contact with experiment and not have anything that shows that, since the research is still hotly ongoing. This practice of yours is wrong, and it is misleading to the public. My response to this is not an over-reaction, but a central and simple request for scientific honesty. I simply take issue with your mixing up your feelings of dislike for the approach (to which you are entitled) with a statement scientific fact (which they are not).

There is nothing wrong with me saying that and pointing it out to those who care to listen. I am sorry if that dismays you. Pressing you on those points -sometimes harshly and with some sarcasm, out of frustration- cannot be equated to making up lies about people.

I really really hope you can see the difference.

-cvj

281. Arun says:

http://arxiv.org/abs/hep-th/0312177

claims to (successfully) fix some problems/misconceptions stemming from V&V and AMS.

The only citation to 0312177 is hep-th/0406055, where Berkovits writes:

Danilov [8] has claimed to be able to compute RNS amplitudes for arbitrary genus, however, this author has been unable to understand his methods.

Interesting also is the first paragraph of 0406055, emphasis added:

The computation of multiloop amplitudes in superstring theory has many important applications such as verifying perturbative finiteness and testing duality conjectures. Nevertheless, this subject has received little attention over the last fifteen years, mainly because of difficulties in computing multiloop amplitudes using either the Ramond-Neveu-Schwarz (RNS) or Green-Schwarz (GS) formalism.

282. Arun says:

Sticking my neck out here:

The demonstration that string perturbation theory scattering amplitudes are finite is a physicists’ proof. As such it has a degree of certainty/uncertainty associated with it unlike the typical mathematical proof. From what little I have seen, the certainty is less than say, the proof of renormalizability of non-Abelian QFTs. Certainly, 15 years after renormalizability was proved, no one wrote a paper to compute higher loop amplitudes in order to verify renormalizability.

Probably one of the reasons for the uncertainty about the finiteness proof is its technical complexity.

Improving the situation is high-risk research, the time needed versus the pay-off (of likely confirming what we believe we already know) is against it. Only a brave few will venture here. Also, I think that the technology of doing perturbative string calculations in arbitrary backgrounds remains even less advanced. Also, perhaps advance will come from a whole new approach, and not by elaboration of the existing methods.

For considering what Woit and Smolin are saying – What we need is a statement of the upper bound of uncertainty – what are various physicists’ demonstrations that are considered valid, but somewhat less certain than string perturbation theory finiteness?

283. For considering what Woit and Smolin are saying – What we need is a statement of the upper bound of uncertainty…

With respect, Arun, Woit and Smolin are quite unequivocal in what they are saying.

This is not an issue of theoretical physicists rigor vrs mathematical rigor. There is no proof at either level. There is an intuitive argument, but that is far from persuasive …

Woit:

Your claim that the AMS paper gives a proof of multi-loop finiteness is a complete mischaracterization of the situation. As Lee correctly explained to you, the AMS prescription for amplitudes is not invariant under the choice of gauge slice. They are therefore working with ill-defined amplitudes, and cannot have a finiteness proof.

They’re not talking about some small, unfilled gap in the proof. They’re not complaining about its complexity. Nor are they talking about the non-constructive nature of the proof making it less-than-useful for practical calculations.

They are claiming it’s flat-out wrong.

Having spent a day or two examining the literature, do you think that’s an accurate assessment?

Now, of course, there could be a Sooper Sekrit flaw, known to Woit and Smolin (and d’Hoker and Phong), that they’re not telling us about. Perhaps, because of its critical role in the GWOT, they can’t reveal the flaw publicly.

What’s your assessment of the likelihood of that possibility?

284. Truth in advertising re: AMS paper says:

Jacques has evaded Arun’s point (is the AMS paper a “physicists’ proof”, a mathematical proof, or what?). We are discussing what that paper contains. Jacques claims to be expert enough to have lectured on it. Can he write a few sentences explaining whether the finiteness of perturbative string amplitudes discussed in the AMS paper is
(a) a well-defined mathematical statement found in the paper
(b) proved to mathematical standards in the paper,
( c) proved to physical standards in the paper, or
(d) something else entirely.

285. Shall I repeat my previous response to that question, or is there something specific in it that requires further elaboration?

286. Truth in advertising re: AMS paper says:

An answer specifically to points a,b,c,d would be useful. You appear to
claim:
a. yes
b. no
c. yes

Is that correct?

287. You appear to
claim:
a. yes
b. no
c. yes
Is that correct?

More or less.

As I said, there’s a sliding scale of rigour, when it comes to “physicist’s proofs.” Because of the subtlety of this particular problem, AMS’s proof tends towards the high end on the rigour scale.

But, I’ll repeat that Smolin and Woit are not claiming that AMS’s proof is insufficiently rigourous, or that it has unfilled gaps in it. They’re claiming that it’s not a proof at all.

288. Arun says:

With respect to what the literature has, I would say it must be an extreme minority view that the AMS proof is flat out wrong. At the same time,(repeating myself), I don’t think there is the level of comfort that there is, e.g., with the proofs of perturbative renormalizability of various QFTs. Please note that these are my impressions only, I do not command enough mathematics to actually evaluate the papers. The only justification for foolhardily attempting this exercise is the rather public debate over string theory.

289. Gina says:

Let me continue with the elaborated critique to Lee’s book.

13. The reactions portrayed negatively to sporadic bold theories and ideas (like ‘t Hooft’s) are, in fact, very reasonable. Scientists current attitude is essentially the correct attitude.

Lee portrayed negatively the attitude of the high-energy physics community towards very revolutionary scientific ideas and theories even when they are proposed by great scientists. I beg to disagree:

The basic principle in scientific and academic activity (unlike other areas) is that everybody, no matter how famous, have the burden to convince the community from scratch in the merits of a new theory or a new idea that she or he presents. Everybody, Smolin, ‘t Hooft, Witten, Penrose, Chomsky, … Everybody. The skeptical approach of the scientific community to ‘t Hooft’s ideas is a healthy sign. You want to do something beyond the line of duty? Take a few months or even a year; Read carefully ‘t Hooft writings, and tell the great man where he is wrong. Point after point.

290. nc says:

“… Iâ€™ll repeat that Smolin and Woit are not claiming that AMSâ€™s proof is insufficiently rigourous, or that it has unfilled gaps in it. Theyâ€™re claiming that itâ€™s not a proof at all.” – Professor Jacques Distler

“Proof. n. 1. The evidence or argument that compels the mind to accept an assertion as true.” – http://www.answers.com/topic/proof

That’s the primary definition. But it also says:

“2.a. The validation of a proposition by application of specified rules, as of induction or deduction, to assumptions, axioms, and sequentially derived conclusions.”

Definition 2.a (logical rigour) seems more stringent than definition 1 (brainwashing or consensus). If it isn’t rigorous, why should anyone take it as proof? Lots of nice looking non-rigorous “proofs” collapse when an attempt is made to make them rigorous. Stanley Brown, editor of PRL, and his associate editor used this against me. I claimed simply that you can (given Minkowski’s spacetime) interpret recession of stars as a variation not only of velocity with distance, but also of velocity with time past as seen from our frame of reference. This gives the stars outward acceleration, which gives them outward force, which by Newton’s 3rd law gives equal inward force, which by the Fatio-LeSage mechanism (applied to gravity causing exchange radiation, not to material rays) for the first time in history predicts the strength of gravity (you just have to allow for the redshift of the force-causing exchange radiation from receding stars weakening gravity and for the increased density of the earlier – distant – universe which tends to increase the outward force aand inward reaction force as seen from our frame of reference). The PRL guys denied it was a proof. However, they never said what they were disputing.

This is an analogy to the position taken by Woit and Smolin over AMS’s proof. If you don’t believe it, you don’t need to say what you think is wrong. That’s professionalism.

291. Lee Smolin says:

Let me try to say something everyone could agree on, which is that the literature is not clear on this point. Jacques, it may be true that, as you claim AMS contains a â€œnonconstructive proofâ€ of finiteness. But the following four things are true: 1) you can find papers that cite AMS and appear to state that finiteness is not yet proved. This is what a fair reading of the papers of dâ€™Hoker and Phong suggest, it and in addition to the example of the paper by Alvarez-Gaume and Vazquez-Mozo mentioned above, one can find, a year after their work, in Sept 88, a paper â€œOn the finiteness of the superstringâ€ by Olaf Lichtenfeld, in which he references AMS in the course of a discussion on technical issues but nevertheless opens his paper by a paragraph in which he introduces the issue of perturbative finiteness and concludes that â€œâ€¦nevertheless surprisingly little progress has been madeâ€¦.â€ 2) Some of these papers do appear to say why AMS is not a proof, as was discussed above. 3) One can find lots of references to finiteness since 87 that do not cite AMS. Indeed the Catoptric Tadpoles paper has only 21 citations in the last ten years which is not what you would expect from a paper that proves a key claim of string theory; instead one would expect that if it were understood generally as the proof of finiteness it would be cited in every Ph.D. thesis and review article in the field. 4) I did a lot of fact checking and discussed the issue of finiteness with numerous string theorists and indeed first discussed the issue more than three years ago in hep-th/0303185. A number of prominent string theorists agreed that finiteness is not proven and of those that claimed there is a proof, none cited AMS to me as the proof.

From this one should conclude first that Peter, myself and others are not in bad faith in discussing this issue, we are just trying to get to the truth. Jacques may be right, but it would be helpful if he could see that the literature is not clear on this point and that, in particular, there are papers that a fair reader would take as implying that AMS does not have a complete proof. Second, a review article would be really helpful here, written by one of the experts who has contributed to the issue, that sets out clearly what are the technical issues involved in proving finiteness and exactly what their status is presently.

Thanks,

Lee

292. Count Iblis says:

#288 – Gina,

Criticism and a skeptical attitude is ok, and it must be present.
But there is a destructive negative attitude that actually leads to people dismissing such
ideas a priori, even though that’s not justified.

If you compare theoretical physics to astrophysics then you see an enormous difference in
attitude toward alternative ideas. I know people who don’t like MOND or TeVeS theory but
who still have written papers on it. There are also people who work on alternative scenarios for
dark energy. That then leads to a discussion in the scientific literature in which others try
to constrain these theories. Such a discussion is exactly the skeptical attitude one needs.

In theoretical physics (hep-th) this is not happening. Let’s take ‘t Hooft’s ideas as an
example. There isn’t really much activity going on in that field. What you would expect to
happen is that there would be papers published where the particular models by ‘t Hooft are
constrained and criticised. Also there would be papers on variants of models considered by ‘t Hooft
(there are actually one or two that have done that). Also there should be people working on
completely different models (alternative to the alternative). I know that Smolin has written
one or two papers recently, but that’s it

293. Lee,

I am comfortable with the proposition that

The AMS proof of finiteness has gaps in it. And some of those gaps remain unfilled, even today.

But that’s not what you said:

This is not an issue of theoretical physicists rigor vrs mathematical rigor. There is no proof at either level. There is an intuitive argument, but that is far from persuasive â€¦

and that’s certainly not what Peter said:

Your claim that the AMS paper gives a proof of multi-loop finiteness is a complete mischaracterization of the situation. As Lee correctly explained to you, the AMS prescription for amplitudes is not invariant under the choice of gauge slice. They are therefore working with ill-defined amplitudes, and cannot have a finiteness proof.

As Arun concluded, the latter statements are impossible to reconcile with even a cursory analysis of the subsequent literature (let alone an actual understanding of the contents thereof).

So I, for one, am puzzled as to how these statements could have been made in “good faith” and why it has taken my persistent badgering, over the space of and over 150 comment thread, for you (if not Peter) to amend your position to one somewhat more consonant with the actual state-of-affairs.

To be blunt, there are lots of statements that you and Peter make, that I similarly disagree with. But I have neither the time, the energy, nor the heart to go to these extreme lengths to get you (well, one of you) to see the light.

294. Moveon says:

@ Gina (#230):

Arenâ€™t there any interesting research areas closer to QED/QCD/ the standard model? Isnâ€™t there too much emphasis on fundamental problems? and not enough effort to identify interesting â€œsecond lineâ€ problems based on progress already achieved on fundamental problems?â€

I do not understand what â€œphenomenological directionsâ€ precisely (or vaguely) mean. ….
I will be thankful to learn in nontechnical (comment or link) what are the areas of high energy physics and what people are doing.

Look, this is a vast field with hundreds if not thousands of people working in it, and you must read some literature yourself. Perhaps one of the recent white papers on the future of particle physics; there was an US one and a European one. In a nutshell, this encompasses all sorts of tests of the standard model and predictions for extensions thereof (like supersymmetric ones). And it encompasses the issues mentiond in the top quote above.

I completely disagree with your last paragraph:

M: â€œBooks and blogs with malicious intentions can do great damage to the â€œcluelessâ€ public who have no means to decide on what is true or not. â€

…..
I do not see here people with â€œmalicious intentionsâ€.

You mean discrediting a whole generation of hard working scientists by claiming their work would be so bad and/or pointless that it is “not even wrong”, is NOT malicious? Do you really believe that orchestrating a media compaign in order to damage the whole field of particle physics stems from a sincere concern about it? I can hardly believe that anyone with good intentions would act in such an irresponsible manner.

@Iblis (291) “In theoretical physics (hep-th) this is not happening”

That’s of course not true; like most what is claimed by outsiders and critics. A lot of different “models” are proposed all the time. I recall that the whole Randall-Sundrum setup was cooked up as an “alternative” to string theory; allowing phenomenologists to deal with quantum gravity and higher dimensions, without having to learn string theory and higher math. Very many people work on that, and models are created and dismissed all the time. I also see papers by Connes and others on various subjects as well. So what are you complaining about? How can one possibly claim that “alternatives” are not being explored?

So it is again just plain nonsense to claim that no approaches to particle physics other than string theory are followed. If something is true in this direction, then it is that there is less diversity in quantum gravity research; much less people work in this field and a potential disbalance is not as serious as it would be for particle physics. The factual dominance of string theory _in this field_ is, I guess, what is in mind by Smolin (and this shouldn’t be confused with particle physics). That there are good scientific reasons for this dominance is of course suppressed.

295. Gina says:

Dear Count,

My point was only that the basic instinct of skepticism is correct. It can be nice if people (especially established tenured people) will chose to read t ‘Hooft theories and try to relate to them and criticize them, and they may well learn something in the process. But this is not something I’d encourage people to do, and especially not young people. (But I would not encourage people to spend much time in weblog debates either.)

296. Gina says:

Dear Moveon,

“You mean discrediting a whole generation of hard working scientists by claiming their work would be so bad and/or pointless that it is â€œnot even wrongâ€, is NOT malicious? Do you really believe that orchestrating a media campaign in order to damage the whole field of particle physics stems from a sincere concern about it? I can hardly believe that anyone with good intentions would act in such an irresponsible manner.”

The short answer is “no, it is not” but I agree it is more complicated than that.

First of all, I am not sure it is the intentions are what matter most, but the basic question is:

“Is it legitimate to discredit a whole generation of hard working scientist claiming that their work is worthless?”

The answer is “yes, it is legitimate”.

There are many sweet aspects to scientific work but one of the draw backs is that it may turn out that your work is a posteriori worthless. (Even in this case I would say that your work and efforts may well be of value as part of the scientific/academic endeavor.) And another draw back, a smaller one, of the sweet academic life, is that somebody will claim that your work is worthless without justification.

As for the intentions, Woit intentions are to “save particle physics”. As I wrote in his blog, I am not impressed by this “noble motive”, but I cannot say he is malicious either. He may well present his ideas on why string theory have failed, and what counts is the substance of these ideas. I was not convinced at all by Peter’s argument, and if you look at the link appearing here (Not Even Wrong Â» Blog Archive Â» Correctionsâ€¦), you can see that I criticized there his unconventional approach towards referees, but this is not related to the question you raised.

297. Plato says:

I think all around this was one of the best debates that I have seen between the people involved, from variouis times, and to me this is progress. Even if you are tired Jacques, I think this has been a most receptive time.

A second review according to Lee, and seeing your points raised Jacques, would clarify once and for all.

I learned lots this time around, and even if the sense of a overall picture still hanging out there it is being adjusted which I find great. I still think this “outreach” to the public is important. Don’t give up on it madam/sirs.

we are just trying to get to the truth

Blinders and all? Who could say that they had “not” been so stubborn? 🙂

298. Gina says:

Jacques

I do not understand you. You said you feel comfortable with Lee’s suggestion:

“The AMS proof of finiteness has gaps in it. And some of those gaps remain unfilled, even today.”

Although earlier you said something stronger: (bold face “gave”, no gaps at sight)

“AMS gave a proof. But their proof was non-constructive. They showed that, at arbitrary genus, the integrand (for the vacuum amplitude) is a total derivative which integrates to zero.”

So why do you blame Lee for saying something stronger earlier? He suggested to change what he said to reach something everybody can agree on. Not that I see much need for such an agreement, but it required you and Lee to modify what you both said before. And this is what you *both* did.

(And why do you have to be blunt? Lee is not blunt. You can be blunt just to Peter who is blunt, or better not be blunt at all.)

299. Gina,

Almost by definition, a “Physicist’s proof” has gaps in it. A completely rigourous proof, with no gaps in it, is one that could pass muster with a Mathematician. The issue that arises when one looks at a “Physicist’s proof” of some result is whether it rises to the level of rigour and completeness that one feels is required for that result. This is a sliding scale, and reasonable people can disagree.

As I explained, because of the subtlety of the subject of fermionic string perturbation theory, and because of the many failed attempts to resolve the various ambiguities and subtleties therein, the standards for rigour are correspondingly raised. So I think it is a reasonable position to hold (regardless of whether I happen to hold it) that the AMS proof has gaps in it that require filling.

But that’s not what Lee and Peter claimed. And (if you read him closely), that’s still not what Lee claims. But he, at least, appears willing to reassess his position.

300. young string worker says:

jacques —

as someone who practically invented physics blogging, you must be familiar with the term “don’t feed the trolls”.

surely you will soon conclude that feeding physics trolls like woit and smolin with attention has not produced any helpful result, and may well be doing the opposite.

301. Gina says:

Dear Jacques,

Probably from the point of view of mathematicians even the statement that has to be proved does not really makes sense. Anyway, if instead of the term “physics proofs” you use the term “mathematical evidence” (and “computational method”) then perhaps the reality of many “proofs” of various qualities becomes clearer, as the fact that the quality of a “physics proof” may well be a subjective matter. (It makes lengthy debates on this matter obsolete, especially blunt debates.)

“Almost by definition, a â€œPhysicistâ€™s proofâ€ has gaps in it…”

“So I think it is a reasonable position to hold (regardless of whether I happen to hold it) that the AMS proof has gaps in it”

“And (if you read him closely), thatâ€™s still not what Lee claims.”

Oh boy, looks that high-level diplomacy is part of standard physicists’ training. 🙂

You say that a physicist proof has gaps “almost by definition”, and yet you do not say if you hold the reasonable position that AMS proof has gaps. Do you hold it, Jacques? And you blame Lee for changing his mind at all, and at the same time for still not sufficiently so.

And Lee says that the basic of his argument is that string theory did not succeed yet, or that there are some concerns about specific results, as well as the whole endeavor, and still opens the door for interpretation of his argument asserting not only that string theory definitely failed, but even that it caused the failure of physics and science as a whole.

302. nc says:

“… his argument asserting not only that string theory definitely failed, but even that it caused the failure of physics and science as a whole.” – Gina

Neither Smolin nor Woit say that; Woit merely suggests that the landscape due to the 6-d Calabi-Yau manifold needed to compress 6-dimensions of superstring theory makes the future dismal. With a vast number of solutions possible it just isn’t falsifiable physics and there is no evidence that string theory is really getting closer to being falsifiable. Woit doesn’t say this is a complete failure of all conceivable types of stringy theory. He focusses on the mainstream idea of 10-d superstrings with boson-fermion supersymmetry. Tony Smith is a regular commentator on Woit’s blog who claims to have a way of getting 26-d bosonic string theory to do useful things. Danny Ross Lunsford has a 6-d unification which I find more interesting. Woit has written that if there is any way of getting string to work, he’s interested in that.

If you look at the problem from the bottom, and ask what is a photon or what is a spinning quark core (ignoring the major modifications due to the vacuum loops around the core), vibrating string is the most simple explanation. By ‘electric charge’ people only mean ‘electromagnetic field’ and so all you have for an electron is what you observe, and then the mass isn’t a direct property but is provided by the vacuum. So the electron is just an electric monopole and magnetic dipole. You get that from a trapped electromagnetic energy current, like a photon trapped by gravity (which deflects photons), see Electronics World, Apr 03. A photon lacks thickness; it only has a transverse extent due its oscillations. So it’s just like a oscillating zero width open string.

303. Count Iblis says:

Moveon: “So what are you complaining about? How can one possibly claim that
alternatives are not being explored?”

You actually prove my point. What you are calling “alternatives” are just ordinary lines of thinking that
are not so different from the mainstream. We have come to a point where anything that is not
string theory is considered to be alternative. That’s like almost all astrophysicist working on
neutralino dark matter, and a minority on axion dark matter. The axion people would then
considered to be working on alternative models. Saying hat dark matter may not exist at all would
be considered to be so outlandish that no one would take that serious. Fortunately this is not
the case.

In theoretical physics we are searching for the fundamental laws of nature. This requires that
that the fundamental principles that we know about are not taken for granted. The Planck scale
is so far removed from what we can observe that it is not reasonable to only look into
scenarios where, say, quantum mechanics is still valid

304. nc says:

The problem that people off the mainstream stringy M-theory bandwagon don’t have an audience for their music, or that they are using the wrong (non-string) instruments, is not restricted to physics.

One good analogy is that mainstream medicine is sometimes off course. The resolution of such crises doesn’t usually come about through criticism of the mainstream, but by new ideas. The question is, how much obstruction to new ideas is taken as mere defensiveness against crackpottery? It’s very easy to ignore new ideas. The Nobel laureate, Barry Marshall, who discovered that Helicobacter pylori in all duodenal ulcers (contrary to mainstream ideas about stress causing ulcers) took it himself to demonstrate that it can cause ulcers. Still he was generally ignored from 1984-97.
Contrary to the popularist description of science as entirely rational and self-doubting, it’s extremely obvious that people’s status matters more than facts or evidence. Peer review decides what publications you get, whether you’re allowed to take a research degree in a given area, and those peers will only understand you if you’re working from the existing paradigms; otherwise, sorry, they are too busy for ‘pet ideas.’

305. Moveon says:

@Iblis: You actually prove my point. What you are calling â€œalternativesâ€ are just ordinary lines of thinking that
are not so different from the mainstream.

Well, I would consider eg Connes’ recent work as an alternative in spirit (while not in achievements); or is this still not different enough because it uses mainstream QFT? How “different” would then be sufficient for your taste?

As if being different to the mainstream would be a virtue in itself….well, there is this tiny little extra requirement, namely that any alternative ought to make also some sense. It is easy to say “look for alternatives”, but actually quite a bit harder to come up with something else that makes any sense at all. So far, a viable alternative to the general framework that string theory provides, is not in sight. Everyone who believes otherwise, is warmly invited to prove his position and contribute a breakthrough.

I am sure that when a new idea that makes good sense would come up,
it would be immediately explored by a lot of people. An example
is Maldacena’s conjecture: At first sight, the AdS/CFT duality may
have seemed absurd to many, because it was such a radical postulate.
But soon people realized that it did makes sense, and that it
“works”, despite having a rigorous proof for it. This shows that
a young person, being not one of the established elder statesmen,
can make a breakthrough once he gets a good idea, and become widely
appreciated.
But I guess does this example does not count because it has been a breakthrough in a discredited field?

A position commonly found in public discussions, is that any new idea that is enough different, or even in opposition, to an established theory, would be morally “better”. But practically all such new ideas of laymen are really just simply nonsense. It is like claiming, for example, that my new “alternative Mars rocket made out from wood” would be better than a Saturn V, and going on at length about how the “establishment” would “oppress” my great idea. This appears as obvious nonsense to almost everybody, except perhaps to small kids and some desert tribes. As for alternatives to fundamental theories, the situation is analogous but unfortunately not as easily recognized by most.

So far, a viable alternative to the general framework that string theory provides, is not in sight. Everyone who believes otherwise, is warmly invited to prove his position and contribute a breakthrough.

Try this: It is a trivial observation, made in math-ph/0603024, that Laurent polynomial gauge invariance is incompatible with nonzero charge. You have to settle for gauge covariance, and unitarity then requires a gauge anomaly.

A simple example is the bosonic string. Conformal gauge invariance requires D=26, and in that case the corresponding charge L_0 = 0. If you want the charge L_0 to be nonzero, you need a conformal gauge anomaly. It work the same way for other gauge symmetries, the important thing is that you allow Laurent polynomials, or more generally a two-sided grading.

Since the relevant kinds of gauge and diff anomalies do not show up in string theory (nor in field theory for that matter), it is not the correct description of charged systems on a genuinely quantum level. The missing ingredient is that one must introduce and quantize the observer’s trajectory in spacetime together with the fields. This is important, because the relevant cocycles in the multi-dimensional Virasoro and affine algebras are functionals of this trajectory, cf e.g. math-ph/9810003.

307. nc says:

“… It is like claiming, for example, that my new â€œalternative Mars rocket made out from woodâ€ would be better than a Saturn V, and going on at length about how the â€œestablishmentâ€ would â€œoppressâ€ my great idea. This appears as obvious nonsense to almost everybody, except perhaps to small kids and some desert tribes.” – Moveon

Strawman argument about “obvious nonsense”. Try choosing something that is censored as “obvious nonsense” without anyone even having read it or said what is wrong with it.

By the way, as a kid I used to launch wood and cardboard model rockets and they went higher than metal ones. Wood’s a good material. Provide some calculation to prove it’s definitely better to use metal for rockets! Wooden rockets were used for a long time before metal ones. The latest technology in engineering and maths is not the best just because its the newest. That’s just as much a logical fallacy as ad hominem arguments.

308. Clifford says:

The wooden rocket comment of Moveon, and nc’s unexpected* response to it, wil keep me laughing all day!

-cvj

(*on second thought…. I should have seen it coming… 🙂 )

309. M says:

are we sure that approximating real rockets with toy wooden rockets is more funny than approximating the real quark-gluon plasma with a toy AdS/QCD?

310. nc says:

“Toy rocket”? Sigh… M, metal has a massive expansion coefficient and also massive conductivity compared to wood, this ruptures seals and joints when it gets too hot, and metal alloys also lose strength with temperature. Wood is 25 times weaker than steel at low temperature, but is stronger and safer at the high temperatures; it just ablates slightly. It wouldn’t burn in space. It wouldn’t even burn while travelling at supersonic speed upwards through the atmosphere. It take a long time to heat up, unlike metal. When exposed to flash heat, a thin layer of surface chars and the carbonated surface protects the underlying wood, like a “smart” material. (It takes a lot of time and oxygen to burn it. No need for expensive and defective tiles which fall off the shuttle, etc.)

311. nc says:

I meant “carbonized”, not carbonated 😉

312. Alejandro Rivero says:

Note that the Hughes H-4 Hercules was critiquised in the basis of lack of power, not in the basis of metal vs wood. Check also http://en.wikipedia.org/wiki/Spruce_Goose .
According E. Schatzberg in Technology and Culture, Vol. 35, No. 1. (Jan., 1994), pp. 34-69., the last operational wood fighting plane was the british Mosquito, during the WWII. Schatzberg article is sort of heavy, but it seems a good introduction to the social aspects of the debate wood/metal during the 1930.

313. John G says:

Clifford, string theory is like a business in the sense there are people making important decisions who are not experts on the technical details. This occurs with funding, it occurs as you go up the hierarchy at universities, and it occurs in the media. Businesses can have stockholders, executives, and the media to satisfy as well (Peter by the way with his blog and book is media-like not CEO-like). Time limits don’t have to be used to give up totally on something but they can be used as an indicator that maybe more people need to look at more things. The more things can be old ideas that were not looked at good enough. Two of my examples fit in this category (E6 GUT and bosonic M-theory). You say people are free to work on what they want to work on. Sometimes though an idea, no matter how good it is, needs championed in order to get off the ground. Perhaps those in position to champion ideas, need to champion more ideas instead of just their current favorite ideas.

314. Clifford says:

John G. Thanks. But perhaps you should find out how the system actually works instead of how you imagine that it works.

Despite what you are told, people do look at other ideas. People do champion ideas other than their current favourites, and more and more people are looking at more and more things everyday in the field.

Best,

-cvj

315. nc says:

Hi Clifford, it’s not the lack of championing that makes my blood pressure go off scale, it’s active censorship that’s the problem! As a specific example, would you have the nerve to ask Jacques if he agreed with the deletion of Lunsford’s published paper from arXiv in 2004? It was published in Int. J. Theor. Phys. 43 (2004) no. 1, pp.161-177 and a non-updatable copy is at http://cdsweb.cern.ch/record/688763 (I know it’s non-updatable because I’ve got a paper on CERN -EXT series which also can’t be updated except via carbon-copy by updating a paper on arXiv, which bans non-mainstream things). Lunsford states:

‘I certainly know from experience that … point about the behavior of the gatekeepers is true – I worked out and published an idea that reproduces GR as low-order limit, but, since it is crazy enough to regard the long range forces as somehow deriving from the same source, it was blacklisted from arxiv (CERN however put it up right away without complaint).’

http://www.math.columbia.edu/~woit/wordpress/?p=128#comment-1932

316. Clifford says:

nc:- There’s censorship, and there is filtering to keep signal-to-noise at a manageable level. You are entitled to your opinion about where to draw the line. I do not know which is which here and will certainly not get into it. (Btw, I ask and tell Jacques whatever I please, and he does so to me. I don’t understand what “nerve” has to do with anything when discussing science with a sensible colleague.) I’m not going to start discussing individual cases here. This is not intended to be a forum for random grievances about one’s pet theories, be they brilliiant revolutions in the making from visionaries or total nonsense from well-meaning nutcases.

Or, come to think of it, be they brilliant revolutions in the making from well-meaning nutcases, or total nonsense from visionaries.

Either way, this is not the place for it.

-cvj

317. gina says:

Before I continue the elaboration on the 16 points I raised (Remark 139) regarding Lee’s book, let me mention where were we. The points were roughly divided to five parts.

A) the evaluation of string theory. These were points 1-5. Point 3 that I discussed first (143) was about finiteness and the work of Mandelstam. Lee responded in (149) and there were many follow ups. Points 4 and 5 (Maldacena conjectures) were raised in (160, 161) and Lee commented on them in (169).

Points 1 and 2 regarding Lee’s overall evaluation of progress in physics in the last quarter of a century are linked in (205)-first link. (Masterclass (18))

B) The matter of pluralism in theoretical physics. My comments (Points 6-8) (pluralism should be studied in a wider context; traditional areas of hep-ph; there is no scientific reason for a unified quantum gravity community) are linked in (205)- second link (masterclass (19)). (Moveon referred to point 7 in (207))

C) The string theory community. Point 9 was presented in (206).

D) Sociology: Point 15 was made in (166) to which Lee responded in (170). The other points on this matter will be addressed next.

E) Philosophy of science, scientific revolutions, and high-risk scientific endeavors. Point 12 (encouraging young scientists to high-risk endeavors) was discussed here in (167) and Lee responded in (170). Point 13 (Attitude towards revolutionary theories by great scientists,) was discussed in (288). (Count referred to it in (291).) The last point 16 (scientific revolutions) will be elaborated last.

Note that for the topics in B), D) and E) string theory is merely an example and, as Clifford said in his original post, this is a place where the natural context of the discussion is much broader. (Which is, in my opinion, quite welcomed.)

318. gina says:

I have to make one retraction. I suggested to call a physics theoretical proof just “mathematical evidence” because of their non-definite and somewhat subjective nature. However, mathematicians I talked with told me that also in mathematics while a (correct) proof gives a definite validation of the statement it proves, it does not lead to a definite understanding of the mathematical phenomenon behind the statement. In this respect, the value of a proof is still somewhat subjective. So, in mathematics, as in physics, the more and better proofs the merrier. Probably, no need for different terminology, after all.

319. nc says:

Hi Clifford, thank you for acknowledging that there is censorship due to mainstream ideas which lack evidence, and for acknowledging that where the line should be drawn isn’t defined by scientific criteria, but is just a matter of personal opinions. That makes it all fine. 🙁

320. Clifford says:

You’re quite welcome. Even though I did not say those things.

-cvj

321. nc says:

Hi Clifford, well I saw what I took to be an acknowledgement from you that censorship of non-mainstream ideas occurs, and you stated that it is a matter for my opinion if that is reasonable or not. Such a point of view is vague on what is right and what is wrong. If I completely misunderstand you, it’s not due to your any problem in your lucidity, instead it’s my stupidity, lack of appreciation for string theory, etc. Similarly, if something gets deleted without even being read (within a few seconds) by mainstream, that’s good noise reduction policy. If their idea is any good, it will be taken seriously by someone who will be in a position to defend it. Excellent.

322. gina says:

NC,

I do not think that you really refer to censorship. The rejection of Woit’s book from CUP was not an act of censorship but entirely reasonable (see comment (132)) and the book appeared elsewhere where it was appropriate. I suspect that the rejection of your ideas from PRL was very reasonable and I hope somebody, beyond the line of duty, will take the effort to look at them and tell you (better, on the record in a blog, maybe here) why they can’t work. But your ideas are presented on your homepage and weblog so everybody can read them.

323. nc says:

Dear gina,

“I hope somebody, beyond the line of duty, will take the effort to look at them and tell you (better, on the record in a blog, maybe here) why they canâ€™t work.”

Sigh. Love the scientific objectivity and lack of prejudice about whether ‘my’ ideas will be found useless! Very unbiased. It’s deliberately built like a jigsaw of pieces from empirically defensible fact, due to other people. I didn’t discover spacetime, Newton’s 3rd law, big bang, etc. Put a jigsaw together from facts nobody disputes, and the sum of those facts is absurd because it correctly predicts gravity, cosmology (no retardation of supernovae, predicted ahead of observations and published in 1996), so they do work.

The investigation of ‘pet theories’ outer than those of mainstream awaits the fall of mainstream theory. Naturally that can’t fall because it isn’t falsifiable. It’s not a blog you need to compete with arXiv’s hyping of string theory, it’s a vast number of cited publications:

â€˜Scientists have thick skins. They do not abandon a theory merely because facts contradict it. … History of science, of course, is full of accounts of how crucial experiments allegedly killed theories. But such accounts are fabricated long after the theory had been abandoned. … What really count are dramatic, unexpected, stunning predictions: a few of them are enough to tilt the balance; where theory lags behind the facts, we are dealing with miserable degenerating research programmes. Now, how do scientific revolutions come about? If we have two rival research programmes, and one is progressing while the other is degenerating, scientists tend to join the progressive programme. This is the rationale of scientific revolutions. … Criticism is not a Popperian quick kill, by refutation. Important criticism is always constructive: there is no refutation without a better theory. Kuhn is wrong in thinking that scientific revolutions are sudden, irrational changes in vision. The history of science refutes both Popper and Kuhn: on close inspection both Popperian crucial experiments and Kuhnian revolutions turn out to be myths: what normally happens is that progressive research programmes replace degenerating ones.â€™

â€“ Imre Lakatos, Science and Pseudo-Science, pages 96-102 of Godfrey Vesey (editor), Philosophy in the Open, Open University Press, Milton Keynes, 1974.

324. Gina says:

D) Sociology/ social science aspects

Before getting into specific points let me make some general remarks about this issue and introduce some useful notions. Let me briefly talk about “goals”, “opportunity costs”, “incentives”, and the tension between rationality of actions and rationality of rules.

1. Goals . I think the vague term “progress in science” can represent the goal which is the basis of discussion, or even more specifically “progress towards answering the fundamental problems of physics” (ignoring my point 7) or “progress towards a sound and correct theory of quantum gravity”. Of course, when it comes to universities, and other academic frameworks/communities, teaching and scholarship are also important goals, and there are others.

2. Opportunity cost. Perhaps the most relevant notion from economics and social science to quite a few aspects of the discussion is that of opportunity cost.
Opportunity cost, is the cost of something in terms of an opportunity forgone (and the benefits that could be received from that opportunity) (Wikipedia)

The whole discussion is to a large extent about opportunity cost. It is not whether it is good to have research in string theory but whether the human, financial and other resources can be better used.

We can practice this notion on two little examples from Lee’s book. Lee mentioned the complaint of string theorist not getting interested quickly enough in “non commutative geometry”. Of course, it is good for string theorists to know and try to use every piece of mathematics (and they come amazingly close). But the “opportunity cost” approach would be: perhaps rather than climbing further on the mountains of Geometry towards the very very new theory of “non commutative geometry”, it is better for string theorists to pay more attention to the large fruitful valleys of Analysis or the mysterious hills of Stochastics, (or Mathematical Logic, or higher Category Theory?…)

Another example is Lee’s suggestion to teach freshmen quantum mechanics which is mentioned in several places in the book. Again, the question is not if this is a good idea that freshmen will know quantum mechanics, but what is the “opportunity cost”.

(While for the fate of string theory, I think we simply do not have enough evidence to call, so I would advice simply to wait several decades, this little question of teaching quantum mechanics in first year university physics, is probably very suitable for a weblog discussion.)

3. Incentives . This is a famous notion. An incentive (again, as Wikipedia tells us) is a name for any factor that provides a motive for a particular course of action.

A little example to practice. Lee compares “peer review” to “jury of one’s peer”:

“This is called peer review. It’s a funny name, because it differs markedly from the notion of jury of one’s peer, which suggests that you are being judged by people just like yourself, who are presumably fair and objective. There are real penalties – prison – juror who conceal a bias”

This is simple example of an incentive: Prison for jurors who conceal a bias provides a strong motive not to conceal a bias. (I suppose a change in this direction in the universities would be truly horrifying. 🙂 E.g., To “punish” people who “shamelessly slant” their recommendation letters, will give a strong incentive not to write letters at all.)

4. The tension between rationality of actions and rationality of rules. The distinction between rationality of actions and rationality of rules is a familiar but not an entirely standard notion. The basic idea (at least in special cases) is well known under different names. (e.g., “precedences” in law.)

Let’s start with one example regarding to quantum mechanics course for freshmen.

While in Yale Lee’s suggestion for first year quantum mechanics course was rejected by his conservative colleagues, in Harvard the story was different. The dean in Harvard rejected Lee’s initiative out-of-hand without considering its merits because the proposal did not pass through the requisite committees. “‘If we let every teach what they wanted to’ he said ‘we would have educational chaos'”.

The dean followed the rule of not allowing and not even considering teaching initiative without the appropriate standard approval procedure. The dean’s rationale for this rule was the goal to prevent educational chaos. This indeed appears to be a rational point of view.

(Lee argues also against the Harvard dean’s goal, and says: “I am not sure that educational chaos is such a bad idea”. Being aware that siding with a dean is never popular and can be a bad mistake, my opinion is nevertheless that educational chaos is a very bad idea.)

Here is another example of the tension between rationality of actions and rationality of rules: Our nc mentioned the long time it took the scientific community to accept the discovery of the bacteria leading to ulcers. Again conservatism may have led, in this particular case, to some delay in recognizing an important discovery (even to a loss of lives), but overall, as a rule, the conservative and careful approaches in science, and certainly in modern medicine, are very rational.

The last example is also from Lee’s book. This is a rare issue where Lee presents a conservative rather than a radical point of view and it is regarding what Lee calls the “ethics of science”. In short, Lee’s point is that even if you belong to a large dominant group in some field the tradition/rule/ethics of science require that you will support also research in competing directions that you regard unpromising or even very unpromising. This argument can also be seen as an example of the tension between rationality of rules and rationality of specific actions.

325. Gina says:

D) Sociology/ social science aspects. Let me move on to the specific points on part D. (See (316) for where the other points are.)

11. Although a substantial part of Lee’s argument is about sociology there appears to be no real interactions with social scientists.

It could have served the quality of the discussion of sociology if it reflected some discussion or interaction with social scientists. Beside the difficulties in the overall discussion which was my point 15, and the emotional rather than rational discussion, some of Lee’s specific suggestions that can look good at first, are problematic when analyzed carefully. And these problems may be quite familiar to savvy social scientists.

14. Lee’s ideas on revolutionizing universities is not detailed and the hints we get are not promising.

I will consider one example. Suppose that you want to improve the difficult academic careers of what Lee calls “seers” and I prefer to call “dreamers” – people who are involved in very high risk individual original projects. As I said, the main problem is that most of these researchers will fail: If you have 50 scientists working on different approaches for replacement of quantum mechanics, I tend to think that they will all fail to achieve a “real progress”. But even Lee may agree that 49 will fail. Of course, a few of the failed ideas may still lead to useful scientific insights but many of these people will not have anything to show for their efforts.

But let us put that aside, agree that “seers'” academic life should be improved, and consider Lee’s specific suggestion for a 5 year support (with an option to up to 10 years extension). Will this make the situation better for the seers?

Carefully analyzed it appears that most likely it will make it worse! (Lets assume that in these 5-15 years they will get conditions comparable to those in universities.)

The chance of people who work in high-risk projects of the kind Lee encourage to be admitted to a university after 5 years of failure or after 10-15 years of very partial success are very small. Given this, the really brilliant high-risk individuals will try to get a university position anyway, so the quality of people left in Lee’s project will be lower. Moreover, these people will have strong incentive to try to be engaged in “normal” research to increase the their chances for a university position.

Moreover, this program will give a negative incentives for universities to hire “seers” in the first round; they will prefer to wait and hire successful “seers” coming out from Lee’s program later in their careers.

At the end, you may reach a situation where “seers/dreamers” will have even more difficult careers than today and the dreamers-support plan will be just a program for second-rate physicists who cannot get ordinary academic jobs.

Again, there is nothing special here about “seers” in physics. This is a classical case of “affirmative action”, and the insight that separate (terminal) frameworks for “affirmative action” are inferior to affirmative action within the ordinary framework (universities in this case).

What could be a better way to support seers (or dreamers)? There is no way around convincing the academic community (or even even part of the community) either in the general principle of the importance of “seers” or regarding specific individuals.

You want to promote seers? This is what you should do: Identify some brilliant young people who do good, highly original, foundational work, against all advice: differentiate between them, identify the better ones and try to support them in the ordinary university frameworks. Help them to get academic positions, spend time in following and criticizing what they are doing; and when they come up for tenure write a detailed recommendation letter, which tells about the candidate and not about the writer, and if they deserve tenure, give them a break: slant it a little, shamelessly.

10. Talking together about the scientific and social issues including funding is by itself very problematic. Not being sufficiently aware of this difficulty is a mistake.

Personally, I enjoy the many aspects of the debate. But I do not think Lee is careful enough to separate the scientific and non-scientific issues and he is not aware of the difficulties arising from such a mixture. Several of the phenomena Lee referred to as sociological are purely scientific, e.g. I do not see a justification to consider the issue of finiteness of string theory as a sociological issue.

Of course, there are relations between the scientific and sociological aspects, but you better try to understand matters very well separately (each one in the correct wider context) before you try to relate them. (Where can we find an example? Here is one: it takes quite a good understanding of quantum mechanics and gravitation separately before an attempt to study them together makes sense.)

Lee’s own interests as a prominent representative of LQG can also cause a difficulty in interpretation of what he says. The not careful mixture of so many issues and ideas, opens the door to the interpretation that on every issue, scientific, social, ethical or philosophical, you can regard Lee’s position as driven by the interest to get more resources for LQG. I do not share this extreme interpretation and I regard as unfair, but the difficulty it expresses is genuine.

To sum, the mixture, even within individual chapters, of social and scientific issues on the expense of studying each issue in the more general natural context, added to Lee’s own biases and interests, obscure Lee’s argument and reduce its quality.

OK, from my 16 points, 15 down and one more to go, and a juicy one indeed (scientific revolutions).

326. nc says:

‘The dean followed the rule of not allowing and not even considering teaching initiative without the appropriate standard approval procedure. The deanâ€™s rationale for this rule was the goal to prevent educational chaos. This indeed appears to be a rational point of view.’ – Gina, comment 323

Similarly, Galileo would have caused chaos if the more rational professors had allowed consideration of his radical, disruptive new approach to astronomy (using a telescope):
â€˜Here at Padua is the principal professor of philosophy whom I have repeatedly and urgently requested to look at the moon and planets through my glass which he pertinaciously refuses to do. Why are you not here? What shouts of laughter we should have at this glorious folly! And to hear the professor of philosophy at Pisa labouring before the Grand Duke with logical arguments, as if with magical incantations, to charm the new planets out of the sky.â€™ – Letter of Galileo to Kepler, 1610, http://www.catholiceducation.org/articles/science/sc0043.html

327. Gina says:

1. Morgenbesser (1921-2004)

“Brother, can you spare a paradigm? –” Sidney Morgenbesser.

E. Philosophy

My last point was:

16. Lees says that science clearly calls for a revolution. Maybe the opposite is true. Lee says that science is now more conservative (anti revolutions) than ever. This is incorrect. The whole revolution terminology is crooked.

(For the earlier points see comments (323 324) and pointers in (316).)

This point is mainly a philosophical disagreement I have with Lee (and others) and it also reflects on practical matters.

2. Philosophy of science

We often see attempts in the debate about string theory to apply insights from philosophy of science, whether it is the Popperian notion of falsifiability, or the earlier statistically-based notions of verification (like the Bayesian notion), to derive definite conclusions concerning various aspects of the debate. Lee’s strong reliance on Kuhn’s philosophy of science is also in this spirit.

While interesting, all these attempts have a limited potential. We have to remember that all the philosophy of science theories that I mentioned, as others, have very partial descriptive and normative value. Rather than giving clear normative rules how science should be done or a clear description how science have been done, philosophy of science is important to understand what science is, and to introduce language and tools to talk academically and scientifically about science.

3. Kuhn

The notion of scientific revolutions was coined by Kuhn. So just to be sure when I am in disagreement with Lee and when I am disagreeing with Kuhn, I did take the trouble to read Kuhn’s book, ( 😉 ). One interesting thing I discovered is Kuhn’s description of how Newtonian physics(!) had been suffering for centuries from problems that resemble the problems of string theory today: lack of experimental conformation, and worse, evidence that appeared to be in conflict with the theory.

The “technical” terms coined by Kuhn of paradigms and periods of normal science and of paradigm-shift were both highly influential and highly controversial on their own. But the metaphor of “revolutions” was what capture the imagination the most. This was a great metaphor. The term “phase transition” or simply “transition” could capture Kuhn’s theory better than “revolution” and as a physicists he was surely aware of these terms, but “scientific revolutions” was a great brand-name which overshadowed everything else. Kuhn’s notion of a revolution is not a myth as nc said but a metaphor, and a great metaphor indeed.

Kuhn agrees (but not some of his followers) that the notion of scientific progress is real and that the ultimate goal is progress. One trouble with the revolution idea is that for some people (especially men ?) revolutions are more appealing than progress, and are becoming the goal rather than a mean. One reason may be that progress is not easy to define or to agree upon. But surely the main reason is that a revolution is a great excitement.

Even if we accept the notion of a revolution, another problem which is very explicit in Lee’s writing but also already presented in Kuhn’s book is the tendency to automatically identify highlights of scientific progress (and other human activities) with revolutions.

Does Mozart’s music reflects a revolution? In my opinion it is not, and it is silly to regard it as such, in spite being a highlight of human achievement.

4. The high-energy physics’ revolutions.

Let’s look at some prominent “revolutions” in this debate. Is the “second string revolution” a revolution? There were five potential string theories studied. As can be fully expected, some unexpected relations between them were found. And then there was the nice idea and supporting works suggesting that all these 5 theories emerge in a larger 11-dimensional description of the universe. This solves some problems and leads to some others. In my opinion, while an important development, it is not a revolution by any stretch of the imagination.

But whose opinion counts? Actually, this is a point Kuhn himself discusses. Perhaps one of his statements that opened the path to “Kuhnism” and “relativism” to which he later objected, was his view that a revolution is in the eyes of the involved scientists and not the eyes of an objective observer.

Was the standard model a revolution? In an article criticizing Kuhn’s book Steven Weinberg claims it was not and on this point he appear to be right. Weinberg’s opinion as a major player in the making of the standard model should count even according to Kuhn.

Was string theory itself (or the “first superstring revolution”) a revolution? Maybe. It looks to me more like the non-revolutionary great progress as we see in music. Time will tell whether it is like Mozart, Chopin or Paganini.

5. Pulling off a revolution; Weinberg and Smolin

“More than any time in the history of science the cards are stacked against the revolutionary. such people are simply not tolerated in the research universities. Little wonder, then, that even when the science clearly calls for one, we can’t seem to pull off a revolution.” (Lee Smolin, TTWP p. 348)

It seems that the whole revolution rhetoric crooked the scientific agendas. Science clearly call for progress, also for some inner reflection about previous progress and about goals. Sure enough, some changes, even sharp changes and some backtracking are required. But the revolution spirit is obscure. One change “clearly” called for is to let the revolution idealization and rhetoric rest. (Not only in science.)

Kuhn metaphor was a great success and his book was an important landmark in philosophy and historiography of science. But taking his views too literally, either to attack them as Weinberg tries to do or, as Lee proposes, to implement them as practical road maps for science are both, in my opinion, bad ideas.

Weinberg’s instincts as a scientists are rather negative towards Kuhn’s and his different analysis of the physics developments that Kuhn based his book on, is very interesting. However, Weinberg’s interpreters Kuhn’s philosophy too literally and his critique is based on this interpretation. This makes his overall argument not so convincing as also his notions of “soft” and “hard” parts of physics; Notions that are even vaguer than the notions Kuhn himself introduced.

Lee interprets Kuhn’s ideas even more literally than Weinberg. Rather than to criticize Kuhn, Lee uses his interpretation of Kuhn as a basis for his ideas how science should be practiced. This leads to his distinction between “seers” and “craftspersons” and to his whole discussion how to encourage and pull off revolutions. The idea of practically basing scientific practices on philosophy of science is misguided, and Lee’s specific suggestions, while bold and interesting, make little sense.

Happy 2007, everybody!

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