I have a long-percolating post that I hope to finish soon (when everything else is finished!) on “Why String Theory Must Be Right.” Not because it actually must be right, of course; it’s an hypothesis that will ultimately have to be tested against data. But there are very good reasons to think that something like string theory is going to be part of the ultimate understanding of quantum gravity, and it would be nice if more people knew what those reasons were.
Of course, it would be even nicer if those reasons were explained (to interested non-physicists as well as other physicists who are not specialists) by string theorists themselves. Unfortunately, they’re not. Most string theorists (not all, obviously; there are laudable exceptions) seem to not deem it worth their time to make much of an effort to explain why this theory with no empirical support whatsoever is nevertheless so promising. (Which it is.) Meanwhile, people who think that string theory has hit a dead end and should admit defeat — who are a tiny minority of those who are well-informed about the subject — are getting their message out with devastating effectiveness.
The latest manifestation of this trend is this video dialogue on Bloggingheads.tv, featuring science writers John Horgan and George Johnson. (Via Not Even Wrong.) Horgan is explicitly anti-string theory, while Johnson is more willing to admit that it might be worthwhile, and he’s not really qualified to pass judgment. But you’ll hear things like “string theory is just not a serious enterprise,” and see it compared to pseudoscience, postmodernism, and theology. (Pick the boogeyman of your choice!)
One of their pieces of evidence for the decline of string theory is a recent public debate between Brian Greene and Lawrence Krauss about the status of string theory. They seemed to take the very existence of such a debate as evidence that string theory isn’t really science any more — as if serious scientific subjects were never to be debated in public. Peter Woit agrees that “things are not looking good for a physical theory when there start being public debates on the subject”; indeed, I’m just about ready to give up on evolution for just that reason.
In their rush to find evidence for the conclusion they want to reach, everyone seems to be ignoring the fact that having public debates is actually a good thing, whatever the state of health of a particular field might be. The existence of a public debate isn’t evidence that a field is in trouble; it’s evidence that there is an unresolved scientific question about which many people are interested, which is wonderful. Science writers, of all people, should understand this. It’s not our job as researchers to hide away from the rest of the world until we’re absolutely sure that we’ve figured it all out, and only then share what we’ve learned; science is a process, and it needn’t be an especially esoteric one. There’s nothing illegitimate or unsavory about allowing the hoi-polloi the occasional glimpse at how the sausage is made.
What is illegitimate is when the view thereby provided is highly distorted. I’ve long supported the rights of stringy skeptics to get their arguments out to a wide audience, even if I don’t agree with them myself. The correct response on the part of those of us who appreciate the promise of string theory is to come back with our (vastly superior, of course) counter-arguments. The free market of ideas, I’m sure you’ve heard it all before.
Come on, string theorists! Make some effort to explain to everyone why this set of lofty speculations is as promising as you know it to be. It won’t hurt too much, really.
Update: Just to clarify the background of the above-mentioned debate. The original idea did not come from Brian or Lawrence; it was organized (they’ve told me) by the Smithsonian to generate interest and excitement for the adventure of particle physics, especially in the DC area, and they agreed to participate to help achieve this laudable purpose. The fact, as mentioned on Bloggingheads, that the participants were joking and enjoying themselves is evidence that they are friends who respect each other and understand that they are ultimately on the same side; not evidence that string theory itself is a joke.
It would be a shame if leading scientists were discouraged from participating in such events out of fear that discussing controversies in public gave people the wrong impression about the health of their field.
“Excuse me? Why in these discussions do I feel like I live in a completely different universe than many of the other participants? When I tell people in other areas of physics the number of postdocs that the average string theorist goes through before getting a job, they’re often shocked. I can think of a few exceptional cases, but the vast majority of string jobs, as best I can tell, go to people on at least their second postdoc.”
My impression was that the string theorists who got jobs over the last decade (at least at the big name universities) usually did so within their first couple of postdocs. It should be easy to check this, and I will check it, but not right now. Second postdoc counts as early in my book. I’m more used to seeing people hanging on for 8+ years in various temporary non-faculty positions before landing something permanent (and that’s not counting the ones who leave the field). And just to be clear, I’m not claiming that *all* string theorists have an easy time and land jobs early on etc.
“Seriously though, have things really reached the stage where journal publications are nothing more than a check on the preprint culture?
What’s wrong with that?”
If nothing I’ve said already moves you, I doubt that anything else I can say will. But one last attempt anyway: In a previous exchange in the Teacup IV post over at asymptotia, Jeff Harvey wrote: “…we are lacking in good (semi-) objective measures of what work should be supported, in main part because of the absence of data.” Would you at least agree that (semi)objective measures would be a good thing to have? If so, then isn’t it worthwhile to consider what, if anything, could be done to establish them in the present data-free environment? The mathematicians have long been operating in a data-free environment and seem to have solved their measure problem through the use of publications in high-standard journals as the measure. It works for them, why not for us? Do you have a better suggestion? Maybe you think we should just accept that there aren’t going to be any objective measures. But in the absence of objective measures, how on earth can string theorists ever hope to justify their dominant position in formal particle theory to the rest of the physics community?
You could also try asking the mathematicians at your university why the maths community continues to maintain their journal hierarchy system instead of going over to a preprint culture with journals simply used to filter out the noise. Is it just because of habit or tradition, or do they actually think it serves some useful purpose?
“I guess I can’t see what the big deal is with PRL. In fact, I seem to remember seeing some pretty ordinary papers in there, but I could be misremembering.”
I never said that its standards are universally high. Ordinary papers do get in. On average though, my impression is that it is tougher to publish there than in the other physics journals we have. That could make it potentially useful as an evaluation measure, albeit a limited one. It would sure beat relying exclusively on the say so of senior influential people imo.
“Regardless, I find your journal argument to be rather circular. Who do you think would be refereeing the relevant papers?”
Circular or not, it works for the mathematicians so why not us? As far as I can tell, the way it works for them is that, firstly there is a strong commitment to maintaining journal standards throughout the community; secondly the editors are accomplished, widely respected mathematicians who carefully chose referees that they can trust to maintain the standards. That seems to be it.
Finally, I’m a bit curious about how things are in your universe. Is it really all rosy and swell with all decisions clearly justifiable by objective criteria and measures that everyone can agree with except a few annoying losers? Is there anything even remotely non-positive about the whole string situation there?
Second postdoc counts as early in my book. I’m more used to seeing people hanging on for 8+ years in various temporary non-faculty positions before landing something permanent (and that’s not counting the ones who leave the field)
Really? Then perhaps I’m more out of touch with the rest of physics than I thought I was.
The mathematicians have long been operating in a data-free environment and seem to have solved their measure problem through the use of publications in high-standard journals as the measure. It works for them, why not for us?
Who do you think is doing the judging in mathematics? It’s not as if the people working on hardcore analysis are getting refereed by the combinatorists. People are always judged by their peers because those are the people that best understand the work. And, it’s not as if there’s this vast free-for-all journalwise. People know what the good journals are and which aren’t. That PRL isn’t at the top of the heap hardly seems like a big deal.
As far as I can tell, the way it works for them is that, firstly there is a strong commitment to maintaining journal standards throughout the community; secondly the editors are accomplished, widely respected mathematicians who carefully chose referees that they can trust to maintain the standards. That seems to be it.
Is what you want to say is that the referreeing process isn’t as rigorous as that of the mathematicians? You might have a case to be made there, but I’m still not sure that’s your point.
Regardless, perhaps you can explain to me, as someone who hasn’t published outside of string theory, just how the string theory refereeing process differs from the rest of physics.
Is it really all rosy and swell with all decisions clearly justifiable by objective criteria and measures that everyone can agree with except a few annoying losers?
There are no completely objective criteria in hiring in any field. Are you seriously claiming that mathematics or the rest of physics, or, hell, the rest of the entire world doesn’t have people talking to each other and asking their opinions of job candidates. Do you think, for example, that the prestige of the person writing a recommendation letter makes no difference? I find it hard to believe that hiring in other field consists of simply counting one’s PRLs and making an ‘objective’ decision. And, even if it were, how is the number of PRLs anything but a proxy for what the “accomplished” editors and referees think of the work?
Of course I’ve never been involved in actually hiring someone, so perhaps in the rest of the world hiring really is purely objective and untainted by more base considerations that apparently overwhelm any concept of merit in string theory. But I doubt it.
Sean Carroll remarked:
mclaren (32): If you brush up on your reading comprehension, you’ll notice that I never compared the evidence for evolution with the evidence for string theory, about which you rant at such length. So your intelligence is somewhat self-insulting.
This exemplifies the single most important reason why string theory is losing the public debate. Treating with contempt someone who stands up for the most basic foundation of post-Enlightenment Western culture — namely, the requirement that people provide evidence for the claims they make — is a starkly anti-intellectual stance.
That kind dismissal of skeptical critical thinking on Sean Carroll’s part embodies a medieval mindset and it’s not the way to win over a popular audience. Americans may not be well educated compared to the rest of the world (American students currently rank somewhere around 15th in the world in knowledge of science/math), but they do have a saying: “I’m from Missouri — I have to be shown.”
Sean Carroll’s contemptuous disdain for skeptical critical thinking seems to me to form part of a larger problem we’ve been seeing throughout the world for roughly the past 25 years. Call it “The New Medievalism.”
Friends who grew up in the heart of the American Bible Belt in the 1940s and 1950s report that evolution was taught in public schools during that period without controversy — yet today, they’re building Creation Museums full of statues of Adam and Eve riding to church on dinosaurs.
http://www.aboyandhiscomputer.com/Greetings_from_Idiot_America.html
In literature departments in major universities throughout America, self-delusion and untestable word games have taken the place of evidence-based scholarship. (See “Come On Back to the Raft Ag’in, Huck Honey,” by Leslie Fiedler, for a classic example: http://www.howardwill.com/Come%20Back%20to%20the%20Raft%20Again.htm)
In music departments throughout the U.S., vacuous numerology based on pitch-class set theory has taken the place of evidence-based scholarship on music using findings from psychoacoustics and ethnomusicology and musicology.
In music, see Milton Babbitt’s “Who Cares If You Listen?” (1958) for a classic statement of numerological superstition as the ideal of music “theory” so-called.
http://www.palestrant.com/babbitt.html
In art departments in major universities, students now study bathroom grafiti
http://www.uninteresting.com/glendale%20reader/sat%20jan%2020/stall_grafiti_art_class.htm rather than engaging in evidence-based study of the history and traditions of art.
In big business, accounting games have taken the place of product development and marketing, and the Enronization of America now substitutes for evidence-based R&D and the scientific method which at one time gave us new industries and new consumer products.
http://www.businessweek.com/bwdaily/dnflash/jun2003/nf20030610_2399_db028.htm
In politics and the media, propaganda and Pravda-style distortions and verbal calisthenics have taken the place of evidence-based factual reporting (see Fox News for daily examples. The most glaring recent case in point: when Scooter Libby was convicted recently, Fox News put up a graphic banner reading “Libby Found Innocent” –of one of five charges.).
In economics, Rational Choice theory is the hot field — except that Rational Choice theory systematically predicts the opposite of what we observe in the real world. For example, rational choice theory confidently predicts (and has mathematics to prove) that Martin Luther King could never have organized southern blacks to march for voting rights int he deep south, since the utility function is so low. Economists’ strategy for dealing with this misfit twixt Rational Choice theory predictions and observed reality is, of course, to ignore observed reality. In politics, the disjunction twixt claims (“We’re winning in Iraq,” “We know where the WMDs are,” “We’ll be out of Baghdad within 6 months”) and the observed reality continues to widen, with increasingly catastrophic results.
In education, phoney statistics and grade inflation show an illusion of continued progress throughout K-12 schools
http://www.tcrecord.org/Content.asp?ContentId=10440
even as ever-increasing proportions of K-12 schools graduate unable to read or write or perform basic arithmetic.
http://www.collegejournal.com/aidadmissions/newstrends/20070226-tomsho.html
And now in physics, the last bastion of skeptical critical thinking and the scientific method, the final refuge of rationality which finds itself under assault in all sectors of American society, what do we encounter? Sneeringly contemptuous dismissal of skeptical critical thinking and ridicule of those who demand hard evidence that a claim is true. And all in defense of a string “theory” which as far as current experimental evidence is indistinguishable from the theory of welteislehre.
http://www.mpiwg-berlin.mpg.de/en/research/projects/DeptIII-ChristinaWessely-Welteislehre
In his classic book Fads and Fallacies In the Name Of Science, Martin Gardner describes audiences of German scientists shouting down lecturers in geology and paleontology while chanting “Welteislehre! Welteislehre!”
When I read that passage as a high school student, I remember thinking, “Well at least we won’t see that sort of spectacle in America.”
I was wrong.
What we’re seeing all across the board in Western culture, it seems, is a systemic retreat from rationality into mindless faith, numerology, and cult belief systems (Rational Choice economic theory, po-mo deconstructionism, creationism, the Rapture Index, string theory) which are either untestable or which systematically contradict or ignore observables, in favor of blind adulation of jargon and tautological assertions which have no demonstrated connection with observed reality.
Somewhere along the line, Americans stopped asking for evidence. They stopped using skeptical critical thinking and settled back into a comfortable smug mindless haze of self-delusion. This happened somewhere between the time Bonzo the chimp’s co-star told fables about mythical welfare queens driving around in Cadillacs (which everyone accepted as factual despite overwhelming evidence to the contrary) and the time we were assured that Iraq lay awash with lakes of sarin nerve gas and mountains of nuclear warheads. Exactly why Americans stopped using their heads and stopped applying skeptical critical thinking and common sense and why they stopped asking for evidence of even the craziest claims, well…that isn’t clear. But you can see it happening all around us, everywhere we look, in economics, in politics, in art theory, in literary theory, in music theory — and now in high energy physics.
It’s clearly evident that Sean Carroll did directly compare evolution with string theory. It’s also clearly evident that he’s now trying to deny he did. The first rule of thumb, Sean, when you’re in a hole is…stop digging. The initial claim was bad enough, but denying you ever made that claim makes things worse for you.
Let’s also be clear on exactly why Sean Carroll made the faulty and intensely disingenuous implied comparison twixt the theory of evolution and string theory. He did it because sensible educated people know full well that the only folks who deny the theory of evolution are kooks. The implication, therefore, is that since string theory is equivalent to the theory of evolution, anyone who denies string theory must also be a kook.
This is deliberately deceptive and it smacks of character assassination of Drs. Woit & Smolin et al. There’s no evidence at all that Woit or Smolin or Kraus or any of the other reputable published scientists who have expressed serious reservations about string theory are crackpots. On the contrary, these people are the very ones calling for hard evidence and skeptical critical thinking in regard to string theory. Every time some vague expansive claim gets made to the effect that some recent experimental result allegedly “tests” some aspect of string theory
http://ucsdnews.ucsd.edu/newsrel/science/stringtheory07.asp
Woit is on the spot, demanding more evidence and applying critical thinking to debunk the deceptive claims.
http://www.math.columbia.edu/~woit/wordpress/?p=510
If there’s one thing you won’t hear from crackpots, it’s a call for critical skeptical thinking and a demand for more peer-reviewed journal-published experimental evidence — and that’s exactly what Woit and Smolin and Kraus have been calling for, over and over and over again.
To imply that people who demand hard evidence and urge skeptical critical thinking are kooks is beyond contemptible. That’s the very basis of science. Throw out peer-reviewed journal-published experimental results and toss out skeptical critical thinking, and you’ve got dianetics, not physics.
http://www.wired.com/wired/archive/12.06/view.html?pg=4?tw=wn_tophead_3
Lastly, folks, keep your eye on the ball. Don’t let Sean Carroll of anyone else distract you from the real issue here. The crucial issue is whether the string theorists have made any experimentally testable predictions, and whether there exist any peer-reviewed published experimental evidence to back up those alleged predictions. I’m still waiting for Sean Carroll to provide the journal titles, article titles, issue numbers, volume numbers and page numbers of those articles chock full of experimental evidence to support string theorists’ experimentally testable predictions.
Since my reading comprehension is defective it’s safe to assume that I missed those citations providing experimental evidence for string “theory” from the HEP literature. Please point ’em out to me.
mclaren, the response you will get is that string theorists should be free to investigate what they want forever at taxpayers expense, hyping their ideas and stamping on alternatives using tactics similar to those used successfully by Germany from 1933-45.
Particles might well be some kind of string or loops of field lines. I’ve no problem with the idea of string.
What upsets me is the elitism attached to the particular mainstream prescription for trying to get a model. They have adopted a methodology which is leading to religious type behaviour. The suggestion by Dr Witten not to engage in arguments for fear of controversy is like the previous Pope’s argument that theologians should not argue science, made for exactly the same reason (negative controversy).
The way to build theories is to collect data, come up with empirical laws based on that data, and them come up with theories to model this data. That’s what Woit and Smolin advocate. Mainstream string theory is exactly the opposite: it builds an elaborate model on a massive amount of speculation and then has trouble getting any definite falsifiable predictions.
Just to be clear, the 8+ years I mentioned is what I often see for people working on non-string formal particle theory topics such as nonperturbative QCD (e.g. Schwinger-Dyson equations and that kind of stuff). I don’t expect that this is a unique situation though; probably it is the lot of people who are not working on the dominant topic in any given field.
“Who do you think is doing the judging in mathematics? It’s not as if the people working on hardcore analysis are getting refereed by the combinatorists. People are always judged by their peers because those are the people that best understand the work.”
Sure, but for the top maths journals the referees are carefully chosen accomplished experts in the relevant field, whose first commitment is to maintaining the standards of the journal. If I understand your point rightly, you are thinking that getting a paper accepted by such a person is effectively no different from getting a strong recommendation letter from them, so what difference would it make in practice? My impression however, is that it can be a huge difference in mathematics. For example, a senior person might be willing to write a glowing letter for some youngster, but that doesn’t mean he/she would be willing to accept that person’s paper for Annals of Math. The latter takes much more than the former; it is really a quality stamp of a magnitude that no reference letter can impart.
“And, it’s not as if there’s this vast free-for-all journalwise. People know what the good journals are and which aren’t. That PRL isn’t at the top of the heap hardly seems like a big deal.”
That’s true, but the problem with this situation as I see it is that it really doesn’t take that much to get published even in the supposedly good journals. Routine papers making incremental advances get published side by side with great papers containing major breakthroughs. Someone from another field has no way of telling the quality and importance of a paper from the journal it gets published in. In contrast, the quality and importance of a maths paper is tightly correlated with the journal it gets published in, so people can know it to a large degree just from the journal. I really think it would be a big advantage for everyone if we could have such a system in physics. It would solve the problem of finding an objective measure and assigning credit once and for all. String theorists could use it to to prove that their dominant position is merit-based (if they can ;)), and non-stringers in formal particle theory could use it to circumvent the need to get the strong personal support of senior influential people (who are almost all doing string theory and therefore not particularly inclined to support people working on other topics). That’s provided we can agree that publications are the primary measure of merit and letters of recommendation etc are secondary (which seems to be the case in the maths community to a large extent).
“Is what you want to say is that the referreeing process isn’t as rigorous as that of the mathematicians? You might have a case to be made there, but I’m still not sure that’s your point.”
Yes, the rigorousness of refereeing and standards for getting published in physics journals are far below that of the top maths journals. The consequence of this that I find so objectionable is that it removes the possibility of using journal publications as an objective measure for assigning merit, and there isn’t really anything else to use in its place. The closest thing we have to this at the moment imo is PRL, but at best it’s nothing more than a pale shadow of what the mathematicians have (and what we could and should have).
“Regardless, perhaps you can explain to me, as someone who hasn’t published outside of string theory, just how the string theory refereeing process differs from the rest of physics.”
As far as I know there isn’t any difference (and I don’t remember suggesting that there was…) Some journals are supposed to be harder to publish in than others (e.g. PRL vs PRD) but I don’t see why string and non-string papers would be treated differently. What there is, however, in general, is resentment when people get jobs ahead of others who look on paper to be better qualified as far as publications etc goes. You can imagine that more senior postdocs working on non-string things and with lots of publications and citations would find it pretty galling to see young string theorists getting jobs ahead of them. (Btw, I’m not one of those people! – my own record is much less than great.) It’s obviously something that would fuel resentment against ST itself. But again, this would be a thing of the past if we could establish a similar journal system to the mathematicians so that there was an objective measure for merit that everyone could accept.
“There are no completely objective criteria in hiring in any field. Are you seriously claiming that mathematics or the rest of physics, or, hell, the rest of the entire world doesn’t have people talking to each other and asking their opinions of job candidates.”
Of course, it is impossible to make hiring decisions etc completely objective; sociological factors will always be there. E.g., I’m sure it helps a lot for getting published in a top maths journal to be working on a fashionable topic at an illustrious institution and with good connections to influential people. But still, it is in principle possible for Dr. Nobody at University of Nowhere to publish in top maths journals if he/she comes up with something good enough, and thereby forge a career. In physics (at least theoretical hep), the way things are now, that isn’t a possibility. Instead, as best I an tell, people are completely reliant on gaining the strong support of influential senior people. To gain that while working on a different topic (which is basically what a non-string formal particle theory person needs to do) is going to be a lot tougher; it would take something quite dramatic.
“I find it hard to believe that hiring in other field consists of simply counting one’s PRLs and making an ‘objective’ decision. And, even if it were, how is the number of PRLs anything but a proxy for what the “accomplished” editors and referees think of the work?”
Of course, the decision to hire someone is always going to involve more than just counting publications, PRL or otherwise. But PRL publications do seem to count for quite a bit in some other fields, e.g. condensed matter. There it seems to be possible for someone who isn’t blessed with good connections to influential people to outcompete via PRL publications someone who does have the former. Sure, it is nothing more than the opinions of a couple of (usually well qualified) referees, backed up by an editor, but it seems to work ok as a neutral currency for merit in CM as far as I can tell.
using tactics similar to those used successfully by Germany from 1933-45
Sean, congratulations! You’ve managed to start a thread on string theory that actually descended into the territory of Godwin’s law!. Well done.
amused wrote:
“Just to be clear, the 8+ years I mentioned is what I often see for people working on non-string formal particle theory topics such as nonperturbative QCD (e.g. Schwinger-Dyson equations and that kind of stuff).”
I suppose it’s not terribly polite to anonymously talk about the details of people’s careers on a blog, but as far as I can tell from Spires the people who have made the largest contributions to Schwinger-Dyson approaches to QCD already had faculty positions when this work began. Also, it’s confined to a relatively small number of people and a very large fraction of it happened in one place (Tuebingen). Not knowing further details of people who went through job searches and had problems, I won’t say that your example is wrong, but I don’t see clear evidence for it…. (Of course, not all aspects of the job market are the same in Europe and the US; nearly everyone involved in that approach is in Europe.)
If people working on such things did have problems getting jobs, I think the reason is probably more that the field is not structured to support people who want to work long-term on a fairly technical program without broadening their interests and working on other things as well.
(There are perhaps other issues here, starting with the fact that it’s not at all obvious that it makes sense to use the SDEs nonperturbatively given the presence of Gribov copies, an issue which I think is now resolved due to work by Zwanziger.)
“Routine papers making incremental advances get published side by side with great papers containing major breakthroughs. Someone from another field has no way of telling the quality and importance of a paper from the journal it gets published in. In contrast, the quality and importance of a maths paper is tightly correlated with the journal it gets published in, so people can know it to a large degree just from the journal.”
I find it rather surprising that there is any field in which incremental advances are not published side by side with great papers containing major breakthroughs: there simply aren’t that many breakthroughs!
Scott, don’t forget comparisons to Pravda, Medievalism, and Rational Choice Theory! Together with the Nazis, we’re talking the Big Four of bad things to be compared to. Also Fox News.
Now if you’ll excuse me, I’ll be back to leading the systemic retreat from rationality.
Wasn’t there consideration for some level of “moderation” on this blog. I am wondering if this thread unfortunately exemplifies the need for that.
Elliot
#150
I am sensitive to your plight. While I cannot speak with any authority and many know this. It is necessary to somehow show the development of string theory in some other way? 🙂
Well, at least make it entertaining. Break up the rigidity for a moment, so one can enjoy “the feelings emanating” from those who have found beauty in the work.
It is unfortunate some of those who choose to do model work of one kind or another, would suffer under such a thing whilst you pursue the interest. It is not about bravado, whilst you suffer under the tutelage and take your lashes, but more that you would excel in your continued research and development from what one find works. You challenge the person to excell in the work, not to challenge the person?
“Change your name” to protect your innocence? Then speak away?
I have to go back and start from the beginning “every time.” 🙂
Elliot,
Notice the “number comments-169” versus the actually responses showing 160?
Eric Mayes writes,
And, of course, a string theorist would never do such things, right? Screaming and yelling is a feature of right-wing particle physicists, while string theorists are polite, soft spoken freedom lovers. That is the idea?
Have you checked a few string theory blogs recently? Frankly speaking, string theorists don’t look to me like helplessly shy people, or at least the blogging ones. Thuggery is certainly not beyond the abilities of (several of) them.
Just to be clear, the 8+ years I mentioned is what I often see for people working on non-string formal particle theory topics such as nonperturbative QCD (e.g. Schwinger-Dyson equations and that kind of stuff). I don’t expect that this is a unique situation though; probably it is the lot of people who are not working on the dominant topic in any given field.
I know string theorists on their third and fourth postdocs, too. The job market pretty much sucks for people who aren’t doing phenomenology or cosmology.
My impression regarding mathematics is that people often get hired (at least at the lecturer level) with no publications at all, purely on the strength of their theses. But at this point, I really don’t know what I’m talking about, so I won’t bother speculating any further.
I tend to disagree with your contention that publishing in PRL is the only way to get noticed. I’d expect that well-informed senior people will notice good work in their specialty.
onymous,
I had a couple of people in mind for the DSE example, and yes, Tubingen was a common factor for both of them although in both cases DSE was just one of a number of things they work on. They have both been in the game for a good long while (satisfying my 8+ criterion), both have very decent publication lists with lots of cites etc. One of them recently managed to get a faculty job, the other is still a postdoc. One of them is in the US, the other elsewhere. Maybe you can work out who they are from this info. But I’m starting to feel a bit bad; like you said, it isn’t so nice to be discussing this stuff in public… Having just looked them up on Spires i also realized that they aren’t such great examples for what i was claiming, since they are more hep-ph (and even nucl-th) than hep-th (although I would still think of them more as QCD theory than real phenomenology or nuclear people). But in any case, the career trajectories of these guys are pretty typical for the non-string students/postdocs I’ve been aquainted with or heard of through friends/aquaintances. I could give more examples, including ones closer to hep-th, but would prefer not to do it in public…
“I find it rather surprising that there is any field in which incremental advances are not published side by side with great papers containing major breakthroughs: there simply aren’t that many breakthroughs! ”
True, I should have said major advances instead. Breakthroughs is overstating it. To publish in a top maths journal the work would have to be considered a major advance. Papers with only incremental advances would only be publishable in lesser journals. (I don’t have personal experience of this but spent some time in a maths dept at one point and had it all explained by the mathematicians.)
This is boring. Let’s talk about something else or, you know, get back to doing physics.
Aaron, once again I never meant to imply that all string theorists have it easy. I know there are plenty who don’t.
“I tend to disagree with your contention that publishing in PRL is the only way to get noticed.”
Ok, I don’t remember contending that, but whatever.
“I’d expect that well-informed senior people will notice good work in their specialty.”
How many such people do you imagine there are for a typical non-string formal particle theory topic? In my case there were two, and they were enemies, so getting support from both was out. I was fortunate to get supported by one of them, but you can imagine for yourself how far the support of one isolated big shot is likely to take someone.
Let’s give this a break.
Peter, you wrote in response to my comment about funding:
So let’s talk about that rather than rehash your critiques of string theory. Everyone, no matter what they think about string theory, can agree that science funding is seriously messed up. The competitive grant system imposes a huge amount of overhead and distorts how science is practiced.
So what’s a better system? To take an extreme example, what if NSF just divided its money equally among everyone? No grant applications, no reviews — just ask for money and you get some. Sure, this would produce waste, but would the waste be worse than what we have now?
George
I am eagerly waiting to Sean’s promised post titled “Why String Theory Must Be Right,” or perhaps “Very Good Reasons to Think that Something like String Theory is Going to be Part of the Ultimate Understanding of Quantum Gravity.”
It will be great to have an account of these reasons and Sean’s overall point of view. Go for it, Sean!!
(A little remark is that the two possible titles are somewhat different. I think, for example, that Lee Smolin would agree to the second title. Also if the second title represents Sean’s point of view, it is an interesting issue if the practices of string theory research really accommodate for the possibility of “something like string theory.” From the outside, progress in string theory looks like very pointed with some sharp turns but not much backtracking. Of course this view may represent distortion caused by the popular descriptions.)
But while waiting o Sean’s promised post, it is a pleasure to read Moshe’s beautiful comment:
“you just start with a purely intellectual exercise, quantizing a relativistic string. You know you’d immediately run into trouble because combining Lorentz invariance and quantum mechanics is very tricky in field theory, requiring delicate structures such as gauge invariance for vector fields. So you expect complete disaster, all kinds of nonsense, but you are stubborn…
Instead, to everyone’s surprise (try to quantize relativistic membranes if you don’t believe it), everything falls into place effortlessly- the theory cannot be tuned and modified, so it lives dangerously, every time you check something new you may prove it inconsistent, and will simply have to abandon it. Somehow, again and again it is just right. Gravity, Einstein equation, matter fields with rough similarity to the real world (gauge fields, chiral fermions), they all just come out. It is impossible I think to go through the first few steps in string theory without the feeling of awe, there is something there that is very correct and unique. ”
Unlike most participants, I don’t know what the future of string theory will be, but however it will turn out to be, I think Moshe’s words beautifully describe the spirit of scientific work and the sweet sensation of scientific progress.
I think that the advantage which mathematics has is also that the most important thing to check is that the proof is correct, and every question can in the end be verified through the manipulation of symbols.This objective standard is infinitely better than any journal or system of authority based on reputations. It is essentially the same as the standard in symbolic logic.
String theorists have had to relax this standard to allow string theory to exist, partly because assuming the truth of conjectures is more common in string theory, but also partly because string theory claims to be physics and not mathematics, and claims to be able to draw on another source of information which is denied to pure mathematicians. You hear mathematicians saying things about string theorists like: “I don’t know how they manage to produce such important mathematical results. They don’t prove the assertions they make, but many of them appear on inspection to be correct.” This has been interpreted by some as evidence that the string theorists have access to some deep truth about something.
After my experiences with string theory, I don’t think this is the case. I believe that what is happening is that the string theorists have hit upon a more productive way of doing research in mathematics. The use of the arXiv for communication has revolutionized the way that mathematics research can be done. It is now reasonable to share ideas while they are still conjectures and while proofs are intuitively understood rather than rigorously finished. Others can help tidy up the details; the big leap forward in understanding often does not come in the form of a proof.
Things can be presented in string theory as great breakthroughs which in mathematics would be considered just a conjecture. The mathematicians don’t get it; don’t see what the success is. The string theorists get excited about it, and major results soon follow. For a mathematician this can make string theorists seem to have magic powers; they can perceive something which the mathematicians cannot and it is bringing them success. But the mathematicians cannot do what the string theorists do, because the string theorists are not rigorous and what is mathematician supposed to do if he abandons rigor?
This has won string theory praise and respect from some of the most recognized mathematicians, and this general thumbs-up has been interpreted by some as evidence that there is a particular thing which might or might not be true, sometimes phrased as “String theory correctly describes the universe” , which is evidently true because string theorists can do things which impress mathematicians.
I was never able to find out exactly where string theory began and where pure mathematics ended. Evidently conformal field theory wasn’t the boundary. Does string theory start when I set the trace of the energy-momentum tensor to zero? Or is it because I study this lagrangian and not that one? How does that give me a source of information which mathematicians don’t have access to? Would it help if I said “String theory correctly describes the universe” a few times?
Everybody following the public string theory circus will know by now that many people claim they work on string theory but that the field of string theory spreads over so many areas of mathematics and has such ill-defined boundaries that this claim is easy to make.
I can only conclude that there is no “string conjecture” which is or isn’t correct (from a mathematician’s point of view) and that the statement that “string theory correctly describes the universe” does not provide any access to a new source of information and has no mathematical content at all. So the subject which string theorists are investigating can only be pure mathematics – they have no other source of information which mathematicians don’t have.
The great success was the introduction of a more efficient way of researching mathematics, and the people in theoretical physics adopted it because they are concerned with the applications of mathematics rather than the proofs. Their successes were all mathematical, but it gave the appearance of being an advance in physics, and the idea that “string theory correctly describes the universe” took on a life of its own in the public imagination.
Dear Po and everyone – yes, this thread has perhaps reached its end with the Godwin’s Law violation, or perhaps with this absurdly long post of mine; but I hope none of the authors of the physics-related posts feel that they wasted their time. This has been the most interesting thread anywhere on the ol’ Inter-tubes for the last couple days.
I’m pretty much the person you are all trying to convince when it comes to “the public debate” – well, me and my congressman. When string theory first came into public view I was the first person in my social group to read about it, and for a long time my friends thought it was silly. Then they all got on the bandwagon when Greene’s books came out, around the time I was starting to think “hm, isn’t it about time this went somewhere a litlle more real…?” Now, amusingly, I find myself again on the outside, simply because I am undecided; anecdotally, among my peers, who I might describe as highly intellectual, countercultural creative professionals, string theory has become decidedly unhip, old hat, and yesterday’s news.
However, I also have noticed that the less a given person knows about physics – even by my knuckleheaded, pop-sci rating scale – the more likely they are to hold that opinion. They heard the buzz around Smolin’s book and that was that. This isn’t to dismiss the book, which is next on my reading list, it’s the exact same social effect The Elegant Universe had when it came out, which extended far beyond people who actually read it. Again, I’m not saying Smolin’s not right, I’m saying that a lot of my peers are intellectual followers, and when I challenge them to defend this new position – taking the pro-string side as a devil’s advocate – it’s clear few of them have even the low level of understanding that I do. They’re interested, they know it’s important, but they don’t grok it well enough to have an opinion they didn’t get from someone else.
In my arrogance, I beleive I understand the debate well enough to know that I should not hold any opinion at all. Opinions get in the way of thinking and right now this all-important field is too unsettled for that.
I learned a lot of interesting things in this thread. Such as:
– Physicists might start off talking about physics – and some of them try to keep the conversation there – but in the end it turns into an argument about jobs. Who’s getting them, who’s not, and who deserves what. It’s understandable, but really quite depressing. As a pro-science taxpayer I’d like to fund you all and let the physics sort itself out over the next couple decades, but it’s clear this is turning into a knife fight over tenure and professional futures.
– people seem to think it’s meaningful to debate what other people “should” do with their academic lives. Young scientists interested in strings are going to keep doing strings no matter what; and those who find them unconvincing or uninteresting are going to find other topics and ways to pursue them, resource availablility notwithstanding, just as early string theorists did when everyone thought they were nuts. Why waste your time arguing over what your peers should or should not be doing with their lives? Get on with your own life and your own work and let the results speak for themselves.
– Peter Woit may be very intelligent, and may be right – from the evidence here, I may be the last person on Earth without a settled opinion or axe to grind on that – but he has an arrogant and manipulative rhetorical style in which he proclaims things to be True because he has decided they are true, as if this should end debate. I despise this form of argument, as it is usually a sign of intellectual dishonesty; and so this person, regardless of his expertise, intelligence or other merits, shall be excluded from my consideration of this debate unless and until he modifies his propagandistic approach. Stop telling me what has failed and what hasn’t. It’s not for you to decide, bub, ‘k?
– Several posters whose names have appeared here many times before are revealed as off-topic windbags whose opinions may be safely ignored from here on out. Also, mclaren’s attacks on sean, IMO, cross the line from merely off-topic/irrelevant ranting to abusive and if this were my blog I’d boot him; and nc should be banned permanently for his insane and extremely offensive Nazi reference. When was the last time a string theorist murdered someone for poltical reasons? I must have missed that. Shame on you, tiny little man.
– this thread may have killed this blog. I hope not. It’s quite a bruising fight and Sean et. al. may not be up for posting any more invitations to such a frenzy. But this sort of thing is exactly what makes this blog worthwhile – not the beer or science v. religion posts, fun as those are.
So keep it up, people, but leave the job & tenure related BS buried in the subtext where it belongs, please. Do your best to convince me. I don’t speak higher math but don’t think I’m stupid either (to be fair, I don’t see a lot of that these days). My current state of mind is that while string theory and its extensions, all the way up to the landscape, are worth continued effort by physicists, funding by the government and others, and learning on my part; but that’s it’s also, in parallel and not instead-of, worth learning, funding and researching the alternatives, whatever they may be.
So, with the exception of the flamers, thanks to you all for a most interesting thread.
Yeah, tyler, if you start banning people for making nazi comparisons, it’s going to be a lonely internerd. Ridicule is probably a more appropriate reaction.
“Somehow, again and again it is just right. Gravity, Einstein equation, matter fields with rough similarity to the real world (gauge fields, chiral fermions), they all just come out. It is impossible I think to go through the first few steps in string theory without the feeling of awe, there is something there that is very correct and unique. ”
Yes, wow, they all just come out. Matter fields with ROUGH similarity to the REAL world just comes out. I am so awed by how matter fields with ROUGH similarity to the REAL world just comes out. Yes, there is something very correct here.
tyler,
“he has an arrogant and manipulative rhetorical style in which he proclaims things to be True because he has decided they are true, as if this should end debate.”
My references to the “failure” of string theory refer to a specific scientific argument about exactly what has failed and what the reasons for this are. The argument is outlined at a popular level in my book, in more scientific detail in many of the several hundred postings on my blog and in some recent talks I gave, available at my web-site. If you want to have an informed opinion about the question of whether my claims about string theory’s failure are correct or not, you need to try and follow that argument. If you want to decide who is right about this based on your dislike of people’s “arrogance”, I think you’ll find plenty of it on all sides of this debate, so it’s not a criterion that will help you very much.
As for your dislike of “the job & tenure related BS”, sorry, but that’s a crucial question here that is driving this debate, as far as the people involved are concerned. How does this academic field allocate resources going forward? The people who have devoted their professional lives to working in this area care deeply about it, on both sides of the issue, and have very serious concerns about the future of this field. This future is going to be determined largely by who gets hired into permanent jobs, and who doesn’t, and everyone in the subject is well aware of that.
George,
I think the grant system is less of a problem in math and theoretical physics than in other parts of science, simply because the size of the grants is smaller and they are less crucial for getting your research done. Unlike experimentalists, who need money for equipment, in this area you can work successfully without a grant. But you can’t work successfully without a job, preferably at an institution set up to provide the kind of environment necessary. The situation in this field is that there are a lot of smart people getting Ph.Ds, and a small number of permanent jobs at institutions that can support research. So, one huge issue on every one’s mind is how that particular game of musical chairs gets played. The grant issue often comes into play through the way in which grant money funds positions or encourages universities to fund them.
If you look at history, the people who have made the big breakthroughs in this subject often do so at a relatively young age, so if you want to think about how to maximize the chances of such a breakthrough, you need to think about how to encourage young people to try and do something new and ambitious. I’ve made some suggestions on my blog and in the book (e.g. instead of many short postdocs, guarantee people support for longer terms, “birth control” to bring the number of people and the number of jobs into better balance). Unfortunately I think it may also be necessary to not just provide incentives to original ideas, but disincentives to unoriginal ones. As long as people see that the most likely path to a permanent position is to keep their head down and work on the most conventionally accepted topics, that’s why many if not most people are going to do. I’d love to see some discussion and debate of these issues.
Hi everyone:
By popular demand (and to get some issues across), I will do a rant on “Why should string theory be important for describing the real world”.
These are my personal points of view. Some may be more technical than I would like for this audiencee. but I think that comments like the one Po made above deserve a reply. Especially since Po thinks that being sarcastic will buy him points for being “oh so clever”.
String theory was born in the late 60’s. It’s origins date to the Venziano amplitude and the era of the dual resonance models. The amplitude was an example of a setup that seems to satisfy all of the details required for an idea (the bootstrap) that was very popular at the time.
The Veneziano amplitude was written down before it was knnown that it related to strings.
The properties of this model were that it predicted an infinite tower of massive particles with high spin. It had the property of Regge behavior. This behavior had been observed in the tables of strongly interacting particles.
Thus string theory was born as a model to explain the strong interactions.
One of the biggest problems that arose then, was that the string model predicted a particle of spin two and zero mass. That particle was the source of a lot of headaches, and people tried to work it out of the string model for year.
When QCD showed up, it took over and very few people kept working on string
theory.
This particle of spin 2 and mass zero shows up in another very different place:
gravity. Any semi-classical quantization of gravitational waves will produce such a particle.
String theory was then reinterpreted as a theory of quantum gravity. One can even check that the gravitational interactions that are described by Einstein’s equations follow from studying string interactions according to the usual rules
for calculating in string theory.
This is a very non-trivial check: random theories of spin two massless particles are inconsistent, unless they reproduce Einstein’s equations.
Afterwards it was discovered that the existence of fermions (something we see every day) required that the string worldsheet have supersymmetry. Things work a lot better in that case, and one ends up with the prediction that critical strings (read Lorentz invariant in all of the dimensions of spacetime simultaneously) required 10 dimensional supergravity.
Morever, it was possible to show that from string theory one could also produce chiral matter and that anomalies cancelled. This is also a very non-trivial check, as otherwise the theory would be inconsistent. In 10 dimensions this requirement is a lot more stringent than in four, and is enough to determine the gauge group of interactions and reduce it to very few choices.
This idea also ties very nicely with Grand Unification ( a popular model for physics beyond the standard model) and many people took these hints very seriously.
More recently string theory has been able to count the degrees of freedom of certain black holes from first principles and to reproduce the Bekenstein-hawking entropy of black holes by a microscopic description.
This is amazing for various reasons: if one reads ‘t Hooft papers on the physics of black holes, if one just counts initial configurations that lead to a black hole in a region, one usually ends up undercounting the entropy. At the same time one gets that the entropy scales with the area, and not like the volume.
‘t Hooft also showed in the 70’s that theories with large gauge groups (of Nx N matrices) lead naturally to a string interpretation. This is believe to be behind the mechanism of confinement in QCD.
The modern version of that idea is embodied in the AdS/CFT correspondence.
That is an example of such a an equivalence where one can be very precise about the field theory and the string theory.
The surprise is that the ‘t Hooft string ends up being identified with the same fundamental string that lives in 10 dimensions and was encountered previously, and that also contains gravity.
People have shown that in toy models of this type, one gets better agreement with observations at the RHIC experiment than by using perturbative QCD. In particular, the setups involve black holes in AdS.
There are a lot of other reasons to be optimistic about strings: it has been a soruce of inspiration for many models of physics beyond the standard model, it has produced beatiful mathematical conjectures and ideas, etc etc.
The biggest question is whether strings will be useful at the level of precision electroweak measurements, and to get better than qualitative agreement with the strong interactions. We don’t know that, but we are hopeful that this is possible.
I hope everyone hass a nice day.
David B.,
“The biggest question is whether strings will be useful at the level of precision electroweak measurements and to get better than qualitative agreement with the strong interactions.”
I’m quite willing to believe that string theory may some day produce a model with better than qualitative agreement with the strong interactions. But what’s the “precision electroweak measurement” reference to? To calculating QCD effects here or to explaining beyond the standard model physics? Have you completely given up on the hope of using string theory to explain where the standard model comes from? If not, wouldn’t a better way to state the question would be “will strings ever explain anything at all about the standard model Lagrangian”?