Dispute Chez Les Physiciens

Yesterday evening there was a public debate about string theory held in Paris, between Lee Smolin and Thibault Damour. So far, accounts of the debate have appeared in Le Monde and at Fabien Besnard’s blog Mathephysique.

The Le Monde article is not very informative, but indicates that Damour defended string theory against charges that it was not testable by claiming that it predicted “possible classes of experimentally testable phenomena” at the LHC. Besnard gives a more detailed account, describing how Damour answered these charges of lack of testability with: “Lee, a subtle thinker, surely doesn’t believe himself the naive Popperian position he is defending”. He also evidently claimed that string theory was testable because it would be confirmed if a violation of the equivalence principle was found (he really should talk to Lubos, see here). Remarkably, he also claimed that observation of the kind of DSR dispersion relations that Smolin thinks LQG leads to would not be a problem for string theory, since one could also get them out of string theory (here I think he needs to talk to both Lubos and Jacques Distler).

Update: I hear that the event was recorded, and audio should be available by the end of the week at the web-site linked to above.

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60 Responses to Dispute Chez Les Physiciens

  1. Aaron Bergman says:

    This translation is from google, so I apologize if it gets it wrong:

    LS explained why certain violations of the relativistic relation of dispersion were predicted by the quantum theory with loops, and that if they were not observed, that would refute the theory,

    Strange, isn’t it, how Lee always leaves that (incorrect) impression.

    It’s worth pointing out that while most of the scientific community works by some combination of positivism and falsificationism (which isn’t nearly as contradictory as historically indicated), the philosophy of science has moved beyond both as I understand it. There’s a lot of stuff out there about the problems with “naive falsificationism”, for example — I’d guess that’s what Damour is referring to.

  2. Peter Woit says:


    The way string theorists are hiding behind philosophy of science is just ridiculous and less than honest. String theory makes no predictions, that’s all there is to say about it right now. You can honestly argue that maybe once we understand non-perturbative string theory, this will change, but invoking subtleties about the philosophy of science to claim that string theory really is testable is just dishonest. And claiming that string theory can be tested by looking for violations of the equivalence principle is just absurd.

  3. Aaron Bergman says:

    And here I thought I was just clarifying a point of philosophy….

  4. anon. says:

    Babelfish translations: Le Monde and Mathéphysique.

  5. Lee Smolin says:


    Please listen to the recording. I was quite precise. I said that LQG pointed to possible new phenomena which were characteristic quantum gravity effects. I gave as an example of such a possible phenomena, DSR , but I also said that there were no agreed upon precise predictions. I also said that I had written a paper deriving such an effect at a semiclassical level, but without a precise coefficient, and I also emphasized that my more rigorous colleagues were as yet unconvinced by this. I also said at least one other time that neither string theory nor LQG had so far made precise predictions by which they could be falsified.


  6. Coin says:

    The cords of the discord agitate the cosmologists

    C ‘ is a scientific argument with old. A controversy as the time offers any hardly any more. Wednesday June 6, in the City of sciences, in front of several hundreds of researchers, students or simple curious, two scientists of high flight discussed one of most attractive – and more inaccessible for the common run of people – constructions of physics: the theory of the cords. For the charge, the American Lee Smolin, researcher in Institut Perimeter of Ontario and signatory of the lampoonist Nothing goes any more in physics (Dunod, 2007).

    Oh, how I love Babelfish. I think their new name for Smolin’s book is maybe actually an improvement.

  7. Aaron Bergman says:

    I don’t know what you said; there doesn’t appear to be a recording available yet. What I was commenting on is the continuing propensity (and the above is far from the only instance of this) of your listeners to come away with the impression that deformed dispersion relations are a prediction of LQG.

    It seems odd, no?

  8. Yatima says:

    Babelfish serendipity:

    …and signatory of the lampoonist Nothing goes any more in physics (Dunod, 2007).

    That is actually the correct translation for the french title “Rien ne va plus en physique”. Far stronger than “The trouble with…”.

    “lampoonist”, however, is clearly wrong – “pamphlétaire” has the meaning of “written by a firebrand”.

    In other news, one can detect despondency at Slate, whereby the tought of the Standard Model soon being buttressed by a Higgs sighting and not much happening thereafter causes depression. Strings only feature on page 2:

    But what happens if the Higgs turns out to be just right? Well, then the standard model predicts that you’d need a machine roughly a quadrillion times more powerful than the LHC to find anything new. (…) Though some theorists—proponents, for instance, of string theory—speculate about what such an accelerator might find, few other physicists take them seriously.

  9. Coin says:

    Yatima: Ah, thanks for clarifying.

  10. Garbarge says:

    “And claiming that string theory can be tested by looking for violations of the equivalence principle is just absurd.”

    I dont think that is absurd, I actually believe that is a very important venue. If GR is *wrong*, and not just due to higher order curvature effects, then we will know for sure ST, in its current form, cannot be right. The same about Lorentz Invariance, unitarity and analyticity.
    The quibble though lies on how big of an effect can this be and whether can it be measurable. To attack the building blocks of a theory, otherwise adjustable to 10^500 different scenarios, sounds like the only possible route to success (or failure depending on which side you want to jump on). What’s wrong with testing the only few properties all these vacuum solutions actually share!

    Of course, violations of these sacred principles will radically modify our views and intuition about the world, but as a side dish will put the ST community on stage for a big change whereas LQG people may even celebrate after all 😉

  11. Peter Woit says:


    My objection is to what I take to be Damour’s claim that an observation of a violation of the equivalence principle would be evidence for string theory. If you believe Lubos, string theory predicts no violation of the equivalence principle, if you believe Damour, it predicts a violation. They need to get their story straight, but can’t, because string theory can accomodate virtually anything.

  12. theoreticalminimum says:

    I have a problem with this rhetoric:
    “le désaccord sera toujours nécessaire à l’avancée de la science” [“disagreement will always be necessary for the advancement of science.”]
    This statement is, I believe, vacuous and incorrect. I think that, within a community consisting of different groups of people motivated in exploring different ideas, disagreement will always naturally occur when these ideas are confronted with each other, or with any form of philosophical discussion. What really counts as progress in science is that, at some point, repeated confrontations bring the members of the community to realise that they have to agree on the correctness or incorrectness of an idea. This agreement is the advancement. Unless we can all agree that some theory is right or wrong, we can spend decades disagreeing, and science will not take a definite step forward. In other words, disagreement is necessary for the exploration of ideas, but ultimately, we have to agree on what makes sense so that we can move on.

  13. Lee, I wish I were more precise about your statements on my blog. Indeed you emphasised that LQG does not yet make precise predictions everyone agrees about, and I’ll make an update. Still, I think the point is not really there, it is more a matter of principles. If I understood well, you wanted to show that in principle LQG is falsifiable, and when you asked Damour about the impact of DSR, should it be observed, on string theory, his answer was that ST could accomodate both DSR and no DSR. Would you agree with this version ? This is why I said that in principle, supposing some consensus is reached in the LQG community about DSR and supposing GLAST experiment sees it, one would be a in strange situation with in one hand a falsifiable theory passing a popperian test and on the other hand an incompatible, non-popperian one, claiming it does not care…

  14. I must also say that Thibault Damour never said that String Theory could be confirmed by some experiments at the LHC, contrarily to what the Le Monde article says. In fact, if I correctly recall, TD said he was not optimistic about this.

  15. Bee says:

    Hi Peter,
    thanks for the links, should listen to that audio. Reg DSR, this is quite ironic. I am reasonably sure there is a comment of mine from last year somewhere in the blogosphere that says I’m waiting for a string theorist to claim they can have DSR as well. I’m just done with the String Pheno conference, giving a talk (half-ways) about DSR – can’t say I had the impression anybody was particularly interested in it (but then, it was before the first coffee break…). Best,

  16. Brett says:

    The claim that string theory can’t violate the equivalence principle or Lorentz invariance isn’t justified either. It’s very hard to study nonperturbative effects in string theories, but in off shell string field theory, there are operators that certainly could give rise to spontaneous breaking of these symmetries. In the twenty-six dimensional bosonic version, it seems that this does not actually occur, but at the same time, there doesn’t appear to be a fundamental reason why this is so; it’s just a matter of which local minimum happens to the global extremum of the effective potential. And for more “realistic” string theories, the question is still open.

  17. Question for Aaron says:

    Aaron Bergman wrote:

    “I don’t know what you said; there doesn’t appear to be a recording available yet. What I was commenting on is the continuing propensity (and the above is far from the only instance of this) of your listeners to come away with the impression that deformed dispersion relations are a prediction of LQG.

    It seems odd, no?”

    I assume Aaron is just as scandalized by, and as prone to criticize, the much larger number of instances where string theory papers or lecture(r)s leave their audience with the impression that string theory makes predictions comparable to the above. That should go without saying, right?

  18. Aaron Bergman says:

    Everyone can be prone to overstatement, but string theorists haven’t gone out writing books trashing their colleagues and setting themselves up as standard-bearers of scientific virtue.

  19. anon. says:

    ‘… but string theorists haven’t gone out writing books trashing their colleagues and setting themselves up as standard-bearers of scientific virtue..’ – Aaron

    That’s the problem! Instead of going out and trashing not-even-wrong hype and ‘setting themselves up as standard-bearers of scientific virtue’, they do the opposite…

  20. Question Answered. says:

    So the “overstatement” of LQG predictions is not different from string theorists’ numerous overstatement of stringy predictions, but Aaron finds other reasons for criticizing only the first? Thanks for confirming that the diss was bullshit.

  21. woit says:


    I think I see what Aaron is saying. He’s attacking someone from outside his group for doing something that he wouldn’t criticize if it were done by someone inside his group, because that outsider accused people in his group of engaging in “groupthink” behavior.

    Sorry Aaron, I know the above is a bit unfair. But, you know, string theorists would get a lot more sympathy if there were evidence of significant internal criticism by string theorists of the excesses going on in their own community. Some days I feel like sending a bill to some leaders of the string theory community for doing work that they should be doing.

  22. Aaron Bergman says:

    Actually, it seems to me that you’re acceding that it was perfectly legit.

    If your only response is that, well, string theorists make overstatements too, then perhaps we’re all kinda the same. There are people who are overly enthusiastic and curmudgeon’s all around. Nobody is more blinded by groupthink than anyone else, and there are mountain climbers and valley crossers everywhere. Lots of people are doing their best to figure out hard problems, and there’s no monopoly on virtue centered in Ontario.

    Which was sort of my point.


  23. Aaron Bergman says:

    To PW: I don’t like to criticize my colleagues in public because I generally don’t think it’s, well, collegial. LS, on the other hand, has chosen to write an book, a fair fraction of which, his protestations to the contrary, is precisely attacking his colleagues. I think that makes his own hypocrisies fair game, and I don’t feel particularly collegial towards him.

  24. Chris Oakley says:

    Aaron & others,

    The important issue for the select group to which most of you belong — a group financed by tax dollars — is to carry out your mission of discovering the workings of nature with the maximum of energy and integrity. If anyone wants loyalty, they should get a Cocker Spaniel. This so-called quality is totally contrary to the spirit of scientific enquiry and leads to the kinds of closed shops that Peter W., amongst others, has been justifiably complaining about all along.

  25. Aaron Bergman says:

    I don’t think exposing the private fights of science (not all of which are substantive) to the public helps anyone.

    (Of course, with the recent recording of talks at conferences and the like, the line between public and private has been somewhat blurred.)

  26. Coin says:

    I don’t think exposing the private fights of science (not all of which are substantive) to the public helps anyone.

    As a member of the public, I kind of have to say I disagree.

    The public of course shouldn’t be settling scientific disagreements or whatever, but I think keeping people informed is an unqualified good unto itself.

  27. tomj says:

    Here is an idea: when physicists use ordinary language, and pretend that the ordinary meaning somewhat applies to what they are talking about, then ordinary idiots which understand the ordinary meaning have every right to ask questions.

    My main complaint with much of modern physics is that common words (not phrases or sentences) are used to describe or tag new ideas. The effect is very similar to teenagers overusing common language for new (private) meanings. Forget about the philosophy of science, how about the philosophy of language? People who call themselves scientists and who can’t get these basic philosophies right probably shouldn’t be proposing theories.

    A philosophy is a framework, it contains principles, ways of comparing more concrete frameworks. Even theories are frameworks, but they are of a more concrete nature. String Theory and the Landscape bs appear to be meta-frameworks, above theory, similar to a philosophy. Viewed in this way, it is easy to see why you cannot disprove it: it is above theory. Only theory deals with data.

    The problem with these meta-frameworks is that they use mathematical language as a means of definition. The effect is to mismatch the language with the level of use. Example: if the general principle of relativity can be described as a result of assuming that the laws of nature are the same in any inertial frame (as defined in GR), which is a pretty simple philosophical principle, how can a heavily mathematical theory be somehow above this? Mathematics is not going to be above philosophy. Experiment and the resultant data is not going to be above theory. And by above, I don’t mean more important. Experiment and data are the foundation. You cannot throw out data based upon a new theory or philosophy. This is exactly what is happening with ST, etc. These are frameworks, above theory, somewhere near philosophy.

    But the problem: philosophy and the resultant frameworks are relatively easy to describe, even if the implications are difficult or impossible to appreciate. ST, etc. somehow fail this test in a huge way. Somehow the details are chased around in an attempt to connect them with experiment or even theory. Unable to catch up with the facts, with data, the only thing left is a repudiation of the theories which are based upon the known facts. It is almost like concluding that the speed of light is infinite because nothing can catch up to it.

  28. Lee Smolin says:

    Dear Fabien,

    Check the recording when it is available, but what I remember Thibault said is that string theory could accomodate broken lorentz invariance, as there are many vacua that have this property. Given that this was a non-technical debate in front of a popular audience I choose not to belabour the difference between broken and deformed lorentz invariance (which I suspect he understands well.) From what I know, no one has demostrated a form of interacting string theory consistent with deformed lorentz invariance, although Magueijo and I found evidence for consistent free bosonic string theories with this property. I know of string theorists who are now working on this problem, and from a much deeper point of view, but so far as I know they have not published yet.

    Aaron, your whole discussion assumes that I exaggerated. I insist that a listen to the tape will show what I said was quite precise and true, indeed I went out of my way to emphasize that 1) many of my colleagues do not think there is strong enough theoretical evidence for the conclusion that 3+1 LQG is DSR and 2) even me who thinks there is agrees that I can only calculate the effect semiclassically up to an undetermined dimensionless constant.

  29. Aaron Bergman says:

    I insist that a listen to the tape will show what I said was quite precise and true

    That may be true, but it’s not my point. As I have already stated said point in multiple threads, I won’t belabor it any further.

  30. M says:

    Aaron, around 1995 the LSND collaboration published a paper claiming a new discovery and one young member of the collaboration, instead of signing the collegial paper, published another single-author paper explaining why he did not believe in the result.

    In the same years, no young string theorist questioned the mono-vacuistic ideology of string gurus, or complained about how the theory was irrealisticaly presented to the public.

    Sometimes good science needs a departure from loyalty.

  31. Bee says:

    Hey Tomj,

    philosophy and the resultant frameworks are relatively easy to describe, even if the implications are difficult or impossible to appreciate

    Whether or not you think philosophy is ‘relatively’ easy is a very relative statement. I happen to think maths is much easier than philosophy for the ‘simple’ reason that it only deals with well defined objects and not to a considerable amount with interpretations of words or juggling with undefined things. I have no idea what you want to say with your comment, do you think physicists should not use words from the ‘ordinary language’ to describe objects because it might confuse the public?

    Forget about the philosophy of science, how about the philosophy of language? People who call themselves scientists and who can’t get these basic philosophies right probably shouldn’t be proposing theories.

    Well, the problem is that ‘the public’ most often doesn’t understand that the theory is not made out of words but of equations. Every description that tries to avoid these equations might seem simpler but is never quite as accurate, and rarely manages to capture the elegance of an idea (my opinion). The obvious way to avoid this is just to learn the ‘language’ of mathematics, instead of accusing scientists to abuse ‘ordinary’ language. ‘Reading’ maths is neither a mystery nor complicated to learn (definitely not more complicated than, say, Polish), it’s just a way to decipher equations. Whether you learn how to ‘speak’ it, is another issue. I’d wish the prejudice that maths is a nerdy thing (whereas French isn’t) would end up in the trash bin. This trend however is supported by dropping equations from pop sci books, and articles etc. because it ‘scares’ the readers.



  32. Bee says:

    Oh, and regarding DSR and so on, see e.g.

    The Minimal Length Scale

    or the slides to my yesterday’s talk. Currently too tired to repeat what I’ve written there. The point is instead of understanding st as a theory of an extended object with standard SR, I am considering a model of ‘standard’ point particles with the additional property of reproducing the presence of a minimal lenght alias UV regulator or generalized uncertainty relation respectively. Thus, strings with standard SR are instead described by point particles with funny special relativistic properties (applies off shell). Plus point is, it’s not necessarily an string-only approach (the only assumption I make is that the underlying theory has something like a minimal length). Differences to DSR Lee is talking about can be found in hep-th/0603032 (there are several, the most important one being my modification is offshell only, see also gr-qc/0412004 cmp. section IV about the Snyder basis and note that p^2 is the square of the four- not the three momentum). With greetings from Warsaw,


  33. Aaron Bergman says:

    M — do please note the word “public”. If you think there haven’t been disagreements over just about every point of theory by string theorists young and old, then you haven’t hung around string theorists very much (or physicists in general for that matter.)

    The other point people seem to have missed is the difference between criticizing one colleagues and criticizing their work. There are papers on the arXiv contradicting other papers every day. A common pastime at lunches in various string groups is to try to figure out why the papers of the day are wrong without reading more than the abstract :). This is a good thing. Similarly, if someone wanted to write a book about the problems with string theory, I’d probably disagree on some of the substance, but I wouldn’t throw a huge fit. Lee, on the other hand, isn’t just disagreeing with string theory; he’s attacking string theorists as scientists. Criticizing one’s colleagues in this manner in a book aimed at the public is something I find extremely objectionable.

  34. anon. says:

    ‘… he’s attacking string theorists as scientists. Criticizing one’s colleagues in this manner in a book aimed at the public is something I find extremely objectionable.’ – Aaron Bergman

    You just need to lighten up a bit, Aaron. Ridicule is a tradition:

    ‘Oh, my dear Kepler, how I wish we could have one hearty laugh together! … 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.’ – 1610 letter of Galileo Galilei to Johannes Kepler, http://www.catholiceducation.org/articles/science/sc0043.html

  35. Chris Oakley says:


    I find your attitude to be a little too convenient. I see neither LQG nor String Theory as providing any insights other than the limited utility of signposting blind alleys, but whereas Smolin expresses himself with invariable politeness and tolerance, your own Motl throws insults around like they are going out of fashion. Why is Smolin “extremely objectionable” and Motl not? I would be interested to know.

  36. nardex says:


    I’ve read that “the study of strings has boosted a great amount of study in many areas of mathematics and of mathematical QFTs, and has revealed very beatiful truths belonging to these areas”.
    Thence, for You this is not important for the string theory itself?
    This is the “because” that you says that the string theory is “not even wrong”.
    I think that any theory that “has boosted a great amount of study in many areas of mathematics” is a useful theory.
    Looking forward to receiving your kind answer

    All my esteem

  37. Aaron Bergman says:

    Chris, why not do a little googling?

  38. Eric Mayes says:

    I’d like to propose the following theorem:

    Any theory of quantum gravity which provides the UV completion of quantum field theory will have a landscape of consistent vacua.

    The reasoning behind this is that quantum field theory can incorporate a large number of consistent models, and so it follows that a theory of quantum gravity which incorporates QFT will do the same. Thus, even if Lee’s loop quantum gravity is able so someday encompass QFT, it will have the same landscape problem of string theory.

  39. Chris Oakley says:

    Hi Aaron,


    Search #1A: “Smolin” “Insult”; top match

    In the debate, Michael said that “to put Stephen Hawking on the same page as Lee Smolin is an insult to the people of this audience” (which was more of an insult to Lee Smolin), yet even Hawking no longer believes there are singularities, and for the very same reason Smolin does not, and the very same reason Barrow does not, and the very same reason I gave in the debate: every going theory of quantum gravity, including Hawking’s, eliminates them.

    Search #1B: “Smolin” “Scorn”; top match

    Smolin points accurately to some of the real problems with the sociology of university life, and seems filled with scorn for those who think that nothing can be done about it.

    Search #1C: “Smolin” “Vituperation”; top match

    It seems to me that the RANCOROUS VITUPERATION is confined to the minor figures.

    I don’t see Smolin or Witten as rancorous squabblers at all, or David Gross…or JB for that matter. They all seem to be above the squabble.

    Smolin had some serious points about policy and science in general, which he made politely and respectfully (I thought)

    Now let’s try

    Search #2A: “Motl” “Insult”; top match (on this blog 9/11/2005)

    Happy birthday Peter. I’ve enjoyed reading your blog, with the exception of Motl’s insult-laden comments, and I look forward to buying a copy of your book when it comes out.

    Search #2B: “Motl” “Scorn”; first relevant (also on this blog)

    Now that it’s available again, the Rumor Mill has the striking news that Harvard has chosen for a faculty position one of its postdocs: Lubos Motl. Lubos is well-known as undoubtedly the most rabidly fanatic string theorist around, always willing to heap abuse and scorn on anyone who questions the idea that string theory is the language in which God wrote the world.

    Search #2C: “Motl” “Vituperation” ; find the same as with “Smolin” – then this:

    lubos motl has published is objections to loop quantum gravity which lee smolin responded to.

    what are some common objections to string theory, esp in NEW, what do string theorists think of these objections? lubos motl calls peter’s book crap, gives it 1 star on amazon. (then it got deleted).


    marcus08-27-2006, 04:30 PM
    what good does animosity and vituperation do?

    I don’t think it does much good.

    Need I say more?

  40. Aaron Bergman says:

    Say more? I have no idea what your point is. It’s certainly not relevant to mine.

  41. The man says:

    Perhaps a fitting cousin of string theory for which “not even wrong” also applies:


  42. Kris Krogh says:


    The point seems clear enough and Googling was your idea. What can you come up with?

  43. Aaron Bergman says:

    Chris asked why Smolin was objectionable and Lubos was not. Seems to me that that’s assuming facts not in evidence.

  44. Kris Krogh says:

    Hi Aaron,

    Maybe Google is attesting to some facts here.

  45. Kris Krogh says:

    Are you agreeing now that Smolin is not objectionable?

  46. mclaren says:

    Haven’t these people ever heard of Occam’s Razor? The claim that some fabulously elaborate conjecture which makes no testable falsifiable predictions is nonetheless verifiable because the simpler proven theory of physics (The Standard Model) to which it reduces in the limit is testable, is just breathtakingly ignorant and shockingly foolish.
    If we accepted this crackpot reasoning, then every crank conjecture without a shred of evidence would be considered “testable” because the standard physics on which the crazy conjecture gets piled (without a shred of evidence to justify it) is known to be testable.
    Ridiculous but obvious example: ESP is good solid science because it’s based on conjectured “ESP waves” (whose precise nature remains conveniently undefined — as undefined as the actual nature of the alleged strings in string “theory” ) which follow the familiar laws of physics, and since the familiar laws of physics are testable, ESP must be solid verifiable science too.
    Other examples of this gross abuse of Occam’s Razor in physics are so obvious it’s insulting even to discuss them, but since these Ivy League physicists seem to persist in this bizarrely defective reasoning, I guess someone has to point out the obvious.
    History is littered with elaborate conjectures that reduced to familiar solid physics in the limit, but which turned out to be unnecessary idle speculation. The most obvious example is the luminiferous aether. As late as 1925 reputable physicists were giving lectures abou “the crisis in the ether.” Experiments were being done to try to detect the ether as late as the mid-1920s. None succeeded in showing any evidence of the ether. That was the crisis. The solution to the crisis turned out to be simple — throw out the ether as an unnecessary conjecture. Use Occam’s Razor. Do not multiply superfluous entities. Problem solved.
    It’s getting unutterably wearisom to hear all this talk about string “theory.” It’s not a theory, people, it’s a conjecture _at best_. Let’s call it what it is: the String Conjecture. It’s not a theory since it hasn’t even advanced to that stage yet. It’s not even an hypothesis yet. It’s just people blwoing mathematical smoke up our asses.
    Moreover, the String Conjecture is a baseless conjecture. There’s not a single shred of evidence in all of physics for the conjecture that we live in a universe with more than 4 physical dimensions. There’s not the merest scintilla of evidence in the entire history fo physics that there exist any universes other than our own, let alone that multidimensional “branes” can come into contact with one another in 11 (or 26) dimensional space and set off Big-Bang-type events.
    There’s not the smallest tincture of evidence from any physics experiment ever done that ultra-tiny strings exist in 11 (or 26) dimensions and give rise to all the elementary particles with their vibrational modes.
    All this stuff is science fictional conjecture. There’s no evidence for any of it. The science ficitonal part isn’t fatal — after all, the notion that particles are also waves is science fictional conjecture, but that weird wave/particle duality conjecture was forced upon us by overwhelming masses of evidence. The string conjecture isn’t required by any evidence, it’s just some neat math. At this point, the string crowd will predictably point out there was no evidence for the neutrino when Fermi hypothesized it. But that analogy is fatally flawed. Fermi based his hypothesis on a rock-solid law of physics, the conservation of momentum. If we throw that out, we’re all in trouble. So a strange conjecture like the neutrino was preferable to the much more unpalatable conclusion that momentum conservation was violated. This is the same principle David Hume used in his reasoning. Choose the conclusion that requires the least miraculous operation of the universe, and you’re usually correct
    But unlike the case of the neutrino, no such rock solid principle of physics requires us to posit the string conjecture. 11-D strings are just idle speculation, with no hard evidence to back it up.
    Well, the problem is that ‘the public’ most often doesn’t understand that the theory is not made out of words but of equations.
    Once again, this string speculation is not a theory. It’s a conjecture. It’s a baseless conjecture, derived from no physical evidence, just math.
    Anyone can make a wild conjecture from elegant mathematics and then posit outlandish disconnected results. For example:
    “Green’s Theorem requires that we live in an 11-dimensional universe in which all elementary particles are made up of vibrating strings.” No it doesn’t. Green’s Theorem is just a set of equations, and they don’t require that strings or higher dimensions exist, they’re just empty mathematics which makes no predictions about observed reality.
    So how is that different from string “theory”? Like the vacuous nonsenical conjecture above, string ‘theory” doesn’t require that strings or higher dimensions actually exist, string “theory” only describes such hypothetical constructs IF THEY DO EXIST. Like my absurdly meaningless Green’s Theorem example, string “theory” makes no testable falsifiable predictions about observed reality. Like my ridiculous example involving Green’s Theorem, no basic physics requires us to make that conjecture.
    Really, too many supposedly educated physicsts suffer from a weirdly superstitious awe of mathematics. Just because you write down an equation, however elegant, doesn’t mean it has any necessary relationship with reality. The math can be true and beautiful and yet flagrantly contradict observed reality. The Banach-Tarski paradox is the most obvious example of beautiful and indisputably true mathematics which completely contradicts observed reality, but you find these kinds of weird results littered throughout mathematics. The kind of naive Platonism we get from the string conjecturists is just bizarre. Don’t any of these string people know that there exist other options beyond naive Platonism? Did John Dewey and David Hume not exist? Where were these people during Philosophy 101? Asleep?
    Wake up, people! There’s nothing magical about equations, they’re just mental models — not reality itself. Just because someone writes down a beautiful series of interlocking equations doesn’t mean they must be true. Keats’ claim “Truth is beauty and beauty truth, that is all ye know and all ye need to know” may sound passable for art or poetry, but it fails disastrously in science. A physics theory is NOT a set of equations, it’s a testable hypothesis with a rational mechanism behind it that happens to be embodied in equations. The equations are not always required for a theory to be solid science, as the second laws of thermodynamics demonstrates. That law of physics was valid for quite a long time before Boltzmann and later Maxwell put the second law of thermodynamics on a firm mathematical footing.

  47. Peter Woit says:


    You’ve already asked that off-topic question under another name and it has been discussed here. String theory is “not even wrong” as an idea about unification in physics, this has nothing to do with whether it is useful in mathematics or in other areas of physics.


    The comments here have gotten pretty much completely off-topic, not to mention not making much sense. If you have something substantive to say relevant to the posting, please do so, but otherwise please just stop it with the pointless argumentation, rants, etc.

  48. Eric Mayes says:

    Dear Mclaren,
    This are many compelling reasons for introducing strings and it is far from being ‘baseless conjecture’.

    This really sad thing about this debate is that there are so many ignorant people out there who are easily manipulated by these fallacious arguments. If we’re honest, you have to admit that what is being peddled is us-against-them -ism. In this picture, string theorist are elitists who live in their Ivy League ivory towers telling the common-folk who really no better what to believe, while the populist heroes Woit and Smolin are the defenders of rationally and common sense. The truth is that the serious people who are really doing physics will continue to study string theory because it offers the best chance to make progress, by far.

  49. Peter Woit says:


    In blog comment sections you’ll find some examples of uninformed populist nonsense, but neither Smolin nor I, with our Harvard and Princeton backgrounds are this kind of populist. I freely admit to a certain elitism, and work at an Ivy League institution (something there are problems with, but they don’t have to do with the level of science and math done here).

    My last comment trying to stop the flow of off-topic comments doesn’t have seem to have succeeded, so I’ll just start deleting such comments now. This may be elitist of me, but I’m not going to tolerate having the comment section here taken over by arguments so dumb that no informed person is going to read it or participate in it.

  50. Aaron Bergman says:

    Are you agreeing now that Smolin is not objectionable?


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