Is String Theory Testable? (Part II)

I recently noticed that, around the same time I was preparing my slides for a talk about Is String Theory Testable?, Michael Douglas was doing something similar, preparing a talk on Are There Testable Predictions of String Theory? There’s a certain amount of overlap in our presentations, and people might find it interesting to compare them.

Douglas goes over much the same story I do, but reaches different conclusions. For him, string theory does “make predictions”, just lots and lots of incompatible ones, so the problem is that:

none of the ideas which have been suggested so far are guaranteed signatures of string theory. We would be happier with one prediction, which could lead to a decisive answer either way.

This is the sort of thing I would call a prediction, so I guess we agree that they don’t exist. Douglas ends by noting that the one way he can think of to get such a prediction is through a statistical argument based on counting vacua and the dynamics of eternal inflation. He doesn’t mention the argument given in my talk that this is already falsified (by the lifetime of the proton), or that such arguments inherently lead to calculations that are inherently intractable and can never be done (this argument is due to him and Denef, it is surprising that he doesn’t mention it).

Along the way, Douglas does make a couple claims about things that he thinks the statistical anthropic landscape arguments disfavor, especially varying constants and large distance modifications to gravity. Seeing these would falsify our current theory, but would not falsify string theory, since it can accomodate them, although perhaps not within Douglas’s statistical framework.

One of the more surprising responses I’ve seen to my recent claims that string theory has failed as an idea about unification because it’s inherently untestable comes from Mark Srednicki, who writes (in the context of mentioning an MSNBC interview with Brian Greene):

We see that the big issue for Brian, and for just about all scientists (though with the apparent exceptions of Lee Smolin and Peter Woit), is what is TRUE. Not what corresponds to some philosophy of what science is or is not. Lee writes that the landscape must be rejected because “it would mean the end of our field” (page 165). It should be obvious that this is not the basis that is traditionally used for accepting or rejecting a theory! Peter’s (essentially the same) argument that string theory must be rejected because (at the moment) it does not appear to be sufficiently predictive (for Peter) is also irrelevant to the question of whether or not string theory is TRUE.

If the landscape is right, we may never get anything more than circumstantial evidence that it’s right. But that’s often the case in science. We’ve been spoiled in particle physics by having extremely precise data and highly predictive and quantitative theories for the past few decades. Most of the rest of science has not been so lucky. Perhaps we will not be so lucky going forward. The only way to find out is to do more work and see where it leads.

Srednicki’s reaction to the lack of testability of string theory seems to be that testability is not what matters. What matters is what is TRUE, and it’s perfectly logically consistent for string theory to be of such a nature that we can never test it. The problem with this point of view is that science is not so much about what is true as about how one knows what is true about the world. Religious believers are also interested in what is true and think they know what this is, but science is different since it provides a means for deciding what is true. Scientific ideas about the universe are true when they make predictions that can be checked in a convincing way. Ideas that can’t be experimentally checked in some way, directly or indirectly, may or may not be true, but they’re not scientific ideas, rather something of a different nature.

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51 Responses to Is String Theory Testable? (Part II)

  1. Tim says:


    “….. the one way ….. to get such a prediction is through …….. this is already falsified (by the lifetime of the proton)”

    Ooooops, did you just say that string theory has been falsified? Consider changing the title of the blog to “Wrong”.


  2. hack says:

    Srednicki is really making a fool of himself. History has not looked kindly on people who were sure they knew what was TRUE and didn’t see the need to prove it.

  3. Robert Musil says:

    Lee Smilin has posted a fairly extensive rebuttal to Srednicki, including to Srednicki’s (mis)use of the quote from Smolin’s book and Srednicki’s suggestion that scientific “TRUTH” can be divorced from falsifiable predictions – with most scientists favoring the divorce. Here:

    Some excerpts:

    “Dear Mark,

    “Your selective quotation of me badly misstates my position. Not only do I acknowledge that the landscape is a possibility, I invented the idea, named it and was the first to explore its consequences, in papers from 1992 on. My issue, since then has been how we can continue to make falsifiable predictions if the landscape is true. …. I hope my point of view is clear: the landscape may or may not be a real feature of string theory-evidence is that I was right and it is. But if it is we are not relieved of our obligation to test the theory by making falsifiable predictions for doable experiments. There is at least one scenario that stands both as an existence proof that this can be done and as a challenge to observers to falsify. Any newer proposal for doing physics on the landscape then has to do at least this well.



  4. tomj says:

    I thought I had included this quote on the previous thread on this subject, but it isn’t there. Probably too long?

    Anyway, from pg 22 of Albert Einstein’s _Relativity_:

    “We thus require a definition of simultaneity such that this
    definition supplies us with the method by means of which, in the present case, he can decide by experiment whether or not both the lightning strokes occurred simultaneously. As long as this requirement is not satisfied, I allow myself to be deceived as a physicist (and of course the same applies if I am not a physicist), when I imagine that I am able to attach a meaning to the statement of simultaneity. (I would ask the reader not to proceed farther until he is fully convinced on this point.)”

    My question is that in the case of String Theory, if there are definitions being used, do they satisfy the above requirement? Can String Theorists point to any concept they use, and words they use whose definition includes a method of deciding something significant?

  5. I agree completely that the debate isn’t about what is true so much as how physics is done. You emphasize the epistemological nature of science as a method of coming to knowledge about the world.

    There’s a parallel, altogether dirtier line, though: the debate is about what physics we will choose to fund. The danger isn’t that physics will wander in the Landscape with no guiding stars, it’s that we will spend all of our time (and money!) wandering while we could have spent it on other possible lines of research.

  6. Chris W. says:

    ..and of course the assertion of the Landscape’s existence must be TRUE, because its existence follows from principles that we know to be TRUE, right? Just as a reminder, what are those principles again? And how, again, are we to be assured of their truth, and know their proper application and interpretation?

  7. Chris Oakley says:

    In abandoning Occam’s Razor in favour of brand loyalty to a particular speculative idea Srednicki drives another nail into the coffin of Scientific Method. To take the most optimistic analogy, supposing that Newton had proposed Lorentz Contraction and Time Dilation in 1700. This would be “true”, or at least more true than the dynamics he actually did propose, but with what justification could anyone living then abandon commonsense notions of space and time if they are not presented with a compelling reason to do so?

  8. Peter Shor says:

    When Marc Sredinski writes

    If the landscape is right, we may never get anything more than circumstantial evidence that it’s right. But that’s often the case in science.

    what kind of science is he talking about? I wouldn’t think it could be any other kind of physics, chemistry, or biology – the fields commonly referred to as the hard sciences.

  9. Thomas Larsson says:

    I learned something new today from this comment of Mark Srednicki’s:

    “For example, the string picture of black hole evaporation requires huge violations of macroscopic causality;”

    Note the comment by “Elliot” a few lines below:

    “If string theory predicts violations of causality, I am not sure this is type of assertion that would lead many “string agnostics” (of which I count myself as a member) to readily adopt the faith. Of all the scientific principles, causality is in my mind one of the fundamental cornerstones. “

  10. Peter Shor says:

    Is there actually a string picture of evaporation of black holes? I have not found any discussion of string theory and the black hole information paradox which looked more concrete than unfounded speculation.

  11. Peter Orland says:

    I think people are getting off track here and criticizing Mark
    Snrednicki for something he didn’t say. He never said that the
    landscape or even string theory is true. He said that it is
    important to get at what is actually true. If you substitute
    the synonym adjective “factual” for the word “true” in his
    statement, perhaps, what he says seems less controversial.

    There are other issues raised by Mark’s remarks, such as making
    assertions about other Peter and Lee (which I disagree with), and
    how one gets to the facts or TRUTH (which is where issues of falsifiablity are important). He’s absolutely right, however, in that science is about understanding reality, not the scientific method.
    The method is only a method, not the goal – it is the proverbial
    finger pointing to the moon. There are no rules in science beyond finding out what is.

  12. TCO says:

    Why don’t the physicists figure out how to make a room temperature superconductor? And why (if they are so smart, and these problems so trivial) was High Tc found experimentally, rather than with theory or modeling?

  13. Peter Orland says:

    Sorry, misspelled Mark’s name above – Srednicki.

    Petre Drolan

  14. woit says:

    I don’t think I’m criticizing Srednicki unfairly. I reproduced here his argument pretty much completely, and in later comments on the same thread he says that he strongly disagrees with the statement that string theory needs to make falsifiable predictions.

    It’s kind of absurd that Srednicki is criticizing Smolin for having too rigid a view of science, since, if you read Smolin’s book, you’ll see that he sees himself in some degree as a follower of the philosopher of science Paul Feyerabend, famous for his “anarchistic” philosophy of science, that there is no fixed “scientific method”. Like Smolin I’ve also read Feyerabend and found myself in sympathy with this sort of idea. Sure, there is no fixed way to get to scientific truths, and all sorts of things should be tried. Personally, I’m partial to a semi-mystical belief that deep ideas about physics and about mathematics go together, so one should try and see if one can make progress in physics by concentrating on the deepest mathematical structures that seem to connect to physics. Other people have reasonable arguments about why this is a dumb idea that can’t work.

    In the end though, however one gets to it, the crucial thing about scientific truth is not that it is truth, but that the rules of logic together with experimental observation provide convincing evidence that it is truth, evidence that cannot be denied without violating logic or the evidence of one’s senses. The current situation, with people like Srednicki promoting the idea that the landscape doesn’t need to make predictions in order to become accepted as our dominant scientific theory of the physical world, is really dangerous to science, both internally and externally.

    The attitude of Srednicki and too many string theorists these days seems to be that it is all right if the theory turns out to be non-predictive, that what is important is that it “has won out in the marketplace of ideas”, i.e. achieved dominance in terms of things like NSF grants and faculty positions. The current situation is that he and others feel comfortable publicly jeering at those, like Smolin, who challenge this notion as “crackpots” (he has admitted to doing this).

    I don’t think this is about the landscape so much as it is about whether the conventional standard we insist on for recognizing a scientific truth will be upheld, or fall by the wayside because it requires some people to acknowledge failure. I disagree with Smolin about the landscape, but we agree about the crucial point: it has to make convincing, conventional scientific predictions, otherwise it’s not science.

  15. matteoeo says:

    Peter Orland,

    also bad science has no rules, beyond finding out what isn’t. So, how can you distinguish them? I guess you can’t or you know somebody upthere that tells you what TRUE is.

  16. Peter Orland says:


    I think you misread my message. I said nothing of the sort you
    impugn to me (no prophet or messiah I!). In particular, I don’t
    think I was defending what you regard as bad science, which I
    assume is the landscape (I also think the landscape is bad science).
    Your question as to how to distinguish good and bad science is an important one, but seems more like a peccadillo directed towards me than a serious remark. But go ahead and metaphorically scream at me some more, if you like. I’m not proud.


    As you know, I also don’t like the prevailing attitudes of string
    theorists. I was not agreeing with the purpose of any attack on
    you or Lee Smolin. I was just pointing out that one of Mark
    Srednicki’s points, which he was being criticized for here, was
    a valid one. I don’t think of scientific facts as TRUE in capital
    letters, nor do I think the term has much meaning these days.
    It has been abused by religionists beyond repair. In this I think Feyerabend (from whom I took a class at Berkeley) is absolutely right. Nor do I think ideas are scientific if they can’t be either verified or falsified.

  17. matteoeo says:

    Peter (Orland),

    believe me I’m not screaming at you. Maybe I’m mistaken, but then I don’t really understand sentences like “There are no rules in science beyond finding out what is.” What is what?

    I think just the opposite, that science (from latin cognosco = I know) is the colletion of facts you know because their existence respects a few rules that were formulated long before Feyerabend was born, and that in a way belong to the logic of smart people without necessarily being taught of, al least until they stick up with an obsessive idea and direspect their own logic (but this is normal, since it’s very hard to mantain a critical thinking just about anything. That’s why phylosophers needed to formulate the Scientific Method as a painful rule). Scientific facts are a representation and a modelling of “what is” but they’re not it – unless we embrace Pitagoreans’ idea that the world is numbers.

    I think it’s very important to distinguish “what is” from “what is knowable”. This is a problem that mathematicians were facing after Goedel’s theorem, and I think QG might encounter similar questions, indipendently of the approach – the AP in the Landscape is an example of that, of a strange and maybe circular overlap of thinking and meta-thinking. But that’s just a silly idea. Anyway something unknown (and unknowable, define it God or whatever) will always resist the attacks of scientists. Would you call that science?

    As to Feyerabend, he was a great “dadist” thinker, but I think that his ideas on imaginative and inductive thinking had such great resonance because for half a century almost any field in science improved in a seemingly very fanciful fashion (owing to the technology mostly, which did very quickly “selective pressure”, to use biological comparison à la Smolin).

    But now I think that String Theory failure is the demonstration that Feyerabend’s ideas are flawed. I almost regard him as (partly) responsible of all this. I know Popper isn’t as appealing, but he might end to be the only guy who really said something correct (besides the no-democracy-suicide statement).

    Hope to have convinced you I wasn’t just yelling.

  18. Peter Orland says:


    Now that you have stated your position in more detail, I
    see you have something interesting to say. Maybe you
    are right that today’s trends indicate that Paul Feyerabend’s
    ideas are flawed. I’ll have to think about it…

  19. Q says:

    Chris, Newton’s motto, “hypotheses non fingo” (feign no hypotheses), kept him safe. Newton worked from data to formulate checkable laws, something that’s fast becoming a heretical approach today, and is the opposite to string theory.

  20. Who says:

    But now I think that String Theory failure is the demonstration that Feyerabend’s ideas are flawed. I almost regard him as (partly) responsible of all this. I know Popper isn’t as appealing, but he might end to be the only guy who really said something correct (besides the no-democracy-suicide statement).

    What is the no-democracy statement. I did a search and came up with this quote of Popper:

    “Dictatorship is morally wrong because it condemns the citizens of the state—against their better judgement and against their moral convictions—to collaborate with evil if only through their silence… It transforms any attempt to assume one’s human responsibility into an attempted suicide.

  21. CD318 says:

    “I think people are getting off track here and criticizing Mark
    Snrednicki for something he didn’t say. He never said that the
    landscape or even string theory is true. He said that it is
    important to get at what is actually true.”

    Well, even that much is wildly off-base. Science does not lead us
    to truth. At best, science allows us to generate models that, to a
    greater or lesser extent, are consistent with observation and
    experiment and allow extrapolation to observations and
    experiments yet unmade.

    I wonder if Snrednicki has ever bothered to think with any
    seriousness at all about how one might define “truth.”

  22. matteoeo says:


    I think this is a little off-topic here. Anyway I coined the epression no-democracy-suicide to make it short. Popper wrote that in a democracy people cannot vote the end of the democratic regime itself, and for example the beginning of a dictatorship – it might sound obvious but it’s not, it’s based on a logic argument and it would be an interesting task to read modern Constitutions and actually see if there’s some explicit article about this (I know italian has). Very boring reading from Popper, but foundamental, The Open Society and its Enemies.

    As to QG and strings, I’d like to know if anyone has ever had the feeling I expressed, that there might be some foundamental inconsistency in unified theories, such as in mathematics Goedel’s theorem (and Chaitin’s reformulation), or if you think that there must be a theory, at all costs.

  23. A String Theorist says:

    Well we really have wandered off onto an epistemological tangent, haven’t we?

    One of the marvelous things about scientific progress is that our understanding of which questions admit scientific answers evolves over time.

    To use a somewhat tired, but very appropriate example: a long time ago there was interest in trying to derive the orbital radii of the planets from some fundamental principle.

    Happily we now understand that this particular question is one which science does not, and CANNOT answer. This is NOT a failure of science! In fact, it represents a great triumph of science—Newton’s UNIVERSAL law of gravitation. By giving up the hope for scientific answers to a few of the “old questions” about the particulars of our solar system, we gain in exchange the answer to infinitely many “new questions”—namely the dynamics of any gravitating system anywhere in the universe.

    Similarly, and this is the essence of Srednicki’s point: it is a logical possibility that, perhaps, there will NEVER be ANY scientific explanation for “why” the unbroken gauge group of the Standard model is what it is, or why the Yukawa couplings are what they are.

    You are still welcome to work on those problems—and if you find a solution, no doubt fame and fortune will certainly be yours! But, again, you must accept the *logical possibility* that no explanation exists.

    String theory finds itself in the awkward stage half way between realizing that the “old questions” that people used to be interested in, such as calculating the electron mass from first principle, are in fact unanswerable, and not yet being at the stage where we understand what the correct “new questions” are.

    Historically some of the most exciting and productive times in physics have occurred as similar “boundaries” between old and new understanding were crossed.

  24. matteoeo says:


    I’ve read my own post once again and I found that my bad english induced me to an error – I meant “including the no-democracy-suicide statement”, and not “besides”. Sorry for that.

  25. Peter Orland says:


    I have a feeling this is getting off-topic, so I
    won’t blame Peter W. for deleting my comments.
    I just can’t resist to responding to what you
    have said about “truth”. As I said above, the term
    has lost its meaning, but maybe we should try
    to restore that meaning.

    Outside of what anyone said, including Sredncki, Smolin
    or Woit, you have to be careful when you say science
    does not lead us to the truth.

    If “truth” is something absolute, then it’s a rotten useless
    string of letters. If instead by “truth”, you mean
    facts (which are not immutable, but can change)
    then there is no problem with the term. A model
    which works well in predicting data is true, even
    if it doesn’t give us the whole truth.

    Even a famous theorem could be untrue if the
    assumptions are found inconsistent, but I am willing
    to accept a theorem whose assumptions I accept
    and whose proof I understand as true. Most of us
    often use the word “true” in this sense (perhaps
    even you). Abuse of the term by religious types
    and even some scientists has led to our reluctance
    to use it. Perhaps we should try and reclaim the word
    from the abusers.

    No good scientist or mathematician is willing to take
    for granted that no ideas are right. Newtonian dynamics
    is right – so why can’t we say it’s true, under certain

    I think scientists should not feel uncomfortable with
    refering to scientific facts as true. Otherwise they
    play into the hands of those who equate science
    with religion or a only a cultural phenomenon.

    Anyway, I won’t say any more about this.

  26. Peter Woit says:

    A String Theorist,

    The problem with the string theory landscape is not that it can’t predict the electron mass, it’s that it can’t predict anything at all. Nothing. If it made even one convincing standard sort of scientific prediction (for instance, allowing calculation of some experimentally measurable number to better than 1%, a number not calculable in the standard model), then it would be science. But the evidence is pretty strong now that it can’t do that. What I find remarkable is the way many string theorists and string theory partisans are reacting to this rather conventional sort of failure (it’s not really unusual to find that one’s speculative idea doesn’t work because it doesn’t predict anything). Instead of admitting failure, they’re trying to change the rules of what science is. It’s pretty amazing to see Srednicki and others arguing that a theory that can’t be experimentally tested is a viable scientific theory.

    Sure, maybe Yukawa couplings are environmental and we’ll never be able to calculate them. But if you want to claim to be doing science, you have to come up with not just excuses, but some kind of predictions. What is going on now is that string theorists are turning Feynman’s criticism of them: “string theorists don’t make predictions, they make excuses” into a new philosophy of how to do science.

  27. matteoeo says:

    sorry Peters, I can’t resist being nasty:

    “Even a famous theorem could be untrue if the
    assumptions are found inconsistent”

    If the assumptions of a theorem are inconsistent (and thus the hypothesis is false), then the theorem is true (Ex Falso Quodlibet). The conclusion might eventually be wrong.

    Anyway you can’t just renormalize the meaning of words so as to be always in agreement with others. “Truth” as is meant by Srednicki is not “Facts”, otherwise we would be talking about SM (as does the string theorist) instead of strings. Scientific facts cannot change with time, their interpretation might.

  28. Peter Woit says:


    I didn’t say that science doesn’t lead us to truth. It certainly does, if there’s any meaning at all to the notion of a truth about the physical world (and I think there is). My point is just that what distinguishes science from other human activities is not that it makes claims about what is true, but that it provides a method to reliably discover truths. I find it amazing to see supposedly serious scientists suggesting abandoning this in the case of the string theory landscape.

    Religion also claims to lead to truths about the universe, and provides its own methods for getting there: consult the Bible, pay attention to what the pope says when he’s speaking ex cathedra, etc. I think it will be very sad if physicists abandon conventional ideas about the scientific method in order to prop up a failed research program.

  29. anon. says:

    ‘I think scientists should not feel uncomfortable with refering to scientific facts as true. Otherwise they play into the hands of those who equate science with religion or a only a cultural phenomenon.’ – Peter Orland

    But happens when there is a radical overhauling of a scientific theory? Examples:

    ‘Fifteenth century Europeans “knew” that the sky was made of closed concentric crystal spheres, rotating around a central earth and carrying the stars and planets. That “knowledge” structured everything they did and thought, because it told them the truth. Then Galileo’s telescope changed the truth.’

    – James Burke, ‘The day the universe changed’, Little, Brown and Company, Boston, 1986, p.9.

    Other examples of ‘false truth’ abound: vortex atoms were the truth to Kelvin, mechanical aether was the truth to Maxwell, phlogiston, caloric, cold fusion, UFOs, alien abduction, etc., are all truth to cult believers.

    The problem is that ‘true’ has always been emotional and hence poorly defined for science, yet well suited to religion. Critics of such ‘truth’ sound unreasonably, or immoral:

    ‘What is truth?’ – Pontius Pilate (Mark 15:2)

    Popularising string theorists make a vague appeal to being the truth without having to actually make any checkable prediction.

  30. Peter Orland says:

    Well I was sort of finished with this topic, but a lot of people are
    still respondingto my last comment, implying that I am defending
    or attacking things that I am not, respectively, defending or attacking. It’s very exasperating. I never said tentative theories (string theory or vortex theory included) should be considered true. I was just answering CD318’s comments above about the word “truth”.

    My last point was just this: are we forbidden from saying
    something is true? It all depends on what you mean by
    “true”. In common usage, the word just means factual.
    Most of us say it every day. Are any of you prepared never
    to use the word again in day-to-day life? If not, why can’t
    we use it as scientists? Just because some
    people (and not everybody) attach a lot of extra meaning to
    it doesn’t mean we should. In particular, I think the word
    needs to be rescued from those (perhaps some of the people
    writing here) who take it too seriously.

    Before responding to what you think I am saying, please
    read twice.

  31. Peter Orland says:

    By the way Peter, I never implied that you said science does not lead to
    the truth.

  32. dark-matter says:

    Come on guys. 21th century and here we are debating about ‘truth’. ‘Truth’ can be defined any way. There are hundreds of truths on any one thing. Science is about being ‘correct’ A theory confirmed by experiments is correct, yielding correct predictions, the basis of reliable knowledge that have built our modern society. They give Nobel prizes for a theory being correct, not being ‘true’. Leave the ‘truth’ stuffs to philosophers, theologians, etc.

  33. Chris W. says:

    The first sentence of a blog post by graduate student Jo Guldi:

    You might understand or not, but I write farce because I’m not convinced I have a handle, let alone a monopoly, on the truth.

    Somehow this seems apposite.

  34. Chris W. says:

    (PS: Note the name of this particular blog.)

  35. Peter Orland says:

    Dark-Matter, isn’t the conventional meaning of “true” in everyday
    usage is the same as “correct”? So why is one word better than the
    other? That is really all I am trying to say here.

  36. Arun says:

    Physics, then and now

    A quote from C.N.Yang, seen by chance, to contrast with the quote from Srednicki.

  37. Jean-Paul says:

    String Theorist — Your argument about planetary orbits is yet another propaganda trick pulled by AP desperados, that appears in the introduction part of all Arkani-Hamed talks (at least of those that I attended). Yes, we do not understand initial conditions for many motions in the Universe, and its not a big deal that we do not understand them for the solar system which is in our nearest proximity. However, you cannot compare this ignorance to our lack of understanding of say electron’s mass which is relevant not only in our proximity, but everywhere that we know in the Universe. If you want to consider the solar system at the same footing as the Universe, then you must subscribe to the multiverse faith which puts the solar system and the observed Universe at the same footing, as minuscule parts of a “bigger” story. Blah blah blah…

  38. Changcho says:

    Peter W. wrote: “The attitude of Srednicki and too many string theorists these days seems to be that it is all right if the theory turns out to be non-predictive, that what is important is that it “has won out in the marketplace of ideas”, i.e. achieved dominance in terms of things like NSF grants and faculty positions. The current situation is that he and others feel comfortable publicly jeering at those, like Smolin, who challenge this notion as “crackpots” (he has admitted to doing this).”

    This is also the viewpoint of people like LuMo. I agree that such a philosophy (if it can be called that) is a danger to science.

  39. King Ray says:

    String theory is no longer a science but a religion.

  40. mclaren says:

    Precisely. Once someone claims that what matters is not whether a claim is testable but whether it is true, we have passed out of science and into the realm of religion.

    Did Jesus rise from the dead after he was crucified?

    We can’t test that hypothesis — but what matters is not whether it’s testable, but whether it’s TRUE.

    Is Mohammed the one true Prophet of God, the only God, praise be to his Name?

    We can’t test that hypothesis — but after all what matters is not whether it’s testable, but whether it’s TRUE.

    Is the Buddha the one Englihgtened one?

    We can’t test that hypothesis — but what counts is not whether it’s testable, but whether it’s TRUE.

    This is the kind of self-deluded attitude that led people commandeer a pair of 757s and steer them into the twin towers. Thank you, but I’ve had quite enough of that kind of mindset.

    If a claim is true, provide evidence for it. Otherwise, shut up.

  41. dan says:

    Hey Peter,
    Since Lubos deletes your comments, have you considered debating it out over at

    “On the other hand, people like smolin and woit – especially woit – lost their battle in the arena of science long ago and are now trying to win it in the court of public opinion. Their books and comments are clearly meant for lay people who can be easily convinced of anything so that even if they prevail here – and it really doesn`t matter for research in quantum gravity either way – the victory would be a Pyrrhic one at best. Since they`re both no doubt already aware of this, one must wonder why they pour so much of their energy into this campaign of manipulation and misinformation.”

  42. tomj says:

    “Precisely. Once someone claims that what matters is not whether a claim is testable but whether it is true, we have passed out of science and into the realm of religion.”

    This is a common theme, very understandable. But an interesting thing is that the religions that I am familiar with make lots of statements (similar to scientific principles) which can be applied to actual situations. The results can be judged, and the principle can be upheld or diminished. This process is not entirely personal, and therefore has some potential to be scientific. But religions have many facts which can never be verified. Maybe because they are singular events which occurred long ago.

    From what I understand, in string theory there are no verifiable facts, at all.

    Religion is already about something, maybe wrong, maybe mixed with unverifiable facts, but in general there is some useful advice, verifiable without the need to believe something you cannot test.

    But equating string theory as it is being describe with religion, is quite the compliment for string theory.

  43. Peter Woit says:


    There’s a limit to how much time I want to spend debating these topics. That’s one reason I wrote the book, to get the case I wanted to make written down in one place. People can read it and judge for themselves.
    While lots of string theory partisans are announcing they refuse to read it, quite a few physicists and mathematicians have, and I’ve been pleased with the response. String theorists were going on a lot at one point about how there was no longer an argument, since their theory had triumphed in the “marketplace of ideas”. Now that it’s not doing so well there, you hear this argument a lot less….

  44. dan says:

    Well thanks Peter,

    Have you considered publishing technical articles in HEP/ARXIV critiquing string theory results such as string theory’s derivation of BH entropy?


  45. Peter Woit says:


    Lee Smolin has already done precisely what you suggest. As far as I can tell, his paper doing this (hep-th/0303185) has pretty much been ignored, especially by string theorists. I’m not so interested in quantum gravity, but have thought of writing up the arguments in my lectures in Italy in a more formal way to post on the arXiv. I suspect they would be ignored just as much in that form as in any other, which is an argument for spending my time writing up not that, but other things.

  46. Aaron Bergman says:

    Ignored? Say, rather, disagreed with, for reasons I’m sure you don’t want to hear yet again.

  47. Thomas Larsson says:

    math-ph/0603024 more or less disproves string theory. Therein I make the simple observation that the Laurent or Fourier polynomial version of an algebra of gauge transformations is incompatible with nonzero charge unless there is an anomaly. Since nonzero charge evidently exists, and the relevant gauge anomalies in 4D do not exist in string theory, the latter is wrong.

    E.g., for conformal symmetry the argument is simply this. If the charge L_0 != 0, then all L_m != 0, because
    [L_m, L_-m] = 2m L_0.
    Hence nonzero charge implies that there is no “local” part of the gauge algebra which is represented trivially, and unitarity then requires an anomaly. But this argument applies equally well to other gauge symmetries, provided that we consider the Laurent polynomial version of the gauge algebra.

    AFAIK, this argument has never been disagreed with, only ignored.

  48. John says:

    “If it made even one convincing standard sort of scientific prediction (for instance, allowing calculation of some experimentally measurable number to better than 1%, a number not calculable in the standard model), then it would be science.”

    String Theory is Mathematics. Are u saying Mathematics isnt a science?Truth in science HAS to be mathematically consistent. String Theory maybe viewed as some mathematical religion but at least it satifies the law: Thou shall be mathematically consistent. (Unlike pretty much all the other theories proposed).

  49. anon. says:

    “Truth in science HAS to be mathematically consistent.” – John

    You’re not even wrong! See

    “The shell game that we play … is technically called ‘renormalization’. But no matter how clever the word, it is still what I would call a dippy process! Having to resort to such hocus-pocus has prevented us from proving that the theory of quantum electrodynamics is mathematically self-consistent. It’s surprising that the theory still hasn’t been proved self-consistent one way or the other by now; I suspect that renormalization is not mathematically legitimate.”

    – Richard Feynman, Nobel laureate 1965 (quote from Feynman’s book, QED).

    “[Renormalization is] just a stop-gap procedure. There must be some fundamental change in our ideas, probably a change just as fundamental as the passage from Bohr’s orbit theory to quantum mechanics. When you get a number turning out to be infinite which ought to be finite, you should admit that there is something wrong with your equations, and not hope that you can get a good theory just by doctoring up that number.”

    – Paul Dirac, Nobel laureate 1933

    Mathematics is used in science as a tool and language for patterns and quantities.

    If a mathematical model for physical phenomena were completely scientific and consistent, it would be the end of scientific research!

  50. Peter Woit says:


    “String theory” (interpreting those words to mean the version of the theory that tries to unify physics) is not mathematically consistent. It has no non-perturbative definition that works, the perturbative definition is based on a divergent series. There’s a conjecture that a mathematically consistent definition exists for which the perturbative definition is an asymptotic series, but no one knows whether this conjecture is true.

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