Susskind Interview at New Scientist

There’s an interview with Susskind in the latest issue of New Scientist by Amanda Gefter, entitled Is String Theory in Trouble? Susskind makes many of the same points as in his recent book The Cosmic Landscape: mixing up positivism and falsifiability, attacking those who ask for falsifiable predictions as “Popperazi”, and saying that the best he can come up with as a prediction from his ideas is the very long-shot that the negative curvature of space due to its origin in bubble nucleation has not been made vanishingly small by inflation.

There’s a discussion forum about the article on the New Scientist site that people might want to contribute to.

Update: Ken Silber writes in to point out that William Dembski, one of the most prominent Intelligent Design ideologues, has now latched on to the string theory controversy as evidence that mainstream science is no better than ID. Dembski has both comments on Susskind and comments on David Gross’s admission that string theory is in trouble.

I’ve been pointing out to string theory partisans for a while that they need to publicly confront Susskind and his followers over their abandonment of the scientific method, otherwise they will have no argument against Intelligent Design. Susskind is making all this much worse with his dismissive comments about the falsifiability of evolutionary theory, as well as the following from the New Scientist interview:

If, for some unforeseen reason, the landscape turns out to be inconsistent – maybe for mathematical reasons, or because it disagrees with observation – I am pretty sure that physicists will go on searching for natural explanations of the world. But I have to say that if that happens, as things stand now we will be in a very awkward position. Without any explanation of nature’s fine-tunings we will be hard pressed to answer the ID critics. One might argue that the hope that a mathematically unique solution will emerge is as faith-based as ID.

Update: Susskind is fast becoming the darling of the IDers. A new posting on the web-site “Intelligent Design the Future” run by the Discovery Institute links to a review by IDer and nuclear physicist David Heddle entitled Susskind’s Sophie’s Choice.

Heddle concludes:

Susskind has presented the physics community with what is, for some (not this writer), a Sophie’s Choice: a hidious, complictated, unfalsifiable String-Theory Landscape, or Intelligent Design.

Susskind rocks.

This entry was posted in Uncategorized. Bookmark the permalink.

39 Responses to Susskind Interview at New Scientist

  1. Pingback: Susskind interview | Cosmic Variance

  2. Dissident says:

    So New Scientist has this moderated “discussion forum” with an invitation to post and highly visible links leading to it both from here and from Cosmic Variance. As I write this there are 127 views, a handful of negative comments in the Cosmic Variance thread – and 0 (that’s zero) posted comments in the “discussion forum”. Shall we guess that they are waiting for a few positive responses for balance? ;)

  3. Tony Smith says:

    In the New Scientist interview, Susskind says: “… Even most of the hard-core adherents to the uniqueness view admit that it looks bad. …”.

    If Susskind is restricting his universe of “adherents” to superstringers, then indeed the difficulty of superstring theory in predicting anything does make it look bad for uniqueness emerging from superstring theory.

    However, the fact that the basic structure of gravity plus the minimal non-supersymmetric standard model is so good at explaining experimental results, even though it is a remarkably restrictive and predictive structure that permits only SU(3) color, SU(2) weak, and U(1) electomagnetic forces along with gravity, and permits only 3 generations of leptons and quarks with clearly defined charges and helicity,
    seems to me to be an indicator that nature IS probably aligned with a unique model,
    even though it is becoming increasingly clear that superstring theory will not be the way to get to it.

    Just because there is now no widely accepted unique model that specifies all the observed force strengths, particle masses, etc, does not mean that such a model does not exist (it might even turn out to be a lot like my currently-much-ignored model).

    In short, it seems to me that, although Susskind’s remark that things look bad for the uniqueness view does apply to superstring theory,
    it does not apply to other approaches based on gravity plus the standard model.

    That, in turn, indicates to me that physics would be advanced if some of the army of people and flood of funding now being spent on superstrings were to be applied to such other approaches.
    Failure of the physics community to make such changes indicates to me a failure of imagination, and fear of trying to think creatively and deeply about gravity plus the standard model, on the part of the people in the now-dominant superstring community.
    Perhaps the leaders of the superstring community actually fear the possibility that an unconventional approach might be successful, because it would disrupt the current rigid sociopolitical “pecking order” of the present superstring establishment.

    Tony Smith
    http://www.valdostamuseum.org/hamsmith/

  4. nitin says:

    “We can hope to get an answer from string theory and we can hope to get some information from cosmology.” Surely Susskind is a bit misled here in his beliefs. A possible answer would naturally come from (observational) cosmology and hopefully some information from string theory (which is, so far as the theory presents itself, rather unlikely)!

  5. secret milkshake says:

    “Ask not what you can do in Physics – ask what you can do to it.”

  6. If the criteria for publishing in a high-impact journal, e.g., the Physical Review Letters, is taken at face value, for instance (see the guidelines in their site):

    “(…) The paper must satisfy criteria of validity, importance, and broad interest. The work must be sound, free of detectable error, and presented in reasonable detail. (…) Papers advancing new theoretical views on fundamental principles or theories must contain convincing arguments that the new predictions and interpretations are distinguishable from existing knowledge, at least in principle, and do not contradict established experimental results. (…)”

    (my boldface) then how anything related to the anthropic reasoning or the landscape issue can be possibly accepted there? I didin´t search to see. But of course, it seems clear that it depends on how “convincing” your arguments are.

  7. Juan R. says:

    String theory always was in trouble. Is cosmological constant explained via graviton mass?

    The problem of string theory is NOT that it ‘predicts’ multiple universes and, therefore, one may use previous knowledge for fixing undetermined parameters of the theory (more than 10000 in some models of compactification 10D –> 4Dx6D). The serious problem of string theory is that none of those ‘billions’ of possible universes coincides with real universe we observe on Nature. For example, string theory works with supersymmetric massless states, whereas our observed universe is non-supersymmetric and non-massless. Imagine that we observe supersymmetric at next HLC data. It does not mean that string theory is correct, because any plausible theory of supersymmetry (if finally observed) may reduce to the experimentally verified non- supersymmetric theory we name the Standard Model, somewhat as general relativity reduces to special one when gravitation vanishes. Simply we may admit string theory is incompatible with all data we know. In fact, there is a joke circulating by the Internet saying that the best definition of observable universe is “that string theory cannot explain”.

    What was the main motivation for string theory in the past? Simple: that “it predicts gravity“. Well again this is not correct, the ‘gravity’ contained in string theory is not Newtonian gravity not relativistic gravity.

    Newtonian gravity describes direct interactions between non-massless particles, but current string theory spectra are massless states and there are not electrons or protons defined. Precisely, since the graviton is massless, it can be defined in string theory. However, if finally the graviton has some mass as some theorists recently argue [see for example Class. Quantum Grav. 20 No 6 (2003) L67-L73 or recent 2004 talk by Vainshtein here] then string theory could not explain it.

    What is more, the relativistic gravity contained in string theory is a 2-spin graviton over a flat background metric. That is not general relativity, as explained in textbooks on matter, and the reason that all of us know that 10D string theory -even if some day was internally consistent and compatible with experimental data- would be improved by its background-independent 11D generalization currently called M-theory.

    Many other criticism on why string theory is not good enough is addressed in moderated newsgroup sci.physics.strings in the Oct 21 post “String theory is not a TOE”

    Juan R.

    Center for CANONICAL |SCIENCE)

  8. Dissident says:

    Juan: http://arxiv.org/abs/hep-th/0512177

    The problem isn’t that string theory can’t produce something that looks like our universe. It’s that it can produce just about anything you want, so it doesn’t predict anything.

  9. Juan R. says:

    Christine Dantas,

    perhaps this link to recent work published in PRL by string theorists Karch and Randall, may be interesting.

    I do not read the letter, but it appears that they are doing ‘convincing’ arguments :-) seeing i am finding on the net

    They believe the way our universe started and then diluted as it expanded what they call the relaxation principle favored formation of three− and seven−dimensional realities. The one we happen to experience has three dimensions.

    The only assumptions were that it started with a generally smooth configuration, with numerous structures called membranes, or “branes” that existed in various spatial dimensions from one to nine, all of them large and none curled up.

    Other realities, either three− or seven−dimensional, could be hidden from our perception in the universe, Karch said.

    “There are regions that feel 3D. There are regions that feel 5D. There are regions that feel 9D. These extra dimensions are infinitely large. We just happen to be in a place that feels 3D to us,” he said.

    “We know there are people in our three−brane existence. In this case we will assume there are people somewhere
    nearby in a seven−brane existence. The people in the three−brane would have a far more interesting world, with
    more complex structures,” Karch said. With gravity diminishing rapidly with distance, a seven−dimensional
    existence would not have planets with stable orbits around their sun, Karch said.

    “I am not precisely sure what a universe with such a short−range gravity would look like, mostly because it is
    always difficult to imagine how life would develop under completely different circumstances,” he said. “But in
    any case, planetary systems as we know them wouldn´t form. The possibility of stable orbits is what makes the
    three−dimensional world more interesting.”

    AMEN

    I only wait that Kaku can someday built a multidimensional teletransporter and all those ‘stringy guys’ can travel to other parallel universe full of nine-branes.

    Juan R.

    Center for CANONICAL |SCIENCE)

  10. Juan R. says:

    Dissident,

    thanks by the link to the recent preprint. But please note that does not invalidate i said. Perhaps, i would resume and emphasize i said:

    1) String theory cannot predict.

    2) There is not model in string theory compatible with the experimentally verified non-supersymmetric and non-massless Standard model of particle physics.

    3) The ‘gravity’ contained in string theory is not Newtonian gravity and is not compatible with relativistic (general relativity) gravity.

    4) brane, stwing, or M theories does not solve the problems opened by string theory.

    Juan R.

    Center for CANONICAL |SCIENCE)

  11. Dissident says:

    Juan: Agree about (1). About (2): the MSSM is an extension of the SM compatible with current experimental data. The LHC may be able to rule it out, but that’s yet to come. About (3): any quantum theory of gravity will deviate from the classical theory at some point (or what would be the point of quantizing it?). Agree about (4).

  12. Jean-Paul says:

    I think that there is a large social/psychological component of the recent anthropic endorsements. There are made by senior, very accomplished physicists who are at the end of their productive lives (or like Polchinski ready for early retirement at 55) and want to ride away into the sunset with “this is the end, my friend” — nothing left to do, we solved all important problems, we won’t miss anything. It is very sad that among younger generation, only Lubos dares to scream foul play…. while the more distinguished people like Vafa and Witten who are clearly opposed to this nonsense hide their heads in the sand instead of energizing their junior colleagues…

  13. Ken Silber says:

    William Dembski has now latched on to Susskind’s landscape-intelligent design dichotomy.

    http://www.uncommondescent.com/index.php/archives/583#more-583

    But shouldn’t life evolve easily in a “fine tuned” universe?

  14. woit says:

    Hi Ken,

    Thanks for pointing that out. Dembski has definitely latched on to string theory, also see:

    http://www.uncommondescent.com/index.php/archives/570

  15. Who says:

    Peter quoted Susskind as follows:
    **Without any explanation of nature’s fine-tunings we will be hard pressed to answer the ID critics. One might argue that the hope that a mathematically unique solution will emerge is as faith-based as ID.**

    this “hope” is a straw-man. the mainstream scientific enterprise exhibits confidence in the gradual INCREMENTAL explanation of nature—not in the appearance of a complete “mathematically unique solution” explaining everything once and for all. Moreover this confidence is not analogous to religious faith, but has been born out by gradual progress over the course of several centuries and many generations. It is the fruit of long experience.

    At least for physicists, the string venture may have been a mistake, and its present quandary should not be interpreted as a portent of anything. One cannot draw wider conclusions from the confused frustration of this one theoretical initiative—-it does not mean anything as regards intelligent design, or the determination of several dozen fundamental numbers, or the cause of the big bang or the fate of science. If string thinking fails to explain the current list of basic numbers, it simply means that a large bunch of theoreticians were misled, perhaps self-deluded, for several decades—this is no reason to start imagining a “sea-change” in the “zeitgeist” (that is portentous over-dramatizing). String is just a hiccup in the history of science.

    Susskind’s phrase “without any explanation of nature’s fine-tunings” is also a straw man—at least a rhetorical exaggeration. We have explanation for SOME of nature’s fine tunings, and can reasonably expect to get more. I mean real physical explanation, not anthropic selection from a postulated ensemble based on stringy conjecture.

    the the Old Guard show is increasingly embarrassing, I’m disappointed with Wilczek—expected better.

  16. David Heddle says:

    That’s “Heddle” not “Weddle”.

  17. Juan R. says:

    Dissident said,

    Juan: Agree about (1). About (2): the MSSM is an extension of the SM compatible with current experimental data. The LHC may be able to rule it out, but that’s yet to come. About (3): any quantum theory of gravity will deviate from the classical theory at some point (or what would be the point of quantizing it?). Agree about (4).

    Thanks by your comment. Unfortunately i was not able to express my thinking correctly and i may correct one thing.

    Of course, any quantum theory will deviate from the classical one (in the contrary case its quantization would be irrelevant) but i was not saying that. i was saying that the classical limit of superstring theory is not general relativity. I mean that gravity contained in strings and superstrings is a quantum spin-2 (graviton) in a flat classical background defining causality structure (e.g. S-matrix). The classical limit looks as a classical gravitational ‘field’ propagating on a flat background. But general relativity is not that (in general), and this is the reason that superstring theorists are now anxiously searching a background free generalization called M-theory. Precisely the perturbation formalism around a flat spacetime metric structure has been always the criticism of loop theoreticians to string/superstring theories.

    In fact, i think that it is a common misconception the claim that general relativity is equivalent to a theory for a spin-2 field on a Minkowski background.

    g^{ik} = \eta^{ik} + h^{ik}

    I think that this error was perpetuated in literature ‘thanks to’ Misner, Thorne, Wheeler 1977 popular book and by some popular authors as Feynman or Weinberg.

    The equivalence between full general relativity and a h^{ik} field theory is valid only in the weak regime, in fact, Deser [Gen. Rel. Grav. 1970, 1, 9.] proved the equivalence between the ‘geometric’ and the ‘ tensor field’ view only to third order in the tensor field recurrence series. But this did that some authors claimed that the two views are fully equivalent to any order when are not. In fact, there is crucial differences in the strong gravity regime between both approaches.

    Juan R.

    Center for CANONICAL |SCIENCE)

  18. blank says:

    I’ve always thought it was only a matter of time until the IDers latched on to Susskind. In fact I’m surprised it took them so long. He actually had to go so far as to publish a popular book with “intelligent design” written on the cover to get their attention.

  19. woit says:

    David,

    Sorry about that. It’s fixed now.

  20. woit says:

    Juan,

    Please stop posting so many comments that don’t have anything to do with the topic of the posting. In this case, if people want to discuss the interview with Susskind, that’s great, but the question of the technical problems of string theory as a theory of gravity is off-topic here.

  21. Hans de Vries says:

    Of all contradictions I’ve never come upon a greater contradiction as this one:
    -
    Firstly:

    The idea that constants of nature, reproducible in 15 digits, going to 16 digits (Frequency Comb work) are represented by 500+ hole clonable Calabi Yau pretzels. (16 digits means an object the size of the earth accurately reproduced with single atom precision)
    -
    Secondly:

    That these Calabi Yau spaces live at Planck’s length in a wildly bubbling space-time chaos at Planck’s temperature of 1.417 10^32 degrees…

    -
    Total chaos meets total perfection….

    -
    Regards, Hans

  22. Eric Dennis says:

    It’s important to keep in mind that rejecting anthropic reasoning in the context of the landscape and string theory does not imply a rejection of anthropic reasoning as such. Given apparently fine-tuned aspects of nature, anthropicism is certainly a legitimate sort of explanation if the necessary ensemble emerges naturally. The problem is just when anthropic reasoning becomes the *pervasive* explanatory mechanism of a theory, leaving it without any distinguishing quantitative predictions.

    In the context of a healthier theory, I don’t see the problem with e.g. the anthropic prediction for bounds on the CC, which I think Peter has criticized (but perhaps I misunderstood his intent). Indeed I think an unwillingness to accept this kind of limited anthropism is rooted in the same epistemic error of the IDers. Limited anthropism recognizes that Nature is just the way She is — She isn’t designed so that our theories will be pretty and convenient and maximally deductive — just like She isn’t designed so that Jesus could die for our sins. She just plain isn’t designed.

  23. Peter says:

    No time for a long answer, but here’s a short one:

    A legitimate scientific theory has to make strong enough predictions that you can rationally decide whether there is good evidence for it by looking at the world. The string theory anthropic landscape doesn’t do this now and there’s no good reason to believe it ever can, so it’s not science.

    One can come up with legitimate scientific theories in which certain quantities are only probabilistically determined, e.g. because they are “environmental”, depending on the history of the universe and one doesn’t accurately know the initial state. It’s certainly possible the CC is such a quantity, but there are lots of problems with the Weinberg “prediction” of it, including:

    1. It comes out an order of magnitude or so too high.

    2. It’s done by taking known values of other similar cosmological parameters, fixing them and just varying the CC. Looking at the joint distribution for several variables, the CC is way, way smaller than one expects.

    There’s also a conceptual problem that bothers me with this specific piece of anthropic reasoning. The assumed a priori probability distribution for the CC is taken to be flat. Such a “theory” of the CC says about it exactly the same thing as my favorite theory: “Hell, I have no idea what determines the CC, so, a priori any
    value is equally likely.” There’s something funny about a “theory” that makes exactly the same “predictions” as deciding that anything is equally likely since you have no idea what is going on.

  24. michaeld says:

    Susskind’s comments strike me as very strange.

    “But I have to say that if that happens, as things stand now we will be in a very awkward position. Without any explanation of nature’s fine-tunings we will be hard pressed to answer the ID critics.”

    It sounds as if he thinks physicists should be opposing ID just for the sake of it. To me, the reason to oppose ID is that the (scientific) arguments for ID are completely ridiculous. If that ever changed… if it happened that there were strong scientfic arguments for ID, then why should physicists be influenced by this and alter their theories simply for the sake of remaining in opposition to ID?

  25. anon says:

    Michael,

    the reason to oppose something just for the sake of it is to blend into the mob. Susskind months ago was quoted on the issue of the reality of the casimir force as saying the problem should be solved simply by banning physicists from using the word “real”.

    It is just fashionable to sneer at laymen and reality by coming up with speculative 11 dimensional super duper theories which are so value that there are 10^500 different dynamical interpretations, and which predict nothing, and are untestable. Different versions of string theory produce different predictions naturally, so there is no clear prediction to be tested by experiment. That is in fashion.

    String theorists have no grasp of science, and think the reason ID is a scientific failure is because it is unpopular in science, and the reason string theory is a success is that it is popular in the media.

    String theory is lucid. Everyone knows what it claims: everything is string. They also know it is popular, so you get the herd instinct … so many people can’t all be wrong, that sort of thing.

    String theorists can’t afford to use scientific criteria or they’d sink.

  26. Juan R. says:

    Peter Woit,

    I am sorry, often i write in a random manner and click the submit bottom too easily. Please receive my congratulations about your blog. Let me write some few comments about New Scientist interview Is string theory in trouble?

    i)
    The first i want say is that recent Landscape trouble has emphasized the problems of string theory. I have noted in many magazines, media and talks this 2005 the emphasis to claim that string theory is in trouble. It appears that all was fantastic in previous years but we know that is not true: as said above String theory always was in trouble and i think that people may know this. Therefore, i would personally rename New Scientist title to Is today string theory more in trouble that yesterday or similar one.

    ii)
    I leave criticism to inflation for other thread.

    iii)
    About cosmological constant, we already discuss about anthropic reasoning and Weinberg last preprint (or would say last nonsense?) here. One of arguments of anthropic symphatizers is that experimental value for the cosmological constant cannot be explained by usual Standard Model more GR, therefore our best option -they claim- is Landscape. However, that is not true and this is reason i cited above some works where the cosmological constant is computed scientifically from hypotesis of a small mass for the graviton. I repeat again, by no means the Landscape argument is the only possible way to explain cosmological constant. In fact, Landscape way is not a scientific explanation, just metaphysics one.

    iv)
    About Steven Weinberg recently comment that Landscape is one of the great changes in fundamental science because changes the nature of science itself. I think that Weinberg has definitively lost the North. Landscape is just a return to so-called magic era before modern science born. The only “radical” that i can see is “to call that science”, when we could call it “proto-science”, “meta-science”, “no-science” or similar. Weinberg attitude is so stupid (and i am sorry by the word) as if your cat does not look like a dog and then Weinberg argues that one may change the traditional definition of dog! If string theory does not fit science requirements, then call to string theory “no-science” or “meta-science” but never change the traditional mean of the word “science” for fitting string requirements.

    v)
    About last Susskind comment

    it seems increasingly likely that the constants of nature are more like the temperature of the Earth – properties of our local environment that vary from place to place. Like the temperature, many of the constants have to be just so if intelligent life is to exist. So we live where life is possible.

    I believe it is an excellent way to illustrate anthropic nonsense.

    Simply compare replies to scientific questions how “estimate the temperature here”, “compute the temperature when”, “draw the temperature profile for” using equations and the model-data from scientific literature [see Thermodynamics of Atmospheres and Oceans basic monograph] with fact anthropic theorists cannot compute anything and their “explanation” looks like

    the temperature have to be just so if intelligent life is to exist.

    It is more, what if there is not life? Curiously the scientific models presented in above monograph can be applied (changing parameters of course, for example to flow radiation received from Sun due to different distance, etc.) to other planets where is not life. See Chapter 14.

    vi)
    Let me finalize saying that Susskind comment

    No more than when physicists discovered that the radii of planetary orbits were not determined by some elegant mathematical equation, or by Kepler’s idea of nested Platonic solid.

    Is not accurate since it appears that radii is determined. I have seen scientific models on that.

    There is a philosophical objection called Popperism that people raise against the landscape idea. Popperism [after the philosopher Karl Popper] is the assertion that a scientific hypothesis has to be falsifiable, otherwise it’s just metaphysics. Other worlds, alternative universes, things we can’t see because they are beyond horizons, are in principle unfalsifiable and therefore metaphysical – that’s the objection. But the belief that the universe beyond our causal horizon is homogeneous is just as speculative and just as susceptible to the Popperazzi.

    Of course! but Susskind perhaps forgets that serious scientists carefully invented the term observable universe for referring to the part of the universe accessible to our current telescopes. No serious scientists claim what there exists beyond is today observable: perhaps pink stars? Nobody knows.

    Susskind reply to question “Is it possible to test the landscape idea through observation?”

    So the landscape, at least in principle, is testable.

    is, of course, incorrect.

    Juan R.

    Center for CANONICAL |SCIENCE)

  27. ks says:

    Michael says: It sounds as if he thinks physicists should be opposing ID just for the sake of it.

    But it is striking that some of Susskinds arguments are mimicking the structure of the conventional ID/creationist ones.

    From the Susskind interview:

    At first, string theorists thought there were about a million solutions [for string vacua]. Thinking about Weinberg’s argument and about the non-zero cosmological constant, I used to go around asking my mathematician friends: are you sure it’s only a million? They all assured me it was the best bet.

    But a million is not enough for anthropic explanations – the chances of one of the universes being suitable for life are still too small.

    Religion is not the only way of reasoning that creates “gap gods” these days.

  28. Tony Smith says:

    Susskind’s book “The Cosmic Landscape” is reviewed by George Ellis in Nature (8 December 2005, pages 739-740. The review is titled

    “Physics ain’t what it used to be”.

    In that review, Ellis says: “… The particular multiverse version proposed by Susskind, however, has the great virtue of being testable in one respect.
    It is supposed to have started out by quantum tunnelling, resulting in a spatially homogeneous and isotropic universe with negative spatial curvature, and hence with a total density parameter OMEGA_o less than 1.
    The best observationally determined value for this parameter, taking all data into account,
    is OMEGA_o = 1.02 plus or minus 0.02.
    Taken at face value, this seems to contradict the proposed theory. … These data are not discussed in the book – a symptom of some present-day cosmology, where faith in theory tends to trump evidence.
    Presumably the hope is that this observational result will go away …”.

    Tony Smith
    http://www.valdostamuseum.org/hamsmith/

  29. Chris Oakley says:

    [Re: String theory] About Steven Weinberg’s recent comment that the Landscape is one of the great changes in fundamental science because it changes the nature of science itself:
    I think that Weinberg has definitely lost his bearings. This is just a return to the so-called magic era before modern science was born.
    The only “radical” that I see is calling it science, when we should be calling it “proto-science”, “meta-science”, “no-science” or similar.
    Weinberg’s attitude is so stupid (and I am sorry to use this word) that if your cat does not look like a dog then Weinberg would argue that one needs to change the traditional definition of “dog”!
    If string theory does not fit the requirements of science, then we should call string theory “no-science” or “meta-science”. But we should never change the traditional meaning of the word “science” just to accommodate string theory.

    Sorry, Juan R. I don’t normally go around correcting people’s English, but what you say here is so sensible that I felt compelled to do so in this case.

  30. Juan R. says:

    Absolutely no problem with that!

    Anyone is free for correcting all my failures from English to math.

    Juan R.

    Center for CANONICAL |SCIENCE)

  31. Eric Dennis says:

    Peter,

    OK, I think we agree on the underlying issue then — the potential legitimacy of some kind of anthropic argument in the context of some independently confirmed theoretical framework. Your point about what happens for the specific case of the CC when you look at the joint distribution given other variables sounds reasonable (if that’s in fact the case — I’m not familiar with the nitty gritty here).

    But I don’t understand your other objections. It’s a bound obtained by imposing some galactic nucleation constraint, right? The “prediction” is just that the bound is satisfied, not that it’s the most informative conceivable bound. About the flatness of the priors, I guess there’s the question (like there always is when choosing priors) about what variable (CC or CC^2 or…) is the right one to have a flat prior distribution on. But aside from that standard Bayesian conundrum, the point of the argument is that we want to impose as little prior information as possible. We’re admitting that we have no clue what are all the causal factors in the “environmental” determination of the CC. But at least we might resolve the discrepancy of it’s (order of) order of magnitude.

    It’s inevitable that some physical processes are gonna be just too complicated to calculate, with whatever theory we settle on. If the hypothetical historical dynamics that determined the CC is one such process, que sera.

  32. woit says:

    Eric,

    I have no problem with the idea that maybe the CC is something “environmental”, depending on the history of the universe, in a way such that we’ll never be able to calculate it. What I object to is people running around saying they have a “prediction” of it, based on nothing more than the fact that if it were 100 times bigger, all else being equal, galaxies wouldn’t form. Even worse, people go on about this being a “successful prediction”, write popular books about how great it is, and use it as an excuse to successfully push a research program which is pure pseudo-science.

  33. Eric Dennis says:

    I agree with that.

  34. Pingback: Bloggernacle Times » This Week In Science and Religion

  35. Juan R. says:

    How much nonsense does one find in the anthropic idea?

    Perhaps reply was in a simple example.

    Look the Moon, why is it there?

    Scientific reply: It is there (effect) because it is the result of the motion guided by gravity force (cause). We can predict the Moon position at some future instant t via mechanics.

    Antrophic reply: It is there (effect) because we are looking it (“cause”) here. We canNOT predict the Moon position at some future instant t.

    Of course, some questions cannot be today solved from science, but then the (honest) scientist admits that does not know the reply. The rest is meta-science, religion, philosophy, etc.

    Juan R.

    Center for CANONICAL |SCIENCE)

  36. D R Lunsford says:

    Check this one out:

    http://xxx.lanl.gov/abs/physics/0510102

    Pornography is more legitimate.

    -drl

  37. Juan R. says:

    Here an extract from Lunsford cited preprint

    In one of our favorite scenarios, our universe is a school-assigned science experiment [1, 2] carried out by a high school student in a meta-universe. Perhaps he or she or it even started an assortment of universes like ant farms and stashed them away somewhere in the basement, out of his or her or its parent’s way. Perhaps by now he has lost interest and forgotten about the universes, leaving some to expand, others to collapse, in complete futility and silence. But, perhaps not without leaving a message for the occupants….

    The interesting is the affiliation:

    - Institute of Theoretical Science (University of Oregon)

    - Kavli Institute for Theoretical Physics

    :-)

    Juan R.

    Center for CANONICAL |SCIENCE)

  38. anon says:

    Are those dope-testing labs, or mental institutes? ;)