Susskind interview

By Sean Carroll | December 15, 2005 2:13 pm

While we’re getting the multiverse out of our system, let me point to this interview with Leonard Susskind by Amanda Gefter over at New Scientist (also noted at Not Even Wrong). I’ve talked with Amanda before, about testing general relativity among other things, and she was nice enough to forward the introduction to the interview, which appears in the print edition but was omitted online.

Ever since Albert Einstein wondered whether the world might have been different, physicists have been searching for a “theory of everything” to explain why the universe is exactly the way it is. But one of today’s leading candidates, string theory, is in trouble. A growing number of physicists claim it is ill-defined, based on crude assumptions and hasn’t got us any closer to a theory of everything. Something fundamental is missing, they say (see New Scientist, 10 December, p 5).

The main complaint is that rather than describing one universe, the theory describes some 10500, each with different kinds of particles, different constants of nature, even different laws of physics. But physicist Leonard Susskind, who invented string theory, sees this huge “landscape” of universes not as a problem, but as a solution.

If all these universes actually exist, forming a huge “multiverse,” then maybe physicists can explain the way things are after all. According to Susskind, the existence of a multiverse could answer the most perplexing question in physics: why the value of the cosmological constant, which describes how rapidly the expansion of the universe is accelerating, appears improbably fine-tuned to allow life to exist. A little bigger and the universe would have expanded too fast for galaxies to form; a little smaller and it would have collapsed into a black hole. With an infinite number of universes, says Susskind, there is bound to be one with a cosmological constant like ours.

The idea is controversial, because it changes how physics is done, and it means that the basic features of our universe are just a random luck of the draw. He explains to Amanda Gefter why he’s defending it, and why it’s a possibility we simply can’t ignore.

CATEGORIZED UNDER: Science
  • Ross Smith

    “While we’re getting the multiverse out of our system…”

    Lines you never expected to hear from a Respectable Physicist, #314159.

    Michael Moorcock has a lot to answer for.

  • Aaron Bergman

    The idea is controversial, because it changes how physics is done

    Only if you let it.

  • http://www.livejournal.com/users/hiviv_xliv_xlvi/ Grey

    Sorry, but the multiverse concept does sound little too close to a “magic” solution to me.
    1)It plays off the sci-fi disposition that such a thing would favorable (like people wanting an afterlife). It is always advisable to be cautious of the giving idea more credibilty because we want them to be real.
    2)It seems to address a key hole with bulldozer. Ackham’s Razor, anyone?

  • Magical

    Hahaha! It’s really quite amusing to watch string theory self-destruct ;)

  • http://eskesthai.blogspot.com/2005/12/rayleigh-scattering.html Plato

    I’ll see you in another dimension, Mother:)

  • Matt B.

    Weren’t you looking for a TOE? Now you’ve got a TOEE (Theory of Every Everthing)!

    “Don’t worry, be happy…”

  • fh

    Susskind invented String theory?
    I’m quite ignorant about this, what was his role in early String theory?

  • Dissident

    fh, go to

    http://www.edge.org/3rd_culture/susskind03/susskind_index.html

    and search for the first occurrence of the name “Veneziano”. That’s where the story begins.

  • Ugo

    As a layman (I’m not a professional physicist) I find all this talking about multiple universes extremely depressing and senseless.
    Is it a wonder to anyone that in last decades not one phycisist working in high energy physics/super string theory has been awared the nobel prize ?
    Where are the new generation of Feynmans, Einsteins, Diracs, Schwingers, Fermis, Bohrs etc, etc, etc….
    Superstring Theory is every day disconnecting itself more and more from physics and is becoming something else.
    I don’t know what but it surely isn’t physics.

  • Dissident
  • Ugo

    Dissident said :

    Ugo, the Nobel prize doesn’t go to “pure” theory – experimental confirmation is required. That pretty much rules out string theory. But HEP has been a dominating theme of the last few decades:

    I know this, what I’m trying to say is that in the past a lot of theoretical physicists working on high energy physics received the nobel prize because they created a theory to explain experimental data.
    Theoretical physics should work this way, there is a symbiosis between experiemental data and trying to devise explanations for those data.
    Now don’t you find it kind of weird (in a depressing sort of way) to see that not one nobel prize has been given to theoretical physicsts working on string theory, string theory effectively dominating the high energy physics landscape. (no pun intended).
    I mean, from my point of view I would like string theory to be ridimensioned within the theoretical physics community.
    It is unbelivable that young researchers to have a career in theoretical physics have only one option : do string theory.
    This is something fundamentally wrong.

  • Dissident

    Alas, the situation of the last couple of decades has been total absence of new experimental data to explain; the standard model has passed every test thrown at it (latest ray of hope is the anomalous magnetic moment of the muon, which just might hint at substructure, but not yet with sufficient certainty). So theorists have been on a prolonged vacation of sorts, engaging in flights of fancy rather than in the scrutiny of puzzling experimental data. Strings are the most notorious result – and no, I don’t find it weird that they haven’t been recognized with a Nobel prize, since that would require connection with experiment.

    But the redimensioning you ask for is looming. Strings have been getting some pretty bad press lately, and if the LHC fails to come up with sparticles in the next few years, anything with the prefix “super” in its name will start looking pretty dated even to the believers. But then the question is what you’re going to get instead. Just another flight of fancy afflicted by the same problems of practical (if not fundamental) lack of falsifiability? Or perhaps just an exodus to other fields, like biophysics, where there’s real work to do?

  • Belizean

    An added source of confusion regarding the landscape is the word “Multiverse”.

    In this context Susskind and others have given it a meaning that differs from its meaning in quantum information theory, where the word was first introduced into physics.

    Susskind himself is confused about this, as evidenced by his remarks from the audience during the panel discussion at Strings 2005 last summer.

  • weichi

    New Scientist: The idea is controversial, because it changes how physics is done

    Aaron Bergman: Only if you let it.

    Hear, Hear! That’s the spirit!

  • Aaron Bergman

    What’s annoying about all of this is that, even if true, the cosmological constant would not be — as is often pointed out by the anthropicists — the first time that some parameter was decided to be anthropically determined. The distance from the earth to the sun is a classic example.

    So, when it was realized that this parameter was probably just random, did people all of a sudden start declaring that there was a new way to do science? Did they start using the theory of planetary formation to come up with a probability distribution for the planetary distances? In this case, there clearly is a ‘multiverse’. We see tons of other galaxies, lots of stars and even a few planets out there. Has anyone bothered trying to probabilistically ‘predict’ the distance from the earth to the sun using some not particularly well formulated principle of mediocrity?

    Of course not. It might be a fun game, but it’s not particularly interesting. We already know what the distance from the earth to the sun is. There was no reason to elevate such games to a fundamental goal of science. Nobody was out proselytizing that “revolution” as far as I know. They just went on to try to understand things that weren’t random.

    I wish people these days would do the same.

  • Thomas Larsson

    Here is where I think that the analogy between fundamental physics and planetary distance breaks down: We see tons of galaxies, and expect there to be tons of planets, and they are all different. We also see tons of electrons, and they are all the same; as far as we know, the mass, charge and spin of all electrons in the universe are identical. If the electron mass (or spin!) were determined anthropically, we would expect it to vary throughout the universe, and there should be ways to detect that variation. If a planet’s distance from its sun were determined anthropically, we should analogously be able to see planets at different distances. And we do!

    Susskind makes the analogy with the fiords in Norway. But all fiords in Norway are different, and they are certainly different from the fiords at CERN (since there aren’t any). But all electrons in Norway look the same as all electrons at CERN!

  • fh

    aaron bergman, that is the precise point. To this moment I don’t understand how the anthropic principle is different or superior to “meassuring things”. In fact abstractly you canphrase it that way: We meassure that humans exist, what can we deducae from that? It sounds unlikely that that would ever produce a better result then meassuring things directly.

  • a.krug

    Ugo wrote:

    It is unbelivable that young researchers to have a career in theoretical physics have only one option : do string theory.
    This is something fundamentally wrong.

    This simply isn’t true. Aside from theoretical condensed matter, theoretical astrophysics, and other parts of physics, this isn’t even true in high-energy physics. There’s a great deal of phenomenological research.

  • http://www.anthropic-principle.ORG island

    Aron, please don’t re-define the anthropic principle for string theorists by generalizing them as anthropicists. String theorists did not originate, nor does their lame interpretation “own” the anthropic prinicple. Quite to the contrary, their interpretation cannot take precedence over the implications for specialness in the one observed universe, unless and if it ever enables them to predict anything more accurately than a single universe interpretation of the anthropic principle allows for.

    The anthropic principle is a cold hard fact of the observed universe whose significance cannot be lost in multiverse “reasoning” unless you can prove that you have good reason to do so.

    Call them crackpot multiverse string theorists like everybody else does, but please do not confuse them with normal people who know that anthropically determined means that there can no accident to it.

    Thanks

  • http://countiblis.blogspot.com Count Iblis

    Thomas Larsson (#16),

    Well, not all possible universes can be equally likely. I’m assuming that you are considering some sort of set of all possible universes and are applying anthropic reasoning to that set.

    There are a huge number more complex models with zillions of arbitrary constants that look like the standard model at low energies. The effect of those parameters would be small, e.g. tiny fluctuations in the electron mass that are measurable but yet doesn’t affect chemistry.

    Because everything indicates that the world is as simple as possible, and not as complex as possible at the fundamental level, there must exist a measure that favors less complex models.

    If one identifies universes with algorithms, then it’s easy to see where this measure comes from. You can always add n bits to a program that don’t affect the program. There are 2^n times more universes with n dummy bits added on. So, if the measure depends only on the number of bits needed to specify the program (Kolmogorov Complexity), then it has to fall off faster than 2^(- program length) to cancel out the exponentially growing anthropic factor.

  • Belizean

    Ugo wrote:

    It is unbelivable that young researchers to have a career in theoretical physics have only one option : do string theory.
    This is something fundamentally wrong.

    This simply isn’t true. Aside from theoretical condensed matter, theoretical astrophysics, and other parts of physics, this isn’t even true in high-energy physics. There’s a great deal of phenomenological research.

    When I first went on the job market, that’s exactly how it seemed to me: string theory or no job. I remember as job candidate lamely attempting to put a string theory spin on my quantum gravity work that actually had nothing to do with string theory. I believe that I was offered a position primarily on the strength of social connections (between my advisor & recommenders and the group that hired me).

    For the most part, jobs are available only to those who are keenly career conscious (or lucky). You really need to think about the job market, when you’re a senior applying to graduate school. At the very least you need to be thinking about it, when you’re a first-year graduate student choosing a specialty. It’s not a bad idea, moreover, to consciously cultivate future references.

    The problem is that lots of bright people focus on physics instead of on a career in physics. The most famous example of this is Albert Einstein, who was academically unemployable after he received his degree. If he hadn’t, on the strength of a social connection, landed a low-stress, leisure-providing job in the Swiss patent office, I shudder to think what might not have happened.

  • http://blogs.discovermagazine.com/cosmicvariance/sean/ Sean

    Aaron– I completely agree that the “new paradigm for physics” business is just silly. The whole point is that we have always done physics this way — some features of nature are deep and inevitable, and others are contingent and environmental. The reason why respectable scientists should spend time thinking about the multiverse is that we would really like to know whether the vacuum energy is the former or the latter. Right now we don’t know why there is such a large hierarchy between the vacuum scale and the Planck scale; maybe there’s some inevitable dynamical mechanism, maybe it’s just a selection effect. The underlying understanding is completely different in the two cases, so it’s important to understand the feasibility of each scenario.

  • Aaron Bergman

    The reason why respectable scientists should spend time thinking about the multiverse is that we would really like to know whether the vacuum energy is the former or the latter.

    I’m just not sure that question’s is going to be answerable any time soon. The odds of observing another universe are pretty slim. I suppose we could get a ton of other evidence for some theory that predicts zillions of universe, but that seems pretty unlikely these days, too.

    In the meantime, it seems to me we ought to be trying to best understand the theory’s we have, multiversal or not, and if people want to think about the cosmological constant, that’s cool, and if they don’t, that’s cool too.

    No need for revolutions, new paradigms or whatever. Just physics. Like we’ve always done it.

  • Moshe

    Sean and Aaron, I like separating anthropic resoning (like Hoyle’s) and the issues involved, from probabilistic reasoning and the completely different issues involved there. The former is conventional physics, and the upshot would be that the CC is a coincidence like the earth-sun distance, and therefore it is not interesting for scientific study. The latter, using conditional probabilities to actually give value to the CC, or the earth-sun distance, is a very different approach. If it is ever going to make sense, it would indeed be a new way of doing physics, paradigm shift etc. etc..

  • Jeff Harvey

    The introduction to the interview says Susskind “invented string theory.”
    This canard can be found on the front flap of Susskind’s book and is
    repeated in various forms in many reviews of the book and interviews
    with Susskind. An early review of string theory (C. Rebbi, Physics Reports
    12 C, no. 1, 1974) says “The first interpretation of the spectrum of states of the conventional dual resonance model as the spectrum of excitations of a one-dimensional system (a string) is due to Nambu[23], Nielsen[24],
    Susskind[25], and Takabayashi[26]. I believe the references are listed
    in chronological order. Readers who want to get the history straight
    are invited to look up the references and decide for themselves.
    My conclusion is that Susskind was among the
    first people to interpret the Veneziano model in terms of what we now call
    strings, but definitely not *the* first. How this makes him the father of
    string theory or the inventor of string theory is beyond me.

  • Doug

    Right on Aaron! You know, what’s just amazing to me is how the arguments can seem to go on forever about the consequences of GR and cosmic inflation, and yet apparently very few are willing to think that it just might be that the concepts of GR, inflation, and the whole cosmological model are the real problem. Given the constants of G, c, and h, we are fixated on interpreting them in only one way, even though it leads to confusion and desperation. Just because GR works does not mean that we understand the nature of space and time correctly, and just because QM works does not mean we understand the nature of space and time correctly.

    In fact, Gross’s continual insistence that we are missing something fundamental about space and time should be the focus of the intense discussion, instead of Susskind’s multiverses. You can be assured that this “period of utter confusion” is caused by our current theories, not by nature. The contradiction in the space and time concepts of GR and QM are certainly a challenge to finding a T.O.E., but stubbornly assuming that they can be reconciled, that they must be reconciled, that they are not both wrong in some respect, is as an unscientific position to take as any ever taken in the past.

    But what’s worse is that when these two theories are employed to devise a cosmological model, knowing that they are fundamentally contradictory, and the result requires an ad hoc invention like cosmic inflation to avoid disaster, the whole thing leading to the absurd conclusions now being seriously entertained, no one is willing to tell the emperor that he has no clothes on. It’s time someone stood up and recognized that the contradiction of GR and QM means that maybe what we think is space is not space, and what we think is time is not time.

    The vacuua, the vacuua, my kingdom for a doggone vacuua. Crap, we think we know, we are absolutely convinced, that there is a suitable vacuum energy out there that can be uniquely determined either by a “deep and inevitable” principle, or, heaven forbid, an environmental “selection principle.” Meanwhile, it’s just too iconoclastic, even for the most daring rebels among us, to think that finding a suitable vacuum energy has nothing to do with how nature is put together. Oh my gosh, we have G, and we have c, and h, and by golly, they give us a Planck length and a Planck mass, so we’re not going back — the answer has to be down there, somewhere way, way down there, in the vacuum.

    Sorry, guys. All indications are that we’re barking up the wrong tree, or walking the plank (pun intended).

  • http://www.math.coumbia.edu/~woit/blog Peter Woit

    If you want to get some idea of the damage to the public perception and understanding of science that the pseudo-science promoted by Susskind and followers is about to cause, take a look at

    http://www.helives.blogspot.com/2005_12_01_helives_archive.html#113465921781166371

    which 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.”

    It’s utterly appalling that virtually no prominent particle theorist besides David Gross is willing to publicly take on Susskind. And not just on the question of whether or not he is the “father of string theory”.

  • http://blogs.discovermagazine.com/cosmicvariance/sean/ Sean

    Well, I like to think that I invented the concept of gourmet ketchup, and this feeling is not dampened by learning that someone else invented it first without telling me. Although, to be fair, I won’t be including that on any book jackets.

  • http://eskesthai.blogspot.com/2005/12/rayleigh-scattering.html Plato

    Imagine “superfluids” as ketchup? Hardly? :)

    Bubble nucleation is interesting and why wouldn’t it be?

    I like Moshe’s point of view better, that indeed perspecive change can initiated “other ideas” about the physics, and the way we do things ( maybe he didn’t say that exactly). Who might have known that Dirac’s sea would not have been a supefluid?

    Of course, I speculate, yet vision is driven down to enormous potentials. Some cannot “fathom” standing at the edge? Heretics the whole works? They should be burned for insighting ID?

    Come on :)

  • Magical

    I knew the ID people would pick up on string theory eventually.

    I’m curious to see the way it’s explained how string “theory” is a valid scientific theory while intelligent design is not?

  • http://eskesthai.blogspot.com/2005/12/rayleigh-scattering.html Plato

    I am a product of “M” What can I say:) I try to understand the “negative expression” as much as I can. It does not mean I am evil:) I’m just learning.

    You just had to know where the hole was to make it flip? I don’t.

    Grue and Bleen?

  • http://1034:Incorrectkeyfilefortableusers;trytorepairit sisyphus

    Why the Anthropic Principle, anyway? Why not the “Quarter-Pounder-With-Cheese Principle” ? Since humans pre-exist hamburgers the universe that produces hamburgers is even more specific (fine-tuned) than the universe that produces humans. Does Susskind have hamburgers covered? With all the fixin’s? Then I’d be impressed.

    Modern theoretical physics looks like philosophy-by-numbers, but that’s ok – philosophy and science are fraternal twins; every few centuries they have a reunion.

    In any case, it seems to me that the multiverse idea is no harder to swallow than the notion of a single universe; both are inexplicable by our best current theories.

    Doug: For sure – we’re missing something fundamental about space and time; you’ve gotta know that in your gut. I doubt that we can understand time and space without being able to answer the ‘hard question’ of consciousness.

  • http://countiblis.blogspot.com Count Iblis

    sisyphus:

    …since humans pre-exist hamburgers

    Hamburgers are an essential ingredient of the modern universe; they explain why we have entered a new inflationary epoch see here.
    :)

  • http://arunsmusings.blogspot.com Arun

    Suppose GR was a perturbatively renormalizable QFT. Would you be any happier right now?

  • http://eskesthai.blogspot.com/2005/12/rayleigh-scattering.html Plato

    I would have been just as guilty of comparing aromatic smells, to the values of sound froma fifth dimenisonal perspectve, as having choosen “M” for Macs?

    Well, Robert Laughlin would have been glad for you choosing what ever building blocks you choose :)

    Cycle of Birth, Life, and Death-Origin, Indentity, and Destiny by Gabriele Veneziano


    The new willingness to consider what might have happened before the bang is the latest swing of an intellectual pendulum that has rocked back and forth for millennia. In one form or another, the issue of the ultimate beginning has engaged philosophers and theologians in nearly every culture. It is entwined with a grand set of concerns, one famously encapsulated in an 1897 painting by Paul Gauguin: D’ou venons-nous? Que sommes-nous? Ou allons-nous? “Where do we come from? What are we? Where are we going?” The piece depicts the cycle of birth, life and death – origin, identity and destiny for each individual – and these personal concerns connect directly to cosmic ones. We can trace our lineage back through the generations, back through our animal ancestors, to early forms of life and protolife, to the elements synthesized in the primordial universe, to the amorphous energy deposited in space before that. Does our family tree extend forever backward? Or do its roots terminate? Is the cosmos as impermanent as we are?

    These were not simple questions that were unprepared for on how we saw the cosmos giving it disrespect? But the true father is certainly dealt his share? :(

  • http://arunsmusings.blogspot.com Arun

    Would life be possible in a universe with a single generation of quarks and leptons of the standard model, instead of three generations? If yes, then doesn’t that put paid to the anthropic principle?

  • http://eskesthai.blogspot.com/2005/12/rayleigh-scattering.html Plato
  • http://helives.blogspot.com David Heddle

    This is a wonderful blog—I am glad to have found it via my site log.

    I want to comment on what Peter wrote in #29, where he refers to “the damage to the public perception and understanding of science that the pseudo-science promoted by Susskind and followers” with the evidence he provides being a excerpt and a link to a post of mine.

    Susskind is not the darling of this (cosmological) IDer. After all, he is out to destroy the fine-tuning. But even that is OK with me, if done with old fashioned, testable physics. The only comfort, if that’s the right word, that cosmological IDers get out of this is that Susskind’s landscape is just as metaphysical as ID. There aren’t many criticisms about cosmological ID that do not equally apply to the Landscape. (Sorry I keep adding the adjective cosmological, but I am not an IDer in the Behe-Dembski sense.) And for the same reasons that Cosmological ID should not be published in journals such as PRL, neither should Landscape speculations, in my opinion.

    Susskind’s conclusion really is, as I pointed out, a Sophie’s choice; but, even as an IDer, I find that disturbing rather than a cause for celebration. I think most of us who are professional physicists, but yet have cosmological ID leanings, want physics to continue as it always has, with a search for testable elegance. Nothing would be more depressing to both the IDer and physicist within than for Susskind to influence a large segment of the HEP community.

    I think Peter’s worry is misplaced. It is not the damage Susskind’s book does to public perception that is the issue, but rather the damage it might do to physics itself. Because at the heart of it, what Susskind is really saying is that HEP physics is dead. If we have just annealed into our habitable universe, any further search for truth and beauty is a fool’s errand.

  • http://eskesthai.blogspot.com/2005/12/rayleigh-scattering.html Plato

    I seem to be the lone voice here, and not the expert one at that.

    How can one not carefully think that such progressions were not considered?

    Yes, it is under the wide “sweeping gaze” of a question, but it still retains the values of science.Nor do I think Susskind by defintion a ID’er.

    Is this the consensus of the whole fraternity of science’s brothers? Maybe that is the easier question? :)

  • Elliot

    Plato,

    Based on my limited reading of the book so far… (I had actually planned to read the book before commenting…) I tend to agree that Susskind is not an IDer.

    I am a layperson as well. I think the more provocative threat that arises is the challenge to the traditional scientific process. Not so apparent so far in the book but clearly apparent in other writings by Susskind.

    Elliot

  • http://eskesthai.blogspot.com/2005/12/rayleigh-scattering.html Plato

    Elliot,

    It has been much consternation to me why the very institution that would support one another would go out to seek and destroy same?

    It is to much for me to understand why such questions would not of been of value?

    You have “this choir” of responsiveness? Is it’s uselfulness(string theory) at a end, like the choir predicts? I don’t know? I think one had to understand the motivation and the concept of “disgruntled employees?”:)This did not lesson the things that we can learn “given the right atmosphere” from the sounds that are emitted in harmony? :) Dedication to research and enlightenment.

    I have not read Susskinds book either or completed Krauss’s, but I have read enough staying close to the front of research, to see the divison created because someone said, “hey, let’s look to the origins of the cosmos” and instituted the expression of same, from the physics of approach.

    I mentioned Moshe earlier becuase this is what happens when you present models to the ways we have always done things?

    THis does not lesson the impact of our methods to percieve into the intracies of the nature of the cosmos does it? It does not lesson our perception to assumptions of such a model, to points of Equilibirum(landscape) does it?

    Thanks Elliot

  • Scott

    david,

    Why don’t you say what you mean, you believe a god made the laws of nature. There is no need to couch, what you yourself consider to be a belief outside of science, in the discovery institutes invented terminology that was designed to confuse the issue of its scientificness.

  • http://helives.blogspot.com David Heddle

    Scott,

    I wouldn’t know about terminology invented by the DI, and anyone who visits my blog would know that I (like many scientists) indeed believe that the ultimate source of the laws of nature is God. That doesn’t affect how I do science. I have no idea what your point is, and don’t know what the word “scientificness” means. I wasn’t even sure your comment was meant for me, but I seem to be the only “David” who has posted.

  • http://blogs.discovermagazine.com/cosmicvariance/sean/ Sean

    Folks, just to be clear: environmental selection in the multiverse is not a close relative of ID in any way — it’s the opposite of ID. It proposes a completely mechanistic and non-teleological explanation for the apparent fine-tunings we observe in nature, without relying on any supernatural intervention.

    Susskind’s mistake, in his enthusiasm for the multiverse, is to suggest that without a multiverse, ID might make sense as an explanation for such fine-tunings. He unfortunately ignores the fact that ID doesn’t make sense under any circumstances. It doesn’t provide any description of the “designer” (including, of course, who designed the designer), any mechanism through which the designer goes about designing things, any criterion for deciding whether something is designed or not, and so on. It’s just empty posturing by people who want to sneak religion into high-school education.

    If there is no multiverse, then we just got lucky that the uniquely-determined laws of nature allow for us to be here. That statement, all by itself, is much simpler and straightforward than the invocation of a mysterious supernatural force with no role other than to fix the laws in their specific configuration.

  • http://eskesthai.blogspot.com/2005/12/rayleigh-scattering.html Plato

    environmental selection in the multiverse is not a close relative of ID in any way — it’s the opposite of ID

    It’s about time. It needed to be said.

    Especially, for those of us on the periphery of this debate about string theory that has been reduced to all the kinds of “the wrong speculation” that that we hear of. The heart and soul of science blemished, towards continued research and developement of M theory.

    If you did not see this in context of the universe, then how would you not know about the physics and cosmological approach, brought together?

    Should we succumb to the leaders who would instigate “ID classification,” to have those who follow this rule of thumb, sing such praises?

    I would defintiely be asking for more clarity. Is there no bubble nucleations initiated in cyclical cosmological variations, hence no return to the very beginnings we saw in the beginning of our own??

    Thanks Sean

  • Dissident

    #36: Arun, until the past summer I guess I couldn’t have come up with a single way that the second and third generations of matter might have been relevant for life. All known chemistry, hence biology, is essentially the physics of the electron shells surrounding nuclei made of protons and neutrons, which in turn are made of up and down quarks. Only the first generation is involved.

    Then, in June, we were told that strange quarks actually have a significant, measurable effect on the magnetic and electric properties of protons:

    http://www.jlab.org/div_dept/dir_off/public_affairs/news_releases/2005/gzero.html

    So at least in principle I can now imagine that removing the higher generations of matter could have a measurable effect on the electron shells surrounding nuclei, hence chemistry, hence biology. But prevent life from arising? That still looks like a really long shot.

  • http://helives.blogspot.com David Heddle

    Sean,

    The fine tuning is only “apparent” if you have a mechanistic explanation for it. In the absence of an explanation, merely designating it as apparent is begging the question. At least Susskind offers a possible explanation, which sort of gives him the right to call it “apparent.”

    You wrote:

    It’s just empty posturing by people who want to sneak religion into high-school education.

    That’s a gross generalization. I and other IDers I work with have no interest in getting religion into public schools. This is no better than generalizing about an atheist “agenda” for non IDers. What’s to be gained by painting with an infinitely broad brush?

    If there is no multiverse, then we just got lucky that the uniquely-determined laws of nature allow for us to be here. That statement, all by itself, is much simpler and straightforward than the invocation of a mysterious supernatural force with no role other than to fix the laws in their specific configuration.

    That is merely opinion, not an incontrovertible fact. If there is no multiverse, then some may decide that Occam’s razor comes down in the favor of design rather than blind luck. In that, Susskind is correct.

  • Who

    Dear David Heddle

    In your post #38 of this thread you say:
    Susskind’s conclusion really is, as I pointed out, a Sophie’s choice; but, even as an IDer, I find that disturbing rather than a cause for celebration.

    On the other hand saying “Susskind rocks” at the end of your blog of 15 December titled “Susskind’s Sophie’s Choice”
    http://www.helives.blogspot.com/2005_12_01_helives_archive.html#113465921781166371
    you appear to be celebrating. If it was meant ironically, a chance visitor to your site might well miss that.

    I merely note the apparent inconsistency, but do not object. I wish the message in your blog was more clearly in line with what you say in this context, but don’t feel I’ve the right to criticize.

    Setting that aside, I’d like to quote your post #38 because I find a lot in it:

    —David #38—
    This is a wonderful blog—I am glad to have found it via my site log.

    I want to comment on what Peter wrote in #29, where he refers to “the damage to the public perception and understanding of science that the pseudo-science promoted by Susskind and followers” with the evidence he provides being a excerpt and a link to a post of mine.

    Susskind is not the darling of this (cosmological) IDer. After all, he is out to destroy the fine-tuning. But even that is OK with me, if done with old fashioned, testable physics. The only comfort, if that’s the right word, that cosmological IDers get out of this is that Susskind’s landscape is just as metaphysical as ID. There aren’t many criticisms about cosmological ID that do not equally apply to the Landscape. (Sorry I keep adding the adjective cosmological, but I am not an IDer in the Behe-Dembski sense.) And for the same reasons that Cosmological ID should not be published in journals such as PRL, neither should Landscape speculations, in my opinion.

    Susskind’s conclusion really is, as I pointed out, a Sophie’s choice; but, even as an IDer, I find that disturbing rather than a cause for celebration. I think most of us who are professional physicists, but yet have cosmological ID leanings, want physics to continue as it always has, with a search for testable elegance. Nothing would be more depressing to both the IDer and physicist within than for Susskind to influence a large segment of the HEP community.

    I think Peter’s worry is misplaced. It is not the damage Susskind’s book does to public perception that is the issue, but rather the damage it might do to physics itself. Because at the heart of it, what Susskind is really saying is that HEP physics is dead. If we have just annealed into our habitable universe, any further search for truth and beauty is a fool’s errand.
    —endquote—

  • http://blogs.discovermagazine.com/cosmicvariance/sean/ Sean

    David, if you don’t want to be unfairly generalized, then don’t call what you are doing “Intelligent Design.” Call it “natural theology” or “the God hypothesis” or whatever you like. But “Intelligent Design” has a very specific referent, namely a certain form of cleaned-up creationism with no scientific content and an explicit agenda of getting religion into schools. If that’s not you, then don’t associate yourself with them.

  • Who

    David, our posts crossed.

    In #37 you say
    “If there is no multiverse, then some may decide that Occam’s razor comes down in the favor of design rather than blind luck. In that, Susskind is correct.”

    I am very interested in getting your reaction to a testable multiverse model (very different from the eternal inflation or string vacua landscape pictures) called cosmological natural selection and described in

    http://arxiv.org/abs/hep-th/0407213
    Scientific alternatives to the anthropic principle
    Lee Smolin
    Contribution to “Universe or Multiverse”, ed. by Bernard Carr et. al., to be published by Cambridge University Press.

    Susskind’s multiverse might conceivably be discarded, if it is found to have no observable consequences, and yet the choice not YET come down to blind luck versus design. As far as the determination of fundamental constants, I mean.
    You might wish to consider a further possibility.

  • http://pantheon.yale.edu/~eal48 Eugene

    David says : That is merely opinion, not an incontrovertible fact. If there is no multiverse, then some may decide that Occam’s razor comes down in the favor of design rather than blind luck. In that, Susskind is correct.

    Sure. But

    (a) I don’t think the fat lady has given up yet.

    (b) Would you advocate the teaching of “Blind Luck Decides that We can Exist in this Universe” in public school science classes? (Since, as you said, both are merely opinion?)

  • http://helives.blogspot.com David Heddle

    Who,

    I have scanned the paper and it looks very interesting. I will take some time to read it carefully.

    Eugene,

    Would you advocate the teaching of “Blind Luck Decides that We can Exist in this Universe” in public school science classes?

    No. If the topic of fine-tuning came up in a tangential discussion (since it is not going to be in the curriculum) I would advocate teaching that the competing explanations, all (in the Popper sense) unfalsiable (in my opinion, I am will to convinced otherwise) are multiverses, design, and blind luck. After that, there isn’t much to say.

  • Elliot

    Just read an interesting challenge to ID. That is if you take ID as true then you most certainly would need to ask who made the designer. It would obviously need to be an even more intelligent designer. This lead to an infinite series of intelligent designers each a bit more intelligent than the previous one. Seems like a bit of a logical cul-de-sac to me.

    Elliot

  • http://helives.blogspot.com David Heddle

    Elliot,

    I assume you are very young or just starting to think about ID, because “who designed the designer” is the oldest, the most repeated, and probably the weakest criticism of ID. It is also probably the most easily handled criticism of ID. It is roughly akin to criticizing evolution by asking “what good is half an eye?”

  • Elliot

    David,

    I don’t see the analogy to asking what good is half an eye. It is strained at best.

    Since it is the oldest and most oft repeated, I imagine it has some creedence.

    I am not young but you are right I haven’t spent much time thinking about ID. Given that it is basically creationism with a new brand name not sure I need to.

    Elliot

  • Who

    Dear David,

    regarding this

    http://arxiv.org/abs/hep-th/0407213
    Scientific alternatives to the anthropic principle
    Lee Smolin
    Contribution to “Universe or Multiverse”, ed. by Bernard Carr et. al., to be published by Cambridge University Press.

    you say

    I have scanned the paper and it looks very interesting. I will take some time to read it carefully.

    thanks for expressing interest. I hope you do respond at more length. If you respond in your blog please call my attention to your reply in this thread so I don’t have to watch two places.

    the CNS explanation of the constants is FALSIFIABLE, which is the whole point. The falsifiability claim is something you should check to see if you find it convincing because the falsifiability responds to what you say here:

    I would advocate teaching that the competing explanations, all (in the Popper sense) unfalsiable (in my opinion, I am will to convinced otherwise) are multiverses, design, and blind luck.

    If indeed you are WILLING TO BE CONVINCED, as you say, that one of the competing explanations is falsifiable, then here it is. Please consider, not whether you like the theory (I am not advocating it) but whether you agree that it is falsifiable.

    CNS presents you with the following challenge: look at the list of fundamental dimensionless constants and find even one in which a small change would promote the formation of more stellar-mass black holes.

    Very simply, the CNS explanation for the basic constants is that they are approximately optimized for black hole production. They may INCIDENTALLY favor life as we know it but this is a side effect. What the constants really favor is black holes.

    Details can be found in the paper I mentioned and references therein.

    It seems clear to me that the conjecture that the basic constants are a local maximum for black hole formation is falsifiable. All you have to do is find one constant (like a quark mass) which, if changed, would yield a significant improvement in the rate of black hole formation.

    If the constants turn out to be fine-tuned for black hole abundance, that provides for a simple explanation as follows:
    Several of the papers at the October Loops ’05—an international quantum gravity conference—were about the emergence of big bangs from black hole gravitational collapse. Quantizing removes the singularity and the collapse at the pit of a hole has to go somewhere and it now looks as if spacetime may continue on out in a bounce, and re-expand. In other words stellar-mass black holes produce other branches of spacetime. The relevant quantum gravity theory predicts signature that can be looked for in Gammaray Bursts. Parampreet Singh at Penn State gave a talk about that in November, which fortunately is online.

    So black hole formation provides a possible reproductive and hence evolutionary mechanism by which a set of fundamental dimensionless constants, like a set of genes can evolve.

    This evolutionary CNS theory does not say anything concerning the existence or nonexistence of a Divine Creator—-it simply offers a mechanism by which the basic parameters are self-tuning.
    there might or might not be some Creator somwhere who set the whole tree-like branching process in motion—-many black holes ago, many iterations, many bounces, many big bangs ago.
    But that imagined Creator, if existent, would not have needed to twiddle the knobs in order to fine-tune the basic constants of our particular spacetime branch

    The fine tuning is taken care of by Smolin’s proposed cosmological natural selection process. Which, it is argued, is FALSIFIABLE. That is why it is a significant part of the discussion and why I suggested the paper to you.

    Cheers,

    Who

  • http://eskesthai.blogspot.com/2005/12/rayleigh-scattering.html Plato

    Given that it is basically creationism with a new brand name not sure I need to.

    I agree Elliot. I am hoping that I am speaking for a part of society, and if not, apologize for “imposing my thinking on them,” if it felt this way. If one did not speak about this, would the “battle not have taken it’s toll” without them knowing the results they are dealing?

    Is this what those who Fight against ID are trying to do?

    Who knows. Maybe a stronger resolve for “empowerment” shall arise out of the chaos, once a resolve is held too?


    The time has come to severe this relationship from the work needed to do by us lay people to get to the “bottom of things.” :) What the underlying basis is of reality without invoking God , but at best hoping to understand our involvement in the continued expression of this reality? So, we are given options and models to work with.

  • Elliot

    Re: CNS,

    Are there variants of this theory which postulate other selection mechanisms than black hole formation? Certainly it is an interesting one but not the only thing that could be selected for that would potentially lead to the emergence of intelligent life in this or any other universe.

    Elliot

  • http://eskesthai.blogspot.com/2005/12/rayleigh-scattering.html Plato

    Who:

    If the constants turn out to be fine-tuned for black hole abundance, that provides for a simple explanation as follows:

    Several of the papers at the October Loops ’05—an international quantum gravity conference—were about the emergence of big bangs from black hole gravitational collapse. Quantizing removes the singularity and the collapse at the pit of a hole has to go somewhere and it now looks as if spacetime may continue on out in a bounce, and re-expand. In other words stellar-mass black holes produce other branches of spacetime. The relevant quantum gravity theory predicts signature that can be looked for in Gammaray Bursts. Parampreet Singh at Penn State gave a talk about that in November, which fortunately is online.

    So black hole formation provides a possible reproductive and hence evolutionary mechanism by which a set of fundamental dimensionless constants, like a set of genes can evolve.

    I think this is a reasonable assessment( my struggle to geometrical propensities in regards to quantum geometries?) in expression.

    Would this contradict Multiverse idealizations or demonstrate compatibility?

  • Who

    Elliot, to reply to your question

    Re: CNS,

    Are there variants of this theory which postulate other selection mechanisms than black hole formation? Certainly it is an interesting one but not the only thing that could be selected for that would potentially lead to the emergence of intelligent life in this or any other universe.

    Elliot

    the answer is almost no other but I seem to recall a paper from the mid 1990s which proposed a variation of Smolin’s CNS. It may have been by Louis Kauffman. Maybe I can find it on arxiv.

    to make the obvious point, black hole formation provides a credible reproduction mechanism: in the past year a fair number of Quantum Gravity papers have been written about gravitational collapse and they mostly point towards a bounce, in which spacetime continues and reexapands in a new branch from the pit of a black hole—inflation providing a fresh endowment of matter.

    admittedly intelligent critters could INTERFERE and perhaps encourage black hole formation, so there could be some extra reproductive fitness associated with branches of spacetime where there were creatures willing and able to do this (so their branch or universe would pass on its characteristics to more offspring branches).

    It is a thought but for me seems just unnecessary complication. the main issue is whether the universe is optimized for black hole abundance or not. it is something that ought to be able to be settled by observation, as long as the fundamental constants of physics (as they effect star, galaxy, and black hole formation) are well understood

  • Who

    Elliot, that mid 1990s paper was by Louis Crane (not Louis Kauffman) and it was
    http://arxiv.org/abs/hep-th/9402104

    more discussion of the CNS idea, including criticism and possible variants, is in this paper of Rudiger Vaas
    http://arxiv.org/abs/gr-qc/0205119

  • Elliot

    Who,

    Thank you very much for your response and the references. The Crane paper looks particularly interesting.

    Elliot

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Cosmic Variance

Random samplings from a universe of ideas.

About Sean Carroll

Sean Carroll is a Senior Research Associate in the Department of Physics at the California Institute of Technology. His research interests include theoretical aspects of cosmology, field theory, and gravitation. His most recent book is The Particle at the End of the Universe, about the Large Hadron Collider and the search for the Higgs boson. Here are some of his favorite blog posts, home page, and email: carroll [at] cosmicvariance.com .

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