Duff on Susskind

By cjohnson | December 5, 2005 1:45 pm

Physics World has a review* of Leonard Susskind’s new book entitled “The Cosmic Landscape: String Theory and the Illusion of Intelligent Design”. The review is by Michael Duff of Imperial College (London), who is well known in the field. Well, I have not read the book, so I’ll simply point out the review, and not make comment directly on the book itself. A review of a review if you like.

I’ve always liked Mike’s sense of humour, and so it is nice to see it sneak into the article here and there, such as at the end of this key pair of paragraphs:

Susskind believes that it is more than dumb luck that the universe is so accommodating to human beings. “Can science explain the extraordinary fact that the universe appears to be uncannily, nay, spectacularly, well designed for our own existence?” he asks.

But does this mean that the religious fundamentalists have won? Must we invoke the existence of a god to account for the gaps in our knowledge? Susskind’s answer is “no” on both counts. As you might have guessed from the book’s subtitle, he argues that while “the appearance of intelligent design is undeniable”, science can nevertheless explain it all. Phew! Thank God for that.

Background (and my humble opinion) on the issue of the Landscape in string theory research can be found in an article I wrote here. (Tread carefully through the 172 (to date) comment bloodbath tagged on the end.)

So it seems, according to those two paragraphs, that Lenny is being provocative with his book title while still holding on to the view that we don’t need to go beyond science to answer several truly fundamental questions about our universe. I’m relieved, because I have great respect for Lenny, and so this is rather good news. Hmmm. We must not, however, forget that he puts forth various versions of the Anthropic Principle to answer the questions instead, and there are those (myself included) who question whether that (at least in its strongest form) is still doing science.

I have not yet made up my own mind whether it sits well with me or not….. Let me tell you one reason why I am conflicted: I don’t mind anthropic arguments when they are used to predict something important…This has been done in science before: I’ve given the example of Hoyle’s amazing result here. But I do not like an anthropic argument to be used to “explain” something we already know. These seem to be two different things in my mind. I could be wrong.

As I said in the other article, what some string theorists, led by Lenny (a very small group, despite what is often said – it is not the entire field) want to put forth is the idea that since the theory (as far as we currently understand it – key point here) seems to give us a vast number of solutions, rather than just one corresponding to our world, this should be regarded as a feature rather than a bug: This vast “Landscape” of solutions each corresponds to a different possible universe, and then we have to use the fact that we are here to ask the question “which one?” as the reason that we are here to ask the question “which one?”.

This bothers me a bit, since we already know that we are in this universe and have this solution…..and so this does not seem very predictive. It is not in the spirit of Hoyle’s precisely predicting a previously unknown resonance of the carbon nucleus on the grounds that we would not be around if it did not exist, in order to allow star to generate heavy nuclei.

Here is a long extract from the article talking about the seeds of the modern Anthropic applications to fundamental physics, in its form attributed to Weinberg:

Nevertheless, no less a person than Nobel laureate and arch-atheist Steven Weinberg believes that one particular constant of nature – Einstein’s cosmological constant Λ – may be anthropically determined. The size of Λ has long been an enigma. Theoretically its most natural value would be unity in natural units, but anything bigger than 10^(-120) would be inconsistent with astronomical data – and a world record for the worst agreement between theory and experiment!

So Weinberg set out to see if any bigger value would prevent life. The answer, it turned out, did not have anything to do with molecular chemistry or the stability of the solar system. Weinberg found that if Λ were just an order of magnitude bigger than 10^(-120), no galaxies, stars or planets would have formed. His anthropic arguments not only provided a limit on Λ, they also give some idea of its expected value. In 1992 he wrote, “Thus if such a cosmological constant is confirmed by observation, it will be reasonable to infer that our own existence plays an important role in explaining why the universe is the way it is.” Even sceptics had to take notice, therefore, when recent astrophysical observations indicated that Λ is, in fact, non-zero and has just about the value Weinberg predicted.

Well, this is perhaps a little strong, but you see that it is somewhere in between the two anthropic practices; the Hoyle practice vs the Susskind practice, if we wish to give these things names….It is perhaps much closer to Hoyle, and a bit more swallowable….but I have my doubts still.

Anyway, Duff ends (almost) by quoting Susskind:

Susskind concludes that questions such as “why is a certain constant of nature one number rather than another?” may well be answered by “somewhere in the megaverse the constant equals this number: somewhere else it is that number. We live in one tiny pocket where the value of the constant is consistent with our kind of life. That’s it! That’s all. There is no other answer to the question”.

I’ll end my review of the review by summarising my view so that I don’t have to do it again in the comments. It will be ignored by readers and the members of the press anyway, as it is not sensational enough. (sigh):

(1) I claim that this (see above quote paragraph) alone is not predictive.
(2) I claim that some anthropic reasoning can be used to do science…..but it must predict, not postdict. See the Hoyle example I link to above.
(3) We don’t understand string theory at all well. So we don’t know if there are the huge number of solutions that Susskind uses to motivate using Anthropic reasoning in string theory. This, in my opinion, is really premature…..but this is why the field is healthy. Nobody knows, so let’s try several approaches.
(4) In the context of string theory, this approach would be believable if we were to build in Anthropicity for one or at most, a few (discuss), undetermined constant(s) (like the cosmological constant Λ), and then actually predicted several new things we can go out and measure as a result. Maybe this will yet happen? Too early to tell.

With (4) in mind, I can see why people are playing with the idea and exploring the program a little. I do not agree that because a few people are playing with such ideas (whether they have my view in mind or not) that the entire field of string theory is therefore doomed, as Peter Woit (see his blog) and others have claimed. That’s a bit apocalyptic…. a rather dark view based on personal reasons, in my opinion. (But a view to be considered and debated…my brighter view is also based on personal reasons…….But personal reasons are irrelevant in science: the research alone will carry the day. We must let the research happen.) So this endeavour is part of the research program in string theory. There are other people carrying on trying to understand several other aspects of string theory.

We’re still doing science here.


(*Thanks Count Iblis!)

  • Aaron Bergman

    Hoyle did not predict the existence of a carbon resonance. He indirectly measured it. It’s sort of analogous to how they found planets way back when. Various other measurements implied that it had to be there. It wasn’t predicted to be there in the useful scientific sense; rather the other measurements told them where to look.

    It’s just not possible for the anthropic principle to predict anything; the physical content of it is the single measurement that life, as we know it, exists. It’s cute that a lot of things can be deduced from that measurement, but it’s not a prediction.

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


    I’m writing a detailed discussion of the Susskind book for my own blog, but here’s the short version: what he’s doing isn’t science because there is no plausible reason to believe it can ever predict anything. I find it disappointing that Duff doesn’t address this issue.

    As for whether the people pursuing this are just a “few”, the list includes Susskind and just about the entire Stanford theory group, Polchinski, Douglas, Weinberg, Arkani-Hamed, and quite a few other particle theorists, as well as many cosmologists (Rees, Linde, Vilenkin, Tegmark). Wilczek is co-author of a very recent anthropic article. Susskind is very explicit the he sees this as a battle for the heart and soul of theoretical physics, and feels that his side is winning, making new converts as time goes on.

    I really wish you’d stop it with the ad hominem argument that my objections to string theory are based on unspecified “personal reasons”. For one thing, we’ve never met and you don’t actually know much at all about my personal reasons. I do my best to stick to scientific arguments about the issues at hand, I suggest you do so too.

  • Elliot

    Forgive a basic laymans question but is the future development of string/M theory now fully wedded to the Anthropic Principle?

    I would assume the answer to this would be no but it would be nice to have that clarified.



  • http://blogs.discovermagazine.com/cosmicvariance/clifford/ Clifford

    Peter… none of us knows the answer to the question about which approach is right. We have opinions about it. Opinions are personal. That’s all I meant. Please stop trying to interpret what I wrote as a personal attack. You keep doing this. I’m not attacking you! Ok? Relax.

    Aaron…. Read Hoyle’s own writings about this. His reasons were anthropic. End of story.



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

    Elliot: No.

    Of course it might turn out that way, but we’re very far away from knowing that. Some smart person might write a paper tomorrow that explains why the vacuum energy is naturally small in string theory, and the whole episode will evaporate. Different people will, of course, have different views about how likely this is.

  • http://blogs.discovermagazine.com/cosmicvariance/clifford/ Clifford

    Elliot: – No. They’re just flirting across the room. The Anthropic Principle has sent a drink over to String Theory’s table.


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

    Clifford, Aaron wasn’t disputing “anthropic,” he was disputing “prediction.” Hoyle used data (our existence) to determine that the resonance must exist — and then we can have semantic quibbles about whether that’s a “prediction” or a “measurement.”

  • http://feynman137.tripod.com/ Nigel


    The scientific community has suppressed a general mechanism for gravity for a decade. This basically looks at the big bang, sees an explosion, calculates the force from the Hubble constant outward, finds that the gauge bosons for gravity will produce an equal reaction (inward), anc calculates it, obtaining gravity as accurately as experimental data warrants. (Afterwards I found that Lesage and Feynman had both investigated it but had managed to screw it up.)

    This has been suppressed from the proper places on the basis of string theory being the accepted theory, and “alternatives” thus being unnecessary (crackpotism).

    I therefore have personal reasons to hate string theory. I wish you would be decent enough to give some publicity to my cause, which is constructive. You might begin with feynman’s error, which is to ignore the fact that bodies contract in the direction of motion, and to assume that there is no contraction, and thus no evidence for a causal spacetime fabric mechanism of gravity.

    Many thanks,

  • http://feynman137.tripod.com/ Nigel

    “Peter… none of know the answer to the questio about which approach is right. We have opinions about it. Opinions are personal.” – Clifford

    This is a damnation of string theory, that it is based on personal opinion, and it also assumes that there is no other approach that is right. I’d say that you are ignorant of the facts http://feynman137.tripod.com .

    I wish you would not speak for others by saying “none know the answer”.

  • Aaron Bergman

    then we can have semantic quibbles about whether that’s a “prediction” or a “measurement.”

    It’s a little bit more than a semantic quibble — if we want to be reasonably Popperian, the reason we focus on predictions in science is that enable falsifiability. Let’s say the resonance Hoyle found wasn’t actually found. That wouldn’t falsify the anthropic principle, so it can’t be an example of a prediction of anthropic reasoning.

  • http://eskesthai.blogspot.com/2005/12/general-relativity.html Plato

    Oh, so string/M theory is more then just “mathematics” and has “science” to it? Oh really:)

    That’s good? From a personal villification Susskind had endured to defend himself, by speaking directly to ID( personal views of Peter and the group) and Anthropic(more form Smolin)present day scenarios, have materialized

    So now that is out of the way. Who said no one was listening to your blog entry Clifford? :) This is the kind of thing that helps, instead of given a widesweeping hand to the subject of string theory as such and such.

    I almost gave up trying to comprehend the model:) Not!:)

    I’ll be good from here on in:)

  • Ted

    I have to say that I agree with Aaron. All applications of the anthropic principle are really just ordinary inferences based on experimentally established results which don’t a priori have anything to do with sentient beings. The only new feature in “anthropic” explanations is the that these experimental results (coincidentally) seem to be necessary conditions for the development of life. For example, Weinberg could have placed upper bounds on the cosmological constant based on the known fact that gallaxies form. As a footnote we could observe that gallaxies seem to be a prerequisite for life. But this is logically irrelevant to Weinberg’s prediction.

  • Maynard Handley

    What is the difference between

    “The 23 parameters of the Standard Model are what they are, random aspects of our universe” and

    “The 23 parameters of the Standard Model are what they are, random aspects of our universe (which by the way also consists of strings, branes, supersymmetric particles, and extra dimensions, none of which I can provide any evidence for, and none of provide any explanatory power)”

    Exactly what is the value-add of 3000 man-years of string theory?

  • Ted

    To drive the point home, suppose there was a race of intellegent fish swimming in a warm and fertile gas cloud foating somewhere between here and Andromeda. Would these fish conclude, based on the fact that the gallaxies were not obviously prerequisite for their existence, that the cosmological constant could be unboundedly huge? Of course not. They would observe the same gallaxies as Weinberg did, and come to his conclusion.

  • Torbjorn Larsson

    Hmm. This is somewhat confusing. Isn’t Hoyle’s and Weinberg’s results examples of some truistic anthropic principle? Which is more or less what Aaron and Ted seems to say, ie the results are consistent with measurements (which are consistent with our existence).

    The landscape seems to me to be about weak anthropic principles, ie about probabilities of values.

    As an innocent bystander I would agree with Cliffords arguments, except that I would like to strengthen 2) to ‘practical predict’ (practical falsifiability) which anyway 4) seems to say.

  • Pingback: It’s Equal but It’s Different » Blog Archive » Physics news…()

  • http://www.crookedtimber.org Kieran

    Personally, I’ve always been amazed at the way the sun comes up in the morning right around the time I’m about ready to get up and go to work.

  • Jack

    What I find annoying about Susskind is that he insists that we *know* that string theory has all these solutions and that, granted this, we *know* that there is no selection mechanism whereby Nature declares that some vacua are more likely to exist than others. His attitude seems to be that anyone who disputes these god-given insights is an idiot. Unfortunately Max Tegmark has a [vastly less obnoxious but still virulent] version of the same disease.
    I think that all such approaches [including eternal inflation and all other theories based on the notion that what we regard as our Universe is just an infinitesimal piece of the whole shebang] should be our last resort, and everyone should be encouraged to search for explanations involving Universes that are as small as possible!

  • Moshe

    Clifford, I am also conflicted but for different reasons. I am not so much concerned with prediction vs. postdiction, granted predictions are more psychologically appealing but in both cases I am more interested in how solid the reasoning is.

    My reason to be conflicted is precisely which type of anthropic reasoning is used. One version uses our existence as experimental input, I generally have no problems with that, though it tends not to give you too much. To get more out of it one has to assume we are typical members in some appropriately chosen ensemble. This is more useful for precise calculations, Weinberg uses it and calls it the principle of mediocracy, note the Hoyle does not need it.

    This is where I get very confused: how is the ensemble to be chosen, if it includes all life then why? and how is that defined precisely, how did we become a typical member of that ensemble (using only causal dynamics) etc etc. This is also when one has a feeling, at least at this stage of the game, that the number of assumptions is at least as large as the number of predictions.

  • http://blogs.discovermagazine.com/cosmicvariance/clifford/ Clifford

    Moshe, your last paragraph hits the nail on the head. It seems that we just don’t really know enough to be truly on a firm footing with this approach, which I why I am very wary, and will remain an observer until I get better internal vibes…. Hence my more conservative view of what I find palatable in this “anthropic” game…. If anthropic reasoning is a sort of philosphy that helps you find new results and predict new things, fine, but I don’t like it being elevated to a sort of “principle” upon which our universe is founded.


  • Moshe

    Agreed Clifford, I am just saying there is no single anthropic approach, there are many anthropic approaches, and they vary from being undeniably correct to being very speculative, depending on precisely what one assumes, which is one reason it is difficult to discuss the subject.

  • Elliot

    Ted and others.

    Consider the following article suggesting even more extreme examples of life.


    Assuming that such bizarre “life forms” could exist, doesn’t this strongly undercut the validity of any anthropic argument by potentially widening the range of acceptable parameters so there is no predictive value left?

    I’d personally really like to see a definitive refutation of the AP once and for all. IMHO it keeps creeping back in and is counterproductive to the effort to truly “understand” what is going on.


  • Aaron

    Thinking about it a bit more, I think the distinction I was trying to make is a bit tortured. As Moshe says, there are a few things that people could mean when they say the “anthropic principle”.

    The simplest is simply the experimental fact that we exist. This bit of data, in the context of a physical theory, can lead to a prediction. The point, however, is that the anthropic principle isn’t being tested here; it’s the theoretical context that is making the prediction. The anthropic principle here is just data.

    After this, you get the Copernican or mediocrity principle: that we should consider ourselves to be equally likely any other qualified being in the multiverse. This is, as I’ve argued elsewhere, fraught with problems. Even if one accepts this principle, however, it does not provide any strict falsifiability. There will always be some scientist in some extremely unlikely universe wondering why its calculations make it seem so special.

    So, I’m still left with the idea that the anthropic principle is completely useless for the actual process of doing science. At best, it’s a justification for what problems one wants to work on; not many people look around for a first principles explanation of the distance from the earth to the sun any more. And, if some people want to stop working on the cosmological constant problem, that doesn’t bother me. I’m not sure I see why they need to proselytize their change in focus, however.

    On another note, I wonder how long it’s going to take for Lenny’s book to get quoted in ID trials. Not having read it, I can’t imagine how it could possibly help things in this particular battle.

  • Aaron Bergman

    Given the recent surfeit of Aaron’s, I suppose I should mention that that Aaron is me. If all goes well, this should change my cookie….

  • Matt B.

    On (1). Why isn’t this predictive?

    If a parameter isn’t measurably different until just beyond the horizon, how does that affect our ability to make predictions here? Or is it only the predictions beyond the horizon that you’re concerned with in this statement?

  • http://blogs.discovermagazine.com/cosmicvariance/clifford/ Clifford

    Moshe, Aaron:- Yes, the biggest problem might be mostly that there are too many meanings of the phrase “Anthropic principle”.


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

    If you take the anthropic principle to be that we are ”typical” observers in the ”multiverse” then we use it all the time when interpreting experimental results.

    I think that Ken Olum gave this example in one of his articles: Cern has failed to detect the Higgs boson and consquently a Higgs below 115 GeV is now ruled out. However, it is only ruled out at a certain confidence level.

    As Aaron wrote above, in a multiverse setting you would expect that there exists unlucky copies of us who live in a world where the Higgs is less massive than 115 GeV. But we simply bet that we will turn out to be the more typical copies.

  • Elliot

    Matt B. It is not “predictive” because we showed up after the value of the constant(s) were set. It violates any reasonable sense of causality.

    Its like saying when a dying man is lying on the floor with bullet holes dripping blood that you are going to “predict” that he was going to be shot.


  • Elliot

    Sean re: your response to #5.

    Are there any “reasonable” prospects (that you are awaare of) for a non-string based/non-anthropic explanation for the value of the cosmological constant?

  • Elliot

    For discussion purposes here are the definitions of AP from Barrow/Tipler. The “carbon based” requirement may be a bit antiquated but I think these serve as good working defininitions

    Weak Anthropic Principle (WAP): The observed values of all physical and cosmological quantities are not equally probable but they take on values restricted by the requirement that there exist sites where carbon-based life can evolve and by the requirements that the Universe be old enough for it to have already done so.

    Strong Anthropic Principle (SAP): The Universe must have those properties which allow life to develop within it at some stage in its history. Because:

    1. There exists one possible Universe ‘designed’ with the goal of generating and sustaining ‘observers’.
    Observers are necessary to bring the Universe into being (Wheeler’s Participatory Anthropic Principle (PAP)). Or…
    An ensemble of other different universes is necessary for the existence of our Universe (which may be related to the Many_Worlds interpretation of quantum mechanics).
    Final Anthropic Principle (FAP): Intelligent information-processing must come into existence in the Universe, and, once it comes into existence, it will never die out.

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


    This is where I get very confused: how is the ensemble to be chosen, if it includes all life then why? and how is that defined precisely, how did we become a typical member of that ensemble (using only causal dynamics) etc etc. This is also when one has a feeling, at least at this stage of the game, that the number of assumptions is at least as large as the number of predictions.

    Tegmark has suggested that the ensemble is just the set of all possible mathematical models. On this set you then need to define a measure favoring less complex models, e.g. models with lower Kolmogorov compexity (i.e. the number of bits to define the model), to make such an approach work.

    Physicists have always had an intuitive notion of this idea. Occam’s Razor is a qualitative notion that you should favor less complex models over complex models. If a theory requires a dimensionless constant that is extremely small or large, we don’t think that is ”natural”. Take e.g. the value of the vacuum energy density.

  • Elliot

    Sorry repost with correct formatting for understandability.

    For discussion purposes here are the definitions of AP from Barrow/Tipler. The “carbon based” requirement may be a bit antiquated but I think these serve as good working defininitions. Also the “many worlds” comment below probably can be replaced with “multiverse” which had not been developed at the time of these original definitions.

    There are three versions

    Weak Anthropic Principle (WAP): The observed values of all physical and cosmological quantities are not equally probable but they take on values restricted by the requirement that there exist sites where carbon-based life can evolve and by the requirements that the Universe be old enough for it to have already done so.

    Strong Anthropic Principle (SAP): The Universe must have those properties which allow life to develop within it at some stage in its history. Because:

    1. There exists one possible Universe ‘designed’ with the goal of generating and sustaining ‘observers’.
    2. Observers are necessary to bring the Universe into being (Wheeler’s Participatory Anthropic Principle (PAP)). Or…
    3. An ensemble of other different universes is necessary for the existence of our Universe (which may be related to the Many_Worlds interpretation of quantum mechanics).

    Final Anthropic Principle (FAP): Intelligent information-processing must come into existence in the Universe, and, once it comes into existence, it will never die out.

  • ksh95

    Hmmm. Tell me which has lower Kolmogorov compexity. The galaxy of andromeda or my pet sloth wibble.

  • http://d5theory.blogstream.com jim wood

    i have a possible alternative to the 2-dimensional argument between intelligent design vs dumb-luck that can be scientifically tested. if anyone is interested my blog is http://d5theory.blogstream.com

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

    Elliot, you asked whether there are reasonable prospects for a non-anthropic explanation for the cosmological constant. Right now none of the ideas seems very compelling, and people have been thinking about it for a long time. But this is a problem that intrinsically involves both gravity and quantum mechanics, and that’s something we don’t understand very well at this point. So it’s just impossible to tell.

  • Aaron Bergman

    The coincidence between the seesaw scale and the cc is rather intriguing, however.

  • Moshe

    Count Ibis, thanks but I am still confused. The issue is the use of (conditional) probabilities. A possible way of justifying this would be a theory which is well-understood enough such that we know the set of all possible states and the processes to make transitions between them. In that case one can envision calculating some sort of meaningful probability distribution. Absent of that, it is anybody’s guess what is the correct ensemble and probability distribution over it, and I have no criterion for judging different proposals.

  • Elliot


    Now you’ve got my laymans curiosity aroused. Can you give a reasonably accessible definiton of the “seesaw scale”?



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

    I’m sure Aaron will chime in, but — it turns out that the scale where we hope to find supersymmetry breaking (about one trillion electron volts, or one TeV) is approximately the geometric mean of the vacuum energy scale (of order 10^-15 TeV) and the Planck scale (10^15 TeV). All you need is a theory that explains why that might be so. It’s reminiscent of the seesaw mechanism, which is a way to explain why the electroweak scale (of order 10^-1 TeV) is the geometric mean of the neutrino masses (10^-15 TeV) and the GUT scale (10^13 TeV). In the case of neutrinos, there are actual models which make this happen via diagonalization of certain mass matrices; in the case of the vacuum energy, it’s just wishful speculation at this point.

  • Aaron Bergman

    I think Sean’s got it pretty much covered.

  • Elliot

    Aaron/Sean. Thanks. I think I kind of get it 😉


  • http://eskesthai.blogspot.com/2005/12/general-relativity.html Plato

    The thoughts about the relationship of positons always comes back to “Susskind and Smolins” comparative views on the Edge.

    But for sensibilities and reason, if we had held to such a thought, such a “superfluid” which could exist?

    Then what role would this play in cosmolgical design?

    What guiding principal Anthropic design if not held to a finer constitution such as here?

    At last, Dantas response to Peter Woits “Canonical voice” from “the group,” speaks for those of us less adept.

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

    What a total disappointment, I wonder if it’s too late to cancel my book order and my membership to a society that is so afraid of a statement like the following that they would make every possible excuse for concocting some imagined “formal refutation” of something that serves as a powerful form of supporting evidence for the validity of our best theories.

    How lame is that?… no more lame than this:

    the appearance of intelligent design is undeniable

    What a dumb statement, Lenny, you’ve quite obviously bought right straight into the creationists hype that “the appearance”, (as you call it), of purpose in the forces of nature, can ever possibly constitute evidence for intelligent design in a universe where every known cause is natural. What has happened to science that they let creationists dictate stupid ideas like that? There can be no such “inference” without direct proof!

    What is it that makes people ignore the fact that the multitude of anthropic coincidences are balanced, either precariously, or they are attracted to a location that lies **near** exactly between diametrically opposing runaway tendencies, where any sustained difference *would* result in conditions that are so far away from your wildest dreams for what constitutes life, that “life as we know it” is the only possible form of life that is even possible.

    What makes people make lame statements that are prejudicially designed to downplay the significance of the anthropic principle by willfully ignoring the actual implications of the evidence?

    “I can’t believe that the Sun comes up at about the same time that I go to work every day”… please, the fact that conditions have to be the way that they are does not even come close to getting it when you think about the above for about no seconds compounded exponentially by orders of magnitude with each additional coincidence.

    I dunno about everybody elses mega-multi-fantasy-universes, but I do know how a vacuum works, and I do know that an ENTROPIC anthropic principle is most-natural in a predominantly expansive universe, so flatness, structure, and even gravity must necessarly still be related to the energy dissemination process.

    I know, for example, that an expanding vacuum has negative pressure, because its density is necessarily less than that of matter, and so the force of the energy is directed in the opposite direction. This results in an antigravity effect which cancels with positive gravitational curvature, thus mimicing the mysterious negative mass effect that showed up in our equations about the same time that physics lost touch with reality. A Positron that is made from this energy must have positive mass because it has positive matter density once the negative pressure energy is condensed down over a finite enough area of space.

    I also know that particle creation from negative pressure energy holds any normal universe flat while causing expansion by way of further vacuum rarefaction because this necessarily results in a counterbalancing increase in both, negative pressure and grvity. So tension between ordinary matter and the vacuum increases instead, and continued expansion will inevitably compromise the integrity of the forces that bind the universe, eventually… and boom goes the causality problem… the horizon problem, the flatness problem, Matter/Anti-matter asymmetry problem, the cosmological constant problem… etc… but without need of an inflationary band-aid scenario.

    I know that Supernovae, Black Holes, and us wee-little humans are the only known or expected sources for vacuum expansion in a universe that expands via the described form of matter generation, except that we are the MOST energy-efficient at it out of all of them.

    And finally, I know that such a defined need for these highly specialized dissipative structures necessarily extends the principle to its biocentric form, where life will necessarily be as common as the universal scale need for it demands.

    So if you want a prediction, then let it be this:

    SETI will prove that the anthropic principle is a biocentric thermodynamic principle that’s predicting that the skies are going to light-up across the universe near-simultaneously with radio transmissions from very similar life-forms on every banded spiral galaxy that exists on the same evolutionary plane as us… at near exactly the same time… in the history of the universe.

    I just hope that we don’t mistake them for god and pretend like we didn’t hear them, because we’re too afraid of what creationists might make of it.

    …must’ve been random patterns in the matrix, but the appearance of intelligent design was uncanny


  • Aaron Bergman

    So, I can’t help but post this somewhere:

    Latest gossip I hear is that WMAP is set to say that the spectral index is less than one at 3 sigma.

    Just throwing that out there. This was apparently announced at a conference in Europe, so I assume it’s ok to publicize it. Any thoughts from our hosts?

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

    Haven’t heard anything myself. I presume if it’s true, we’ll be hearing soon enough.

  • Thomas Larsson

    Latest gossip I hear is that WMAP is set to say that the spectral index is less than one at 3 sigma.

    So what would the implications of this be?

  • Elliot


    Lets assume your prediction about the ubiquity of life was correct. It still DOES NOT affect in any manner whatsoever the basic parameters underlying our universe as the parameters were here first. There’s the rub.

    I don’t understand how you don’t see the obvious causal paradox inherent in particularly the SAP. The WAP is simply a statement of the obvious (with the causal paradox inherent) and the FAP is religion or something like it.

    Our existence constrains nothing that happened 15 billion years ago. Our existence is an emergent feature of the universe. In my opinion the goal of science is to understand how and why we are here not use the fact we are here and work backwards. I don’t have a problem in using the fact that we are here as a data point but this whole line of reasoning is fundamentally flawed. If string theorist are beginning to embrace it they do so at their own peril in my opinion.

  • Dissident

    #46: A scale-invariant fluctuation spectrum is usually stated to be a prediction of inflation (though the odd Dissident has been known to question that whole line of reasoning, so if true, this would pose a problem for inflation-based scenarios. Maybe time for Luminet et al to get a second hearing on their football universe?

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

    It’s actually the opposite of what Dissident just said, I’m afraid. The generic prediction of inflation models is a nearly scale-invariant spectrum of perturbations. Whatever the precise measurement turns out to be, we already know that it’s nearly scale-invariant; the question is, how close? In fact, if inflation is right, it would be kind of surprising if the spectrum were extremely close to scale-invariant; it’s easier to deviate by 5% or so. So if there is evidence for a deviation from scale invariance, it will fit into the inflationary paradigm very nicely, and would presumably be a stringent new constraint on inflationary models.

  • Dissident

    Hm, I may have overinterpreted the gossip. I thought Aaron was implying a sizable deviation from 1. Let’s put it this way then: at what level of deviation form 1 would the “new constraint” on inflation become difficult to satisfy? If 5% is OK, what about 10%? 20%? Where does it become troublesome?

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

    Current limits are already better than 10% or so. Anything we discover at this point will count as “nearly” scale-invariant.

  • Dissident

    OK, then I guess the only way this could become really interesting is if the WMAP people came out and said their data is in conflict with current limits – thus explaining the long delay in the official release, I guess.

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

    Anthropic structuring is perpetually inherent is the point, Elliot, I think you’ve missed that LaPlace’s demon is valid in the finite bound closed spherical universe where “god” doesn’t throw dice. We represent a cumulative emergence of something that was determined at the get-go by the constraints that were convolved forward into the matter field by our big bang. The stucturing is perpetually inherent, in other words.


    The EWAP, (entropic weak AP), is about environmental enabling:

    1) The observed values of all physical and cosmological quantities are not variable, but are fixed by the requirement that there exist sites where carbon-based life will arise and evolve when the universe is old enough for the cumulative gravitational effect to require us to do our thing.

    The ESAP is about… why:

    There exists one universe that has perpetually inherent stucturing, with the goal of generating and sustaining disspative structures that are capable of enabling a universal scale evolutionary leap ever closer to absolute symmetry.

    The EFAP is…

    1) Who cares, ours is a blue colar universe, not an academically derived idealization where intelligent information processing is merely an efficiency enabling mechanism.

    2) There is a weird implication for some kind of universal self-awareness when the skies light up simultaneously… *que erie music*… I’d hate to read too much into that!


    Right-on, Dissident!

    … or can we ignore direct observational evidence that the Copernican Cosmological extension is superceded by something that’s more biocentric in nature?…



    … and that Einstein was right all along about higher structuring in nature, because the most natural extension of his theory with a cosmological constant is not unstable after all, because matter generation in this model causes the previously described effects which hold the universe flat and stable as it expands?

    After all, the creationists might twist it into some kind of supernatural god theory, donchano?


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  • http://eskesthai.blogspot.com/2005/12/general-relativity.html Plato
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