Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Smolin: Anthropery is not science

  1. Jul 26, 2004 #1


    User Avatar
    Science Advisor
    Gold Member
    Dearly Missed

    this just out

    An new essay by Smolin, to be a part of a book that Cambridge University Press is publishing (edited by Bernard Carr et al)

    http://arxiv.org/hep-th/0407213 [Broken]

    "It is explained in detail why the Anthropic Principle cannot yield any
    falsifiable predictions and therefore cannot be a part of science."

    Smolin offers an alternative that he argues does yield falsifiable predictions which, although it has not so far been shown false, is nevertheless vulnerable to refutation by observations now planned or in progress.
    Last edited by a moderator: May 1, 2017
  2. jcsd
  3. Jul 26, 2004 #2
    Did you have a proper link for this Marcus?
  4. Jul 26, 2004 #3


    User Avatar
    Science Advisor
    Gold Member
    Dearly Missed

    There I fixed it, earlier i wrote http:arxiv
    instead of http://arxiv [Broken].
    thanks for getting me to correct it.

    Hi sol,
    you know I have never gotten much interested in the Anthropic
    business in string theory, so i am posting this in case other people
    want to discuss it. If no one wants to that's fine with me.

    Smolin's article is also about the Multiverse business, how there could
    be lots of other regions with different fundamental constants---different alpha, different Lambda---essentially different physical laws.

    He has an idea how universes might EVOLVE by those values of alpha and Lambda being favored if they were in the right range to cause the universe to have a long life and make lots of baby universes-----good genes are those that get passed on a lot.

    Again I have to say that this idea may be a fascinating one but I didnt personally get involved with it. It may actually be an experimentally testable theory explaining why our alpha is what it is: very close to 1/137 (which happens to be so good for the existence of complex life and long-burning stars.) but I put it out just in case it might interest others.

    the paper is called

    "an alternative to the anthropic principle"

    the link should work now
    Last edited by a moderator: May 1, 2017
  5. Jul 27, 2004 #4


    User Avatar
    Science Advisor
    Gold Member

    I find that unpalatable. The anthropic principle, I believe, is the only 'given' that is absolute. The fact we are here [and I presume most everyone will agree with that] precludes solutions that forbid our existence. I'm not excluding the possibility of universes where creatures, such as us, do not exist. Just excluding the possibility they are relevant.
  6. Jul 27, 2004 #5
    Thanks Marcus

    The Anthropic Landscape of String Theory

    Leonard Susskind


    On page 11 Smolin's article also refers to the use of the word Landscape? :smile:

    Of course we all like to have proof of all these theoretics.
  7. Jul 27, 2004 #6


    User Avatar
    Science Advisor
    Gold Member

    Ranting. I object to using unobserved extra dimensions to explain the four we can observe. Apologies to all. I am old, stubborn, and won't let go of background independent relativity until somebody sticks the observational evidence in my face.
  8. Jul 27, 2004 #7


    User Avatar
    Science Advisor
    Gold Member

    More ranting: I wasted 4 years of my life trying to prove Einstein was wrong [keyword: wasted]. He was not wrong. Even his 'cosmological constant' was totally on target. Einstein saw more than we even dreamt of seeing.

    I really get frustrated when the truly brilliant people here go off on tangents. What a waste of brain power. I will never be as smart as you guys. I lurk in the background and watch.
    Last edited: Jul 27, 2004
  9. Jul 27, 2004 #8


    User Avatar
    Science Advisor
    Gold Member
    Dearly Missed

    Hello Chronos, let's not quarrel about Anthropism. I for one am not concerned with it. (however Smolin may have some useful points to make, why not read his essay?)

    I think all he is saying is that a scientific theory is meaningful only to the extent that it is falsifiable---runs the risk of making predictions which can cause it to be shot down.

    so a principle can be a valid part of Philosophy and of one's system of beliefs without necessarily being a part of science. this is a rather strict idea of Science but at least it is clear---a scientific theory is meaningful only to the extent that it is vulnerable to empirical refutation.

    I'm cool with that, I have a number of important tenets and faiths and convictions that are not empirically testable. Also i like certain poems.
    It is obvious to me this is an absolutely wonderful universe and very conducive to a happy wholesome life (if we could just get our act together).

    So I propose to believe whatever you say in an Anthropic vein---to agree with you wholeheartedly----but not to consider it part of science. Do you think we can manage that in a spirit of peace and fellowship (if some problem with it please say) :smile:

    are you claiming Curmudgeon status BTW? this is or should be a position of high honor
  10. Jul 27, 2004 #9
    Einstein was more than right, but I believe that his 'wrong' lines of workings were actually deliberate! May be due to the surrounding Human and scientific worldwide problems of the day. Some of the so called greatest minds of early last century mocked Einstein and his 'later years', the much quoted sentence of:Einstein wasted the later years of his life working on an Unified Field Theory, which yeilded no scientific fruits?

    Or...did he? :biggrin:

    It is no coincedence that Some of Einsteins greatest work is placed in specific writings, "Time-locked" for "future" generations hidden (so presicely) between the pages of the very distinct book , which has the title:Albert Einstein-Out Of My Later Years.

    This is Einsteins Magnum-Opus, ..you just have to read its content in a certain way..with the awe of a Child of unbiased learning.
  11. Jul 27, 2004 #10


    User Avatar
    Staff Emeritus
    Gold Member
    Dearly Missed

    Last edited by a moderator: Apr 21, 2017
  12. Jul 27, 2004 #11


    User Avatar
    Science Advisor
    Gold Member
    Dearly Missed

    I thought about making this my sig
    (as a quote from you)
    I wouldnt excuse it as ranting though, Or apologize
    for steadfast rejection of the unobserved.

    In one of the historical parts of Rovelli's book he argues that
    major scientific advances have not been achieved, as a rule,
    by "Great Leaps of Imagination" but actually in a conservative
    manner by taking seriously what you already had that worked
    and modifying it only as much as you had to.

    One of his examples was 1905 Special rel---something about
    taking seriously both galilean relativity and Maxwell equations
    and not wanting to let go of either-----and not going for novelty
    but simply making the minimum modification necessary (different time for
    different folks) to get consistency. I'm not sure I got this right
    but there is a philosophical part of that book that argues for this
    kind of conservative taking seriously the core of what works and
    avoiding the Wild Goose of novelty.

    It struck me as a good motto so I tried to imagine it as a sig.
    The following is a test (not a real sig)

    What extra dimensions? I'll hold to background independent relativity until observational evidence shows it wrong.
  13. Jul 27, 2004 #12
    Any one of us could be the negative :smile: and from that, a position taken.

    I like Olias's perspective on what could have "spaces inbetween" and find that in future years Einstein's implication still reverberating(what is the dimensional significance of this statement if we consider Ramaujan view about the reality we live) and holding a collider eye to the very fabric. I mean we take reductionistic processes and we find this vast field of energy, being really fuzzy, we had only gone so far to Planck length? So we had to explain the energy? Some particle trails leave us wondering and the rest of the energy?

    So what lies beneath? Geometrically, the necessity of consistancy, cries for some continuance, expressed logically. What had been learnt so far in these extension through this historical journey? Can LQG and M Theory succeed in this quest?

    Are we so wrong then, if we look at emergent realities that one might have built glass palaces for living theoretcally in , while we look at all the rooms? I do not think we should all be faulted at trying to explain this reality, and at the same time find discoveries along the way.

    Smolin recognizes the philosphcal journey that must be taken and speaks to the rational and logical requirement such journies must take. Much like Peter Woit on demands for scientific validation require a more fundamental approach, but still to me, the imaginiative valution of theoretical journies are quite artistical embued. You have to be creative as well as logical. I think the etiquette of scientifdic pursuate is generally well understood.

    We do not discard the anomalies of perception(Kuhn) that cause great consternation in what is wrong with our views, that we set it all aside becuase it just doesn't make sense. You plug away. Some did not not find the connecting circumstance so they discard the view.

    My statement should read opposite Marcus's and I admire Marcus determinations. The Solvay format is very much alive when we accept the spirit of it :smile:


    What extra dimensions? I'll hold to the background dependant :smile:
    Last edited: Jul 27, 2004
  14. Jul 27, 2004 #13


    User Avatar
    Science Advisor

    Please be aware that there are many anthropic principles. They run the gamut from simple common sense to the metaphysical. I haven't looked carefully, but the author might only be assailing the cosmological anthropic principle, as espoused by Barrow and Tipler.

  15. Jul 27, 2004 #14
    So again Smolin Takes us to the Edge?

    You have to understand his mode of operandi? :smile: There is always this proverbial headshaking that goes on, and a consolidation of factors, when you become spread out? Sort of like a greg egans Gravity well picture? :smile:

    http://citebase.eprints.org/cgi-bin/search?submit=1;author=Smolin%2C%20Lee [Broken]

    So we are back to earth and have taken our heads out of the clouds have we? Its funny how you can look up at the clouds and see this changing reality, and if you look hard enough, for sure, there seems to be this animal or that face? :smile:

    Do anomalies of perception pay off? Maybe Einstein asks us to look deeper?They most certainly do in science
    Last edited by a moderator: May 1, 2017
  16. Jul 27, 2004 #15


    User Avatar
    Science Advisor
    Gold Member
    Dearly Missed

    Smolin introduced the "Landscape" in 1995

    It is interesting to note that Lenny Susskind and other string theorists have recently (essentially since Kachru's paper and the 10100 possible string vacuums) become converts to Smolin's 1995 idea of
    the "Landscape" of possible parameters of the Standard Model----essentially an evolutionary landscape of possibility for the laws of physics.

    I went back to Smolin's landmark 1995 paper where he introduced the concept of the Landscape

    http://arxiv.org/gr-qc/9505022 [Broken]
    Cosmology as a problem in critical phenomena
    Lee Smolin
    (see page 33)

    "...We can then make predictions about our world if there are statistical predictions that can be made about the properties of randomly chosen members of this ensemble. We can do this because this theory is isomorphic to models of biological evolution, in which natural selection is described in terms of the evolution of probability distributions on fitness landscapes.

    As a result there is a natural mechanism of cosmological self- organization, that is formally analogous to biological natural selection. It goes like this. We may consider the space of parameters of low energy physics to be analogous to the space of genes. On this space there is a “fitness” function, which is the average number of black holes produced by a region of the universe that expands from a bounce.

    Now, just like the fitness functions of biology, this function is strongly variable, as I said in our universe it is quite large, and there are simple astrophysical arguments that tell us that with many values of the parameters it will be much smaller. The reason the fitness function is strongly variable is worth mentioning: it is that it is not easy to make a black hole. In our universe, a black hole can only be made if a large amount of matter can be compressed into a very small space, and for this to happen there must be rather special circumstances. The fact that this happens at least once a century in each galaxy..."

    the more I see of Smolin's work the more it impresses me

    In 1995 he is talking about quantum gravity removing the Black Hole singularity and replacing it by a quantum bounce that continues into an extension of our spacetime which (because of the horizon) we cant detect signals from and which may therefore be considered (if one wishes) as another universe---one with parameters (fundamental constants) to some extent inherited from ours.

    And dammit if yesterday that postdoc Leonardo Modesto didn't go and put up his paper which uses quantum gravity to eliminate the Black Hole singularity and replace the classical ex-singularity with a bounce---and a continuation of spacetime.

    But the stringers didnt go Landsc ape AFAIK
    S. Kachru, R. Kallosh, A. Linde, S. P. Trivedi, de Sitter Vacua in String Theory hep-th/0301240
    that is, until january 2003
    and even then they seem to be appealing to Anthropery!

    Smolin saw the landscape in 1995 and called it a landscape by analogy
    with the pre-existing concept in Evolutionary Biology
    (which does not require the Anthropic Principle!)
    Last edited by a moderator: May 1, 2017
  17. Jul 27, 2004 #16
    You have to remember Marcus, that each one of these guys is being influence by the scholarly envirnoment around them. This does not limit them to branches, but forces them tospeak to new starting points in their considerations.

    They are all trying to describe the same thing but in different ways?

    Some like Chernekov's version, and is pleasing to the color palette of experienece? :smile: Some like pure abstractness.

    Pretend you were raised in the wild and had never seen straight lines? :rofl:
  18. Jul 29, 2004 #17

    It is important for me to see the sequence of events as they are unfolding for you Marcus, and by looking to Baez, you are true to form with guiding principals? :smile:

    Last edited by a moderator: May 1, 2017
  19. Jul 29, 2004 #18
    This is exactly what I was complaining about earlier, in the "not even wrong" thread. Smolin claims the anthropic principle isn't falsifiable. Of course it isn't: it's an epistemological or decision-theoretical principle, not a contingent claim about the physical world. The question whether it's valuable is a philosophical, not scientific question. The same is true of the "principle of mediocrity".

    Okay, so then we can read Smolin as saying that it's theories like eternal inflation, with its multiverse, that aren't falsifiable. But then he claims that non-falsifiable theories should automatically be taken as false. I think this is bizarre: we have no business telling nature how to behave, and whether a theory is experimentally testable has no bearing on whether it's actually true (though of course, the more tests a theory passes, the more likely it is to be correct).

    The rest of the paper left a bad taste in my brain as well. I'm not convinced Smolin's reproducing-universes theory is any more falsifiable than e.g. eternal inflation: (IIRC) he refers to the fact that under his theory "almost all" universes should have parameters optimized for black hole production. This seems like a dubious claim to me, given that (IIRC) there are infinitely many universes under his theory, making "almost all" a difficult concept. More importantly: he can't claim that observing different parameters would falsify his theory, because our universe could be one of the exceptions. Such an observation would make his theory less probable, but then we're out of Popper-land and into Bayesian probability theory and decision theory, which is IMO the only place where all these anthropic questions make sense in the first place (Smolin doesn't even mention it).

    It looks to me like Smolin misunderstands the relevance of Weinberg's explanation of the cosmological constant as well. It's not just that the cosmological constant can be predicted from the observed fact that there are galaxies; we can explain the CC by the anthropic principle because all the observers in the universes with too high cosmological constants just aren't there.

    Smolin dismisses the "doomsday argument" as ridiculous because of an objection that is dealt with in the first entry of the FAQ and another that is dealt with in question 6. All this leads me to think he hasn't even bothered to read up on what philosophers think on the subject (or googled for a minute). He's much more fanatical than the strength of his arguments allows, just like in his book Three Roads to Quantum Gravity (which I recall as having interesting science content but trying to force badly-argued philosophy on me).

    Blegh. Sorry for ranting.
  20. Jul 29, 2004 #19

    You have to understand this is a cosmological view that had to be defined, and this is being looked at in different ways?

    If critical density of OMega is being established, then what is happenng to our unverse? Remember we are talking about billions of years here and the universe has allowed us to consider the dynamics taking place.

    You must undertsand where Smoln and those of LQG(SRians) have placed themselves in their attempts at discribing the nature of this uinverse and how M theory(GRaniums-members of the http://astrosun.tn.cornell.edu/courses/astro201/images/merc_adv.gif [Broken]) :rofl: is doing likewise. These are the new flower children of science :biggrin:
    Last edited by a moderator: May 1, 2017
  21. Jul 29, 2004 #20


    User Avatar
    Science Advisor
    Gold Member
    Dearly Missed

    I am trying to sort this out. here are some quotes. Let's be sure we are all talking about the same AP and understand Smolin's critique of it:

    "I have chosen a deliberatively provocative title, in order to communicate a sense of frustration I’ve felt for many years about how otherwise sensible people, some of whom are among the scientists I most respect and admire, espouse an approach to cosmological problems that is easily seen to be unscientific. I am referring of course to the anthropic principle. By calling it unscientific I mean something very specific, which is that it fails to have a necessary property to be considered a scientific hypothesis. This is that it be falsifiable. According to Popper[1], a theory is falsifiable if one can derive from it unambiguous predictions for doable experiments such that, were contrary results seen, at least one premise of the theory would have been proven not to apply to nature."

    "...I also have no argument against straightforward consideration of selection effects, so long as the conditions invoked are known independently and not part of a speculative theory that is otherwise unsupported by any evidence. I will discuss this in some detail below, but the short version is that there simply is a vast logical difference between taking into account a known fact, such as the fact that most of the galaxy is empty space, and arguing from a speculative and unproven premise, such as that there is a large ensemble of unseen universes.

    In recent discussions, the version of the anthropic principle that is usually put forward by its proponents as a scientific idea is based on two premises.

    • A There exists (in the same sense that our chairs, tables and our universe exists) a very large ensemble of “universes”, M which are completely or almost completely causally disjoint regions of spacetime, within which the parameters of the standard models of physics and cosmology differ. To the extent that they are causally disjoint, we have no ability to make observations in other universe than our own. The parameters of the standard models of particle physics and cosmology vary over the ensemble of universes.

    • B The distribution of parameters in M is random (in some measure) and the parameters that govern our universe are rare.

    This is the form of the Anthropic Principle most invoked in discussions related to inflationary cosmology and string theory, and it is the one I will critique here. Here is the basic argument why a theory based on A and B is not falsifiable..."

    Onto, Chronos, sol, and others, are we all talking about the same thing in this thread? If so, let's proceed.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook