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Bad Science and the Anthropic Cosmological Principle

  1. Apr 8, 2005 #1
    "Bad Science" and the Anthropic Cosmological Principle

    Many observers have noted that the physical laws, parameters and constants of our cosmos appear to be remarkably "fine tuned" in accordance with our existence. There are a number of suggestions that if certain parameters were to be significantly different to what they are then the cosmos would be completely different and possibly unable to support life (see for example Barrow & Tipler's book The Anthropic Cosmological Principle).

    If (and I grant that is currently a big "IF") one accepts that the cosmos does appear to be fine-tuned in accordance with our existence, then I believe there are three basic possible approaches to understanding this particular observation :

    Argument from Design
    One possible answer is that the universe comprises one cosmos, and our universe was simply designed this way (ie to support life). This would then be strong evidence for a "Designer". This would explain why the physical laws, parameters and constants are what they are, and also why they are consistent with intelligent life. Of course it does mean that "humans are special" (but that is exactly what we would expect if the universe had been designed for us!).

    Argument from Good Luck
    Another possible answer is that the universe again comprises only one cosmos, and the physical laws, parameters and constants all arise from (ie are predicted by) some grand Theory of Everything (ToE), which ToE also (fortuitously for us!) happens to be compatible with the emergence of intelligent life. However, this approach has the unsatisfactory consequence that although it would explain "why" the physical laws, parameters and constants are what they are, it would NOT explain why they also happen to coincide with the requirements for intelligent life. Like the Design argument, this hypothesis would also seem to put humans in the position of "we must be special", since there is only one cosmos, and fortuitously the ToE which constrains the parameters of that cosmos is also just right for our existence!

    Argument from Anthropic Considerations
    A third possible answer is that the universe comprises a multiple (possibly infinite) number of possibly parallel "worlds", of which we happen to inhabit just one. Each "world" has slightly different physical laws, parameters and constants (perhaps selected at random in each one), and (as we would expect) only some of these are compatible with the emergence of intelligent life. We, of course, happen to inhabit one of the compatible ones. This argument has the advantage that it posits no Designer, does not require any fortuitous fine-tuning of parameters, and consequently also implies that "we are not special" (we just happen to have emerged where conditions were right). Such a principle could also be consistent with the many "eternal inflation" theories going the rounds.

    In summary :

    Argument from Design : There is one cosmos, we are special, and there is a Designer.
    Argument from Good Luck : There is one cosmos, we are special, and there is a ToE which fixes the parameters.
    Argument from Anthropic Considerations : There are multiple worlds, we are not special, and there is no ToE which fixes parameters.

    The Anthropic argument is often criticised on the basis that it makes no testable predictions, and for this reason is usually rejected by many mainstream scientists as being "Bad Science". Presumably most of these scientists would favour instead the "Good Luck" argument, and prefer to spend their time in pursuit of the ToE.

    I want to say some words in defence of the Anthropic argument.

    Firstly, if it turns out that the universe IS very finely tuned to support our existence, then it seems to me that the Anthropic argument is the ONLY one of the three explanations which does not assume a "special status" for human beings. As a scientist, this is appealing to me, and I think should be appealing to others.

    Secondly, if the Anthropic principle IS correct, then we may end up wasting an enormous amount of time and energy trying to chase the Holy Grail of a ToE which does not exist.

    Thirdly, it may indeed be the case that the Anthropic argument does not make any testable predictions at the moment, but this does NOT mean that it will continue to be devoid of predictions forever. If we do indeed live in a universe comprising "multiple worlds" then it may be the case that one day we can somehow probe the other worlds (which should have different physical parameters to our own). Just because an hypothesis cannot make testable predictions today is NO reason to consign it to the trash heap.

    In closing - a small joke :

    A drunk was down on his hands and knees under a streetlight at night, obviously looking for something. A policeman came along and asked him what he was looking for.
    “My keys,” replied the drunk.
    The officer, in much better shape than the other, could plainly see there were no keys there. Curious, he asked “Where did you lose them ?”
    To the officer’s surprise the drunk pointed down the dark street and said, “Back there.”
    “But if you lost them down the street,” asked the policeman, “why are you looking for them here ?”
    “Because,” came the drunk’s reply, “the light is much better here."

    In searching for the ToE and ignoring the Anthropic principle, are we, like the drunk in the story, perhaps searching for solutions only where the light makes it easy to see?

    MF
    :smile:
     
  2. jcsd
  3. Apr 8, 2005 #2
    A grand theory of everything doesnt necessarily involve what your saying it would. For example physicists are trying to merge gravity with QED, if done then that would be their holy grail, ToE. But I know what your saying, a ToE for exsistence. What is the point of your post? Are you asking a question? I have already figured out everything you said on my own. Everything is clearly designed for the development and support of life. Besides what would be the point of the exsistence of a vast Universe, full of rocks?

    parallel worlds? No. Why? What is the point of parallel worlds? Anyone who even mentions them is a nut. Besides they dont work.

    "humans are special", you better believe it. Are you kidding me? Damn right we are. Can you even imagine a species uh, more special? I can't. I mean I could, but who knows where we will go, evolve into. On the question of how advanced are we, Id say pretty damn advanced, and we arent going backwards only forwards so who knows where we will go. Eventually, we will know how it all goes together, and when we reach that point, what is the difference between us and the original creators?

    Basically it goes like this, in order to create the Universe we live in, you need to figure out the laws of physics. In other words you cannot create the Universe without establishing laws of physics first, then implement them- by experiment. You cannot create the laws of physics without knowing them, you cannot know the laws of physics without learning the laws of physics - by experiment, by test worlds to get everything to work together. The Universe and the laws of physics didnt just create themselves, didnt just bang into exsistence, there is just NO way.

    My 2 cents.
     
  4. Apr 8, 2005 #3

    Chronos

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    I'm not convinced we will ever find the ToE to end all ToE's. It would be a huge disappointment if we did, for it would signal we have reached the limits of our imagination. Every answer raises new questions. We know less about the universe now than ever. And the questions are profoundly difficult. A few centuries ago our ancestor looked at the night sky and wondered "What is that fuzzy blob in the constellation Andromeda?". A door that opens into a room with no other exits is called a dead end.
     
  5. Apr 8, 2005 #4

    SpaceTiger

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    A link to a similar thread in the philosophy section. Most of what I have to say on the issue was covered there.
     
  6. Apr 13, 2005 #5
    Yes, sorry, I should have said that to my mind a ToE would be what it claims to be - a Theory of Everything (not just a theory linking gravity & QED).

    I am trying to stimulate discussion and an exchange of views - isn't that what a forum is supposed to be for?

    Well done!

    No, this is not "clear". Does this mean that you support the "Design" argument?

    Why does there have to be a "point"? Is there purpose in everything?

    I could say that anyone who believes in a Designer is a nut, but I have more respect for my weak-minded brethren. :smile:

    Oh yes they do.

    I think you totally misunderstand the meaning of special in this context. Have you heard of the Copernican Principle?

    This does not logically follow, but I respect your faith. Thus you believe the universe was designed and created by something even greater than the universe?

    MF
    :smile:
     
  7. Apr 13, 2005 #6
    I tend to agree with you. I suspect it may be "turtles all the way down".

    But if it turns out that the universe is "finrly tuned" to allow our existence, then I would put my money on the Anthropic principle rather than one of the other explanations (because the other explanations simply replace one question with a deeper one).

    MF
    :smile:
     
  8. Apr 13, 2005 #7

    marcus

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    I am sympathetic to the general spirit, but I wonder if you would accept as a FRIENDLY addition to your trichotomy a fourth possibility.

    this is the possibility that the parameters of the standard models of particle physics and cosmology are "fine-tuned" to promote the abundant formation of black holes.

    not "fine-tuned" a conscious agency, of course, (the almighty Turkey of the Cosmos, who happens to like black holes :smile:) but that the parameters HAPPEN TO BE FAVORABLE to black hole formation, which may be explainable or may not be.

    One possible explanation for why the physical constants seem favorable to black holes has been offered (you may be familiar with the paper) in the 2004 paper "Scientific Alternatives to the Anthropic Principle" due to be published this year by Cambridge Press.

    the conjecture appears to be empirically testable----i.e. possible to refute if one could find some parameters which are grossly suboptimal from the BH production standpoint.

    to make a lot of black holes you need a long-lived tract of spacetime that doesnt die in a crunch soon after inception, and which does not expand too fast for galaxies and stars to condense, and which has enough heavy elements like carbon etc to help gravitating clouds radiate away heat so they can condense. and one may guess that there should be not too high a limit on the mass of neutron stars above which they collapse-----so it seems possible that a lot of the constants of physics could be included in the picture and constrained by this requirement (this is what the author of "Scientific Alternatives" tries to accomplish)
     
  9. Apr 13, 2005 #8
    I disagree with the way the second argument is presented. There is no need for the existence of a TOE for the good luck argument to be applied.

    In fact, I disagree with the third as well. There is no need for the lack of existence of a TOE in that case; there could be a TOE that allows many universes of which we are one. The landscape of string physics is one such example.
     
  10. Apr 13, 2005 #9
    certainly open to suggestions.....

    ok..... but so far this seems to be very similar to the third option - the anthropic principle - if black holes are necessary for the existence of intelligent beings. However I see no reason why black holes should be necessary for the existence of intelligent beings - so why does it matter whether the universe contains black holes or not? (I think I know the answer, but am asking the question because you have not stated it explicitly.....)

    Nope, can't say I am familiar with the paper. What is the explanation you refer to please?

    OK.

    OK, but you have not explained why it should matter whether the universe contains black holes or not?

    MF

    :smile:
     
  11. Apr 13, 2005 #10
    Can you elaborate please?
    (1) assumes Design - good luck is hardly relevant here (the universe is the way it is because it was deliberately designed that way)

    and

    (3) as I have stated it assumes an unlimited (infinite?) number of different worlds, each with different parameters, thus all possible combinations of laws exist and we happen (necessarily) to inhabit a world where the laws allow our existence. There is therefore also no "good luck" involved here.

    In case (2) the ToE would seem to result in precisely the right kind of universe for our existence - which seems like good luck to me.

    Can you please elaborate on your statement that "There is no need for the existence of a TOE for the good luck argument to be applied."?

    I agree (3) does not imply the total "lack" of a ToE, but it does imply that the ToE does not "need to explain" why the physical laws and parameters are as they are in our world - whereas the ToE in (2) DOES need to explain why the physical laws and parameters are as they are in our world (or, in absence of an explanation, we simply assume that we have been extremely lucky).

    MF
    :smile:
     
  12. Apr 13, 2005 #11
    The universe could be made up of many separate physical systems that require entirely separate theories and therefore can never be described by one TOE; each of these could luckily be tuned correctly.

    I'm not saying I believe this, but as long as you are making a good luck argument, there is no reason to include a TOE.
     
  13. Apr 13, 2005 #12

    marcus

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    "Scientific Alternatives to the Anthropic Principle"
    http://arxiv.org/hep-th/0407213

    for more discussion
    https://www.physicsforums.com/showthread.php?t=70737
     
  14. Apr 13, 2005 #13
    OK, I think I see what you are saying.

    Please correct me if I am wrong :

    The suggestion you are making is that there is one cosmos.
    That there may not be one single all-encompassing ToE in this one cosmos, but that we need several unrelated theories to explain why the physical constants are what they are.
    This would (I agree) imply that we are indeed lucky.

    However, this then seems to be a variant of (2) - ie one cosmos, we are special, and we are very lucky - the only difference with (2) is that there is no single ToE but instead multiple unrelated theories.

    Possibilities (1) and (3) still stand (and these possibilities do not imply luck).

    MF
    :smile:
     
  15. Apr 13, 2005 #14

    marcus

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    "Scientific Alternatives to the Anthropic Principle"
    http://arxiv.org/hep-th/0407213

    for more discussion
    https://www.physicsforums.com/showthread.php?t=70737

    I'd say that one of the main points of Smolin's paper is that the Anthropic Principle is "Bad Science" because it is not falsifiable. It does not bet its life (and risk refutation) on the outcome of some future experiment. Instead it appears to be able to accomodate any outcome of any future observation because, well, "here we are". :smile:

    So the title of your thread, "Bad Science" and the AP, is (perhaps unintendedly!) a propos.


    the trichotomy you give at the beginning does not exhaust the possibilities

    One possibility is that the parameters of the Standard Models (for particle physics and astronomy) are approximately optimized for Black Hole production by an evolutionary mechanism described in Smolin's paper and also discussed in the thread for which I provided the link.

    the implications of Smolin's model, and the opportunities to test it, are only partially worked out, and it could be falsified tomorrow for example by observing a neutron star with a mass exceeding what the theory predicts.
    But it is a possible theory with some predictive and explanatory power, and one which can be wrong which the premise of conscious life cannot be.
     
  16. Apr 13, 2005 #15
    Thanks!

    I do not agree that this means the anthropic principle will necessarily "always be" not falsifiable, therefore it does not qualify as "bad science" in my book (a point I tried to make in my post). Any hypothesis (inlcuding the anthropic principle) must have some assumptions or axioms, and it is these assumptions or axioms that we need to have access to in order to try and falsify the hypothesis.

    One variant of the anthropic principle is that there are an unlimited number of worlds, each with slightly different physical laws/constants. Thus an assumption or axiom in this variant is that such other worlds exist.

    Nope, it was entirely intended, since I anticipated exactly what you said!

    OK, thanks, I will read up on it and get back to you

    OK

    MF

    :smile:
     
  17. Apr 13, 2005 #16

    Garth

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    Whether the Anthropic Principle is 'bad science' or not because it is not falsifiable is an interesting question.
    Like the theory of evolution then? Which is ironic because Smolin's own alternative CNS is a cosmological version of the theory of evolution!

    It depends how exactly the principle is being defined. As a simple acknowledgement that our existence requires tight constraints on physical and cosmological parameters, ("The universe is as it is because we are" - Stephen Hawking), it is not so much a theory to be falsified but a tautological truth; it is self-evident.

    The Anthropic Principle makes plenty of predictions, the problem is, "because here we are" they all have to turn out to be correct! So that's not falsifiability?

    Just a thought or two.

    Garth
     
  18. Apr 13, 2005 #17

    marcus

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    reason and courtesy shows, I will try to manage not to be outdone in that respect. I hope you do have a look at the article (and perhaps the first halfdozen posts of that thread). Am looking forward to your getting back about it.
     
  19. Apr 14, 2005 #18
    I agree, which is why to be acceptable the Anthropic Principle (AP) stated simply as "the universe is as it is because we are here" is not enough. What needs to be developed from that is an Anthropic Hypothesis (AH).

    It's a bit like the Cosmological Principle (CP), which simply says that we are not in a special place in the universe. This principle is well accepted because it in turn implies the hypothesis that the universe should then appear isotropic and homogeneous to us - which is falsifiable.

    To be credible, perhaps the AP needs to be linked to one or more AH's.

    I think the real message of the AP is not "we are here because we are here" (which as you say is tautological) but that it assumes (like the CP) that humans are not in a special place, that we are not specially favoured by good design or good luck. This to me seems a very strong principle.

    One AH could be the suggestion that there are multiple worlds each with slightly varying constants. This would be consistent with the AP and thus would not require design or "good luck".

    The alternatives to the AP seem to require either good design or good luck - which to me seems far less acceptable than the AP.

    MF

    :smile:
     
  20. Apr 14, 2005 #19

    Garth

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    "The alternatives to the AP seem to require either good design or good luck" ..... or a multiverse.

    The problem is that at the limit of scientific observability the preference of either of these three possibilities requires an act of faith, for until we can observe 'other universes' in which the laws of physics are demonstrably different from our own then the hypothesis of a multiverse is as much an act of faith as the hypothesis of a creator. Neither are scientifically verifiable or falsifiable.

    Garth
     
  21. Apr 14, 2005 #20
    All hypotheses require an "act of faith" as you put it, unless and until such time as they can be tested.

    At the moment the multiverse hypothesis does not seem to be verifiable, but as I said in my original post, does this mean it will never be verifiable?

    I am glad you prefaced your comment with the word "until".

    Should we always discard a plausible hypothesis just because it cannnot be tested immediately, and focus on only what we can verify today, just like the drunk searching for his keys under the streetlight? Or should we remain open-minded and work with all plausible hypotheses, attempting to move towards a situation where we can find evidence to falsify each of them?

    IMHO, unless and until such time as the 3 optional explanations I have suggested can be tested, I am more comfortable believing that we live in a "multiverse" which is not "designed" and does not require incredible "good luck", rather than believing in a Designer or that intelligent life has somehow been incredibly lucky to exist.

    MF
    :smile:
     
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