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Best CNS paper that I've seen so far

  1. Apr 29, 2005 #1

    marcus

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    The clearest and most thorough discussion of the Cosmic Natural Selection conjecture that I have seen so far is

    Is there a Darwinian Evolution of the Cosmos? Some Comments on Lee Smolin's Theory of the Origin of Universes by Means of Natural Selection
    Rudiger Vaas

    http://arxiv.org/abs/gr-qc/0205119


    as a sample, here is the final paragraph:

    "Smolin's scenario cannot explain everything (nor does it want to, so this remark is not meant to criticize it but to stress an important limitation). Suppose, Smolin is right. Then we would know why the fundamental physical parameters are the way they actually are. They would be explained, or we would need no explanation anymore. However, this merely shifts the crucial question further back, because
    • we would still not know why the laws are the way they actually are, for instance, why quantum gravity implies the birth of universes out of black holes and why quantum gravity is true at all,
    • we would still not know how the first universe (the "mother of all universes") came into being, or, if there is an infinite chain of universes, why there are universes at all. Thus, Smolin's hypothesis does not give us a sufficient reason. Probably, a sufficient reason cannot be given at all [cf. 72, ch. 6] which is not to deny that it may play an important heuristic role in the development of science. But Cosmological Natural Selection is not a First Cause or a principle proven by itself. It cannot help us to overcome contingency. It cannot answer why there is anything at all (nor can the speculations about cosmic engineers). And it cannot explain why the physical laws are the way they are. In the ultimate sense, the cosmos remains a mystery."
     
    Last edited: Apr 29, 2005
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  3. Apr 29, 2005 #2

    wolram

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    As you say Marcus a clear view of-------

    I have some questions, 1, why does he think the multiverse theory is valid.
    2 if particles did not have the mass that are ascribed to them today how
    could we predict a different mass for some other universe.
    3 the same goes for emergent universes and the constants that describe
    them, how could we predict a pure radiation dominant universe, from a
    balanced matter radiation universe, or other variation?
     
  4. Apr 29, 2005 #3

    ohwilleke

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    Here is the full abstract of the paper. Claim three would presumably be of the greatest interest to Marcus. Also, bonus points to anyone who can identify the historical significant of Aachen.

     
  5. Apr 29, 2005 #4

    wolram

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    I would like to think that this means something, as L Smolin is one of the
    top theorists, but it all comes down to the hypothosis of bouncing
    black holes, which AFAIK is untestable and one of a multitude of theories
    that describe BH dynamics without the luxury of fundamental data.
     
  6. Apr 29, 2005 #5

    marcus

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    Charlemagne's court IIRC
     
  7. Apr 29, 2005 #6

    marcus

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    the conjecture to be tested is local optimality for BH production

    Smolin challenges you to think of some small change in a parameter of the Std Mdl which would result in our universe making more BH.

    His conjecture is that you cannot, because the parameters are already optimal for BH production.

    this conjecture is eminently testable.

    I think you are confused Wolram. NOBODY WANTS YOU TO BELIEVE THAT BH MAKES BB. I dont care what you believe and I am not trying to persuade you. Smolin is not trying to persuade anybody that our universe was bounced from a parent BH and that other universes bounce from our BHs, with gradual variation of parameters each time.

    that is what Rudy Vaas calls "Smolin's central claim" and it is not falsifiable.

    you really should read Rudy Vaas article. he is a paper that will definitely repay any study you have time to give it. Rudy Vaas discusses this "central claim" and why it is not falsifiable. BTW I would not call it a "central claim" but that is just a difference in language I guess.

    for me the main point to be tested is whether or not the parameters are optimal for BH production. I am very interested in that. I neither believe nor disbelieve it. It is currently being tested. It is outstandingly falsifiable. It may well be falsified by observation. I hope that it is THOROUGHLY tested, because it is an exciting possibility, and tested in a VARIETY OF WAYS.
     
  8. Apr 29, 2005 #7

    marcus

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    1. AFAIK Smolin has not said that he thinks there is a multiverse.
    In the two papers of his that I have read which I think are representative
    (gr-qc/9404011 and hep-th/0407213) he does not say he thinks "the multiverse theory is valid"

    what I have heard him argue strongly for (with real energy and commitment) is that it should be observationally tested whether or not the parameters are optimal for BH production. It seems so far that they are, and this would certainly be an important finding if it were confirmed.

    If it checks out that the numbers in the Std Mdl are optimal, that is the numbers are AS IF CHOSEN TO PROMOTE BH PRODUCTION, then this would have to be explained. You can try thinking of ways to explain that. Smolin has speculated about ways to explain it.

    CURRENTLY NO PHYSICAL THEORY (unless you count the CNS idea) OFFERS A MECHANISM TO EXPLAIN THE VALUES OF THE PARAMETERS. Smolin CNS is the only contender in this field that I know of (I dont take seriously the thought of "intelligent design" by some allpowerful fantasy projection of ourselves).

    But let's not put cart before horse. The first thing on the agenda is to thoroughly test the conjecture that the parameters are optimal for BH production. Only when that is done and (if it so turns out) one can be reasonably confident that they are optimal, ONLY THEN, does one begin to compare and test various explainations for that.

    -----questions 2 and 3-----
    2 if particles did not have the mass that are ascribed to them today how
    could we predict a different mass for some other universe.


    Not sure I understand. We do not need to predict parameters in universes connected to ours. As a way of explaining optimality (if it checks out) we can assume that parameters do not get perfectly transmitted.

    the parameters of the Std Mdl are probably built into spacetime in some way we havent figured out yet, and when spacetime goes thru a kind of meltdown and is forced thru the wringer of a BH then it is hard to imagine how it would come thru completely unchanged---so I have a hard time picturing 100 percent perfect transmission. just my viewpoint.


    3 the same goes for emergent universes and the constants that describe
    them, how could we predict a pure radiation dominant universe, from a
    balanced matter radiation universe...


    Again I dont think we need to be able to predict. The assumption (to explain optimality, if it is checked out) would be only that the parameters in the daughter universes are ALMOST but not exactly THE SAME. One wouldnt be worrying about what they are. For evolution to occur one simply needs resemblance but not a perfect copy.
     
    Last edited: Apr 29, 2005
  9. Apr 29, 2005 #8

    wolram

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    Marcus i must admit i am warming to Smolins idea, but we must not
    forget that BHs and there dynamics are not tested AFAIK to date.
    I know that some things are observable in the center of galaxies but
    again BHs are not a proven entity.
    I can relate this to archeology where the professor states that a stone
    is a stone, but a stone on top of another stone is a wall, a wall with
    a piece of roman pottery found by it is a roman wall
     
  10. Apr 29, 2005 #9

    ohwilleke

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    Bonus points won!
     
  11. Apr 29, 2005 #10

    marcus

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    I agree. Personally i am not skeptical about the existence of black holes. But I think we need a deeper understanding of them. It is one of the reasons for further work in quantum gravity.

    just as a reminder of how very much is still undecided here:

    1. LQG could be wrong.
    2. LQG people have not yet been able to say for sure whether the
    model of BH you get in LQG will lead to an offspring universe.
    3. You posted a "baby universe in string theory" item recently, but there is a similar uncertainty there: string/M might be wrong, and even if some version turned out to be an adequate theory, can we be sure that it would contain the "baby universe" result?
    4. In my view an even more serious reason to be doubtful is this: it may turn out to be simply not true that the parameters of nature are optimal for BH formation. The idea that they might be optimal in this way is a daring, and on the face of it, extremely unlikely thing to imagine. It seems that there would be dozens of possible ways to rule it out just by measuring a parameter and showing that it is not the best possible value from the BH standpoint (but apparently so far no one has).
     
    Last edited: Apr 29, 2005
  12. Apr 29, 2005 #11

    marcus

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    thanks, it was a welcome reminder. I've heard some good stories about Charlemagne. I guess that was circa 800 AD

    I remember now another historical association with Aachen, besides being the site of Charlemagne's court. I saw this on Alejandro's
    "Nobel Prize Geneology" chart:

    http://www.physcomments.org/wiki/index.php?title=Genealogy::nobel

    If you look down in Alejandro's chart to the third generation from Arnold Sommerfeld

    you see that
    Martin Bojowald's advisor was
    Hans Kastrup, whose advisor was
    Werner Heisenberg, whose advisor was
    Arnold Sommerfeld, whose advisor was
    C. Ferdinand Lindemann, whose advisor was
    C. Felix Klein, whose advisor was
    Julius Plücker, whose advisor was
    Christian Gerling, whose advisor was
    Gauss

    And Bojowald's earned his degree at Aachen in the year 2000.

    I ran across the link to Alejandro's geneology chart in this thread
    https://www.physicsforums.com/showthread.php?t=59360
     
    Last edited: Apr 29, 2005
  13. Apr 29, 2005 #12
    Nice thread.

    I was wondering, if LHC at CERN is able to produce planck scale BH's, then what does that say for CNS? Will there be any way to test whether a BB will occur (maybe this is what you were talking about when you said it was testable).

    Paden Roder
     
  14. Apr 29, 2005 #13

    marcus

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    No actually, the testing I was talking about IIRC is by ordinary means and has been going on for some time. If you take a look at the articles with URL in my sig it will bring you up to speed on the opportunities for testing.


    BTW in case anyone has checked out the Rudy Vaas article, it begins with a neat quote from David Hume (1779) taken from this context:
    http://www.anselm.edu/homepage/dbanach/dnr.htm
    Click on "Part V" and look at the paragraph labeled [167]

    The quote itself is a comic picture of the Creator trying to make a universe and failing to get it right-----botching the job----over and over again:

    "But were this world ever so perfect a production, it must still remain uncertain, whether all the excellences of the work can justly be ascribed to the workman. If we survey a ship, what an exalted idea must we form of the ingenuity of the carpenter who framed so complicated, useful, and beautiful a machine? And what surprize must we feel, when we find him a stupid mechanic, who imitated others, and copied an art, which, through a long succession of ages, after multiplied trials, mistakes, corrections, deliberations, and controversies, had been gradually improving? Many worlds might have been botched and bungled, throughout an eternity, ere this system was struck out; much labour lost, many fruitless trials made; and a slow, but continued improvement carried on during infinite ages in the art of world-making. In such subjects, who can determine, where the truth; nay, who can conjecture where the probability lies, amidst a great number of hypotheses which may be proposed, and a still greater which may be imagined?"
     
  15. Apr 30, 2005 #14

    marcus

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    the quote from David Hume part V of Dialog concerning natural religion reminds me of some quotes from Newton and from Leibniz that "moving finger" supplied
    https://www.physicsforums.com/showpost.php?p=507074&postcount=14

    (e.g. Leibniz criticising Newton's cosmology) "According to their Doctrine, God Almighty wants to wind up his Watch from Time to Time: Otherwise it would cease to move. He had not, it seems, sufficient Foresight to make it a perpetual Motion. Nay, the Machine of God's making is so imperfect, according to these Gentlemen, that he is obliged to clean it now and then...and even to mend it..."

    I understand that the French original of this passage may be found in the first part of an exchange known as the Leibniz-Clark controversy:
    "Il semble que la religion naturelle même s’affoiblit extremement. Plusieurs font les ames corporelles; d’autres font Dieu luy même corporel. M. Locke et ses Sectateurs doutent au moins si les ames ne sont materielles et naturellement perissables. M. Newton dit que l’Espace est l’organe, dont Dieu se sert pour sentir les choses. Mais s’il a besoin de quelque moyen pour les sentir, elles ne dependent donc point entierement de luy, et ne sont point sa production. Monsieur Newton, et ses sectateurs, ont encore une forte plaisante opinion de l’ouvrage de Dieu. Selon eux Dieu a besoin de remonter de temps en temps sa montre. Autrement elle cesseroit d’agir. Il n’a pas eu assés de veue pour en faire un mouvement perpetuel. Cette Machine de Dieu est même si imparfaite selon eux, qu’il est obligé de la décrasser de temps en temps par un concours extraordinaire et même de la raccommoder, comme un horloger son ouvrage; qu’il sera d’autant plus mauvais maistre, qu’il sera plus souvent obligé d’y retoucher et d’y corriger. Selon mon sentiment, la même force et vigueur y subsiste tousjours, et passe seulement de matiere en matiere, suivant les loix de la nature, et le bel ordre preétabli. Et je tiens, quand Dieu fait des miracles, que ce n’est pas pour soûtenir les besoins de la nature, mais pour ceux de la grace. En juger autrement ce seroit avoir une idée fort basse de la sagesse et de la puissance de Dieu”.

    dont mind these quotes. just had to track them down. they arent meant to relate to CNS, although the David Hume one isnt a bad match.
     
    Last edited: Apr 30, 2005
  16. Apr 30, 2005 #15

    wolram

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    Logic dictates that, our universe will end one day, i doubt if the end
    of our U will be the end of everything, the energy that made it will
    always exist somwhere, if that energy is somhow ejected en mass,
    then i can not see why it would not follow the history of our own
    universe, so the CNS seems logical to me in that new Us come into
    existence, but that any variations on the constants would be minimal.
     
  17. Apr 30, 2005 #16

    wolram

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    BY MARCUS

    4. In my view an even more serious reason to be doubtful is this: it may turn out to be simply not true that the parameters of nature are optimal for BH formation. The idea that they might be optimal in this way is a daring, and on the face of it, extremely unlikely thing to imagine. It seems that there would be dozens of possible ways to rule it out just by measuring a parameter and showing that it is not the best possible value from the BH standpoin

    No BHs? heat death, is heat death the end? i think i preffer BHs.
    So get on yer bikes chaps and get measuring
     
  18. Apr 30, 2005 #17

    wolram

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    http://physicsweb.org/articles/review/10/12/1/1 dec 1997.

    Smolin, a physicist renowned for his research in quantum cosmology, offers a radically different approach to the problem. He rejects the explanations offered by the anthropic principle and the final theory, arguing instead that the physical constants (and perhaps even the laws of physics themselves) have evolved to their present form through a process akin to mutation and natural selection. (In other words, the physical constants are contingent rather than fundamental.) He harnesses various physical, biological and philosophical arguments in support of this proposal. The status of each of these three types of argument is very different, so I will discuss them in turn.

    Evolving constants, or fundamental constans? I guess the stuff that is in a
    BH is in a non random condition "state", and if it is ejected ,a repeatable
    cycle of" events", could continue for all eternity.
    It would be different if the stuff inside a BH was in some sort of mixed state
    or if the ejection process could vary.
    A perfect oscillator or not? a perfect recycler or not?
     
    Last edited: Apr 30, 2005
  19. May 12, 2005 #18

    marcus

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    this business about a small variation of the constants during bounce
    (gravitational collapse followed by re-expansion)
    is very interesting.

    when we were discussing earlier, in this thread, I did not know about a 2002 paper by Gambini and Pullin that offers a possible mechanism for a slight changed in the constants during bounce

    http://arxiv.org/abs/gr-qc/0212033
    Discrete quantum gravity: applications to cosmology
    Rodolfo Gambini, Jorge Pullin
    19 pages, 9 figures
    Journal-ref: Class.Quant.Grav. 20 (2003) 3341

    "We consider the application of the consistent lattice quantum gravity approach we introduced recently to the situation of a Friedmann cosmology and also to Bianchi cosmological models. This allows us to work out in detail the computations involved in the determination of the Lagrange multipliers that impose consistency, and the implications of this determination. It also allows us to study the removal of the Big Bang singularity. Different discretizations can be achieved depending on the version of the classical theory chosen as a starting point and their relationships studied. We analyze in some detail how the continuum limit arises in various models. In particular we notice how remnants of the symmetries of the continuum theory are embodied in constants of the motion of the consistent discrete theory. The unconstrained nature of the discrete theory allows the consistent introduction of a relational time in quantum cosmology, free from the usual conceptual problems."

    Except for this vague reference, they do not mention this in the abstract. I will look for it in the paper.
     
    Last edited: May 12, 2005
  20. May 12, 2005 #19

    marcus

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    yes, here on page 8, right below Figure 2

    "One can also notice that while going through the singularity the universe re-expands, but the behavior at both sides of the singularity is different. In this sense the discrete cosmology may implement the proposal of Smolin [5] that different physics takes place when one goes through a singularity."

    It is only the barest suggestion. this was back in 2002 and it took a bit of nerve just to be talking about a cosmological bounce in the first place.
    nothing is worked out in detail.

    now the bounce idea has more currency
    and they will probably go back and work some more on this result in the consistent discretizations version of QG

    they mentioned it again in that essay which wolram flagged
    https://www.physicsforums.com/showthread.php?t=75354
     
    Last edited: May 12, 2005
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