Unusual Features of Our Place In the Universe That Have Obvious Anthropic Explanations

By Sean Carroll | August 7, 2007 5:02 pm

The “sensible anthropic principle” says that certain apparently unusual features of our environment might be explained by selection effects governing the viability of life within a plethora of diverse possibilities, rather than being derived uniquely from simple dynamical principles. Here are some examples of that principle at work.

  • Most of the planetary mass in the Solar System is in the form of gas giants. And yet, we live on a rocky planet.
  • Most of the total mass in the Solar System is in the Sun. And yet, we live on a planet.
  • Most of the volume in the Solar System is in interplanetary space. And yet, we live in an atmosphere.
  • Most of the volume in the universe is in intergalactic space. And yet, we live in a galaxy.
  • Most of the ordinary matter in the universe (by mass) consists of hydrogen and helium. And yet, we are made mostly of heavier elements.
  • Most of the particles of ordinary matter in the universe are photons. And yet, we are made of baryons and electrons.
  • Most of the matter in the universe (by mass) is dark matter. And yet, we are made of ordinary matter.
  • Most of the energy in the universe is dark energy. And yet, we are made of matter.
  • The post-Big-Bang lifespan of the universe is very plausibly infinite. And yet, we find ourselves living within the first few tens of billions of years (a finite interval) after the Bang.

That last one deserves more attention, I think.

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  • DrFish

    But if the lifespan of the universe is infinite, surely the last point is true no matter what the finite interval you choose is. For instance, some other beings 100s of billions of years in the future could also quite rightly say “And yet, we find ourselves living within the very first trillion years (a finite interval) after the Bang.”
    Perhaps a better way to look at it is that we are here within the first few generations of stars (although that “few” gets a bit hazy with the short-lived high mass ones), which you need to make the metals etc necessary for us, but we’re here almost as soon as it is possible. (The word “almost” is probably crucial there…)

  • http://evolutionarydesign.blogspot.com/ island

    The “sensible anthropic principle” says that certain apparently unusual features of our environment might be explained by selection effects governing the viability of life within a plethora of diverse possibilities…

    No this is the “Denier’s Anthropic principle”, which assumes unobserved possibilities in lieu of the physics that is actually observed, while ignoring many relevant features and more that have been discovered since it was first put forth that make it even stronger.

    How convenient.

    http://evolutionarydesign.blogspot.com/2006/11/very-strong-anthropic-principle.html

    The observed structure of the universe occurs in dramatic contrast to the most natural expectation, (without appealing to “bold attempts” like yours), to produces many fixed balance points are commonly or “coincidentally” pointing directly toward carbon-based life.

    The actual evidenced sensibility is that carbon based life is linked to the structure mechanism.

    Denial is the only thing that allows the scientific method to supercedes this fact, so the claim of “sensibility” is highly dependent on an intentional distortion of the observation.

  • http://www.lepp.cornell.edu/spr/2000-11/msg0029236.html Neil B.

    Yes, interesting. These points however, concern the features that occur once already given a universe with life-friendly constants. In other words, once we already have a fine structure constant of around 1/137 instead of the “logically” clean value of say, one (sorry, “island,” I couldn’t resist….) and etc., then there are going to be places and ways that life develops. Some of those outcomes are going to be ironic, because life may need special nooks even in a “friendly” universe.

    Of course, remember that given a universe with lots of space, mostly gas, etc., then if some small part of it is habitable we can find ourselves there. But that is selection among what already exists, like winning a lottery when you have lots of slot machines. Is our own universe itself a selection among other universes? Does that explain “why it is the way it is” in some way? Perhaps, but there are many ironies. Such universes are so far unobserved and may be literally unobservable, barring some sort of extra-dimensional collision or etc. Also, where does it stop? If universes can have “other laws of physics” then why not ones that aren’t lawful looking at all, that more resemble magical fantasy realms, or heavens and hells, heh heh…

    The most stunning point to make, that I still don’t find appreciated is this:
    There is, serious as a hear attack, no genuinely logical way to define “existence” above and beyond logical description. IOW, no way to define “matter” aside from the structural descriptions of it, other than appeal (ironically) to metaphysical issues like the realness of our experience, etc. Now you might say, no big deal, since you can imagine just thinking of “the universe” as being pure mathematics/structure (which is evasive since it leaves out experiential qualities, but I digress.) The trouble then is, you have to admit all the other “descriptions” as being equally pseudo-real as well, like it or not. Then, you’ve got a mess on your hands, as I explained before. Sorry, but the whole “cold-blooded materialism” thing is empty posturing, and we don’t even know what “materialism” means when thinking gets beyond sound bites.

    PS: DrFish’s comment was very clever. There are however ways to draw statistical conclusions from one’s circumstances, but dealing with infinity is indeed a problem. If you really want to worry about an infinite universe, that is supposed to mean that there are an infinity of happenings just like ours within it, and all the little and big variations, etc. Yikes.

  • WhatMeWorry

    I don’t understand the one-sided infinity thing. Seems to me, once you have a starting point, an eternal future is out the window, for at any point kajillions of years later, the past is finite and the future merely potential.

    I think you need an eternal past as well, for the infinity thing to work. But I don’t understand that either.

  • http://www.allysonbeatrice.com/blog Allyson

    This is one of those posts that is awesome to read to stoned people.

  • http://evolutionarydesign.blogspot.com/ island

    That’s okay, Neil, I don’t disagree with the relevance of your point, and neither would Sean, I don’t think:

    http://arxiv.org/abs/hep-th/0512148

  • http://www.lepp.cornell.edu/spr/2000-11/msg0029236.html Neil B.

    Well, so to contribute more than just metaphysical snark, let me note maybe the first modern-style anthropic prediction, in a sense. It is discussed in pages 250-255 of the opus The Anthropic Cosmological Principle by Barrow and Tipler. Fred Hoyle predicted that there must be a resonance level for the C12 nucleus around 7.7 MeV. It was experimentally confirmed soon after by D. Dunbar and others. Hoyle’s prediction was not motivated by nuclear theory, but by the fact we existed – there wouldn’t have been enough carbon produced by the sun unless that resonance was there. There’s more, involving Oxygen too, and the whole thing shows just how strictly nuclear interactions must be constrained to allow life-friendly mixes of elements. (Island, you should find this interesting – and BTW I am not saying you don’t have a point as self-consistent physics goes. The trouble is, concepts supporting the naturalness of our laws inherently involve some degree of circular reinforcement. If the laws were very different to begin with, then the supportive argument developed from our situation wouldn’t necessarily apply. It’s hard to show self-contradiction of the alternative, from our point of view, and aside from whether you believe in pan-platonism or not.)

  • Elliot

    I believe I have referenced this before on CV but it seems appropriate to do it once again.

    Life could be much “broader” than we imagine somewhat undercutting the “anthropic” reasoning.

    http://www.bigear.org/vol1no2/life.htm

    We are continuously victims of our perspective.

    Elliot

  • http://astro.berkeley.edu/~bgerke Brian Gerke

    Dammit! I had just been kicking around an idea for a fun little project regarding that last point. It’s such an obvious idea, I’m sure someone will beat me to it now.

    Curses…

  • http://www.lepp.cornell.edu/spr/2000-11/msg0029236.html Neil B.

    Yes, Sean’s paper “Is Our Universe Natural?” is fascinating and grand in scope. Just keep in mind though what I said about defining existence as such, and the problem of arguing broadly from a base given us by our circumstances. All the talk of “vacua” and Planck constant etc. implies that something like our universe would have to be the basis, but would it?

    OK, here is a “groaner” (?) I thought of years ago, that Allyson can read to her stoned friends (who know a bit of physics and biology):

    How did life start?

    From atom and eV.

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

    All of our posts are awesome to read to stoned people! You’ve broken the code.

    Brian, let me know if you have any good ideas. I’d be happy to ride on your coat tails.

  • Paul Valletta

    “Most of the planetary mass in the Solar System is in the form of gas giants. And yet, we live on a rocky planet….
    .. The post-Big-Bang lifespan of the universe is very plausibly infinite. And yet, we find ourselves living within the first few tens of billions of years (a finite interval) after the Bang.”

    Why is most of the above data that has been gathered together, formulated by a rock-bound-species? ..would this factor(a species being rocky planet bound) have a baring on
    the available evidence?

    Could the sensible anthropic reasoning, be a falsely constrained principle, by fact it is unique to a developed planetary species?

    I suppose I am asking if the species local environment, influences the data results?..is there any species external to our solar system, and what effect would this have upon locally gathered data, would the discovery of other data gatherer’s, strengthen or weaken OUR anthropic notions, how credible would the any-anthropic principle be if the Universe were teaming with varying species.. life?

  • http://evolutionarydesign.blogspot.com/ island

    I don’t think that there is any “circular reiforcement” involved with David Gross’ expectation for a “dynamical structure principle”.

    But even he ignores the **most apparent** implication that WE ARE IT, and physicists, like Weinberg and Susskind, who do recognize the OBVIOUS anthropic significance, ONLY do so when they can bail on the expected structure mechanism.

    In the mean time… it’s still, as Gross says, “the biggest failure of science in the last 20 years”… and will remain so, for as long as these FACTS are willfully ignored by scientists.

    I’ve got another one for Sean’s List that Lovelock pointed out… ecobalances, (anthropic balance points), are “self-regulating”.

    If the anthropic coincidences are self regulating… then so is the cosmological constant, as well as observed “flatness”, and that minor little detail throws a big monkey-wrench into the projections and assumptions of the cutting-edge who has to ignore this to employ “selection effects” over principle.

    Eddington also thought that the cosmological constant version of the general-relativistic field equation expressed the property that the universe was “self-gauging”.

    Coincidence?… I don’t think so… but denial supercedes the facts.

  • http://www.dorianallworthy.com daisy rose

    How does carbon turn into life ?

  • Dr Who

    Andy Albrecht says [http://arxiv.org/abs/astro-ph/0210527]

    To us, the familiar arrow of time is driven by gravitational collapse as it destroys a
    homogeneous state. In many models of inflation there are huge regions of the universe
    that are undergoing extremely long epochs of exponential expansion. As time progresses
    and various imperfections get diluted by the expansion, these regions will asymptotically
    approach the high entropy de Sitter state, and by doing so will exhibit increasing entropy.
    That is another manifestation of an arrow of time, which is quite different from the one
    we are used to which is based on gravitational collapse, not dilution. Is it possible for
    other types of creatures to exist that harness the “dilution” arrow of time as effectively as
    we harness ours? If the answer is yes, perhaps these creatures will start to evolve as
    today’s cosmic acceleration takes over.

    Any comments, Sean?

  • http://countiblis.blogspot.com Count Iblis
  • http://www.dorianallworthy.com daisy rose

    All inteligent people are of the same religion – (they never tell)

  • http://www.lepp.cornell.edu/spr/2000-11/msg0029236.html Neil B.

    daisy rose –

    Nobody really understands how carbon turns into life, which is different from how life changes over time. Sure, you have “atom and eV” getting together and getting it on (atoms driven by energy to combine and break away and recombine) but that vague description doesn’t really get to why cells with working DNA come about. It is part of the “cleverness” (how that grates on some here) of the features of the universe, to be so inclined to lead in that direction. There seems such resistance to the idea of it being like that, so that can be the outcome. Sure, that is philosophy and not science, but the whole subject is really philosophy regardless of where you come down.

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

    Dr Who– I think Andy is right, it’s an interesting question, although I don’t have any interesting answers. A related one: could life exist in the atmosphere of an evaporating black hole?

  • http://www.dorianallworthy.com daisy rose

    Of course it is Philosophy – Science is philosophy – it cant be otherwise – Yes life can exist in the atmosphere of an evaporating black hole – no one can say other wise –

  • http://magicdragon.com Jonathan Vos Post

    The post-Big-Bang lifespan of the universe is very plausibly infinite. And yet, I am told by experts (excluding Cryonics buffs and Transhumanists and Nanotechnology True Believers) that I shall die in a small and finite number of years, almost surely at an age less than 137 years.

    Most of the volume of the crust of the Earth is inside of Oxygen ions, and yet people have more hydrogen atoms in them than they have oxygen atoms.

    Most of the people in the world speak Mandarin, or Arabic, or French, or Hindi, and yet I speak English. Most of the organisms on Earth don’t speak English at all. In fact, most of the mass of life on Earth is not in peoiple, or any kind of mammal, at all.

    My name, “Jonathan Vos Post”, contains only 15 letters, and 17 alphanumeric symbols including spaces. And yet almost all sequences of letters, or sequences of alphanumeric symbols including spaces, are much longer than 15 or 17.

    My name contains 5 vowels and 10 consonants, for a ration of excatly 1/3 vowels per letter, instead of the “logically” clean value of say, one.

    Exactly how do the above facts differ from the astronomical Unusual Features of Our Place In the Universe That Have Obvious Anthropic Explanations?

  • Moshe

    Probably an obvious thing I am missing, but why can’t life form from dark matter?

  • Dr Who

    Sean: thanks for the reply. When you say “A related one: could life exist in the atmosphere of an evaporating black hole?” are you thinking of radiation from the horizons [cosmological in one case, black hole in the other]? If so, are these situations really similar? I mean, our Sun gives us a source of low-entropy photons, but this only works because the radiation is not isotropic — the Sun is a hot *spot* in the sky. Similarly for the black hole. But radiation from a cosmological horizon would be isotropic. So I guess that a black hole would be a better bet than relying on cosmological horizons!
    Tell me if I am talking nonsense….

  • Dr Who

    Forgot to add: the point being that [if we really have a cosmological constant] a cosmological horizon is [unlike an evaporating black hole] something that lasts forever, so life based on it would contradict the claim that life is not infinite in such a spacetime……

  • Dark Matter Man

    Moshe: it can, but sex loses a lot of its fun when you just keep flying through each other.

  • http://magicdragon.com Jonathan Vos Post

    Re #22, #25:

    “Ring” is a 1994 science fiction novel by author Stephen Baxter.

    “… Lieserl is abandoned for five million years, leaving her to observe the sun’s interior. She discovers dark matter -based life, which she names photino birds. These birds gradually drain the energy from the core of a star, ending fusion and causing premature aging into a stable red giant—the birds’ preferred habitat, as it has no risk of going supernova and destroying them….”

    http://en.wikipedia.org/wiki/Ring_(Baxter_novel)

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

    Moshe, one of the few things we know empirically about dark matter is that it’s mostly dissipationless; it doesn’t collide and stick together. (Otherwise it wouldn’t make big puffy halos with ordinary matter accumulated in the center, at the bottom of the potential well.) It doesn’t follow that you can’t make life out of dark matter, but if nothing else indicates that the corresponding timescales for the dark metabolism would be enormously longer.

    Dr Who, I am thinking of the Hawking radiation in the vicinity of an horizon. Which is not anisotropic, which (as you say) makes it much easier to make life. In fact, my guess is that there’s absolutely no way to support life from de Sitter radiation, but with black holes you at least have a shot.

    And now I have to catch a plane to China. Have fun.

  • http://www.cse.buffalo.edu/~regan/ Dr. Kenneth W. Regan

    My query posted belatedly at the end of the July 29 item on the Reykjavik conference may be relevant to this item (here I’m taking as given that our Big Bang was a bubble nucleation in a larger multiverse, and that “the universe” in Sean’s last point refers to our bubble):

    What was said in Reykjavik about the measure problem in multiverse cosmology?

    In particular, (a) does it make a big difference whether the measure is defined on individual bubbles (e.g., on points in the “Landscape discretuum”) or takes volumes of bubbles into account? In the latter case, (b) is it compelling to regard the measures of individual bubbles as finite, even for bubbles that have infinite spacetime extent?

    The possible relevance is that a “yes” answer to (b) might say that the finite measure rather than the infinite future lifespan is the important factor, thus removing the “anthropic surprise” of the latter.

    (Or am I talking thru my CS-only hat? At least I found this recent talk by Maloney(-Shenker-Susskind) asking my question (a). My possible research angle is actually on the former case of (a), asking whether some Landscape points are “simpler” than others, and whether those points would be favored.)

  • Anonymous

    The fact that a Caltech physicist (albeit a non-tenured one) is parading this nonsense would have Feynman rolling in his grave.

  • Anonymous, but not silly

    Who knew Feynman was such a fan of appeals to authority?

  • http://quasar9.blogspot.com/ Quasar9

    So Brian, would that be life as we know it, which requires oxygen and/or water had to wait for mud to form, to crawl out of the mud, and is finite – whereas life in other forms (tinkerbell-like) could have existed since the dawn of Time? or soon after the big bang. After all if the elusive higgs field gives particles mass, there could always be something even more elusive – which cannot be fathomed or measured – yet.

  • jeff

    is there any species external to our solar system, and what effect would this have upon locally gathered data, would the discovery of other data gatherer’s, strengthen or weaken OUR anthropic notions, how credible would the any-anthropic principle be if the Universe were teaming with varying species.. life?

    Then we’d have to answer the question of why we are us and not them. This is conceptually the same as the childhood question “why am I me” (and not someone or something else), or in many-worlds QM, the question of why I find myself in one universe and not another. I don’t know if anthropic reasoning can be extended to answer these questions. Analyzing the why-am-i-me question can lead you down a rabbit hole so deep you may never return.

  • marc

    Moshe—Sean is correct that life can’t be made out of dark matter. It can, however, be made of dark energy. Proof: Richard Cheney

  • JerseyBoy

    For the last point, the current instance of life on Earth is viable only for a very narrow range of temperatures. It would be neat to determine the likelihood of finding a planet with that stable temp range as a function of distance from the Big Bang.

  • Thomas D

    OK, another counterfactual question:

    Most of the ordinary matter in the universe (by mass) consists of hydrogen and helium

    Helium is actually rather complicated stuff. Why couldn’t life be made of vortices in blobs of liquid helium?

    And another: why couldn’t life be made of black holes? It has at least been shown that one can make a Turing machine out of them.

  • Thomas D

    … The question of the possible future infinity of the Universe is a funny one. But unless there is some highly energetic matter-creating event in the future, heat death surely wins in the end. That is, very slowly through fusion or fission everything turns to iron – and if protons decay, not even iron survives. So there is a finite interval of time within which chemistry is possible.

    The problem is that we seem to live very early in this interval – unless there are additional conditions on astrophysical evolution which prevent anything from living much later.

  • Dr Who

    “The fact that a Caltech physicist (albeit a non-tenured one) is parading this nonsense would have Feynman rolling in his grave.”

    You mean Archie Feynman, who used to be the janitor in your building? Certainly not that other Feynman who used to sit around in hot tubs discoursing on nanotechnology.

    Let me explain to you how it works. Questions about the origin of the arrow of time are real science — only a few crackpots think otherwise. Playing with questions about the possible forms that life might take is just an attempt to find new ways of thinking about that real problem. Of course it is not important whether life might evolve around an evaporating black hole. But understanding *exactly* what the sun does for *us*, in terms of the second law of thermodynamics, is of course a genuine question. Again, the fate of the arrow of time in the remote future is a question worthy of anyone at Caltech. Or even at a good university [sorry, sorry :-) ]

  • http://backreaction.blogspot.com/ B

    Hi Sean,

    Why do you think the last one does deserves more attention?

    Also, I have recently been thinking about the talk you gave at PI some while ago. The entropy/arrow of time stuff – I’m still chewing on that. A somewhat odd question: how much of your argumentation relies on QM being non-deterministic?

    Best,

    B.

  • Dr Who

    But, Thomas D, did you see my earlier post about the views of Andy Albrecht? I don’t think he is right, for various reasons, but the possibility is there that an arrow of a *new* kind might be getting started now that acceleration has taken over…..

  • Dr Who

    B, since Sean is in China, maybe I can make a stab at that: quantum indeterminacy has nothing to do with it. Again, see Andy Albrecht’s wonderful paper. I agree with him on this matter.

  • http://www.lepp.cornell.edu/spr/2000-11/msg0029236.html Neil B.

    As for oddball life (which I find fascinating): The late Dr. Robert L. Forward, who also championed offbeat (but physically plausible) new propulsion schemes, wrote some books (articles/excerpts first, in Analog first I remember) about life on a neutron star. Dragon’s Egg was first in the series. The Cheela were essentially spiced-up nuclear matter. They were the size of sesame seeds, and their activity rate was millions of times faster than ours. It’s fascinating. There were also some writings by Poul Anderson about the Kyrie, “energy” beings. In one touching story (IIRC), one of them sacrifices itself to save some humans, IIRC, and falls into a black hole. Because of time dilation approaching the event horizon, a telepath partner of the Kyrie can experience its thoughts for the rest of her life. (If it’s still working, you can listen to a reading of it at Link)
    BTW, there’s some recent rethinking of what happens around black holes, but it doesn’t look like fundamental theory (like evaporation) but the nuts and bolts of what actually happens when matter falls in:
    Link
    For life to arise in or around black holes would be very weird and interesting indeed.

    One of the cutest notions wasn’t about alternate life in our own universe, but the saga of the 2-dimensional Ardeans that had a rough time coping with their planar world. (This was a true 2-D analog, with the planet being a circle and movement going around that, instead of the floor-like world of Flatland.) It was The Planiverse: Computer Contact with a Two-Dimensional World by A.K. Dewdney, who later got some notoriety challenging official reports of 9-11 events. The Ardeans had to walk over each other when the met on the planet’s surface! The attempt to adapt to 2-D was ingenious, and made me almost think it could work somewhere. (Note there were real Ardeans who revolted against Rome long ago.)

    Supposedly consistent physics was developed for the Planiverse, with “obvious” features like 1/r force attraction between masses and charges. However, that would make the potential energy between any two masses or charges infinite. If energy has mass, that’s a real problem (and not at the quantum level here.) I also can’t see how EM radiation would work out consistently. That reminds me, where can I find a good rundown of extrapolations of classical EM etc. to other dimensionalities, not high-brown string theory etc? Thanks.

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

    B, the last statement deserves more attention because it doesn’t start with: ” Most of the…” :)

  • http://backreaction.blogspot.com/ B

    Hi Dr. Who:

    Thanks. I will have a look at the paper. Maybe I should clarify my question. On Sean’s earlier post (against bounces) he wrote you have one of two choices: either the entropy continues to decrease as we travel backwards in time through the Bang, or it changes direction and begins to increase. Sadly, neither makes any sense. I remarked that to me the obvious conclusion (besides throwing away the model) would be that entropy remains constant.

    I still don’t understand that point. What is entropy? It is the number of possible microscopic configurations for a given macrostate. If I start with a universe that has entropy soandso, the second law of thermodynamics tells me it doesn’t decrease. This is based on a stochastic reasoning. The probability that the macroscopic state remains ‘ordered’ is just very small. Fine, I understand that. But think about what ‘ordered’ means if the evolution is deterministic. The present state would be a one-to-one map of the initial state. It might not appear to be ordered, but it’s in no way more or less random than the initial state was. This argumentation relies on a determinism though, in which case there is no ‘true’ stochastic evolution. It’s only with QM that outcomes of interactions/scattering are truly random and disable the possibility to trace the state back in time.

    Best,

    B.

  • http://backreaction.blogspot.com/ B

    Hi Count:

    😉 Well, yes ‘deserves attention’ can be interpreted in many ways. I just meant to point out one has to be careful with probability distributions over time, as we know there are evolution laws (causal connections) that have to be obeyed, so one can’t just ‘distribute’ without correlations according to a given density (as one could do over space-like surfaces). See my post on the Doomsday argument and comments there. Best,

    B.

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

    B, thanks! That was an interesting posting on your blog that I missed. My opinion on this matter is essentially what Ken Olum has pointed out.

    The Doomsday paradox is, i.m.o., an artifact of, on the one hand saying that we could have been any person in the history of the human race (that can be disputed e.g. using your arguments, but let’s accept it for argument’s sake), and on the other hand not taking into account that then we must also take the a priori probability for finding ourselves alive at all to be proportional to the total number of people that will ever live.

    This is explained in detail in the article by Olum.

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  • http://magicdragon.com Jonathan Vos Post

    Re #29, 30, 37:

    Technically, there have been at least 5 Feynmans on the Caltech campus several times each.

    Richard Feynman (my mentor and coauthor); his (2nd) wife (now widow); his sister (who lives in Pasadena and does NOT have her brother’s thick Brooklyn accent); his son; his daughter (most recently on campus when the Postal Service released the Feynman postage stamp). His daughter apologizes for the Permissions Editor screwing up and leaving a poem I coauthored with Richard Feynman out of the Selected Letters.

    “Footnote to Feynman”, Jonathan V. Post and Richard Feynman, [Engineering & Science, Caltech, Pasadena, CA, Vol.XLVI, No.5, p.28,
    ISSN: 0013-7812, May 1983; reprinted in Songs from Unsung Worlds, ed. Bonnie Bilyeu Gordon, intro by Alan Lightman (award winning author of Einstein’s Dreams), Birkhauser Boston/AAAS, hardcover ISBN: 0-8176-3296-4, paperback ISBN: 3-7643-3296-4, 1985

    “Starscapes” for Chamber Choir, Three Woodwinds, Piano and Magnetic Tape;
    Composer: Van Decker; texts by Jonathan V. Post & Richard Feynman, “Footnote to Feynman”, University Music Center, California State University, Long Beach, CA, 18 May 1990]

    I am lucky indeed to have coauthored with Feynman, Forward, and so many other collaborators. Indeed, I am collaborating now on a paper which discusses in depth two of Sean Carroll’s arXiv papers.

    As to the far future, my article on this, which cited Freeman Dyson and others, which first published the idea that we are most likely simulations by a far future dilute electron positron plasma civilization, and which served as the extensively quoted basis (quotation marks accidently omitted) of some Greg Benford novels, is:

    “Human Destiny and the End of Time” [Quantum, No.39, Winter 1991/1992, Thrust Publications, 8217 Langport Terrace, Gaithersburg, MD 20877]
    ISSN 0198-6686

  • http://predelusional.blogspot.com/ Stephen

    We find ourselves in a young Universe, but we may indeed find ourselves in an old Universe, at some time in the future. It’s a great experiment. It may take billions of years, but, i’m willing to wait.

    Time flies like an arrow. Fruit flies like a banana.

  • rblaa

    #4 I don’t understand the one-sided infinity thing. Seems to me, once you have a starting point, an eternal future is out the window, for at any point kajillions of years later, the past is finite and the future merely potential.

    What is this obsession about infinity? As far as we are concerned, in practical terms infinity does not exist for us. How can you tell when you have found one? It would take forever to measure it. How can you tell when one has elapsed? It would take forever to wait that long.

    Finite but unbounded is the best we can do.

  • eye-of-horus

    To: all
    From: CEO

    Subject: Devilish vendor causes major anthropic screw-up

    It was the Corporate Committee on Systematic World Ordering which initiated an RFP, cost-plus basis. Failure to recognize that Hellaburton was an unreliable contractor, certain problems with shoddy workmanship and substandard materials quickly emerged.

    These however were plastered over for at least 4 billion years until the first multicellular creatures appeared in planet’s Precambrian oceans. By then it was too late to adjust any nucleotides. After all, it is a double blind test.

    The last 550 million years, however, have proved one unforeseen disaster after another, culminating in Nature’s Greatest Mistake, humanity. Currently, almost 7 billion cases of hypertrophy of the prefrontal cortex!

    Looks like heads must roll. The Corporate Committee on Oort Cloud Exploitation hopes to find a suitably large comet in the next 65 million years, give or take 5 million years.

    However, let there be light. The standing Corporate Committee on Bio-organics has estimated that the average species lasts only about 2 million years.

    Personally, I find myself inordinately fond of beetles. Call it the arthropodic principle.

    eye-of-horus
    copyright asserted 2007

  • WhatMeWorry

    the saga of the 2-dimensional Ardeans that had a rough time coping with their planar world

    That would be because they couldn’t actually one another unless their 2D world extruded somewhat, anywhat, into the 3rd dimension. You’re a male square, say, and you’re trying to check out the hottie female square next to you, and you can’t see a thing unless the hottie square has some ‘thickness’ in a 3D way.

    I think similarly our 3D world, to be detectable to us, must extrude into a 4th spacial dimension. Or maybe it’s merely confirmation that space is granular, and the 2D space the Ardeans live in, has a thickness of one, um, grain.

    I know what I’m trying to say but maybe haven’t said it well. Wouldn’t be the first time.

  • Haelfix

    B, Sean is probably thinking about the coincidence problem in cosmology. Namely that we happen to live in the exact time where matter and dark energy are roughly of the same order of magnitude.

    In the far future, dark energy will completely dominate and black holes will be just about everywhere. Life has a very strict threshold of existence time in the infinite accelerating universe.

    Anyway, I have no problem with the AP, except in so far as its predictions are tautological. Fred Hoyle’s ‘discovery’ should be viewed as a simple statement of observational science, not as verification of the predictive power of the AP

  • Dr Who

    “It’s only with QM that outcomes of interactions/scattering are truly random and disable the possibility to trace the state back in time.”

    I thought something like that until I read Albrecht’s paper. Do let us know what you think after you read it! MAybe you would like to write something in your own blog? Warning: reading that paper may have irreversible effects on your brain…..by the way, I should also have mentioned that you should look at the beautiful art-work in Penrose’s “The Road to Reality” — I mean in the chapter which he devotes to this very question. His explanation of course-graining is probably the clearest ever written.

  • http://backreaction.blogspot.com/ B

    Hi Dr. Who:

    Will do… I think I have that book somewhere… Thanks, I will come back to the question. Might take some time.

    Hi Haelfix:

    I see – yes, that might be. What I dislike most about the AP is that it is called a ‘principle’. I’d prefer was it called the anthropic ‘constraint’. That’s essentially what I think it is. To everything we observe, we have an additional constraint following from the ‘observation’ that it must be possible for us to observe. This might be useful in some cases, but it shouldn’t be overemphasized and there’s nothing spiritual, religious or mysterious about it. I admittedly don’t see why all that discussion around something so obvious. Best,

    B.

  • http://www.mpe.mpg.de/~erwin/ Peter Erwin

    Let me suggest that the “sensible anthropic principle” does not explain “certain apparently unusual features of our environment” except in a very limited sense. That is, it explains why we find ourselves in or near such features, but not why such features exist in the first place. The danger is that people will think that anthropic principles are reasonable substitutes for the hard scientific work of explaining the latter.

    For example:
    Most of the planetary mass in the Solar System is in the form of gas giants. And yet, we live on a rocky planet.
    Most of the total mass in the Solar System is in the Sun. And yet, we live on a planet.

    The SAP may explain why we find ourselves on a planet, and a rocky one at that. But it does not explain why there are planets, or why some planets are rocky, or why our solar system has the particular set of rocky and non-rocky planets it does. And in fact these latter questions are things which can be (and have been) investigated by the normal processes of science, including the “starting from simple dynamical principles” bit.

    If we had ample observational evidence for other universes with other sets of physical constants, some or many of which were probably inhospitable to life — as is the case for non-rocky planets, interplanetary and intergalactic space, etc. — then answering the question “Why do we happen to find ourselves in a universe with such-and-such a set of physical constants?” with the SAP might make sense.

  • Jason Dick

    Even without experimental knowledge of other universes, we can still make statements using the anthropic principle regarding the physical constants within our own universe. It’s really, really difficult to do. But it is, in principle, possible.

    The first thing one needs to calculate is the probability of intelligent life given a set of physical constants (P(IL|C)). This is, unfortunately, an exceedingly difficult thing to calculate. But at least we can obtain some order-of-magnitude estimates fairly easily.

    Then, once we have at least a rough estimate of P(IL|C), we can go about examining various theories that would give rise to the physical constants, to give us an estimate of P(C). Comparing the two, we can obtain information as to whether or not it is likely that our theory for generating P(C) is accurate.

    For example, let’s imagine that upon examining physical constant X, we find that it can potentially be much larger (let’s say, a hundred to a thousand times), and we still might have life, but it can’t get much smaller than it is. In this situation, we expect that our theory-derived P(C) must provide us with an estimate that shows that low values of X are more likely than high values. If, instead, the theory predicts we should see high values of X preferentially, then we can rule out this theory as describing reality with high confidence.

  • http://evolutionarydesign.blogspot.com/ island

    Haelfix said:
    Anyway, I have no problem with the AP, except in so far as its predictions are tautological.

    That depends on how you apply the physics, and to what. For example, the goldilocks enigma predicts that life, past or present, will not be foud on Mars nor Venus, due to the runaway effects that they are subject to that anthropically balanced planets don’t succumb to. Approximately 9 mos from now this prediction will be tested, yet again.

    B says:
    I see – yes, that might be. What I dislike most about the AP is that it is called a ‘principle’.

    Maybe the one that you follow isn’t a “principle”… but the one that I follow is an energy conservation law, and it damned sure is a very strong cosmological principle.

    All this talk about deterministic QM makes me think of ‘t Hooft. He also knows where the real problem is… which is the missed interpretation of the negative energy solutions.

  • http://evolutionarydesign.blogspot.com/ island

    The SAP may explain why we find ourselves on a planet, and a rocky one at that. But it does not explain why there are planets, or why some planets are rocky, or why our solar system has the particular set of rocky and non-rocky planets it does…

    Wait a minute here… Brandon Carter said that this “line of thought requires further development”, and I interpret this to mean that you have to complete the principle before you can answer this.

    Have you done what Carter said needs to be done… first?

  • http://www.math.columbia.edu/~woit/wordpress Peter Woit

    Jason,

    The situation you describe holds precisely for the string theory landscape and the proton decay rate. Experimentally, it is at least something like twenty orders of magnitude lower than the anthropic upper bound, and, within the string theory landscape framework there is no known reason for P(C) to be concentrated at such exponentially low values. So, according to you ” we can rule out this theory as describing reality with high confidence”. Any idea why people are still promoting the string theory landscape despite this? Do you think it might be because this field has become a pseudo-science, abandoning standard ideas about how to evaluate a theory, because following standard scientific practice would require an admission of failure that people would rather avoid?

  • http://www.mpe.mpg.de/~erwin/ Peter Erwin

    Jason (#56),

    Leaving aside the issue of string theory/landscape/etc. — what you describe, especially in your last paragraph, doesn’t need the anthropic principle. If the theory predicts large values of X, but we observe (in our Universe) a small value of X, then we can rule out the theory on the usual scientific basis of agreement or disagreement with the evidence. Whether or not low values of X make life more likely is irrelevant.

  • http://evolutionarydesign.blogspot.com/ island

    “i” wrote:
    ‘t Hooft. He also knows where the real problem is… which is the missed interpretation of the negative energy solutions.

    Carroll orignally said:
    Most of the energy in the universe is dark energy. And yet, we are made of matter.

    Not if dark energy is rarefied mass energy, baby.. because then they are equal.

    The “extra” 1/2 in the eigenvalues of the harmonic oscillator Hamiltonian can be thought of as having a phase factor of -1, which represents vacuum energy as being equal to matter.

    “vacuum energy” 1/2?, which equates to negative pressure, (-0.5*rho(matter)*c^2), necessarily arises if we require that e-iHT=?1.

    This doesn’t just happen to coincidentally fit perfectly with Einstein’s finite static model.

    I’d say… “go figure”… but I already know that nobody will… 😉

  • Jason Dick

    Peter Woit,

    Well, as far as I know, you can only ever rule out a very specific class of theories with very specific dynamics. If we show that our theory doesn’t fit the anthropic bounds, then that doesn’t necessarily mean that we should throw out our theory entirely. Yes, it means that this specific incarnation of the theory is almost certainly incorrect, but it doesn’t mean that any potential modification of the theory is.

    I will admit that I don’t know a whole lot about the string theory landscape. I like the principle of the idea, in that I think it’s the sort of idea that can one day successfully explain our observable region of the universe, but I don’t know enough about the details to comment on the merits (or lack thereof) of the string theory landscape.

    Now, then, if I take what you have said at face value, and assume that nobody has yet found a better solution within the string theory landscape, then we have the question as to where to go next: do we have another answer from some other theory that provides a better fit to observation? Or is this the best we have where a truly fundamental theory is concerned? If the string theory landscape, even if it is a really bad fit to the data right now, is the best fit we yet have, then that seems to be reason enough to examine the string theory landscape further. It might be interesting to see comparisons of other theories along anthropic bounds, to provide an argument for why theory X is preferable to pursue.

  • Jason Dick

    Peter Erwin,

    Actually, we need the anthropic principle, because we need to know whether or not our value of X is large or small, and investigation into what sorts of universes can contain life can potentially tell us that.

    Taking vacuum energy as an example, most theories would predict that our value for the vacuum energy is absurdly small. But what is it compared to the subset of universes that can contain life? Is our vacuum energy just barely small enough that life can form? Or could it have been a few orders of magnitude higher and still produce life? If it could have been a few orders of magnitude higher, then we need to find a theory that predicts a very small value for the vacuum energy. If we find that the vacuum energy could not have been much higher at all, then any theory that predicts a large value, as long as it allows the possibility of a small value, is just fine.

  • http://backreaction.blogspot.com/ B

    Hi Island,

    Maybe the one that you follow isn’t a “principle”… but the one that I follow is an energy conservation law, and it damned sure is a very strong cosmological principle.

    I’ve made very clear what I am talking about here:

    Thoughts on the AP

    And for me that’s it. I don’t think it deserves more thought. If you want to talk about the energy conservation law (not sure though which), why don’t you talk about the energy conservation law ?

    All this talk about deterministic QM makes me think of ‘t Hooft. He also knows where the real problem is… which is the missed interpretation of the negative energy solutions.

    Oh, really? That’s quite interesting, do you have a reference?

    Best,

    B.

  • http://www.math.columbia.edu/~woit/wordpress Peter Woit

    Jason,

    Before deciding that the string theory landscape is the “best fit we have”, and that you like the principle of the idea, I suggest you look into it a bit more closely. I think you’ll find that it’s a classic example of pseudo-science: carefully constructed so that it can’t be confronted with experiment, and, in the few cases when it appears that it can, it fails badly and its proponents start going on about “well, we’re going to ignore that, and hope that some fix will someday be found for that problem.”

  • http://evolutionarydesign.blogspot.com/ island

    No, it’s the tags!, I’m certain of it… heheh

    Hi B,

    http://arxiv.org/abs/0707.4568v1
    The states with n for some reason. Of course, we also do not have the ‘vacuum energy’ 1/2 ? , which would have emerged if we would have required e-iHT = ?1 . This minus sign is as harmless as an overall addition of 1/2 ? to the hamiltonian, but perhaps it will mean something in a more complete theory; we will ignore it for the time being.”

    Just like the WMAP anomalies… “for the time being” is infinite…

    The disappearance of the negative energy modes is very troublesome, however. In a single oscillator, one might still say that energy is conserved, and once it is chosen to be positive, it will stay positive. However, when two or more of these systems interact, they might exchange energy, and we will have to explain why the real world appears to have interactions only in such a way that only positive energy states are occupied. This is a very difficult problem, and, disguised one way or another, it keeps popping up throughout our investigations. It still has not been solved in a completely satisfactory manner, but we can try to handle this difficulty, and one then reaches a number of quite interesting conclusions. In short, our problem is this: in a deterministic theory, one can reproduce quantum-like mathematics in a multitude of ways, but in many cases one encounters hamiltonian functions that are either periodic (in case time is taken to be discrete), or not bounded from below (when time is continuous). Can the real world nevertheless be approximated by, or rather exactly reproduced in, some deterministic model? What then causes the hamiltonian of the real world to be bounded below, with a very special lowest energy state, the ‘vacuum’, as a result? Without this positivity of H , we would not have thermodynamics. The hamiltonian is conjugated to time. Is there something about time that we are not handling correctly?

    Bee said:
    If you want to talk about the energy conservation law (not sure though which), why don’t you talk about the energy conservation law ?

    The *necessarily inherent* prediction of any true anthropic cosmological principle is that there exists a mechanism that enables the universe to “leap”/Bang/evolve to higher orders of the same basic structure in order to preserve the second law and the arrow of time… INDEFINITELY.

    This is also empirically evidenced by our leap from apes to harness fire… and beyond.

    I don’t make *inherent* predictions… I simply don’t ignore the physics that makes them… 😉

  • Eric

    Peter,
    We could consider something like the landscape to be pseudoscience if it didn’t come from a well-motivated and consistent theory like string theory. Since the landscape does appear to be a feature of string theory, then we have to take it seriously since this is the best theory of quantum gravity around. We may not like the landscape and hope it turns out to not be true, but we can’t just dismiss it out of hand. The universe has no obligation to conform to our wishes.

  • Pingback: Seed's Daily Zeitgeist: 8/9/2007 - General Science()

  • http://www.math.columbia.edu/~woit/wordpress Peter Woit

    Eric,

    Yes, the universe has no obligation to conform to our wishes, but we do have obligations as scientists, and these obligations include admitting that a theory is wrong when it implies things that are drastically different than what is observed. To the extent the string theory landscape makes any predictions at all, it makes one that protons will decay at a rate many orders of magnitude faster than observed. The universe has no obligation to conform to your wish that string theory is true, and it has spoken…

  • Eric

    The landscape predicts that protons will decay at a rate many orders of magnitude faster than what’s observed? Maybe for specific vacua, but I don’t think you can claim this as a general statement. There are certainly many vacua with an MSSM-like particle content where the proton decay rate is within experimental bounds.

  • Jason Dick

    Peter Woit,

    Bear in mind that I haven’t claimed or concluded that the string theory landscape is the best fit we have. Given my ignorance, it would be foolish to do so. It was more of a question, really, as to whether we had anything better.

    My liking of the idea has little to do with the experimental validity, but rather more to do with the approach: string theory, it seems, is a theory that can describe a tremendous variety of potential low-energy physics. And yet we may have the potential of describing our own realization of low-energy physics as one of a small subset in which life can form. These properties alone are what make me think it a pleasing theory. I won’t claim that this offers the theory any merits, just that it seems to me an argument that it is something useful to investigate until something else comes up that can provide similar descriptions, but do so in a way that is more likely to describe our own region of the universe.

    So, I guess my question would be: do you think there [i]is[/i] a theory that provides as fundamental a description of our universe, but offers predictions that are closer to observation?

    And yes, I think one day I may educate myself more strongly in string theory, or perhaps some other theory attempting to describe some of the same things, but for the moment I have enough on my plate, and am content to just be a bit of an armchair physicist where this is concerned.

  • http://www.math.columbia.edu/~woit/wordpress Peter Woit

    Eric,

    I’m talking about the kind of statistical prediction that the anthropic landscape people push as the only kind of prediction you can get out of the landscape (the kind Jason was explaining). If you want to throw these out and say that any vacuum in the landscape is fine, no matter how statistically unlikely it is, then string theory inherently has no testable predictions at all, and you’re still doing pseudoscience.

  • http://www.math.columbia.edu/~woit/wordpress Peter Woit

    Jason,

    Asking for a theory with “predictions that are closer to observation” doesn’t really make any sense, since string theory essentially makes no predictions at all. Unfortunately you just can’t evaluate string theory at all on the basis of how close it is to observation. Which is why it is in danger of devolving into pseudo-science rather than science.

  • http://www.lepp.cornell.edu/spr/2000-11/msg0029236.html Neil B.

    Neil B: … the saga of the 2-dimensional Ardeans that had a rough time coping with their planar world…

    WhatMeWorry: That would be because they couldn’t actually one another unless their 2D world extruded somewhat, anywhat, into the 3rd dimension. You’re a male square, say, and you’re trying to check out the hottie female square next to you, and you can’t see a thing unless the hottie square has some ‘thickness’ in a 3D way.

    I think similarly our 3D world, to be detectable to us, must extrude into a 4th spacial dimension. Or maybe it’s merely confirmation that space is granular, and the 2D space the Ardeans live in, has a thickness of one, um, grain.

    No, there doesn’t need to be an extrusion into the 3D world – the 2D beings would see the world in front of them as a line, with brightness and maybe “2D” vision of relief front to back (not like seeing a plane!) if they had one eye above the other for 2-stereo vision! The idea of extrusion does have some interesting physical ramifications for curled up extra dimensions etc.

    The real problem for the Ardeans is their physics, as I noted: With a 1/r consequence of the generalized Gauss law, the potential energy between charges and masses would be infinite. That should cause infinite inertia due to mass-energy equivalence at the crude classical level, but somehow the Planiverse enthusiasts didn’t note that.

    BTW: I know, I may have bragged about being part of top Google search for “quantum measurement paradox” rather too much. Oddly: several days ago, the search results referencing me dropped from the top 2-4 lines consistently for years down all the way to #9, I mean almost overnight. Um, could someone have Googlewashed those links or Googlebombed upwards the competition or somesuch? Well, it would be hard and fratricidal to kick down lepp.cornell, but maybe kicking up the alternatives wouldn’t be so hard? It’s just interesting – someone/s going to all that trouble would be a spiteful bastard with no life. So really, did Google just change their way of rating pages? Thanks, the answer would be broadly interesting in any case.

  • http://www.dorianallworthy.com daisy rose

    Let my mind light up your mind.
    How can it be words combined from thousands of years ago still ignite

  • Eric

    Peter,
    As far as I know, only a small fraction of the landscape has been expored so far, so it seems to me to be premature to be making statistical predictions based on the totality of the landscape.

  • Jason Dick

    Peter Woit,

    Sure it does! It makes one big, confirmed prediction: that Einstein’s equations should be satisfied in a space-time in which strings propagate. As Sean has pointed out on numerous occasions, this alone is a pretty good reason to pursue string theory. And one day, given a specific dynamic (such as the string theory landscape), perhaps we’ll be able to make other more specific, probabilistic predictions.

    Of course, my opinion on the matter makes no difference at all, but there are a large number of theorists who believe that it is something worth pursuing.

  • http://www.math.columbia.edu/~woit/wordpress Peter Woit

    Jason,

    As Lisa Randall likes to point out, yes string theory does predict gravity: 10 dimensional gravity.

    Eric,

    If you know of a possible reason the landscape implies baryon number conservation, let’s hear it. If not, the argument that “OK, it looks like there’s a huge problem with this idea, and there’s not a smidgen of experimental evidence for it, but I want to believe it anyway, so maybe if we study the idea more its problems will go away” is just classic methodology of pseudo-science.

  • http://tyrannogenius.blogspot.com Neil B.

    OK, folks, someone please explain what we’d get any idea of a “landscape” (other than the platonic everyworld idea) off the ground with? I mean, since every (?) attempt to construct with “first principles” is conditioned by what we have – isn’t it hard to say, something quite different couldn’t also be rationalized by its inhabitants to be naturally constructed etc.? (Or, did I get the idea of landscape wrong?) In any case, at the link above you can see a discussion of how three dimensions are special for conservation laws applied to electromagnetism. It’s just a summary, food for thought.

  • WhatMeWorry

    Neil B:

    No, there doesn’t need to be an extrusion into the 3D world – the 2D beings would see the world in front of them as a line

    I don’t see how they would. Say their 2D world is represented as a sheet of paper. In that case, yes, they see others as 1D lines. But they only see those lines because that paper has a smidgen of thickness in the 3rd dimension. Reduce that thickness to literally zero … from cardboard to bond to really skinny onion paper … keep compressing the sheet of paper until it is squeezed out of existence in the 3rd dimension, and that 1D line becomes undetectable. Heck their 2D existence ceases to be. It can only ‘be’ if that sheet of paper has some thickness.

    So their space can exist if (1) it extrudes ever-so-slightly into the 3rd dimension, or (2) it is granular, not infinitely continuous

    That must be some kind of identity. Granularity = Extrusion. Also a continuous space cannot exist; it must be ‘supported’ by some grain :-)

  • http://tyrannogenius.blogspot.com Neil B.

    WhatMeWorry: Most mathematicians and physicists would say that your intuition about planes is an unconscious 3-D chauvinism. Our three dimensions of space are not mathematically specially, although physically they may be (which is argued and arguable.) Euclid’s definitions of lines, planes, etc. are fully self-consistent. We can’t imagine the infinitesimal line that would be the presenting view for a 2-D being, but it is just as valid as a surface, or our 3-space, not needing further extrusion into a higher space. I mean, can’t you imagine “surfaces” without something outside them, without thickness? The specialness of space, thickness etc, is just an illusion deriving from our experience and familiarity with our own world. I know it’s hard to believe.

  • Jason Dick

    WhatMeWorry:
    Though Neil B. provided a decent enough answer, imagine this: we see things because photons bounce off of them and hit us (in the eyes). Consider a two-dimensional being living in a two-dimensional world. It would observe things in much the same way: particles of some sort or other would come from the object it is observing and strike the two-dimensional being. If this two dimensional being has no thickness, is it possible for this particle to hit?

    Most definitely! All that we need is for the particle to be itself constrained to two dimensions, and if it is traveling in the right direction, it cannot help but strike the two-dimensional creature. No thickness is required: the particle can’t go above or below because there is no above or below. So if it’s traveling towards are hypothetical 2D creature, it hits.

  • martin g

    In Sean’s list would there be any logical difference if the words “we live” were replaced by “life exists” and “we are” with “life is” (and where in the last point one would say “we find life existing”)? Further, could “we” (or “life”) in this context be replaced by something different, some inanimate phenomenon just as (apparently) unique to our earth, perhaps “ice floating in water”, and still preserve the apparent probabilistic paradox? (I am guessing that oxygen is considered a heavier element in point #5 since “we” are mostly water by weight.)

  • Eric

    Peter,
    I do not argue for the string landscape or anthropic reasoning. I’d much prefer that there be one unique vacuum or at least some vacuum selection principle. However, as a scientist I cannot ignore the possibility that it may be true. If so, it simply means that there are questions that we cannot answer. I understand why you don’t like this. I don’t like it either. However, at the present we simply do not know enough. We won’t know either, if people do not work on these problems.

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

    There already are questions that we cannot answer. Since the invention of Quantum Mechanics we gave up on predicting the precise outcome of experiments. But we did make a net gain. If a multiverse exists we will, in principle, be able to predict more things than can be predicted in single universe theories.

  • Jason Dick

    Eric,
    I would like to present a very short argument for why the string landscape (or some similar theory) might be preferable to one unique vacuum. Consider, for a moment, the case where there is one unique vacuum. In this situation, we have set all of the current parameters for which we currently have no explanation by appeal to the fundamental laws of nature. And we have gotten a universe where life exists, and in fact must exist by the laws of nature. It’s seems to me absurd that the laws of nature should work out such that life must be possible, particularly given the tiny range of parameter space enclosed by those parameters which allow life to exist in the first place.

    It seems much more natural to me to envision a universe where we have a theory of nearly anything at the heart of it all, such that life is inevitable not because the low-energy physics have to work out the way they have in our region of the universe, but instead because the universe produces so many regions with different low-energy physics that life is inevitable at some point. In this way, we no longer have to have special fundamental laws to describe us. We instead have very flexible fundamental laws where special things inevitably occur from time to time.

    I think a lot of theorists dislike this idea because they seem to think it means that we stop working on theory, as if we’re going to explain everything by anthropics, why explain anything at all? Another argument to be had is that we only use the anthropic argument as a stand-in for a real explanation. Well, I claim that neither is the case. First, anthropic reasoning doesn’t remove theoretical work, it merely shifts it. Instead of looking for fundamental laws, we look for dynamic processes. Second, it doesn’t remove the need to look for fundamental laws, it merely adjusts our methodology in determining which theories that provide these fundamental laws are more or less likely to describe our universe.

  • Watcher

    Sean’s post misleads. Each example can be treated using simple physical principles without appeal to “selection bias” aka “selection effect”. Mentioning “selection effect” or using the term “anthropic” is something of a red herring.

    This statement is just wrong: “…rather than being derived uniquely from simple dynamical principles. Here are some examples of that principle at work.”

    To translate each example into practical operational terms one can ask if your job were to look for signs of extrasolar life where would you point your telescope. At wet rockies or at gas giants? At the surface of stars or at planets? At stuff in galaxies or at regions of intergalactic space? If you have a research grant to look for signs of life then presumably you have a working definition of what physical phenomena you are going to call life and what the physical signs are. And I think there are clear “simple dynamical principles” that explain why you and the funding agency would think it more likely to find signs of life (however you might reasonably define it for purposes of study) on wet rockies instead of on the surface of a star, a gas giant, or in nearly empty space.

    The only one of Sean’s examples that doesn’t translate into a pragmatic telescope-pointing question is the last one. But this has been dealt with by for example Lineweaver and Egan in a recent (2007) paper available at arxiv. If you go by the standard LCDM cosmology, take into account the rigors of living in the cold dark old age of the universe and allow time for planetary system formation and biological evolution to elapse since bang, then now is a pretty ordinary time to be observing the universe. They explain the fact that the matter fraction and dark energy fraction are roughly comparable as something which is NOT an “unusual feature” but TO BE EXPECTED based on known physical principles. Indeed they estimate that 68 percent of all observers, during the effective lifespan of the universe, would be observing during this present era during which the matter and dark energy fractions are at least as roughly comparable as they are today. In other words, following Lineweaver and Egan’s argument, whatever reasonable definition of OUR ERA you adopt, it is NOT SURPRISING to be be an observer in this era. One should expect, on the contrary, that it is rather commonplace. If there are any other observers at all, they are not unlikely (e.g. 68 percent) to be, in a crude sense, contemporary.

    It’s a great (and rather usual) time to be watching! :-)

  • WhatMeWorry

    Jason Dick and Neil B:

    Thanks yes now I see it might be 3D chauvinism. Seen through one 3D eye, we 3D beings see the equivalent of a 2D ‘surface’. A 4D being contemplating this in the same way I did, would say to herself ‘that hypothetical 3D guy cannot detect that 2D surface unless his 3D space extrudes into my 4th dimension.

    The 2D photon hitting the 2D eye … from my 3D perspective, if both the photon and the eye have zero thickness, that space has no existence for me and I simply cannot visualize that 2D intersection. I was wrong to think ‘if that 2D space was granular, then I can visualize it’, because I was imputing a 3rd dimension to the 2D grains, making that space detectable to me.

    As a 3D being, I am only able to visualize that 2D space if it is not continuous and the ‘atoms’ extrude ever so slightly into the third dimension. Ditto to the 4D being contemplating our 3D existence. Hey maybe that’s where the extra string dimensions hole up.

  • Aeon Flux

    This provides an outline for a debate between myself, a student of engineering, a student of philosophy, and myself, a student of Business, a few weeks ago.

    My philospher/scientist friend posited that though life on our planet exists in its present state, our composition (matter specifically), relative to that of the universe is more the exception than the rule; but that there could still possibly be environments other than our own, that could sustain us.

    My engineer/CEO friend posited that life as we understand and experience it, likely exists uniquely in the universe; due to the unlikelyhood that there are other environments in our universe with the atmospheric and elemental properties neccesary to sustain life. ( e.g., We don’t know if there is oxygen there or an atmosphere to hold it in; what kind of radiation is there? etc.)

    I (the meandering basement philospher, and student of life)posited that life as we experience it (and in general), is an alchemical inevitability of the elements of our environment (at the micro and macro levels-from our planet’s ecosystem to the overaching structure of the universe); and that our perception of “life” is limited to our perspective, and ultimately our understanding of what life is; therefore life as we know it, or otherwise, may possibly exist within environmental constructs unfamiliar to us. (Who says one needs a body to “live”?)

    I eventually came to the realization, like with any argument, we were ultimately presenting different perspectives on the same fundamental dynamic.

    Now onto this:

    “…certain apparently unusual features of our environment might be explained by selection effects governing the viability of life within a plethora of diverse possibilities.”
    Yeah… what Darwin said…

    Or, depending on your interpretation…What Dr. Frankenstein said…. “It’s alive!” Gaia is alive!

    Question: Wouldn’t it stand to reason that the “simple dynamical principles” that govern and order the existance, and behavior of all particles, and thier eventual arrangement into matter/antimatter or whatever, would be the very reason for the “..plethora of diverse possibilities” before us; upon which our development into what we currently are, is based? I think so.

    Then’s there’s this:
    Given that the subatomic particles of physical matter fall at the lower frequency end of the electromagnetic spectrum (as I understand it), this kind of begs the question:

    Are we down here on the physical plane, riding the short bus on the highway of existance?

    Sean brings up some interesting points, culminating (again, to me anyway) in a theory that we (at least in our present state) are very young, in our developmental journey through the universe-physically, at the very least.

    Hell, maybe we are even still hauling ass down the sidewalk, trying to catch the short bus…

    Or just maybe, just maybe….we’re right on time….

  • Jason Dick

    Aeon Flux,
    I seriously seriously doubt that life that makes use of similar metabolism to ours is not out there somewhere. Now, I think that the specific building blocks of life may be incredibly different from what we have here on Earth, but I think we can be reasonably confident that there is other carbon-based life that makes use of the same sorts of basic molecules (DNA, RNA, proteins, etc.).

    I claim this for the following reasons:
    1. Life like our own doesn’t need terribly special conditions to arise. The carbon, nitrogen, and oxygen that such life requires are going to be reasonably plentiful around any population I stars. In such a situation, basically all you need is roughly the right mass planet at roughly the right distance from the host star (in the “Goldilocks zone”). We’ve already found one potential such planet within 30 light years of our own sun (though there are significant caveats there…), so it seems that such planets are probably pretty darned common.

    2. From what little I know of abiogenesis, it appears that the basic building blocks of life (amino acids, nucleotides, and the like) are the way they are due to basic chemistry, and can’t change a whole lot (for carbon-based life, anyway).

    So, from what I’ve read on the subject, I think the start of life is pretty much guaranteed to happen if the host planet has the right conditions, and it doesn’t seem that those conditions are that uncommon (compared to the 400,000,000,000 stars in our own galaxy, and the 100,000,000,000 visible galaxies). Once life starts, however, evolution takes over, and though I think we can expect convergent evolution to occur, I doubt there’s going to be much similarity at all in the specific DNA coding, the specific proteins used, or the various forms into which life organizes itself.

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  • http://www.mpe.mpg.de/~erwin/ Peter Erwin

    Jason @ 63:

    I think you’re missing the point. If we have a theory that actually predicts a certain value for X (be it the vacuum energy or whatever), then that’s all you need in order to evaluate the theory vis-a-vis our measured value of X. (The fact that certain arguments from our theories of low-energy physics predict values of the vacuum energy which are much too large compared with the measured value means that there are problems with those theories, or at least with the arguments made to estimate the vacuum energy from those theories.)

    Knowing whether our measured value of X is “large” or “small” in terms of potentially allowing life is philosophically interesting, but irrelevant to the basic scientific issue of using theories to make predictions and testing those predictions against the observed data. A theory whose predicted value of X is 10 standard deviations too large is just as wrong as a theory whose predicted value is 10 standard deviations too small.

    You wouldn’t apply this thinking in any other realm of physics or science. (“While it may be true that Ptolemy’s model for planetary motions badly mis-predicts the current position of the planets, we need to consider which planetary positions are consistent with our being here, or our continued survival. If Ptolemy’s theory predicts a planetary position that is consistent with our existence, then it’s just fine.”)

  • Jason Dick

    Peter Erwin,

    There is a fundamental difference between predicting something like the motions of the planets and the properties of our observable universe. But this is a fair enough analogy to work with.

    We expect that a proper theory of how the planets move relative to Earth-bound observers should be explicit: that there should be no anthropics involved. We know that general relativity is as yet the best description of the motions of the planets, as this theory predicts their motions to very high precision. The reason why there is no anthropic argument involved here is because the actual prediction is only one of time evolution. It doesn’t predict, for example, the distances of the planets from the Sun, the shapes of the orbits, the masses of the planets, the numbers of moons, etc.

    Now imagine we don’t just want a theory that describes our solar system as it is today, but instead want to describe its origins. Why is the Earth habitable? Why is it just the right mass? Why is it just the right distance from the Sun? Why does it have just the right composition?

    To answer these questions, we expect there to be some combination of anthropic reasoning and knowledge of dynamics. For example, we know today that our planet largely has the right chemical composition for life because our sun is a population I star. But we shouldn’t expect any theory to give a high probability of Earth itself forming around our sun, because we don’t have any reason to expect that the Earth itself is probable. It could have been an obscenely freak occurrence and still have happened, given that there are some 10^22 stars in the visible universe.

    Now, given the properties of cosmic inflation alone, we can be reasonably confident that the universe as a whole is significantly larger than what we can observe. And it is entirely plausible that different regions of the universe have different low-energy physics. So we should not unduly bias our attempts to find a fundamental theory by claiming that all of the universe is like the small region that we can observe, just as we don’t try to bias our theories of solar system formation by claiming that all solar systems are like our own.

  • http://tyrannogenius.blogspot.com Neil B.

    Jason Dick expounded forth (#86):

    It seems much more natural to me to envision a universe where we have a theory of nearly anything at the heart of it all, such that life is inevitable not because the low-energy physics have to work out the way they have in our region of the universe, but instead because the universe produces so many regions with different low-energy physics that life is inevitable at some point. In this way, we no longer have to have special fundamental laws to describe us. We instead have very flexible fundamental laws where special things inevitably occur from time to time.

    Well, first to remind folks in general that the constants (?) have to be very very narrowly within the current ranges or life can’t really take off. Also, this involves all kinds of things that need to be just right, like the carbon nuclear cycle inside stars, as explained well per the oft or even over-quoted classic The Anthropic Cosmological Principle. It goes down to properties of water, etc., really a lot of stuff needed to line up (so it’s more about whether the right values line up to within 1:10^100 or in 10^200 type of thing, and BTW not to be confused with what chance of life starting, given our laws as they are.)

    Also, I’m not sure how we can imagine constants being different in other regions of our same (contiguous?) space. Are you really saying, that hydrogen atoms would not be the same as ones around here etc? If instead “matter is matter” then the “laws” and constants are intrinsic to the stuff, not to a boss medium they operate in. It would not be per what I consider the fallacy of the laws being a separable enforcer on otherwise property-free basal “vanilla stuff.” If matter does not boss itself in effect, you could then imagine different “legal classes” of particles being created out of the same event, instead of particles all acting the same anywhere unless subject to extreme stress.

    Finally, the idea that matter can be/act differently elsewhere in the “same universe” brings up interesting perplexities, like: what if we brought some of it here? Would it act like our matter because our spatial region holds in it the guidelines for how to act, or would we have some oddly behaving (“self-bossing”) material that’s clearly not ordinary matter? Well, what if we could somehow import particles from “another universe” with different laws of physics instead, then what? Would they bring their funny laws with them, or be conditioned by existence in our space? Would say the latter, the properties of “vacua” invoked here? – but is the template similar enough to translate over? Great food for thought … and yes it’s very metaphysical I suppose, but let’s admit that’s what most of this subject is, OK?

  • Alejandro Rivero

    What about the equality between tidal forces of Moon and Sun? Could it be anthropic?

    (If you are tempted into the affirmative, think 30 seconds before reading the next remark) A couple years ago a lot of people was giving as an example of coincidence without further meaning the one of angular sizes of Moon and Sun. But, as you can read in the volume III of the Principia, the difference between tidal forces is the product of proportions between densities and between angular sizes, because the tidal force goes as the cube of the distance. So if tidal forces are anthropic-explained, then also the coincidence of solar eclipses is anthropic-explained.

  • http://tyrannogenius.blogspot.com Neil B.

    To start a partial answer to my own question above: I suppose the virtual-particle repertoire, and what rules in principle apply to them, in a given space are what is “natural” to that space. That still doesn’t tell us what would happen to particles moved to regions of different laws, if such can be the case.

  • Jason Dick

    Neil B.,

    One potential solution to the problem of envisioning different regions of space having different low-energy physical laws is that perhaps due to the way the physics works out, the different regions are separated by horizons. Thus there would be no problem of transferring mater from one region to another, as the horizons would prevent that from ever occurring.

    Now, if this is not the case, then presumably understanding the most fundamental physics would tell us precisely what would happen when we try to move matter from a region with one set of low-energy physical laws to another. For example, if we imagine a string theory scenario where the different regions are separated by different compactifications of the higher dimensions, and we further imagine that they are not separated by a horizon, then we could easily ask the question of what would happen to a string from one region if it attempts to enter another. We might find that the differences in compactification prevent the string from entering the other region, or we might find some sort of scattering going on at the boundary, somewhat akin to what photons do when they cross the boundary between air and glass.

    In either case, if we were capable of answering the question, “What is an electron, really?” then we would probably also be capable of answering the question as to what happens to it when it tries to pass to a region with different low-energy physical laws.

  • whomever1
  • Plato

    Smolin’s most famous suggestion may be his theory of fecund universes, also known as cosmological natural selection, which attempts to apply principles of biological evolution to cosmology, suggesting that universes evolve in favor of the production of black holes. Leonard Susskind who now promotes a similar cosmic landscape theory, stated “I’m not sure why Smolin’s idea didn’t attract much attention. I actually think it deserved far more than it got.”

    …..source wikipedia

  • Plato

    Lee Smolin’s hypothesis of cosmological natural selection makes the assumption that each universe created in such a way possesses slightly modified versions of the mass fields of its “parent” universe. This concept is of course borrowed from Darwin, and is analogous to mutation of genes in modern evolutionary theory. There is some conjectural support for this in both string theory and quantum gravity. The change in the mass fields would be due to the intense energies and small scales reached within a black hole. By a simple extrapolation it is easy to see that universes which generate more “offspring” will ultimately become more numerous. A universe with no stars and consisting entirely of hydrogen gas can produce only one offspring because it can produce no black holes. All it can do is collapse back in on itself in a “big crunch”, a reverse big bang, to generate a singularity. Given enough universes, some would by chance possess the matter fields necessary to generate stars and thus black holes. Since these would produce far more offspring, they would become far more numerous than universes without stars. (There is no known mechanism that “kills off” universes and so there is no actual parallel to “natural selection” in the theory of cosmological natural selection. It is for this reason that it is now technically referred to as fecund universes.)

    source.. Fecund Universes on Wikipedia

  • Jason Dick

    Well, I can think of two potential problems with the Fecund universe. The stronger gravity is, the more black holes form. This would predict, then, that the strength of gravity in most universes containing life would be just barely small enough to contain life (after all, if gravity is so strong that only black holes form, then no life can form either). Granted, I’m not sure what the numbers are here, but it would, in principle, not be that difficult to calculate within Smolin’s model the probability of a gravitational constant given the existence of planets. I rather doubt that this would result in our universe being likely.

    The second potential problem is the existence of vacuum fluctuations. I rather expect that the number of black holes that are produced as vacuum fluctuations vastly exceeds the number of semi-stable black holes. Therefore, if Smolin is right about the interiors of black holes being other universes, then it seems to me that he is unlikely to be correct about universes that create black holes from gravitational collapse being preferred.

    Granted, I haven’t examined the idea much at all, it just naively seems to be unlikely to me. By contrast, the idea of the string theory land scape seems much more plausible, given the possibility of future-eternal inflation.

  • http://tyrannogenius.blogspot.com Neil B.

    BTW folks, what genuine basis do we have for actually figuring mechanisms “behind” physical laws, and what would change them? You can make up (that’s what it is) a construct that would be able to change and pretend you’re getting different constants out of that, but that looks suspicious in the grand scheme. I know that gravity might be tunable etc, but the whole structure of things is just wide open. It can’t be some essential structure that’s just the default for “existing” in some sense. The better thinkers about fundamental issues (framing issues) can tell you, “existence” is not a predicate, and there is no way to tie it logically to any particular manifestation.

    From whence “the landscape”? When people come up with foundational entities like strings, they are just working back from whatever we see around to some concept that fits. It’s almost a circular argument, and we can imagine entities in something completely different imaging the alternative “building blocks” that would fit into their reality etc. Yeah, we don’t have access to such entities, but neither to the realms nearly like ours (and where does it end?) needed to make sense of legally distinguished other universes either. We are not starting a priori and working back up to what a or the universe must be like. That’s just the breaks.

  • Jason Dick

    Neil B.,

    The typical mechanism for producing different low-energy physical laws in different regions is spontaneous symmetry breaking. The analogy that is usually used is that of a ferromagnet. In a ferromagnet, there is a tendency for the magnetic moments of the various atoms to line up with other atoms nearby at low temperatures. At high temperatures, the magnetic moments will be pointing in random directions, bouncing all over the place. As the temperature is lowered, the magnets will start to line up. But they don’t do so uniformly: they will line up in one direction in one region, and an entirely different direction in another region. This is because the magnetization happens slowly: it starts when a few atoms have moments that, due to random chance, tend to line up, or around some sort of impurity. Once they start to line up, the pattern spreads, and the region magnetizes. But more than one region will do this at any given time, so eventually it’ll run into another spreading region, and since neither direction is preferred over another, the magnet itself will stabilize with a large number of domains with magnetic fields pointing in different directions.

    A similar setup is typically thought of for producing the low-energy physical laws in our present universe. The idea is basically that certain of the constants we observe are produced as a result of one field or another taking a particular value, not because that value was somehow special, but because the neighboring points also took that value. In string theory, one way of thinking of this is by examining the different ways in which we can compactify the higher dimensions.

    But, in any case, I think we do expect that there must be some fundamental structure that just exists. I don’t think the universe could make sense were this not the case.

  • http://tyrannogenius.blogspot.com Neil B.

    Jason, you have a point, and the discussion was good middle-brow description (like I usually need) of cutting edge fundamental physical theory. That could well be how the fundamental structure “that exists” works, but it’s hard to know since how can we experimentally produce for testing, regions with literally different low-energy laws (not to be confused with the non-linear response of given matter in space to higher energy etc.) If you have writings out there about this issue, yours or favorites from others, please leave some links or etc.

    Now, what I meant about fundamentals was: sure there is a structure that just exists, behind everything else. However, logic itself doesn’t give any reason for that structure to be inherently natural to “existing” versus another, it is a given “put in by hand” as they say. (I mean, even the structure like strings that would underlie different expressions of physical law, not merely a given set of laws and constants. Despite their flexibility and power over some laws, the strings still have laws of their own, a certain way to be. They are a little patch carved out of “all possible descriptions.”)

    As I have explained before, existence is not a predicate and cannot even be logically defined, such as could separate described model universes into “the ones that exist” and the ones that don’t. Check “modal realism” on Wikipedia etc. Ironically I don’t actually believe in MR. It’s just that either “everything exists”, or, something outside logical necessity must be responsible for the limited set of existing things being as they are. You can imagine that “something” as you wish.

  • jeff

    sure there is a structure that just exists, behind everything else. However, logic itself doesn’t give any reason for that structure to be inherently natural to “existing” versus another, it is a given “put in by hand” as they say. (I mean, even the structure like strings that would underlie different expressions of physical law

    And after a while you run into the basic problem with reductionism – A depends on B, and B depends on C, and… is it turtles all the way down for ever and ever amen? Or as deep as you’re willing to look? How far down do you go before you can’t reduce anymore? At some point you go beyond the limits of observation (like string theory), and you’re using heuristic mental constructs to explain things. In other words, you’ve reduced realism to idealism.

  • Jason Dick

    Neil B.,

    One of the interesting things about spontaneous symmetry breaking is that it can, indeed be tested. And hopefully will be quite soon. It is, for example, a fundamental aspect of the standard model of particle physics, which has so far been confirmed to a tremendous degree. And the most interesting prediction of this model has yet to be confirmed: the existence of the Higgs boson. It is my hope that if the Higgs is discovered at the LHC, that we will obtain much more direct evidence of the existence of a spontaneous symmetry breaking event in our distant past.

    Now, as for the existence of a fundamental theory, I have to ask, why can’t there be a fundamental reason why a certain theory is the correct one? We certainly don’t know of any such fundamental reason, but that doesn’t mean it isn’t there. One fundamental reason that would satisfy me, however, would be if we were to show that there exists only one mathematically consistent theory of the universe, and there is a principle where everything that can happen does happen. This would be a fantastically difficult thing to show, and we are not even close to doing so. It may also be entirely wrong. But in any case I think we should expect that were we to discover the most fundamental theory of the universe (something rather unlikely to happen in the lifetime of anybody currently alive), that we would also find that there is a deeply interesting and simple reason why it is the fundamental theory of the universe.

    In other words, at some point, we should expect the most fundamental theory of the universe to explain itself. I don’t know if mankind will ever find this theory, but one can always hope. In the mean time, we should continue to do what we have been doing: expanding our knowledge through further observation and experiment, and expanding our awareness of what might be by asking as many “What if?” questions as we can pose.

  • Jason Dick

    Oops, I don’t think I worded that first paragraph properly, expressing far too much certainty. Sorry about that. My field of study is not quantum field theory, so I cannot say with certainty that this particular aspect of the standard model will be tested soon. What I can say is that it is a significant aspect of the theory, and the discovery of the Higgs would be a tremendous step forward in confirming the theory. I’m not quite certain precisely how this would impact the testing of whether or not there actually was spontaneous symmetry breaking, but I expect that it will lend significant evidence in support of such an event.

    That out of the way, there is potentially another method of testing for spontaneous symmetry breaking, that has so far yielded a null result. Specifically, spontaneous symmetry breaking events tend to leave what are called defects, and those defects are dependent upon the dimensionality of the space. Imagine, for instance, a flat plain. On this plain is an array of pencils, each with one end attached to the plane. We also have a bunch of springs connecting the other ends of the pencils to one another. Thus, we have a situation where if we drop one pencil down in one direction, the pencils nearby will tend to also fall down in a similar direction.

    Thus the obvious stable low-temperature configuration of a region of this plane is all of the pencils pointing in the same direction. There is, however, another configuration: imagine one pencil standing straight up, with all of the pencils around it pointing radially outward. This one standing pencil is stable because it is being pulled in all directions equally, and those around it are stable because they have pencils around them pointing in nearly the same direction as themselves. This is what is known as a defect.

    In three dimensions, we tend to get defects that are like long strings (not to be confused with the strings from string theory). Now, cosmic inflation tends to dilute such things, so we don’t necessarily expect to be able to find any. However, if we could find a cosmic string, it would be a dramatic confirmation of the existence of at least one spontaneous symmetry breaking event happening in our past.

  • http://evolutionarydesign.blogspot.com/ island

    sure there is a structure that just exists, behind everything else. However, logic itself doesn’t give any reason for that structure to be inherently natural to “existing” versus another, it is a given “put in by hand” as they say.

    Not necessarily if there is an inherent imbalance in the energy of the universe then there exists a natural, impetus that will drive the structure perpetually “down-hill” in a purely natural effort to to reconcile the disequilibrium.

    How it got there?… I dunno, but that isn’t a factor since we have no evidence that “nothing” can or ever did exist, so I can’t assume that this imperfect energy ever didn’t exist, since I can justify that it is plausible that it has.

    Why is the energy less than pure?… I don’t know that either, but I know that you can’t square the circle and no two snowflakes or molocules are exactly alike, so I have no evidence that there should be any kind of absolute symmetry in the energy either, so your questions require assumptions about stuff that isn’t observed to be possible.

    In this context it’s “existing versus”… nothing that you can justify should be expected.

  • Plato

    Neil,

    When people come up with foundational entities like strings, they are just working back from whatever we see around to some concept that fits.

    Mathematics is suppose to be the foundation of the natural world?:)

    Anyway the landscape is attractive to some while undestanding fully that you are pushing perspective back to the micoseconds of our universe. “Island” may be describing the potential, of hills and valleys?

    Then, we see perspective forming around our collider uses. One has to think what use this method if it did not imply some connection to the cosmological formulation of our early universe?

    Is “dimensional perspective” possible within the confines of these collisions processes? Within the universe and why not?

  • http://magicdragon.com Jonathan Vos Post

    The problem with the Fecund Universe concept, which I told everyone I spoke to about Cosmology immediately after Smolin’s publication, was that evolutionary biology shows how sexual reproduct explores genome space exponentially faster than asexual revolution. Cosmos budding off daughter cosmos is asexual reproduction. Fine tuning of physical constants to anthropic values is reached if we can figure out a way to have TWO universes in the landscale combine to create a daughter cosmos, with some combination of the physical constants of each, plus some random mutation due to, whatever, quantum uncertainty in superspace. Sexual reproduction of universes — that gives a new meaning to “Big Bang.”

    The Establishment approach to eliminating crackpots is to restrict to authors of refereed papers, and further, in the disciplines in which they are published (to eliminate the phenomenon of an expert in one field pontificating spuriously in another field).

    That eliminates a small number of famous rejected but signifcant papers, and lets in a few goofy things that referees mysteriously okayed, but is generally useful to, say, academic bloggers.

    The background of my article “Human Destiny and the End of Time”, in the magazine Quantm (edited by a PhD Chemist, by the way) and published years before Bostrom’s rediscovery, was my own prior publications on extrapolating the advance in computing power.

    Jonathan V. Post, “Quintillabit: Parameters of a Hyperlarge Database”,
    Proceedings of the Sixth International Conference on Very Large
    Databases,
    Montreal, Canada, 1-3 October 1980

    The above coined the term “1 Shannon = 1 mole, Avogadro’s number, of bits.”

    Simulating a person, or the entire universe, is estimated in Shannons. How many Shannons do you think it takes to simulate the obervable universe to, say, femtometer and femtosecond resolution?

    My PhD work included analyses of how many bytes per second are processed in a single cell (bacterium or yeast) and extrapolating to how many computations per second are needed to simulate an entire organism in ultra-high resolution. The chapters of that dissertation, arguably the first ever on what became Nanotechnology, were read worldwide when repackaged as refereed papers, and expecially intrigued scientists at U. Moscow and U. Leningrad, which the State Department preferred I not correspond (this being the Cold War, and my doing highly classified work for Boeing, Rockwell, Lockheed, Army, Navy, and Air Force).

    The government explanation to me was: “We consider your research to be bullsh*t. But on the off chance that it is not, we don’t want you even to send repreints of existing literature to the communists.” Then they asked if they could have the Bulgarian postage stamps from some letters they intercepted, inviting me to chair a session at an international conference in Sofia, on the basis that one of these Men in Black had a son who collected stamps. I refused, rather curtly.

    In any case, I am not asserting that I published PART of what made Bostrom famous. I’m asserting, with complete support from edited literature, that I discovered ALL of what he later claimed, and that I left out the more foolish parts of his quasi-religious hand-waving.

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Cosmic Variance

Random samplings from a universe of ideas.

About Sean Carroll

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

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