Life, the multiverse and everything

vernon200The idea that our universe is but one of infinitely many in a multiverse, represents an extraordinary leap in our conception of the cosmos. It is often said of quantum mechanics that if you think you have understood it, you haven’t. Something similar might be true of the multiverse: if you think you can imagine it, you can’t.

Little wonder that it is easy to find cosmologists who think the hypothesis is barely scientific at all. They have a point. For if the multiverse is so wildly speculative, as even its advocates acknowledge it to be, then might the theory be a case of science being led more by metaphysics than physics? Or to put it more personally: are the religious convictions of individual cosmologists – atheistic or theistic – playing a role in determining what is presented as pure science?

Martin Rees is quite clear that metaphysics, let alone faith, should have nothing to do with physics. I sat with the astronomer royal in his 16th century, wooden panelled sitting-room, one of a suite in the Master’s Lodge at Trinity College, Cambridge. The sash windows held glass bubbled with age. The surroundings are grand, though Rees himself is the embodiment of intelligent humility in the face of big questions. ‘Fifty years ago we all thought of the big bang as very speculative,’ he suggests: ‘Now the big bang from one millisecond onwards is as well established as anything about the early history of the earth.’

So is there anything different about the multiverse? Just what is at stake?

One way of approaching the subject is to note how over the last ten years or so, there has developed a wide recognition amongst physicists that certain features of the universe appear uncanny. This observation is referred to as fine-tuning or the “anthropic principle”. The basic notion is that the existence of life appears to put limits on the values certain physical constants can take.

The anthropic idea was mocked when it was first proposed in 1973. Stephen Jay Gould penned one of the most amusing lines of ridicule. It is like declaring that ships were created so that barnacles could cling to them, he wrote. More generally, physicists shied from the principle, not just because it encouraged speculation that the universe might have a purpose, namely life, but also because they held out the hope that physics might be on the verge of deriving a “theory of everything”. One test of such a theory would be the fine-tuning were shown to be nothing but the internal consequences of such a TOE.

But the anthropic principle is mocked less frequently these days, if at all. For one thing, physicists have grown less confident that a TOE is imminent. And then, in 1998, a discovery was made which appears to give fine-tuning an astonishing boost.

In that year astronomers discovered that the universe is not just expanding, but expanding at an accelerating rate. It was a baffling finding because they expected the expansion of the universe to be slowing down, as a result of the braking effect of gravity. What the acceleration seems to imply is that there is another force at work in the cosmos, one that is pushing matter apart and can overcome everything, even gravity. What is it? Physicists don’t know, and have called it the “dark energy”.

There was one key candidate for this mysterious force, though. It came from quantum mechanics. In the strange world of the super-super-small, a vacuum is not all that it seems. In fact, it is not a vacuum. Rather, it is teeming with virtual particles that pop in and out of existence, only like the white noise on a digital radio, this mass of activity is so subtle that we don’t notice it. Physicists had known about the possibility of a quantum vacuum energy for some time. With the discovery of dark energy, they returned to it to calculate just how large it might be. Would it be right to match the acceleration of the universe?

It was not just not right, it was catastrophically too large. The calculations indicated that the quantum vacuum energy was oversized by a factor 10120. That is an extraordinary large number. There are “only” 1090 atoms in the entire known universe. If the actual dark energy were that large, the universe would be expanding so fast that light wouldn’t have time to reach our eyes from the end of our noses before they both shot apart to be amongst the stars. Only, such a large dark energy would mean there couldn’t be any stars too, and so we wouldn’t be here at all.

This new twist in the story of fine-tuning astonishes even the most atheistic of physicists. I spoke with Steven Weinberg, the Nobel-prize winner who has himself penned some witty lines mocking belief. On the telephone, from his office at the University of Texas at Austin, he said: “This is the one fine-tuning that seems to be extreme, far beyond what you could imagine just having to accept as a mere accident.”

Hence, anthropic debates have moved centre-stage in contemporary cosmology. And with them, the multiverse. The multiverse hypothesis is that our universe is just one of many. In each separate universe, the laws of nature are different. In some of those universes, the dark energy will be large – too large for stars and galaxies, rendering them cold and dead. In others, like ours, it will be about right. The notion appears to knock fine-tuning on the head, since the old rebuttal against it can be reinstated: we shouldn’t be surprised the magnitude of forces and the values of constants are as they are in our universe, since if they weren’t, we wouldn’t be here to measure them.

A handful of theories in modern physics have raised the possibility of a multiverse. For example, there is the so-called “many worlds” interpretation of quantum mechanics, championed by physicists such as David Deutsch. This view “explains” the probabilistic nature of quantum theory by postulating that the universe splits with every option that every quantum particle has. A massively splitting universe equals a multiverse.

Alternatively, the dominant model of the big bang can lead to a multiverse too. It includes what is known as inflation, a period in the early stages of the universe when it expanded rapidly. A variant on that, called eternal inflation, imagines universes continually emerging from the quantum background, and inflating to form universes in their own right. A massively inflating universe equals a multiverse.

Or again, multiverses can be part of string theory. To be precise, some string theorists have proposed that there might be 10500; universes in the multiverse.

Bernard Carr is an astronomer at Queen Mary University, London. Unlike Martin Rees, he does not enjoy wooden-panelled rooms in his day job, but inhabits an office at the top of a concrete high-rise, the windows of which hang as if on the edge of the universe. He sums up the multiverse predicament: “Everyone has their own reason why they’re keen on the multiverse. But what it comes down to is that there are these physical constants that can’t be explained. It seems clear that there is fine tuning, and you either need a tuner, who chooses the constants so that we arise, or you need a multiverse, and then we have to be in one of the universes where the constants are right for life.”

But which comes first, tuner or tuned? Who or what is leading the dance? Isn’t conjuring up a multiverse to explain already outlandish fine-tuning tantamount to leaping out of the physical frying pan and into the metaphysical fire?

Unsurprisingly, the multiverse proposal has provoked ideological opposition. In 2005, the New York Times published an opinion piece by a Roman Catholic cardinal, Christoph Schönborn, in which he called it “an abdication of human intelligence.” That comment led to a slew of letters lambasting the claim that the multiverse is a hypothesis designed to avoid “the overwhelming evidence for purpose and design found in modern science.” But even if you don’t go along with the prince of the church on that, he had another point which does resonate with many physicists, regardless of their belief. The idea that the multiverse solves the fine-tuning of the universe by effectively declaring that everything is possible is in itself not a scientific explanation at all: if you allow yourself to hypothesize any number of worlds, you can account for anything but say very little about how or why.

John Polkinghorne is a physicist who would have some sympathy with the cardinal, and not just because he is an Anglican priest. He is also a distinguished scientist, having played a key role in the discovery of quarks. “I think it’s a very remarkable fact that the universe is intelligible to us,” he says. (This time, I’m back in another 500-year-old room as Polkinghorne was the Master of Queen’s College, Cambridge: a grumpy looking Erasmus peers out at us from a gilded frame on the wall.) “I must say talking to some militantly non-believing colleagues, the intelligibility of the universe is one thing that does give them pause.” Polkinghorne himself calls the multiverse proposal a “fairly desperate measure.”

However, he adds that science only provides him with “a thin notion of God.” He is also quite clear that physics and theology are intellectual cousins, each with their own integrity that must be carefully guarded. And it is because of the integrity of physics that he primarily objects to the multiverse. It seems to be an untestable theory: astronomers can’t see to the edge of our own universe, let alone probe others. To him, that puts it beyond the realm of science. He recalls that when he was working on quarks, there existed a balance in physics between the theoretical and the empirical. Today, he believes that balance is at risk of being lost.

Countering that view is Steven Weinberg. He is an interesting voice in the debate, not just because he is a distinguished physicist, but because in the past he has been accused of favouring certain cosmological theories as they appeared to support his atheism. Another cosmologist and early advocate of the anthropic principle, Frank Tipler, made the accusation. He said that Weinberg had favoured the old steady state theory of the universe over the then new big bang, because it least resembled the account of creation in Genesis.

Weinberg is sanguine about the accusation: he changed his mind once the big bang was verified by evidence. Moreover, in relation to the multiverse hypothesis, he points out that it existed before the refinement of the anthropic principle in 1998. “The multiverse idea predates any of this thinking about fine tuning,” he says. He suggests it might be thought of as an answer waiting for a problem, and now we have both.

Also, it should be pointed out that there is no necessary correlation between being an atheist physicist and believing in the multiverse, or conversely being a believer and denying it. Again, Bernard Carr sums up: “I think if there’s a multiverse it doesn’t disprove God at all. The status of god – it could go either way if there’s a multiverse.”

What does Rees make of our central question: physics or metaphysics? “It’s not a matter for emotions and faith,” he insists. “It seems to me that it’s a scientific question and we just don’t know the answer yet. We want to know if there was one big bang or many. Obviously it affects the way we interpret the universe, just as the fact that we now know our solar system isn’t unique affects how we interpret the universe. But people’s personal prejudices are irrelevant. There is no particular reason to think our big bang was the only one, or that the volume of space we see with our telescopes is anything other than a tiny and maybe atypical fragment of reality. I think we have to be open minded about this.”

That is undoubtedly true. Evidence is what eventually settles science. But in the meantime, one should also be wary of sleights of hand. The multiverse is a hypothesis for which there is no evidence, and perhaps can never be any evidence. It is only since 1998 that it has leapt off the blackboards of a few physicists doing esoteric mathematics and lodged itself in the popular imagination. As is the way with popular science, it is easy to move from speculating that there might have been more than one big bang to proceeding on the basis that there has been more than one big bang.

So, I’d like to give the last word to another physicist, Paul Davies. He is the author of many widely read and highly readable books on cosmology and its ramifications, his latest being on the fine-tuning: The Goldilocks Enigma: Why is the Universe Just Right for Life? He is a multiverse sceptic, preferring another explanation of the fine-tuning. Very roughly, he suspects that the universe, its laws, and the presence of life somehow all emerged together. He calls it a “self-explaining universe”, that is without any external deity; though containing within it what he terms “the life principle”. Again, it is a speculative proposition: “there are many details to be worked out,” he admits.

But what is interesting about Davies is that he believes the evidence of fine-tuning is taking science in a direction that collapses the traditional distinction between physics and metaphysics: “I do take life, mind and purpose seriously, and I concede that the universe at least appears to be designed with a high level of ingenuity.”

He is quite aware that some scientists will already feel his approach is “crypto-religious”, even though he explicitly makes no appeal to non-natural processes. He retorts that all physicists are committed to some form of ideology. In another New York Times opinion piece, published in 2007, Davies argued that believing the universe is governed by laws is a form of faith too, faith in the existence and efficacy of laws. It is a faith that is well justified by evidence. But, as yet, science itself cannot account for these laws – where they come from, why they work. Davies concluded: “Until science comes up with a testable theory of the laws of the universe, its claim to be free of faith is manifestly bogus.”

Davies’ piece itself produced a slew of letters. In the present climate, it is a provocative opinion to express. And yet, the implication is that a testable theory of the laws of the universe, let alone the multiverse, isn’t going to appear any time soon. Until then at least, in some scientists’ mind, physics will inevitably rub shoulders with metaphysics.

Mark Vernon’s latest book is Wellbeing (Acumen), part of the Art of Living series, which he edits.

  1. Morgan-LynnGriggs Lamberth

    Ah, but the math would be evidence. The anthropic principle is vacuous in that it begs the question that all teleological arguments do- assuming that something had us in mind. The fact as the teleonomic/atelic argument notes , as George Gaylord Simpson and Ernst May, Eugenie C. Scott notwithstanding, is that the weight of evidence reveals no cosmic teleology, and thus no reason to invoke any supernatural or other non-natural entity. To invoke any kind of telos contradicts for instance, natural selection. T’would be the new Omphalos argument that albeit that scientists can find no telos, divinity or whatever blinds us to its involvement so that what we see as the product of natural forces is truly the act of that telos. Nay, balderdash! Nature displays no telic activity so that to allege any is asinine.
    Tipler and Polkinghorne are just another bunch of obscurantists, whom Victor J, Stenger calls the ‘ premise keepers.” He could tell this writer that he needs to do his homework!
    And Voltaire makes the argument that the nose was designer for glasses centuries ago and disposes of that silly argument.
    Again the argument assumes that we had to arrive. Google Jerry Coyne to read his ” Seeing and Believing” where he demolishes Miller and Giberson’s asinity on their use of the silly principle. Also the antepunultimate issue of Skeptic magazine also sispose of that silliness by noting that had we not appeared no other intelligent being would have arrived.
    Causalilsm involves no purposes whilst teleology does, presupposing the end state before the cause, backwards causation as Dr. Weisz notes in ” The Science of Biology.”

  2. Morgan-LynnGriggs Lamberth

    magazine disposes of that
    sorry for the typo

  3. You seem to have a problem with writing numbers:
    “There are “only” 1090 atoms in the entire known universe.”
    “there might be 10500; universes in the multiverse”
    I’m guessing you want 10 to the 90 and 500 respectively.
    About Rees’ comment:
    ‘Now the big bang from one millisecond onwards is as well established as anything about the early history of the earth.’
    Unless this is his way of saying the early history of the earth is not well known at all, I suggest his statement is far from accurate. The BB, at least in the way it is generally given presents loads of problem. Many problems have already been “resolved” a number of times, usually with the help of energies, matter and gravities that only exist on paper so far. I’ve always considered it incredibly arrogant of these people, even with the workings of quantum theory and relativity (I purposely leave out string theory)at their disposal, to declare everything from the first 10 to the minus 43rd of a second is well understood. I have many problems with this, e.g. how was it in the first few minutes of the BB atoms formed? In some respects I suppose atoms (without their electrons) are not all that complicated at least compared to dna or proteins. But why, without the time to randomly bounce around,say, a billion years or so before they decided what was needed to create our universe, would atoms form?
    Cosmology, to me is sounding more and more like a religion. It certainly has its high priests and its laws such as THERE SHALL NOT BE ANY OTHER GODS BEFORE ME. And perhaps best of all, they have a language that (necessarily?) only they can understand. Even when ordinary language is used too few people can appreciate the meaning of what’s being written, e.g.
    “With the discovery of dark energy”. Dark energy wasn’t discovered yet. They’re still looking for it.
    When I first read the anthropic principle and with it the multiverse solution, I decided maybe I should look around for a reasonable god to bet on. Haven’t found one yet.

  4. “Now the big bang from one millisecond onwards is as well established as anything about the early history of the earth.” Well-established it may be, but does it represent a true picture of ‘reality’ – whatever that might be? How can it be possible (ever) to prove that what we regard as having happened, historically, did in fact happen?

    ‘..some string theorists have proposed that there might be 10500; universes in the multiverse.” But where do they get these figures from? Hypothesis piled upon hypothesis. Presumably a ‘hypotheses’?

    “I think it’s a very remarkable fact that the universe is intelligible to us,” says John Polkinghorne. He seems to be getting things the wrong way around. It is not surprising that we use language to describe and try to explain that which we find around us. There are many stories that have and will be told about the nature of our existence. The big question is can they ever be ‘accurate’ descriptions, in the ‘scientific’ sense? The universe / environment is intelligible, to some degree, to all creatures (and plants) – in the sense that all interact with it.

    I can only agree with Paul Davies’ view that “Until science comes up with a testable theory of the laws of the universe, its claim to be free of faith is manifestly bogus.” And remain an existentialist… doing theoretical physics is presumably fun and enjoyable for those who do it, and a nice way to pass the time between birth and death.

  5. Actually, Mark Vernon, it was Prof. Steven Weinberg himself who said that he preferred the Steady State Theory because, to quote Weinberg, “it least resembled the account in Genesis.” In his book The First Three Minutes (1977), Chapter 6, Weinberg recounts the reason for his previous rejection of the Big Bang Theory:

    “”
    Our mistake is not that we take our theories too seriously, but that we do not take them seriously enough. It is always hard to realize that these numbers and equations we play with at our desks have something to do with the real world. Even worse, there often seems to be a general agreement that certain phenomena are just not fit subjects for respectable theoretical and experimental effort.
    “”

    So as Prof. Weinberg points out above, the Big Bang Theory was an unavoidable result of the laws of physics, yet even so, Weinberg had avoided the Big Bang Theory because of the intellectual vexation it brought him (i.e., due to Weinberg being an atheist and the Big Bang Theory being regarded by the physics community as lending credence to the traditional theological position of creatio ex nihilo, and because no form of physics can apply to a singularity). Prof. Frank J. Tipler details that

    “”
    as [Weinberg] himself points out in his book, the Big Bang Theory was an automatic consequence of standard thermodynamics, standard gravity theory, and standard nuclear physics. All of the basic physics one needs for the Big Bang Theory was well established in the 1930s, some two decades before the theory was worked out. Weinberg rejected this standard physics not because he didn’t take the equations of physics seriously, but because he did not like the religious implications of the laws of physics. …
    “”

    From Frank J. Tipler, “Refereed Journals: Do They Insure Quality or Enforce Orthodoxy?,” Progress in Complexity, Information, and Design (PCID), Vols. 2.1 and 2.2 (January-June 2003).

    And God has been proven to exist based upon the most reserved view of the known laws of physics. For much more on that, see Prof. Frank J. Tipler’s below paper, which among other things demonstrates that the known laws of physics (i.e., the Second Law of Thermodynamics, general relativity, quantum mechanics, and the Standard Model of particle physics) require that the universe end in the Omega Point (the final cosmological singularity and state of infinite informational capacity identified as being God):

    F. J. Tipler, “The structure of the world from pure numbers,” Reports on Progress in Physics, Vol. 68, No. 4 (April 2005), pp. 897-964. http://math.tulane.edu/~tipler/theoryofeverything.pdf Also released as “Feynman-Weinberg Quantum Gravity and the Extended Standard Model as a Theory of Everything,” arXiv:0704.3276, April 24, 2007.

    Out of 50 articles, Prof. Tipler’s above paper was selected as one of 12 for the “Highlights of 2005″ accolade as “the very best articles published in Reports on Progress in Physics in 2005 [Vol. 68]. Articles were selected by the Editorial Board for their outstanding reviews of the field. They all received the highest praise from our international referees and a high number of downloads from the journal Website.” (See Richard Palmer, Publisher, “Highlights of 2005,” Reports on Progress in Physics website.)

    Reports on Progress in Physics is the leading journal of the Institute of Physics, Britain’s main professional body for physicists. Further, Reports on Progress in Physics has a higher impact factor (according to Journal Citation Reports) than Physical Review Letters, which is the most prestigious American physics journal (one, incidently, which Prof. Tipler has been published in more than once). A journal’s impact factor reflects the importance the science community places in that journal in the sense of actually citing its papers in their own papers. (And just to point out, Tipler’s 2005 Reports on Progress in Physics paper could not have been published in Physical Review Letters since said paper is nearly book-length, and hence not a “letter” as defined by the latter journal.)

    See also the below resource for further information on the Omega Point Theory:

    Theophysics: God Is the Ultimate Physicist http://geocities.com/theophysics/

    Tipler is Professor of Mathematics and Physics (joint appointment) at Tulane University. His Ph.D. is in the field of global general relativity (the same rarefied field that Profs. Roger Penrose and Stephen Hawking developed), and he is also an expert in particle physics and computer science. His Omega Point Theory has been published in a number of prestigious peer-reviewed physics and science journals in addition to Reports on Progress in Physics, such as Monthly Notices of the Royal Astronomical Society (one of the world’s leading astrophysics journals), Physics Letters B, the International Journal of Theoretical Physics, etc.

    Prof. John A. Wheeler (the father of most relativity research in the U.S.) wrote that “Frank Tipler is widely known for important concepts and theorems in general relativity and gravitation physics” on pg. viii in the “Foreword” to The Anthropic Cosmological Principle (Oxford: Clarendon Press, 1986) by cosmologist Prof. John D. Barrow and Tipler, which was the first book wherein Tipler’s Omega Point Theory was described. On pg. ix of said book, Prof. Wheeler wrote that Chapter 10 of the book, which concerns the Omega Point Theory, “rivals in thought-provoking power any of the [other chapters].”

    The leading quantum physicist in the world, Prof. David Deutsch (inventor of the quantum computer, being the first person to mathematically describe the workings of such a device, and winner of the Institute of Physics’ 1998 Paul Dirac Medal and Prize for his work), endorses the physics of the Omega Point Theory in his book The Fabric of Reality (1997). For that, see:

    David Deutsch, extracts from Chapter 14: “The Ends of the Universe” of The Fabric of Reality: The Science of Parallel Universes–and Its Implications (London: Allen Lane The Penguin Press, 1997); with additional comments by Frank J. Tipler. Available on the Theophysics website.

    The only way to avoid the Omega Point cosmology is to resort to physical theories which have no experimental support and which violate the known laws of physics, such as with Prof. Stephen Hawking’s paper on the black hole information issue which is dependent on the conjectured string theory-based anti-de Sitter space/conformal field theory correspondence (AdS/CFT correspondence). See S. W. Hawking, “Information loss in black holes,” Physical Review D, Vol. 72, No. 8, 084013 (October 2005); also at arXiv:hep-th/0507171, July 18, 2005.

    That is, Prof. Hawking’s paper is based upon empirically unconfirmed physics which violate the known laws of physics. It’s an impressive testament to the Omega Point Theory’s correctness, as Hawking implicitly confirms that the known laws of physics require the universe to collapse in finite time. Hawking realizes that the black hole information issue must be resolved without violating unitarity, yet he’s forced to abandon the known laws of physics in order to avoid unitarity violation without the universe collapsing.

    Some have suggested that the universe’s current acceleration of its expansion obviates the universe collapsing (and therefore obviates the Omega Point). But as Profs. Lawrence M. Krauss and Michael S. Turner point out in “Geometry and Destiny” (General Relativity and Gravitation, Vol. 31, No. 10 [October 1999], pp. 1453-1459; also at arXiv:astro-ph/9904020, April 1, 1999), there is no set of cosmological observations which can tell us whether the universe will expand forever or eventually collapse.

    There’s a very good reason for that, because that is dependant on the actions of intelligent life. The known laws of physics provide the mechanism for the universe’s collapse. As required by the Standard Model, the net baryon number was created in the early universe by baryogenesis via electroweak quantum tunneling. This necessarily forces the Higgs field to be in a vacuum state that is not its absolute vacuum, which is the cause of the positive cosmological constant. But if the baryons in the universe were to be annihilated by the inverse of baryogenesis, again via electroweak quantum tunneling (which is allowed in the Standard Model, as baryon number minus lepton number [B - L] is conserved), then this would force the Higgs field toward its absolute vacuum, cancelling the positive cosmological constant and thereby forcing the universe to collapse. Moreover, this process would provide the ideal form of energy resource and rocket propulsion during the colonization phase of the universe.

    Prof. Tipler’s above 2005 Reports on Progress in Physics paper also demonstrates that the correct quantum gravity theory has existed since 1962, first discovered by Richard Feynman in that year, and independently discovered by Steven Weinberg and Bryce DeWitt, among others. But because these physicists were looking for equations with a finite number of terms (i.e., derivatives no higher than second order), they abandoned this qualitatively unique quantum gravity theory since in order for it to be consistent it requires an arbitrarily higher number of terms. Further, they didn’t realize that this proper theory of quantum gravity is consistent only with a certain set of boundary conditions imposed (which includes the initial Big Bang, and the final Omega Point, cosmological singularities). The equations for this theory of quantum gravity are term-by-term finite, but the same mechanism that forces each term in the series to be finite also forces the entire series to be infinite (i.e., infinities that would otherwise occur in spacetime, consequently destabilizing it, are transferred to the cosmological singularities, thereby preventing the universe from immediately collapsing into nonexistence). As Tipler notes in his book The Physics of Christianity (New York: Doubleday, 2007), pp. 49 and 279, “It is a fundamental mathematical fact that this [infinite series] is the best that we can do. … This is somewhat analogous to Liouville’s theorem in complex analysis, which says that all analytic functions other than constants have singularities either a finite distance from the origin of coordinates or at infinity.”

    When combined with the Standard Model, the result is the Theory of Everything (TOE) correctly describing and unifying all the forces in physics.

  6. “a Roman Catholic cardinal… called it “an abdication of human intelligence.” ”

    *cough*

  7. China’s Savings Syndrome - Idea of the Day Blog - NYTimes.com - pingback on July 14, 2009 at 10:23 am

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