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Belief in multiple universes requires exceptional vision. So does belief in telepathy.


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The multiverse, a psychologically pleasing, logically elegant entity that is, as of now, complete fiction (Image: Proetcontra)

I exaggerate with the title of this post, but only slightly. The title is a reaction to a strange article on multiple universes written by Tom Siegfried at Science News. It’s the kind of article that harms the cause of a field and causes the rest of us to take it less seriously . For those who haven’t been following the multiverse mania, multiple universes have been invoked as “explanations” for a variety of conundrums in modern physics; among them, the fine-tuning of the physical constants and the measurement problem in quantum mechanics. All speculation without evidence of course.

But Tom Siegfried tells us that the real reason why people don’t believe in the multiverse is not a lack of evidence, it’s apparently a lack of vision. He starts by pointing out that just because we can’t see something does not mean it cannot exist.

If you can’t see it, it doesn’t exist. That’s an old philosophy, one that many scientists swallowed whole. But as Ziva David of NCIS would say, it’s total salami. After all, you can’t see bacteria and viruses, but they can still kill you.

Yet some scientists still invoke that philosophy to deny the scientific status of all sorts of interesting things. Like the theoretical supertiny loops of energy known as superstrings. Or the superhuge collection of parallel universes known as the multiverse.

That’s about as bad an analogy as I can think of. There’s massive, and I mean really massive, direct as well as indirect evidence for the existence of bacteria and viruses; the tens of thousands of electron microscopy images over the past five decades for one thing. The same goes for atoms, neutrinos, black holes and supernovae. All these may not be directly felt or seen but there’s incontrovertible and overwhelming evidence for their existence; if I were an atom I would be feeling quite insulted by now by this analogy. Siegfried unhelpfully compares those who may not believe in superstrings or the multiverse to Ernst Mach, the strident 19th century German physicist who kept up a dedicated attack on the reality of atoms until he died. And yet, as Siegfried obligingly reminds us, there was massive indirect evidence for the existence of atoms, exemplified by Einstein’s explanation of Brownian motion.

Yes, there was. But there’s two things to be considered here. Firstly, even the indirect evidence that existed arose from a variety of different fields and was exemplified by a palpable chain of physical reasoning that manifested itself  through real entities, for instance pollen grains and elemental spectra. There was a lot of internal consistency between the various explanations put forward for the existence of the subatomic world and the whole package when put together by invoking the existence of atoms made good sense. No such causal chain of physical reasoning exists for the multiverse. All we have are logical and elegant sounding, purely theoretical constructs.

But the most egregious thing in that article is an assertion that we can just use the unobservable for explaining the observable:

Similar reasoning can be applied to parallel universes. If other universes exist, they may well be forever beyond the power of humankind’s observational instruments. But perhaps the laws explaining observable things also require unobservable universes.

Come again? This treads dangerously into the territory of pseudoscience and even crackpot science; after all, every New Age guru and preacher says the same thing, that the world that we can observe is somehow controlled by unobservable entities like spirits, Gods, “chakras” and the like. I can come up with an explanation right now for the simultaneous occurrence of identical thoughts in two individuals on opposite sides of the planet based on a “theory” of telepathy. Basically when you start making connections between untestable and unobservable phenomena and the real world, anything goes.

Siegfried alludes to a paper by physicist Frank Wilczek which is far more circumspect in speculating on the multiverse. Wilczek is right that sometimes scientists don’t grasp a whole new domain of physical reality because they lack the vision. But what happens when that domain becomes so far removed from the slightest semblance of observable phenomena that it devolves into a broad realm of symbol manipulation and philosophizing? And more important, when there’s not a shred of hard evidence for its existence? We don’t believe in the multiverse because we lack vision but because the concept is untestable. Now let me go back and concoct an explanation for why my enzyme is not behaving the way it should; it must be all those darn gnomes messing around again with the amino acids in the active site.

Update: Peter Woit nicely weighs in.

Ashutosh Jogalekar About the Author: Ashutosh (Ash) Jogalekar is a chemist interested in the history and philosophy of science. He considers science to be a seamless and all-encompassing part of the human experience. Follow on Twitter @curiouswavefn.

The views expressed are those of the author and are not necessarily those of Scientific American.





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  1. 1. rkipling 12:35 pm 08/15/2013

    The expression is, “that’s baloney” not salami. But it’s closer than if you said, ” that’s kielbasa.”

    Just trying to be helpful.

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  2. 2. David Cummings 12:41 pm 08/15/2013

    Another excellent post, Ash. Always good to read your blog.

    And I think I can say I agree with you completely even though I personally like the idea of the multiverse. I can’t say I “believe” in it, because it is an unprovable concept. But it does attract me.

    I do think there are three distinct lines of reasoning that support it (without proving it):
    1. The measured value of dark energy.
    2. The 10^500 possible universes described by string theory.
    3. The implications of the (fairly well-tested) theory of cosmic inflation in the explanation of the Big Bang.

    Again, I know its not proof, but it’s not quite the same thing as believing in fairies.

    I think what we are looking at here is a philosophical proposition rather than a scientific hypothesis. Maybe someday multiverse theory will take on aspects of a scientific hypothesis. It certainly hasn’t as of yet.

    But isn’t there room for philosophy in our meditations of the cosmos? I certainly think so. And I enjoy thinking about and reading about the multiverse, even while agreeing with you and other critics 100%. It is not science.

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  3. 3. M Tucker 1:50 pm 08/15/2013

    “…multiple universes have been invoked as “explanations” for a variety of conundrums in modern physics; among them, the fine-tuning of the physical constants and the measurement problem in quantum mechanics.”

    When you say, ‘the measurement problem,’ are you referring to the ‘many-worlds’ interpretation? I kind of think you are and that has always been my first encounter with some physicists bringing up multiple universes.

    Then inflation theory came along and it seems to now be well accepted that inflation, once begun, does not end but leads to eternal inflation. As best as I can understand this is interpreted to be a never ending, infinite, creation of separate universes – the multiverse.

    Many physicists seem to like the mathematics, they like the evidence for inflation that have come from several space probes, and so they seem to be big believers in the existence of multiple universes.

    I also am aware of a small group of physicists who think their might be problems with the necessity for inflation and we just might have ended up with the CMB radiation we observe without the need for inflation.

    For me inflation has not been demonstrated to be a necessary part of the big bang theory and I definitely am not convinced that multiple universes are necessary either. But I seem to find myself in the minority. At least, of the non-professional people who have heard of the multiverse, I seem to be one of the few who is not a believer. I’m not sure who those people are that Tom Siegfried is talking about. If they are physicists they are not doing a very good job of making themselves known. I became aware that a small group of prominent physicists are having trouble with the current interpretation of the big bang theory when the April 2011 issue of SA came out. I mean, when the Albert Einstein Professor of Science at Princeton has objections, that is something I must take notice of. After all Professor Steinhardt is one of those who first helped to develop inflation theory.

    So for me the multiverse is just like string theory, or M-theory or supersymetry, nice ideas without a way to test if they are right or, as with supersymetry, no evidence has so far been found.

    I think Siegfried should be happy that the multiverse theory has been getting so much attention from physics popularizers like Brian Greene.

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  4. 4. David Cummings 2:38 pm 08/15/2013

    Is there anyone saying that inflation is non-scientific/untestable? It’s one thing to say that it might not be necessary in big bang theory, it’s another to say its untestable.

    I think that there are tests for inflation and that so far those tests have done well, or at least provided mixed results.

    And what is the implication of inflation other than a broader inflation, an eternal inflation, an inflation that contains multiple big-bangs? I know that to ask the question is to step out of science and into something else (which I choose to call philosophy) but to me its hard to imagine contemplating inflation without contemplating the possible implications of inflation (no matter how untestable they may).

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  5. 5. curiouswavefunction 2:47 pm 08/15/2013

    David Cummings and MTucker: I indeed think that the multiverse should be pursued as a fruitful line of speculation, and it certainly makes for wonderful science fiction. I have to admit that when I first read about it, I thought it was a stroke of genius on the part of Hugh Everett to come up with the multiverse as a solution to the problem of wavefunction collapse. Optimism soon gave way to despair however when I realized that Everett had probably created even more exotic problems than what he had purported to address. I appreciate the logical elegance that some of these ideas have, but that’s very different from employing these unobservable entities as ad hoc explanations for known physical phenomena.

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  6. 6. David Cummings 3:30 pm 08/15/2013

    You are absolutely right. There is a difference between logical eloquence (or mathematical beauty — as in string theory) and testable scientific hypotheses.

    I do have a question, though. It seems that to some people there is no difference between the many worlds interpretation of quantum mechanics and the eternal inflation scenario of an infinite number of big bangs. Those ideas seem to get conflated sometimes and to me they are two very different ideas. In the first idea, MW, the different worlds are very strongly connected to each other. I make an observation and suddenly there are many worlds where before there was one. But those worlds are all copies of each other (with a slight change in one variable throughout).

    In MultiVerse, however, meaning multiple big bangs, there is no connection whatsoever between the different worlds.

    Personally I have a very difficult time “wrapping my brain around” the multi-world interpretation of quantum mechanics while at the same time, the scenario of eternal inflation with an infinite number of big bangs fills me with a sense of awe and wonder. I know, it’s not science, but I still wonder.

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  7. 7. M Tucker 4:29 pm 08/15/2013

    Professor Steinhardt does make a case against the necessity for cosmic inflation. He also, in the same April 2011 SA article, makes a case for inflation. It has nothing to do with being ‘unscientific.’ For me the uniformity of the CMB is not a necessary reason to suppose inflation did happen. But I am not an expert. That physicists have now worked out mathematically that once begun inflation does not end and leads to infinitely many universes that cannot be verified seems to add another level to an already knotty problem. Professor Steinhardt seems to allude to possible problems that arise from infinitely many spontaneously erupting universes.

    I also agree with Ash, it ought to be pursued as a line of speculation. Who knows, maybe they will come up with a way to test for multiple universes. Twisted space-time was merely speculation that many believed in without evidence until Gravity Probe B came along.

    Modern physics as come up against the difficulty of talking about its discoveries, theories and untested hypotheses. Not only do they have trouble speaking to non-experts they also seem to have trouble talking with each other as evidenced in the current issue of SA. I recently saw a protracted discussion between a physicist and non-physicists on how to explain why the electron does not ‘stick’ to the proton in a hydrogen atom. It becomes very technical very quickly and it is very difficult for someone who has not studied quantum mechanics to understand. It seems at first straightforward: what is the force that is counteracting the Coulomb force? But that explanation involves areas of quantum mechanics that some have not heard of before and are difficult to express in layman’s terms.

    I forget who said it, Einstein or Pauli or perhaps someone else, but physicists ought to be able to explain these things in terms that a milkmaid could understand. Since that now seems a bit ‘sexist’ and since milkmaids are not so common I would say so a steelworker, or auto mechanic or plumber, can understand. It seems we have left that level of explanation almost 100 years ago.

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  8. 8. David Cummings 4:39 pm 08/15/2013

    “I think I can safely say that nobody understands quantum mechanics.” — Richard Feynman

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  9. 9. rloldershaw 6:05 pm 08/15/2013

    It is getting hard to distinguish between the science and the fiction these days.

    A growing number of celebrity physicists think it may be time to merge the two – arguing that theorists are now so sophisticated that the traditional scientific method, especially its predictions/testing steps, are passé and only get in the way of their wondrous visions.

    Who needs science when you can create your own personal reality and the sycophants will merely nudge each other and fart in approval?

    Robert L. Oldershaw
    http://www3.mherst.edu/~rloldershaw
    Discrete Scale Relativity/Fractal Cosmology

    [And yes DSR is derived form observations, has made 15 definitive predictions and passed some already, thank you very much.]

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  10. 10. M Tucker 7:10 pm 08/15/2013

    “Peter Woit nicely weighs in.”

    Yes he does and it is really about science writers taking sides and coming down on the side that has no evidence to support it. Until we have evidence they are interesting ideas that should be investigated. They should not be taken as fact.

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  11. 11. senseilance 11:01 pm 08/15/2013

    I would have used Imagination rather than ‘Vision’

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  12. 12. rloldershaw 10:45 am 08/16/2013

    Einstein famously said: “Imagination is more important than knowledge”. I’ll buy that, but I would say they are BOTH very important to science. If one really wants progress in good science, then one must use one’s imagination to question dogmatic assumptions (like absolute time, absolute space, simultaneity, the necessity of Euclidean geometry,…).

    One must be able to imagine the implications of traveling at the speed of light (time stops for you).

    But the celebrity physicists are not taking Einstein’s path of good science, which always involved definitive predictions by which his speculations could be tested.

    Oh no. Some of these celebrity physicists have pseudo-scientific visions that cannot be tested, so they are saying maybe we can do without the traditional predictions/testing steps of the scientific method. A very slippery slope that almost guarantees that we will land in the cesspool of pseudo-science.

    Robert L. Oldershaw
    http://www3.amherst.edu/~rloldershaw
    Discrete Scale Relativity/Fractal Cosmology

    PS: One has to be a visionary Platonist to buy into the “conservation of information” assumption and the whole “firewall” mental master…, well you know. None of it is testable, but the celebrity physicists can strut their stuff and feel oh so important.

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  13. 13. curiouswavefunction 11:02 am 08/16/2013

    I like Feynman’s take on it: He described science as “imagination in a straitjacket”.

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  14. 14. bucketofsquid 1:20 pm 08/16/2013

    Not having read the original piece from Tom Siegfried, my impression is that his article serves more as a cautionary tale about the dangers of schizophrenia. Quantum and theoretical physics are in the same stage that aircraft were in the 1880s. Lots of ideas and postulates, a couple of real hypothesis and mostly a bunch of fuss and bother.

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  15. 15. M Tucker 2:07 pm 08/16/2013

    The important question to ask is what should we call a belief in the existence of the multiverse considering the complete absence of any evidence or a way to test for its existence?

    “Physicists reason that if the universe is unnatural, with extremely unlikely fundamental constants that make life possible, then an enormous number of universes must exist for our improbable case to have been realized. Otherwise, why should we be so lucky?”
    [From SA article 6/1/13 “New Physics Complications Lend Support to Multiverse Hypothesis”]

    That complication is the same as the old complication. Why does the universe that we live in seem to have been taylor made for us. So abhorrence of the anthropic principle and ‘logical’ mathematical constructs propel the multiverse enthusiasts to proclaim the multiverse exists.

    I say design a test and bring me some evidence and I will become a convert.

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  16. 16. rloldershaw 4:01 pm 08/16/2013

    One idea: “Physicists reason that if the universe is unnatural, with extremely unlikely fundamental constants that make life possible, then an enormous number of universes must exist for our improbable case to have been realized. Otherwise, why should we be so lucky?”

    Another idea: Physicists reason that life evolves to fit the Universe, not the other way around.

    In the case of the second idea one does not need to invoke 10^500 universes, all with different physics.

    Those who like the first idea should beware. A guy named Occam is coming for you and that’s not a smile of pleasure on his face.

    Robert L. Oldershaw
    http://www3.amherst.edu/~rloldershaw
    Discrete Scale Relativity/Fractal Cosmology

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  17. 17. bsmith821 3:15 pm 08/17/2013

    You might be forgetting that it is important for us to allow our scientists freedom to hypothesize without immediate evidence. Experiments and evidence should follow later. And if the scientists (and others) do their job, then the evidence will disprove the hypothesis (remember you can never PROVE a hypothesis only disprove it). I do think the scientist making the hypothesis should also be required to lay out one or more propositions upon which the experiments and evidence will be assessed. You may recall Popper’s idea about doing science – that after your observations, “you formulate a hypothesis, try to prove it wrong, and, from your results, formulate a new hypothesis”. Karl Popper (1902 – 1994). The question might be what was the observation that led to the multiverse hypothesis? And what are the propositions?

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  18. 18. rloldershaw 3:42 pm 08/17/2013

    The “propositions” you mention are more typically referred to as predictions.

    Ideally they are definitive predictions, which are prior to observations, feasibly tested, quantitative, NON-ADJUSTABLE, and unique to the theory being tested.

    The observation that led to the “multiverse” fantasy was that “string theory” opened up a Pandora’s Box of 10^500 different vacuua (“universes”)and our heroic string theorists needed a cover for this horrendous embarrass de riches. There has never been the slightest hint of a physical observation that motivated the “multiverse” fantasy. The so-called motivation is purely theoretical, or in my opinion pseudo-scientific.

    Robert L. Oldershaw
    http://www3.amherst.edu/~rloldershaw
    Discrete Scale Relativity/Fractal Cosmology

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  19. 19. dburress 3:30 pm 09/23/2013

    This blog makes a standard bad argument that conflates two unrelated issues.
    1. There is at present a lack of strong data supporting the many worlds hypothesis. Treating it as accepted theory would of course be foolish.
    2. Nevertheless it might (or might not) be a valid scientific hypothesis. The existence of unobservable entities in the theory is simply irrelevant. What is important is whether:
    a. these unobbservable entities are embedded in a testable theory
    b. the theory passes some emprical tests
    c. referring to these entities leads to the simplest or most convenient or most understandable statement of the theory
    d. no other theory can perform as well.
    -David Burress
    Kansas Progress Institute

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  20. 20. Brain1 12:27 pm 09/25/2013

    TRY AND UNDERSTAND just how *Emotional this topic is to atheists. Getting this wrong is not like just missing the ice cream truck for some. To them..its probable there is a God if multiverse is not true.

    Understand that..and you understand why so many have made this tremendous leap.

    The sad thing is that even if you formulate with Naturalism as a fact..it still doesnt solve the problem

    1 Naturalism is true
    2 a single Universe is fine tuned to unacceptable
    degrees.
    3 Multiverse exists.

    The problem with this is multiverse is the conclusion. Its something far away..something not reached yet for analysis. Its kickin the can down the street. You need to go down the street and see it must be fine tuned as well.

    How could it not be? Your postulating a mega universe machine that creates everything that can be. It just happens to pop out exactly what you need–random universes. Why should it do such a thing?

    and if this ridiculous extrapolation that we thought the earth was the center–then the solar system was all there is–then we found galaxies–so there is multiverse….logically following this absurd line of reasoning there must be another level behind that.

    So proponents reach exceeds their grasp. To use multiverse as an answer to fine tuning–you MUST be able to prove it is also not fine tuned–which is impossible. This alone is a defeater for their true motivation so there is simply no reason for them to ruin science for their own personal needs. Wait for evidence and if you get it understand it doesnt solve fine tuning anyway.

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  21. 21. Brain1 12:51 pm 09/25/2013

    Part2
    Let me just add
    Psychologically, Fundamentalists and Hard Atheists are suffering from a shared disease. They “need” for what they express to be true.
    If you are an atheist or agnostic and have not jumped to multiverse it says something about what your needs actually are. Now, if you deny the fine tuning then your needs are actually stronger and more biased but if not, you feel more comfortable in your beliefs than these others.

    Its an important service to point out the real motivation to your peers as it is the Christian to the fundamentalist who will not accept the clear data of science. We can disagree about the conclusions of the data but the world would be a much saner place if these extreme people would not muddying the waters for all of us.

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