Is the Multiverse Immoral?

[Warning, somewhat of a rant follows, and it’s not very original. You might want to skip this one…]

In the last week or so, I’ve run into two critiques of the currently fashionable multiverse mania that take an unusual angle on the subject, raising the question of the “morality” of the subject. The first of these was from Lee Smolin, who was here in New York last week talking at the Rubin Museum. I probably won’t get this quite right, but from what I remember he said that discussions of a multiverse containing infinite numbers of copies of ourselves behaving slightly differently made him uneasy for moral reasons. The worry is that one might be led to stop caring that much about the implications of one’s actions. After all, whatever mistake you make, in some other infinite number of universes, you didn’t do it.

Over at Scientific American, yesterday they had John Horgan’s Is speculation in multiverses as immoral as speculation in subprime mortgages?. There’s more about this in a Bloggingheads conversation today with George Johnson, where Horgan describes his current reaction to multiverse mania as “I can’t stand this shit.”

I’m in agreement with Horgan there, but my own moral concerns about the issue are different than the ones he and Smolin describe. The morality of how people choose to live their everyday lives doesn’t seem to me to have much to do with whatever the global structure of the universe might be. The world we are rapidly approaching in which a multiverse is held up as an integral part of the modern scientific world view isn’t one in which many people are likely to behave differently than before, so I don’t share Smolin’s concerns. Horgan’s exasperation with seeing the multiverse heavily promoted by famous physicists appears to have more to do with the idea that this is a retreat by physicists from engagement with the real world, something morally obtuse in an era of growing problems that scientists could help address. For what he would like to see instead, I guess a good model would be John Baez’s recent decision to turn his talents towards real-world problems facing humanity, see his blog Azimuth for more about this. Personally, I’m not uncomfortable with the fact that many mathematicians and physicists find that they don’t feel they are likely to be of much help if they go to work on the technology and science surrounding social problems. Instead, one can reasonably decide that one has some hope of making progress on fundamental issues in mathematics or physics and choose to work on that instead. One can try and justify this by hoping that new breakthroughs will somehow, someday help humanity, although this may be wishful thinking. Or one can argue that working towards a better understanding of the universe is inherently worthwhile, so pursuing this while taking some care to avoid worsening one’s local corner of the world is a morally reasonable stance.

My own moral concerns about the multiverse have more to do with worry that pseudo-science is being heavily promoted to the public, leading to the danger that it will ultimately take over from science, first in the field of fundamental physics, then perhaps spreading to others. This concern is somewhat like the one that induced Alan Sokal to engage in his famous hoax. He felt that abandonment by prominent academics of the Enlightenment ideals exemplified by the scientific method threatens a move into a new Dark Ages, where power dominates over truth. Unfortunately, I don’t think that revelation of a hoax paper would have much effect in multiverse studies, where some of the literature has already moved beyond the point where parody is possible.

For a while I was trying to keep track of multiverse-promoting books, and writing denunciatory reviews here. They’ve been appearing regularly for quite a few years now, with increasing frequency. Some typical examples that come to mind are Kaku’s Parallel Worlds (2004), Susskind’s The Cosmic Landscape (2005), and Vilenkin’s Many Worlds in One (2006). Just the past year has seen Sean Carroll’s From Eternity to Here, John Gribbin’s In Search of the Multiverse, Hawking and Mlodinow’s The Grand Design, and Brian Greene’s new The Hidden Reality. In a couple weeks there will be Steven Manly’s Visions of the Multiverse. Accompanying the flood of books is a much larger number of magazine articles and TV programs.

Several months ago a masochistic publisher sent me a copy of Gribbin’s book hoping that I might give it some attention on the blog, but I didn’t have the heart to write anything. There’s nothing original in such books and thus nothing new to be said about why they are pseudo-science. The increasing number of them is just depressing and discouraging. More depressing still are the often laudatory reviews that these things are getting, often from prominent scientists who should know better. For a recent example, see Weinberg’s new review of Hawking/Mlodinow in the New York Review of Books.

While most of the physicists and mathematicians I talk to tend towards the Horgan “I can’t stand this shit” point of view on the multiverse, David Gross is about the only prominent theorist I can think of known to publicly take a similar stand. One of the lessons of superstring theory unification is that if a wrong idea is promoted for enough years, it gets into the textbooks and becomes part of the conventional wisdom about how the world works. This process is now well underway with multiverse pseudo-science, as some theorists who should know better choose to heavily promote it, and others abdicate their responsibility to fight pseudo-science as it gains traction in their field.

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107 Responses to Is the Multiverse Immoral?

  1. Kea says:

    After I (the one copy of me) was physically denied entry to a multiverse conference in Oxford in 2009, I had a good laugh about it with a friendly stringer. Then he told me that the conference was secret so that the participants could debate (in secret) whether or not the multiverse was science. It seems they have still not made up their minds …

  2. The universe we inhabit exhibits immorality in a narrow range, defined by the constant I, which is just immoral enough to allow for the possibility of free will, but not so immoral that we annihilated ourselves the moment we gained the technology to do so. Less immoral, and the inhabitants of the universe would bore themselves into petrified non-existence, more immorality, and they vanish in a flash of look-what-we-can-do. I present this as irrefutable evidence that Erdős’s SF has planted us in the only or single universe with just the right amount of I to support intelligent life, teetering between determinism and destruction.

  3. Friend says:

    I think that multiverses are a misinterpretation of the Path Integral used in QFT, etc. Instead of it predicting the actual existence of alternative paths/universes, it really predicts that it takes ALL possibilities to make just one universe. Thus it is impossible for multiverses to exist.

    However, physics may have something to say about morality. Moral belief systems do consider cause and effect of deeds, which are actual physical events. Perhaps such belief systems can be considered to have some structure and entropy associated with them. Then it might be that maximum entropy limit theorems prevent instant dissipation of those structures so that they do have some physical effect. But then how would one measure belief?

  4. John Baez says:

    Maybe a branch of science is ripe for infection by pseudoscience whenever it stops making enough progress to satisfy the people in that field: as a substitute for real progress, they’ll be tempted to turn to fake progress. One could expect this tendency to be proportional to the loftiness of the goals the field has set for itself… and to the difficulty its practitioners have in switching to nearby fields that are making more progress.

    But is this really true? Does anyone know other examples, beside the current situation in fundamental physics?

  5. Shantanu says:

    Peter, there are many other critics of multi-verse, although they may no be very vocal. some other examples of critics include Steinhardt, Turok, Woodard, Polyakov, Krauss, Turner, Strominger (which you pointed out)

  6. Friend says:

    John Baez, how about the financial market;-) Unsatisfied with economic progress, they’ve invented extravagant financial theories of prime-lending rates and complicated security instruments. Funny, I’ve heard that some physicists have found work in the financial industry. Perhaps their theories work in some other universe.

  7. Casey Leedom says:

    I hesitate to offer a serious response here but …

    As far as I’ve heard, all of the promoters of multiverses are using them to explain the “current universe” as just “an” arrangement of a bunch of fundamental parameters of much larger theories. But at the same time, also saying that all of the other universes are beyond our horizon. (The motivation for which seems to be to get out of the hole created by theories which have high degrees of freedom.)

    The proposed multiverse models don’t appear to offer us any ability to make predictions about this universe. Thus this doesn’t give us any more insight into how this universe works.

    So beliefe in this multiverse story is at best an amusing diversion along the lines of worrying about the number of angels which can dance on the head of a pin. At worst, that diversion gets in the way of people actually trying to understand what we see around us. Amoral? Meh.

    I say: “Where’s the beef?”

  8. Andrew L. says:

    This argument shows how desperately insecure these people are from a purely empirical viewpoint. They know there’s no more empirical substance to thier grandoise hypotheses then that host of MIT engineering students who famously picketed a science fiction convention with a 200 page mathematical “proof” that Larry Niven’s Ringworld was unstable. They HAVE to know-they’re PHD’s in physics,for heaven’s sake! The problem is if they let people look behind the curtain,75% of the current funding in theoretical physics and mathematics in the Western World will vanish in a flash of insight. It’s rather sad,truth be told.

  9. Tim van Beek says:

    Peter said:

    For what he would like to see instead, I guess a good model would be John Baez’s recent decision to turn his talents towards real-world problems facing humanity…

    Well, John switched to “real-world problems” from a topic that was and is seeing a lot of progress (n-categories), the switch from quantum gravity was earlier.

    John said:

    Does anyone know other examples, beside the current situation in fundamental physics?

    Well there are a lot of topics in fundamental physics that make a lot of progress, even in theoretical high energy physics. Besides that, I do think that the situation in string theory is quite unique:

    a) Physicsists that spend their time at their desk, thinking strange thoughts, can become global celebrities, this phenomenon did not exist before the 20th century,

    b) the growth of the scientific community led to the formation of a subgroup of a size so big that its members became unable to see beyond it. This, too, is new.

    c) There is this unfortunate tendency that at least some physicists think that they are the smartest people on the planet and that everybody who does not appreciate what they do is simply unable to understand it. (Most of these guys are also smart enough to keep these thoughts to themselves, for which I am very thankful.)

    To elaborate on the second point: An active researcher monitors the work of his collegues, how many may the average researcher be able to follow? 200? If a research community becomes too big, it usually splits into more specialized subgroups such that its members stand a chance to stay up to date with respect to the work of their collegues, and have time to communicate with their neighbors. It would seem that this did not work well for the string community.

    Why do I think this? Because I heard a lot of criticism of string theory way before Peter published his book, from all kind of tenured and not-tenured physicists, both experimentalists and theorists (all outsiders to the string community, of course). Sometimes voiced with very unusual aggression. Yet most members of the string community seemed to be both completely oblivious of this (maybe not anymore), and immune to any criticism from outsiders.

    Is there something we can learn from this? I don’t know. Maybe funding should be cut in a way that never more than 100 people do research on the very same topic.

  10. Myke says:

    Friend restates Feynman’s view, which seems better to me than the multiverse nonsense! Besides, just look up on a clear night and see what is a ‘multiverse’ of galaxies. The final theory might well show that the mix of galaxies is the ‘multiverse’ by another description. John’s pseudoscience (as judged by his crackpot index) seems to have its epitome in the ramblings of Tomas Campbell, through his big toe, and multiverse mania seems just a small step behind…

  11. Bee says:

    Well, one may like or dislike the multiverse for scientific reasons, but there’s no denying it’s interesting from a philosophical point of view and it’s a fairly new idea, so I don’t find it very surprising it’s getting its share of attention. Whether that’s helpful for physics is a completely different question.

    One shouldn’t worry about the multimoraliverse, one just has to postulate that our universe is finetuned for moral. It has to be, because otherwise your blog wouldn’t be here to discuss the issue 😉

    In any case, the question of moral is moot because there’s no such thing as free will, and what is moral if your decisions were predetermined already before you were born anyway? Now imagine what’s going to happen if that became a popular concept. Then you should be worried…

  12. John Baez says:

    I wrote:

    Maybe a branch of science is ripe for infection by pseudoscience whenever it stops making enough progress to satisfy the people in that field But is this really true? Does anyone know other examples, beside the current situation in fundamental physics?

    Friend wrote:

    John Baez, how about the financial market;-)

    That’s a nice analogy because it seems to have been caused by a desperate search for “high rates of return”.

    But I’d really like examples of branches of science that “sank into pseudoscience” as certain portions of fundamental physics seem to be doing now. Or is this a historic first? That seems hard to believe.

  13. John Baez says:

    This just in: Brian Greene is interviewed by Terry Gross on her show “Fresh Air”: A physicist explains why parallel universes may exist.

    By the way, just to lay my cards on the table: I think that parallel universes do exist. I just don’t think they’re worth writing papers about.

  14. simplicio says:

    Was Smolin discussing the multiverse from Sting Theory or the one from the Many Worlds interpretation? I thought only the latter had the “slightly different versions of yourself making slightly different decisions”, but Peter’s rant seems directed at the former.

    (also, do people that hold with both ideas think each universe from String Theory has its own near-inifinte set of “Many Worlds” universe. thats a lot of universes! I wonder if William of Occam exists in all of them)

  15. Anton Tykhyy says:

    @John Baez 8:45 — good insight!
    As a recent and important example, may I offer paleoclimatology? Also teaching methodology (?) — there are reams of research on how to teach children the three R’s, but young adults have been getting progressively worse at them for decades. Philosophy, e.g. philosophy of science, also appears to offer many stellar examples and has been doing so at least since Kant’s remark that

    I do not wish to hide the fact that I can only look with repugnance … upon the puffed-up pretentiousness of all these volumes filled with wisdom, such as are fashionable nowadays. For I am fully satisfied that … the accepted methods must endlessly increase these follies and blunders, and that even the complete annihilation of all these fanciful achievements could not possibly be as harmful as this fictitious science with its accursed fertility.

  16. Peter Woit says:


    I don’t actually know which version of the multiverse Smolin had in mind. One of the things that annoys me about the subject is that discussions of it typically involve conflating all sorts of completely different ideas (it’s not that Smolin was intentionally doing this, as some do, it’s just that’s the context in which these discussions are often held).

    You’re right that my main problem is with the use of this to avoid the implications of the failure of string theory unification. Unfortunately I think that’s the main motivation for some very smart people taking up and promoting a dumb idea.

  17. Giotis says:

    This is the main thing I don’t like about Brian Greene’s new book. He presumably mixes various notions of the multiverse together with some exotic concepts. This I think would obscure the multiverse idea derived from string theory and eternal inflation. This idea has strong theoretical support and it’s not some wild ungrounded interpretation of QM. But let’s wait to read the book first…

    Regarding Peter’s commetns I think he forgets the main motivation for the introduction of the multiverse.

    With the observation of the small CC physicists were facing a big problem with the apparent fine tuning of the universe. It seemed indeed that the universe was fine tuned for life. Trying to make sense of this weird observation they found that the degeneracy of string vacua combined with eternal inflation give rise to the multiverse concept where such a extraordinary fine tuning (and the implied intelligent design) is not necessary. What’s wrong with that? People are trying to give a theoretical scientific explanation to an observation. This is what science always does.

  18. This question of morality really belongs to the department of metaphysics. Leibniz soundly and cogently rejected the worldview that underlies the multiverse some 300 years ago. The rank pessimism of Voltaire’s Candide as a satirical response is echoed by today’s widely held “scientific” tenet that the fundamental law of the universe is irrationality. We meet this type of rather flagrant pessimism in this statement from Hawking: “But our genetic code still carries the selfish and aggressive instincts that were of survival advantage in the past.”

  19. Peter Woit says:


    I’m not likely to forget the anthropic multiverse explanation of the CC. It’s the only “evidence” for the multiverse, explained over and over and over again by those promoting it.

    The problem is that I’m just not convinced. The string theory + eternal inflation + anthropic tautology pseudo-scientific ideology makes exactly the same predictions for observable physics as my personal theory of the CC (which is that I have absolutely no idea where it comes from, so its a priori probability distribution is flat).

    And to some extent I agree with John Baez. Maybe there are parallel universes. But if you’re going to write papers about them and promote the idea to the public as science you need to follow the scientific method. This means having a real theory you can calculate with, one that makes distinctive, falsifiable predictions. Right now, the “theory”being promoted is just a complex mess of failed ideas that “predicts” that a priori any value of the CC is equally likely.

  20. Joel Rice says:

    Giotis indicates that it looks like a Darwinian backlash against an implied ‘intelligent design’ and thus fine tuning might be irrelevant. But why should fine tuning be assumed due to intelligent design ? Both fine tuning and intelligent design may well be irrelevant. Suppose the design of the world requires the construction of atoms – the association of building blocks – how would one have such a nested hierarchy without the effect looking fine-tuned ? One might ask – do forces explain atoms, or do atomic structures determine the forces ? Normally one thinks forces explain – but maybe we have it all backwards, or upside down.

  21. Is there actually an awareness of how we can move on with proper science? Which real world measurable phenomena are currently unexplained and require new models / methods ? What could become / falsifiable possible if we obtain an overarching grand theory?

  22. Emanuel Derman says:

    Re John Baez’s post:
    Maybe a branch of science is ripe for infection by pseudoscience whenever it stops making enough progress to satisfy the people in that field But is this really true? Does anyone know other examples, beside the current situation in fundamental physics?

    The Efficient Market Model and the tendency of financial theory to become irresolutely axiomatic irrespective of whether the axioms describe the world seems a reasonable example.

    In physics it used to be fairly easy to tell the crackpots
    from the experts by the content of their writings, without having to know their academic pedigrees. In finance, as in nutrition, it’s not easy at all. Perhaps physics is going that way too.

  23. Anton Tykhyy says:

    @Frank: that’s just the problem. In fundamental physics, there is precious little to chew on — SM has enough free or underconstrained parameters to fit available experimental data; BB cosmology also rehashes the same few datasets — microwave background, elements’ abundances etc. It appears that either we have entered the age of diminishing returns on research effort, or (and?) research has self-focused into areas which have rather small measure in the idea space. But whereas 200 years ago it was within the powers of a single individual of independent means to master the available data, theories and methods, come up with new ideas and test them, today it is nearly impossible for multiple interacting reasons.

  24. Arun says:

    In reply to John Baez:

    Paul Krugman calls what has befallen on macroeconomics “The Great Ignorance”.

    Not exactly the same phenomenon as certain portions of fundamental physics. But the lapse into pseudoscience is probably rare enough that the common causes, if any, are hard to perceive.

  25. Peter Woit says:


    It’s very well understood by people in the field exactly what the open problems are, as well as what a convincing solution to any of them would look like. These problems are hard though and have resisted solution for a long time. One reason for this is that much of the last 25 years the field has been dominated by investigation of one set of speculative ideas that don’t work. The continuing problem is that instead of admitting this, prominent physicists go to the public with claims that these ideas do work, it’s just that the “multiverse” makes them impossible to test. Thus my shared feelings with John Horgan…

  26. Chris Austin says:

    In my experience, the “moral” impact of taking the Everett-Wheeler “many worlds” picture seriously is the opposite of what Smolin suggests: you start becoming concerned about what happened on other paths. If by chance you narrowly escape a serious accident, you realize, “On another Everett path I got killed just then,” which can be a frightening thought. And more generally you find yourself thinking, “What would have happened if … ,” and trying to think through increasing numbers of diverging paths, which can become a serious burden. Nowadays I try to follow a principle, “Make every path, including this one, as good as it possibly can be,” and not to concern myself about other paths.

  27. Low Math, Meekly Interacting says:

    While the observation of putative dark flow, and the proposed observation of evidence of bubble nucleation in the CMB intrigue me, what has been true of multiverse speculation appears to remain true. Specifically, I see no practical evidence that the field depends crucially on empirical observations of any kind, nor that it will do anything but continue indefinitely regardless of whether or not hints of other “universes” are ever seen beyond the chalkboard.

    Regardless of what value judgement one puts on this state of affairs (I lean strongly toward the negative), there’s no question it’s a paradigm shift that we’re well in the midst of. “Science”, like it or not, has clearly changed. Whether one wishes to call the new era pre- or post-Baconian, empiricism appears now to be too quaint for a core discipline. It pioneered the scientific and technological successes of the modern era, and now a new course is being charted, for good or ill.

    We’re past the point of arguing against it. I find that extremely sobering, to say the least.

  28. Pingback: El multiverso es ciencia o pseudociencia « Francis (th)E mule Science's News

  29. Yatima says:

    “Paul Krugman calls what has befallen on macroeconomics … ”

    Oh…pullease. Not Paul Krugman; he always reminds me of the poor court alchemist trying to justify why repeated attempts to generate gold out of lesser materials has so far met with complete failure lest the well-funded speaking occasions dry up; sorry I meant to say lest the royal executioner pay a visit.

    Keynesianism – Multiverse Theory for the economic profession. And look where it has lead us to.

  30. Peter Woit says:

    Please, informed analogies of economic to physical theory are welcome, but arguments over which economic ideology is best of the same quality as typical arguments over string theory and the multiverse aren’t.

  31. Fred Zarguna says:

    Tipler essentially made this argument going on seventeen years ago in *The Physcis of Immortality* wherein he claimed to have neatly disposed of the Problem of Evil by virtue of the Many Worlds interpretation. Possibly he was correct: unfortunately, if Many Worlds describes actual worlds it also does away with the “Problem of Good,” which most theologins and ethicists never saw as a problem in the first place.

    Content yourself with an update to an ancient aphorism: “Sufficient to each path is the evil thereof.”

  32. Bugsy says:

    I am confused by what role a probability distribution is supposed to play (or not) in both of two “multiverse” ideas- the Many Worlds one and the recent CC one. If there is a probability measure on some uncountable set (like the unit interval) then one can think of “all” events (points) occurring, with the one observed (in this case, inhabited by us) distributed in that way- but with the other points also existing. Alternatively, only one occurs (the one we are in). For example, coin-tossing can be modeled by Lebesgue measure on the unit interval with the binary expansion of each point giving a sequence of 0’s and 1’s; alternatively you imagine a single randomly chosen
    infinite sequence, almost surely with the right statistics. Regarding “MW”, if different worlds are supposed to constantly branch off, then that is severely problematic to model, in either case. One could perhaps imagine branching occurring at all times something like the
    direction changes of a Brownian motion path, but with only one path surviving and actually existing, like the coin-toss sample path. Ok, but if it is splitting at every moment at every location…???

    And regarding “CC”, if these other universes “actually exist somewhere else” then where? There isn’t enough room in any n-space for uncountably many worlds. So maybe it is envisioned as a
    fiber bundle over the probability space. But is any case is sounds very difficult to make any real sense of, to say the least….

  33. Brendan says:

    Peter, don’t discount the degree to which fundamental physics, and our collective understanding of it, inform culture. People do live their lives according to how they see the world. When I was a kid “radical!” was common slang. Today, “random!” is a more common exclamation. I think these are both examples of pop culture tracking science trends. So, I don’t think it’s out of line to consider the moral implications of a particular theory. But it’s an article in Rolling Stone at best. The outcome of considering the possible moral implications of a theory shouldn’t interfere with primary research. But the underlying portrayal and execution of “philosophy of science” is a worry here. I don’t like to think of the message being sent to kids when we have major theories which aren’t subject to much Popperian gravity – just floating around out there in the ether, waiting for the rest of us to have faith that “we’re on the right track, you’ll see. Just keep funding x…”.

    I also agree that both finance and physics are “ripe for infection” There’s a lot of energy and diversity of opinion in physics right now. The pent up urst for a true discovery in physics is probably driving some unprotected research. But I’d point to the oft pooh-pooh’ed idea of “the edge of chaos” to suggest that that might not be a bad thing. I think both physics and finance are sailing close to the wind. In sailing terms, you can win the race sailing close to the wind, but sail too high and you luff the sails, you lose the race. Whether I’m comparing science to a boat race, or randy adolescent boys, the importance lies in competition and having a some “grown-ups” around to establish the boundaries.

  34. milkshake says:

    Examples for John Baez: My impression is that wishful thinking and pseudoscience have played an important role in psychiatry, psychology and management theory.

  35. Casey Leedom says:

    Let me be more brief.

    I don’t care if there are multiple universes or not. I care so little that I’ll even grant it to the proponents just to get them to shut up.

    And then I say: what about _this_ universes? Now that you’ve had your fun dodging the hard problems, can we get back to making concrete predictions about what we _can_ see?

  36. Joe Bob says:

    “But is this really true? Does anyone know other examples, beside the current situation in fundamental physics?”

    Probably one can see things such as the research fraud committed by Marc Hauser as similar (this related to cognition in monkeys). In the biosciences there is more money and more opportunity for popular exposure, and so the degeneration is even greater, into outright fraud. Or, perhaps, the difference is that the fraud can be debunked, whereas metaphysical quasi-religious speculations are inherently more difficult to counteract.

    Looking back to the nineteenth century, perhaps the degeneration into social darwinism was a similar phenomenon.

  37. Bee says:

    Regarding the question what infected economics, you might find this amusing:

  38. John Benavides says:

    Dear Peter

    It would be interesting to make a post to expose in a detailed way your objections about the multiverse, pointing the difference between the many world interpretation or the consistent histories approach to quantum mechanics (for example I would like to know what do you think about Deutsch’s work and Omnès’ ideas, where I think there is lot of ideas that should be take seriously), and the inflationary and string theory’s multiverse (where I think there is a lot of pseudo science)

  39. I think that a popular science book outlining the currently open subjects in physics would be a very nice subject that would be quite refreshing from the bold books that seem to be pouring out these days.

    Such a book is obviously subjected to a high risk of becoming obselete quickly, but it would be of great service to the public. Or maybe there is one still accurate enough? Or maybe I am a minority…

  40. SteveB says:

    I listened to Brian Greene’s interview on Fresh Air last week. Brian was reasonably fair about mentioning the speculative nature of his arguments and that many disagree with his ideas. What came across was his passion for the beauty of the mathematical outcomes that come from extrapolating from other mathematical theories that come from the Standard Model (QFT) which is itself a mathematical predictive tool that attempts to describe the real world.

    And that is where I see the problem. Mathematics is a wonderful, beautiful endeavour. Extending mathematical knowledge is a great and worthy career choice. But as I see it, mathematics in Physics is a tool that is used to try to understand the real world and not an end in itself. While extending the mathematical tools used in Physics can lead to new insights and discoveries, they can also lead to nowhere (in the real world). I think Greene is mistaken that some beautiful mathematical result makes for a plausible theory of physics. Maybe Dirac did it that way once, but that does not prove it to be the best method to use. GR came from the elevator/gravity gedanken experiments and not from the Math.

    As others have mentioned, one can argue that the scientific method itself is being abandoned when one goes the routes that have lead to the current multiverse ideas. I do not support that.

  41. Peter Woit says:


    Thanks, that’s great, I hadn’t seen it. Maybe the argument that particle physicists need to be kept busy or they’ll bring down the financial system will help get funding for the subject.


    As far as I can tell, the string theory multiverse and the many-worlds multiverse have nothing much to do with each other. The string theory multiverse I understand, and it’s clearly pseudo-science. QM interpretational issues are something I’m just not expert in (I know basically nothing about the work of Deutsch or Omnes), so mostly try and avoid comment on. To the extent I have tried to follow the subject, there seem to be very interesting issues there, with most writers ignoring them and devoting themselves to arguing about things that are not interesting (at least to me…).


    Well, I did write a book with a chapter devoted to this (see chapters 8 and 9 of NEW).


    I strongly object to blaming the multiverse on the pursuit of mathematical sophistication and beauty in physics. Most multiverse papers use nothing but high-school mathematics. The “string theory vacuum” constructions that motivate this are just hideously complex and ugly beyond belief. Anyone looking for mathematical beauty would give up on this line of research immediately after looking at these things. The “derivation” of these things from some supposedly beautiful “M-theory” suffers from all sorts of problems, not least of which is that no one knows what “M-theory” actually is, making claims for its supposed beauty to be taken with an immense grain of salt.

  42. Physics has been on the wrong side of the rabbit hole since the 1980’s or so. The fundamental problem is that there’s very little going on physics that grabs the public imagination, so science fiction starts to move in.

    (You’re just not going to get the public excited about, say, Spin Glasses)

    I think of the way the Bell Inequality got popularized in the 1980’s. It’s real science, but it’s a much less profound expression of quantum entanglement than the way that fermion character makes solid matter possible. And if you start taking it too seriously pretty soon you’re Jack Safaratti or Clifford Stoll.

    In the time I was in grad school, quantum gravity went from a holy grail to an embarrassment of riches: people invent new theories of quantum gravity every day, theories in which it’s actually possible to calculate something. Now, “possible to calculate something” means unitarity, and unitarity means “no information loss in a black hole” which means that the 1970’s classical picture of a black hole interior is obviously wrong, but on some level the study of black hole interiors is futile since we’re never going to send a probe into a black hole that sends back pictures.

    Cosmology has always been linked with concerns that are essentially theological. Einstein found an expanding universe distasteful, so he added a cosmological constant to keep it from expanding. Once we learned the universe was expanding, many cosmologists believed in a steady state universe that had neither beginning nor end, rather a process of continuous creation that creates new hydrogen in the spaces between the stars.

    Then the CMB was discovered and it became clear that the universe must have been much smaller and very different in the past. Although cosmologists had little evidence that the universe was either closed or open, it seemed like most of them believed that the universe was closed (How could you have a beginning without an end?) until inflation came on the scene, and pointed to a universe that’s exactly flat.

    Today the multiverse, true or not, reflects a theological preference for ‘continuous creation’. It’s something that many of us (myself included) find emotionally appealing… in the same sense that some people find it emotionally appealing to believe that God created the world 6000 or so years ago.

  43. Joel Rice says:

    Peter, regarding the idea that it is well understood what the open problems are and what a convincing solution would look like, well, I often wonder if the present situation is not similar to the state physics was in just before Spin finally made sense. There was no lack of ideas, just that none of them actually worked. And Spin was a limited problem. And the answer was in quaternions. It appears that Nature is really good at making a lot with a little. The problem with this is that subtlety can be as big a problem as just being complicated. All of today’s ideas might end up like Heisenberg’s Core Model, if we are not noticing something that we ought to notice.

  44. Geoff says:

    “None of the so-called “unified theories” are considered in this book, as in our opinion their physical significance is inversely proportional to the number of variants advanced, now more than twenty.”

    From the preface to Petrov’s Einstein Spaces

    Perhaps physicists could clear up some of the confusion by not prefacing a chalkboard equation with the statement “Morally speaking, the following should be….”

  45. John Bresnahan says:

    Larry Niven wrote “All the Myriad Ways” with this as it’s theme. The original copyright is 1968.

  46. Pingback: Android OS news » The Hidden Reality Draws Ire From Physicists

  47. thomas says:

    any reasonable person would do the same thing with or without a non-collapsing wavefunction, since the reasonable thing to do is to maximize your chances of success, and the non-collapsing wavefunction should still respect probability distributions, after all, we observe it to!

    I guess what I’m trying to say is that stuff that by definition has no effect on our world might just as well not exist.

    Anyway, for a science that has fallen into pseudoscience, we have economics, which Krugman says has been taken over by right-wing ideologues who don’t have any awareness of the arguments that people used to have.

    Psychology, which started with Freud’s brand of pseudoscience, continues to be full of it. That’s not a descent into pseudoscience, though.

    Medicine maybe? About a decade ago, some people started taking certain alternative medicine theories seriously. That was never really mainstream, though.

    It’s worth mentioning that neither geology nor biology have fallen into pseudoscience, much as the right wishes it so.

    I think that pretty much rounds out our collection of sciences!

  48. John Fro says:

    All cosmologists these days are caught up in the legacy of Einstein and the glorious notion that they can rewrite all of physics with just an idea, even one that is counter-intuitive. This notion is very mistaken. There are no multi-verses because there is no way to produce them. What you have are potentials, but after an event those potentials collapse. Don’t try to be the next Einstein. He was solving a very narrow problem with a specifically tailored solution that fit the known facts. While this resulted in predicting unseen phenomena, the goal was not to discover something new, but to solve an old problem. The odds are that you are going to get it wrong.

  49. El Cid says:

    Is the Multiverse Immoral? what is immoral is this post, let me remind you, that your criticising against string theory is for money, too. WTF?

  50. felix says:

    I’m surprised that Greene didn’t name the book “The Elegant Multiverse”.

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