Theories of Everything

I’ve written a review for the latest issue of Physics World of a short new book by Frank Close, entitled Theories of Everything. You can read the review here.

As I discuss in the review, Close explains a lot of history, and asks the question of whether we’re in an analogous situation to that of the beginning of the 20th century, just before the modern physics revolutions of relativity and quantum theory. Are the cosmological constant and the lack of an accepted quantum theory of gravity indications that another revolution is to come? I hope to live long enough to find out…

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26 Responses to Theories of Everything

  1. Doug McDonald says:

    “Cosmological observations appear to
    indicate that this is a non-zero num

    ber, with an order of magnitude so
    big that it doesn’t fit at all with what
    one might expect from the Standard
    Model and general relativity.”

    Please explain “big”. I though that the (non stringy) particle physicists said “small”,
    by 30 or 120 orders of magnitude.

  2. Peter Woit says:

    Doug McDonald,
    Oops, that’s a mistake that seems to have crept in during the editing, and I wasn’t paying enough attention in proof-reading. For “big”, read “small”.

  3. neil says:

    Despite the outstanding success of the standard model, I do not think we are in a position analogous to that of 1900 with apparently settled physics but for a couple of clouds on the horizon. Kelvin thought his clouds would eventually be explained by the “standard model” of his time. That is why he thought them mere clouds. I don’t think anyone labors under that delusion today. Our clouds are looming cumulonimbus, and the big question is whether we can discover the physics needed to explain them given the limited tools available to us.

  4. Snowden says:

    A revolution a day keeps progress away – especially true in quantum gravity, where the revolution now is that the previous revolutions haven’t gone anywhere. It is amazing that people confidently claim that properties that are true of every low energy Hamiltonian will somehow magically lead to insights about quantum gravity (

  5. Peter Woit says:

    Doug McDonald,
    Thanks for pointing out the problem. It’s now fixed in the pdf here and online at Physics World.

  6. Pascal says:

    What about nonzero masses for neutrinos: is that compatible with the standard model?

  7. Low Math, Meekly Interacting says:

    What about dark matter? Is that not a “cloud”? I’ve read many an account of Einstein’s doomed attempts to find a unified field theory. The general consensus being ignorance of two more forces of nature didn’t exactly help his efforts to unify gravity and EM. What if dark matter completely up-ends our notion of what “matter” is? What if gravity has to be modified? Could a major part of the problem also be tied up in the answers to those questions?

  8. Peter Woit says:


    Neutrino masses and dark matter are also possible “clouds”. Unfortunately in neither case have they provided any promising hints for a revolutionary change in our best fundamental theory. This may be why Close points to the quantum gravity problem as one more likely to lead to such a change.

    The problem is that all of these have received a huge amount of attention from theorists trying to interpret them as evidence for a new theory, without much to show for the effort. Maybe a very different cloud would be more promising. One of my personal favorites is the difficulty of non-perturbatively formulating chiral gauge theories such as the electroweak sector of the Standard Model.

  9. KJ says:

    Your review certainly implies that your general impression of the book is favorable – you say Close is “on the right track”- but I finished the review not being sure whether or not you recommend the book, and if so, to what audience. Does Close have anything new to say about the situation that has not been covered already by some of the plethora of popular books on the Standard Model? Or is it more a case of “If you feel like you must read every popular book on quantum gravity, at least this one won’t mislead you into multiverse mania”.

  10. Peter Woit says:

    It’s a short popular book, much of which is a subset of what is covered in various longer books (including some by Close himself). He’s trying to emphasize one particular question, about unification and the current state of affairs. But it is at the level of a non-technical essay, and if you’ve followed the issues discussed on this blog I don’t think you’ll find anything particularly new. My review mainly attempted to just convey the point of view of his essay, perhaps wasn’t very good as a consumer guide.

    Yes, one market for the book is for those who must read every popular book on fundamental physics, and for such readers I’d describe it as a sensible but unsurprising take.

  11. Low Math, Meekly Interacting says:

    I guess. But maybe lacking more specific observational or experimental information about the nature of dark matter is a lethal impediment, akin to operating under the assumption that EM and gravity are the only fundamental forces and then seeking to unify the forces of nature. Maybe it’s just setting oneself up for certain failure? True, it’s been a disappointing avenue of exploration so far, but what if it’s impossible to get around nonetheless? Given the “nightmare scenario” that appears to be unfolding, I do wonder why there isn’t much public discussion of such a possibility. I.e. maybe we’ll never get close to completing this puzzle until we’ve found this one piece that’s so obviously missing.

  12. AcademicLurker says:

    Maybe this belongs in the “Why string theory is still not even wrong” thread, but I don’t want to derail the discussion there.

    Peter, in your books both you and Lee Smolin dealt at length with the ways in which you thought the sociology of HEP theory was discouraging the exploration of new or unconventional approaches.

    Since now post LHC new ideas seem to be more needed than ever, do you see any improvements in the sociology of the fundamental physics theory community relative to 2006?

  13. Paul says:


    We are not yet in “post LHC” mode. Not by a long shot.

  14. Peter Woit says:

    Academic Lurker,

    There have been changes in the sociology since 2006, some for the worse, some for the better. Net though I think we’re worse off than in 2006.

    One change for the better is increased skepticism about string theory. That string theory hasn’t worked out as hoped and no longer provides a promising route to unification is now a widespread point of view in the physics community, probably even the dominant, majority one. Even lots of people who call themselves “string theorists” are now working on different ideas that have little to nothing to do with string theory.

    On the still a problem front, I’d list the herd sociology of the subject. Yes, you can not work on string theory, but if you want a career you better stick to one of a small number of “hot” topics. If you have an idea that is not related to string theory or one of the latest hot topics, pursuing it is as likely to doom your career as ever.

    There have unfortunately also been significant changes for the worse. The multiverse is one I go on about too much, but it’s hard to over-emphasize what an awful idea it is to give up on conventional science in that way. I had some hope that negative LHC results about SUSY and extra dimensions would have a wake-up effect, but that does not seem to be happening. Those devoted to SUSY seem to be taking the line that losing their bets that they would be vindicated by the LHC is no reason to change their thinking.
    Another major change for the worse I think is the way that most of the physics community seems to have decided that the reason string theory didn’t work out was that it used too much mathematics (as opposed to just being a bad physical idea). The engagement with deep mathematics was one of the best aspects of string theory, and that kind of work is nowhere near as healthy as it used to be.

  15. Jesper says:

    Hi Peter

    When you write “On the still a problem front, I’d list the herd sociology of the subject. Yes, you can not work on string theory, but if you want a career you better stick to one of a small number of “hot” topics. If you have an idea that is not related to string theory or one of the latest hot topics, pursuing it is as likely to doom your career as ever ” — then I cannot agree with you more.

    If this does not change then I think that young researchers must and will begin to consider alternative routes for funding. Personally (and I am not that young any longer) I have taken the consequence and am financing my research via crowdfunding. I just don’t see any possibility within the academic world of theoretical physics of today to successfully — i.e. financed — pursue a research project that is both serious (which means, involves years if not decades of work) and independent of the existing power structures. I imagine that others might begin to consider alternative options too.

    I don’t mean to suggest that this will be easy — it is not! — but if the choice boils down to abandoning your own ideas or research altogether, then I imagine and hope that there will be some who simply refuse to accept the basic premise that research belongs in academia. In fact, there are also upsides to working outside of academia. And one thing that I have learned is that there are many people who are interested and willing to finance alternative ideas as long as they are certain that its serious research.

    On another note: I agree with you on the role of mathematics in theoretical physics. In my view its possibly the most important guidance we have forward.

  16. Mitchell Porter says:

    Since people express so much agitation in a forum like this, about the theoretical physics establishment still pursuing its failed agendas, etc, may I point out that every month on hep-ph there are several dozen papers on models employing neither supersymmetry nor grand unification – to name two of the popular, post-1970s, beyond-standard-model research programs that are also part of the string theory edifice.

    For example, there are papers on flavor symmetries, especially for the neutrino sector; and there are papers looking at rather minimal extensions of the standard model, in order to explain the extra phenomena like neutrino masses and baryon asymmetry. (An example of the latter would be the “SMASH” paper, that received a little media coverage recently.) There are always a handful of papers trying to challenge more basic conventional wisdom, in ways that look misguided. And there are still further papers which don’t fit any of those categories.

    I think all this would be apparent to anyone who actually checks the daily releases on arxiv. So it makes me wonder about the people who express agitation about the state of physics: who are they, and what are they angry or despairing about? Some of these people might be laypeople who only read a type of “secondary literature” – hype and anti-hype, in media and blogs. Some of these people might be theorists (amateur or professional) who have a theory of their own to push, and whose dissatisfaction is really that *their* theory doesn’t get funded or isn’t widely accepted. And some of these people may be part of physics culture, but are only focusing on the elite – the big institutions, the big conferences, the big-name theorists who do all the interviews. Perhaps they want these “leaders of the field” to reform themselves, not caring that there is a big wide world of universities and researchers developing a multitude of heterodox viewpoints away from the limelight.

    This is just an impromptu analysis. I would like to know what it overlooks.

  17. Peter Woit says:

    Mitchell Porter,
    hep-ph has always been mainly non string theory, with HEP phenomenologists traditionally a part of the subject opposed to string theory. The problem for hep-ph is the same now as it has been for a long time: no new -ph to study (except for experimental misfires like the 750 GeV diphoton).

    If there’s no new input from experiment, hopes for progress have to come from new theoretical tools and ideas, and that’s supposed to be the realm of hep-th. hep-th has much less string theory on it these days, but just as many “string theorists”, and it’s there that the range of new ideas under consideration is problematic.

  18. Ted says:

    I’m curious to know: what would your advice be to young academics just starting off their careers, who want to explore new ideas? Leave academia and research independently in ones spare time? Go into a “hot” area without truly believing in it? Quit altogether?

  19. Peter Woit says:

    I don’t think there’s any single good career strategy to suggest. Besides the making a living business, two problems with working independently are that you lose the experience of teaching a subject (which is the best way to deeply understand it) and you lose having others to regularly discuss things with. If you happen to be financially independent, it would probably be a good idea to find a high quality, friendly academic department which would allow you to have some kind of affiliation and even sometimes teach courses. Many academic departments will not turn away a qualified Ph.D. who shows up and offers to help with teaching basic courses.

    If, like most people, you need a paycheck, I’d suggest trying to consider the widest range of possibilities for academic employment, looking at many institutions, many departments, many types of positions. People in the usual HEP theory career track often have narrowed possibilities because of no experience teaching.

    At the very start of a career, as a graduate student, it’s probably a mistake to decide that you know what the best unconventional research direction to pursue is. You need to learn your subject, and there are lots of different kinds of projects that will help with that, while making you a viable candidate for a postdoc. If you get a postdoc, you generally can spend your time doing what you want.

    Where the standard career path becomes very problematic is going from such a post-doc to a longer term position, and it’s in preparing for that transition that I’d suggest looking at any possibility you can think of. Trying to play the game of working on a “hot” topic you don’t believe in, with the hope that this will get you tenure and freedom is something I don’t think really works. Most likely you will end up just losing out to others playing the same game better than you, or after a decade of working on things you don’t believe in, you’ll no longer know how to work on things you do believe in.

  20. Ted: I’m not a physicist, but I am a serious worker in a field dominated by academics, namely computer music of the sort that focuses on software synthesis and algorithmic composition, and I have concertized, published, and presented in the main venues of the field.

    What I found is this. For the most part there has been no barrier to acceptance of my work arising from my not being an academic. However, I am quite clear that the quality and quantity of my work has suffered from not being in the academic context, where I would have had much more interaction with my peers, and would not have had to have a day job. I believe that even teaching helps, as one is still spending time in the thought-world of the field.

    My advice to an aspiring physicist is (a) see if the lack of barrier is also the case in physics, but I wonder because there are a lot of physics crackpots and not many computer music crackpots, and (b) don’t work independently if there is any way to make it work inside the academic world. But in that case, a serious theoretician would absolutely have to find a way to build a private space for the kind of deep thinking that is required. You need long stretches of just thinking and even of being quite alone. Perhaps one could keep two research tracks going — one to keep your funders and bosses happy and one to keep oneself happy. But that sounds like real overwork!

    Conversely, for someone working outside academia, I think it would extremely helpful, perhaps vital, to live in a big center like New York or a major university town and try to get to know some of the leaders in the field. I have been able to do this in music, and it has been really helpful.

  21. Jeff M says:

    Ted : My advice for young academics. I’m a mathematician, I’ve been on a bunch of search committees, so I have a good idea of what the field is like for young math types. It’s much worse in physics, since physics isn’t a service department. At my university, we have 32 people in the math department, and 5 in physics. I would second everyone who says try to stay in academia if you really want to be part of the field, but be willing to teach anywhere. Might mean a much heavier load, many fewer connections, but it’s a different world, and if you’re out of it, its very hard to stay active. I know someone (in math) who did what Peter suggested, and got himself affiliated with a very good university, who didn’t pay him anything. He won the lottery, so he didn’t need money. But I think a lot of people in physics just dismiss the idea of teaching at a liberal arts school, or a second rank state school like mine. But you can have a good life doing it, stay active, find interesting things to do. I went to a liberal arts college, the physics professor I did most of my work with stayed very active, published, and after I left he actually started a research institute. One of the people associated with the institute won the Nobel. My son, who was at the same school this year, worked with a new physics prof, serious research degree, I have no doubt she’s going to stay active. He’s transferring to a research one place, I’m very curious what he’s going to think of the difference

  22. Scott says:

    As a physicist, but not HEP, I always thought
    one of the “clouds on the horizon” was the
    matter/anti-matter asymmetry. Would that
    qualify or is there a feeling among HEP that
    while an issue, it is secondary.

  23. Peter Woit says:

    Sure, that maybe a “cloud”, but one problem with that is that it depends a lot on your understanding of what happened during the big bang, so it’s not a clear indication that there’s something wrong with our fundamental theory of particle physics (as opposed to the details of our understanding of very early universe cosmology).

  24. Peter Woit says:

    A correspondent points out to me that the idea of quantum theory requiring replacing our understanding of space and time goes way back, with Russian physicist Matvei Bronstein discussing this already in 1936. For more about this, see


  25. Chris W. says:

    The physical motivation is less clear-cut than the arguments put forth by Bronstein, but this fairly well-known quote of Einstein (on Sabine’s Backreaction) indicates that he had been worrying about this for some time as of 1916.

  26. Thomas says:

    off-topic, but .. care for 28 000 pages of notes from Grothendiek?

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