Reality is Not What It Seems

This Sunday’s New York Times has a rather hostile review by Lisa Randall of Carlo Rovelli’s popular book Reality is Not What It Seems, which has recently come out in English in the US. Rovelli responds with a Facebook post. Another similar recent book by Rovelli got a much more positive review in the NYT, his Seven Short Lessons on Physics.

I haven’t written about these two books mainly because I don’t think I have anything interesting to say about either of them (although if someone had asked me to review one of them I might have tried to come up with something). They’re aimed very much not at physicists but at a popular audience that doesn’t know much about physics. From the parts I’ve read they seem to do a good job of writing for such an audience, and I noticed nothing that seemed to me either objectionable or particularly unusual. Rovelli’s two slightly different angles on this topic are an interest in the ancient history of speculation about physics and a background in loop quantum gravity rather than HEP theory/string theory. Instead of wading into the controversy over string theory, he just ignores it and writes about what he finds interesting.

I’m not so sure why, since to me this seems harmless if not particularly compelling, but Randall strongly objects to Rovelli’s attempts to draw connections between modern physics and classical philosophy:

Wedging old ideas into new thinking is analogous to equating thousand-dollar couture adorned with beads and feathers and then marketed as “tribal fashion” to homespun clothing with true cultural and historical relevance. Ideas about relativity or gravity in ancient times weren’t the same as Einstein’s theory. Art (and science) are in the details. Either elementary matter is extended or it is not. The universe existed forever, or it had a beginning. Atoms of old aren’t the atoms of today. Egg and flour are not a soufflé. Without the appropriate care, it all just collapses.

She’s also quite critical of the way Rovelli handles the unavoidable problem of writing about a complicated technical subject for the public:

The beauty of physics lies in its precise statements, and that is what is essential to convey. Many readers won’t have the background required to distinguish fact from speculation. Words can turn equations into poetry, but elegant language shouldn’t come at the expense of understanding. Rovelli isn’t the first author guilty of such romanticizing, and I don’t want to take him alone to task. But when deceptively fluid science writing permits misleading interpretations to seep in, I fear that the floodgates open to more dangerous misinformation.

Here I’m a bit mystified as to why she finds Rovelli any more objectionable than any other similar author (or maybe she doesn’t, and he just happened to be the lucky one to have the first such book she was asked to review in the New York Times). As should be clear from this blog and book reviews that I’ve written, I agree with Randall about a problem that she leads off the review with:

Compounding the author’s challenge is the need to distinguish between speculation, ideas that might be verified in the future, and what is just fanciful thinking.

However, to me it seemed that Rovelli met this challenge better than many, far better than any of the huge popular literature about supersymmetry, string theory and the multiverse. She may be right that someone not paying careful attention could get the wrong idea from Rovelli about cosmological loop quantum gravity models. It’s equally true though that readers of her own books about extra dimensions, dark matter and the dinosaurs might come away not understanding exactly what the strength of evidence was for those speculations.

Note added for clarification 3/6/2017: the following is not part of the commentary on Randall’s review, it’s another related topic I thought readers would find interesting. The relation between the two parts is that they both have to do with the question of distinguishing solid argument/speculation, but it’s not about Randall, and the context is different (communicating with other physicists versus communicating with the general public}.

On this question of how/whether physicists (here mathematicians are very, very different) make clear what is a solid argument and what is just speculation, another interesting case is that of Nima Arkani-Hamed, who came to prominence in particle theory with Randall, both of them working on extra dimensional models. Both of them got a huge amount of attention for this, from the public and from within physics, although these ideas were always highly speculative and unlikely to work out.

There’s a wonderful new “Storygram” by George Musser of a great profile by Natalie Wolchover of Arkani-Hamed. It’s all well worth reading, but related to the topic at hand I was struck by the following:

Arkani-Hamed considers his tendency to speculate a personal weakness. “This is not false modesty, it’s really a personal weakness, but it’s true, so there’s nothing I can do about it,” he said. “It’s important for me while I’m working on something to be very ideological about it. And then, of course, it’s also important after you are done to forget the ideology and move on to another one.”

Arkani-Hamed is an incredibly compelling speaker, but his talks often have struck me as putting forward very strongly some particular speculative point of view, while ignoring some of the obvious serious problems. If you’re not pretty well-informed on the subject, you might get misled… From the quote above he seems to have a fair amount of self-awareness about this. Also interesting in this context is his talk last year at Cornell on The Morality of Fundamental Physics. He gives an inspiring account of the intellectual value system of theoretical physics at its best. On the other hand, he pays no attention to the very real tension between that value system and the way people actually pursue their work, often very “ideologically”. For particle theory in particular and the current situation it finds itself in, this seems to me an important issue for practitioners to be thinking about.

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19 Responses to Reality is Not What It Seems

  1. Jeff M says:

    “Compounding the author’s challenge is the need to distinguish between speculation, ideas that might be verified in the future, and what is just fanciful thinking.” OK, coming from someone like Randall, that’s just funny. I seem to remember, a long time ago, physicists did actually try to stick to things that might possibly be verified. Though I shouldn’t taint all physicists with that brush, I’m guessing solid state folks and the like still do. I’ve read a little of Rovelli’s pop science stuff, and it always seemed pretty good, and quite well grounded.

  2. Yeah, the author of a book proclaiming that dark matter likely did in the dinosaurs criticizing Rovelli for lack of clarity about what is speculation seems a bit rich to me.

  3. Peter Woit says:

    Jeff M.,
    Rovelli’s specialty is quantum gravity, and in this new book he’s trying to write about this topic. The problem with such a topic is that there’s no experimental evidence, and no general agreement even on what’s a successful theoretical approach. I can’t think of any other field of science where scientists try and write books for the public about ideas that haven’t gotten any empirical backing. Even in physics, this was not the sort of thing serious physicists did before the 1990s. The problem is that, not because they want to but by necessity, physicists are working this way and people want to hear about what they are doing.

    One could make a serious argument that physicists shouldn’t be writing books for the general public about speculation not backed by experimental evidence, on the grounds that it’s just going to mislead people. Or, one could argue that when physicists do this, they should put huge warning labels on what they are doing to make sure no one gets misled. Given Randall’s own books though, she’s not in a good position to make that argument. I suspect she sees herself as having put enough caveats in her books, and feels that Rovelli is not doing this, but things tend to look very different if you’re writing about your own favorite idea vs. reading someone else writing about their favorite idea (which you don’t at all share).

  4. Paolo says:

    Scientists should write for the general public. The work of “popularization” of science is of extreme importance and its utility is not only limited to the pleasing of “armchair scientists”: I am actually using the books by Carlo Rovelli as short inspiring sources to motivate and engage *graduate level* students in pure mathematics (that, in the country where I work, do not usually have any technical exposure to physics beyond an introductory 1-semester elementary course as beginning undergraduates). I am also using them, with very good results, as a background reading for a weekly discussion group on mathematical physics with (well-experienced) professional mathematicians.
    Clear warnings should be placed when material that is speculative in nature is presented … although everything is quite relative here since, strictly speaking, for a “rigorous” mathematical physicists most of what is currently done in theoretical physics (including standard quantum gauge field theory on 4-dimensional Minkowski space) is still mathematically not-well-founded speculation (no matter its experimental confirmation) 😉
    Scientists should write … and having critical reviews should be perfectly OK as well. The problem here is, as always (as clearly stated by M.Planck’s famous quote, cited by T.Kuhn), … in the “socio-pathology” of the research environment, where (for reasons of career, funding, narcissism, etc) researchers are politically fighting for the supremacy of certain “fashionable trends” and cannot tolerate the existence of dissonant opinions. The fact that speculations based on work in string theory should be considered “more scientifically founded” and “precise” compared to similar speculations based on work on loop quantum gravity (or other even less fashionable trends) seems an example.

  5. Peter Morgan says:

    Against your Randall quote (because she’s right that one always has to pick at details), there is a beauty in the “precise statements” of physics, but to me it is a mathematical beauty. The precise mathematics of our physics is always tenuously related to the experimental data that we hope to take as the ground for our physics when we consider it in its finest details. The beauty of the human endeavor of doing physics is to me in searching relentlessly for formal models that are slightly less tenuously related to the experimental data and in recognizing the valor of those who constructed the very good models we already have. In physics I think of progress coming from our reimagining any or all of the mathematics, the experimental data, and the relationship between them; I take the ground of Not Even Wrong to be discussing how any of these three can fail.

  6. piscator says:

    Can’t share your enthusiasm for that Storygram. The original piece by Wolchover had all the journalistic scepticism and critical analysis of a Profile of the Dear Leader, and Musser’s piece has the same vibe.

    Of course Nima is highly charismatic and fun to listen to, but physics is about results, and one would expect journalists to engage critically with the question about what Nima has really done that will still be around in thirty years.

  7. Peter Woit says:

    I sympathize with your point, and I hope at some point we’ll see a more critical analysis. But I think this is more of a failing of the HEP theory community than one of journalists, who aren’t experts, and aren’t equipped to provide such a critical analysis if there’s no source for it among experts.

  8. Shantanu says:

    Peter , something OT but check out Stacy’s blog article which discusses Dave Merritt’s article
    showing how the goal posts in supersymmetric dark matter have moved.

  9. Thomas says:

    I read (well, listened to) Rovelli’s book and I tend to agree with Randall’s criticism of the book. I was actually rather annoyed with the whole thing and started to skip long sections. Rovelli puts way too much stock in the idea that he is traveling along a path laid out by the Greek atomists, he provides rather misleading explanations of conventional physics, and makes no attempt to explain what the difficulties with the loop quantum gravity approach are.

    In this country we like no sin better than hypocrisy, and it is easy to say that this is an odd criticism from somebody who just published a book on dark matter and the dinosaurs (which was reviewed mostly favorably in the pages of the NYT). Indeed, Randall faces some of the same problems in her book. Putting a disclaimer in every other sentences would have made the book unreadable, and begs the question why it was written in the first place.

    I think there is an important difference, however. By staying pretty close to how scientists actually work Randall makes it clear that this is a book about the journey, not the final answer. By focusing on the poetic connections between himself, Aristotle, and the nature of the time, Rovelli ends up writing a book that is just a little too much.

  10. Bernhard says:


    I haven’t read Rovelli’s book yet, but I read Randall’s…. Of all people, is SHE really in position to make this kind of criticism? Chutzpah comes to mind.

  11. neil says:

    I just finished Rovelli’s new book. I liked it a lot. Basically, it is LQG for dummies, but I appreciated Rovelli’s “fluid science writing” and clear exposition of LQG. Yes, the book is a “sell job” for this approach to quantum gravity, but so what? Rovelli does not try to disguise that fact. I would defend the book against some of Randall’s criticisms. I encountered no place where I found Rovelli misleading about what we actually know and what is speculation. He admits in his chapter on potential empirical confirmation that the evidence is not yet in and that “we will have to wait and see.” What more should he do? I thought he made a telling point when he says that LQG does not need extra dimensions, new symmetries or new particles, just good old fashioned GR, QFT and the SM. And yes, Rovelli is a bit excessive with his sweeping connections to debates in Greek philosophy about whether the world is continuous or granular but, hey, the man is writing a book about the granularity of spacetime. I’ll grant him some literary license.

  12. jimmy says:


    Did Rovelli mention any of the numerous arguments against LQG?

  13. martibal says:

    “Either elementary matter is extended or it is not. The universe existed forever, or it had a beginning. Atoms of old aren’t the atoms of today.”

    Could add: either an electron is a particle or a field….
    I am not so sure physics is working that way 🙂

  14. neil says:


    He does not. His exposition is broad and simplified and, as I said a “sell job”, so he does not discuss problematic issues like computation and self-consistency checks, for example. He claims you can compute physical phenomena by “summing over spin-foams”, but he doesn’t give a concrete example. On issues like deriving the classical GR limit and testibility he is simply optimistic things will work out in the future. The potential tests of LQG he mentions are primarily cosmological (he expects a lot from LISA.)

    As a non-expert, I was content to get a coherent explanation of how LQG is structured.

  15. Narad says:

    Art (and science) are in the details. Either elementary matter is extended or it is not.

    I’m pretty sure that’s ontology, rather than either art or science.

  16. Curious Wavefunction says:

    I did read Rovelli’s book and I don’t think it’s supposed to be a solid introduction to loop quantum gravity for the layman. Rovelli’s style is very impressionistic, and while this works well in his previous book it doesn’t really do the job in this one. At the very least, you would have to build a substantial edifice of physics to launch into a discussion of loop quantum gravity. This Rovelli does not do I think, and others seem to have done it much better. Whatever your opinion of Brian Greene’s books for instance, at least he does a very good job of laying out the basic physics (QM, relativity etc.) in his books.

  17. Richard Gaylord says:

    I don’t expect you to publish this since you seem to automatically delete any comment i make on any of your columns without any explanation to me as to why (which is your perogative since it’s your blog) but the review of Rovelli’s book in the Washington Post ( is worth reading.

  18. Pingback: The Beauty of Computation | A bunch of data

  19. Richard J. Gaylord says:

    my comment was finally published on 3/11, long after i submitted on 3/4. Rovelli appears to have followed my suggestion in that comment (which you edited out of my comment) that he respond to Randall’s review somewhere other than just on his Facebook page and he has just published a condensed version of his reply in tomorrow’s NYT Sunday Book Review

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