Seek Criticism

Two weeks ago I read Penrose’s new book Cycles of Time. I enjoyed his review of the time’s arrow puzzle, and was intrigued by his proposal that distances fade away in vast infinite futures, allowing them to become tiny flat big bangs again. But not only did Penrose wave his arms pretty wildly on how there could be a metric along which metrics would disappear in approaching the vast-tiny border, he seems to make a very elementary mistake in positing that entropy could have a similar magnitude in our big bang post and our vast distant future, because info is lost in evaporating black holes. The entropy in black hole radiation is more than the holes themselves, which is far more than a tiny flat big bang before.

Raphael Bousso (co-author of that Anthropic breakthrough I raved about in ’08) reviews the book in Science, and seems to agree:

Penrose is at his best when he explains this deep and beautiful mystery, and the book may be worth reading for this chapter alone. However, he compounds the shortcomings of his cyclic universe model when he argues that it can solve the low-entropy problem. At this point, another idea is introduced: like vacuum cleaners, black holes appear to reduce disorder by swallowing matter. By the end of one “aeon,” Penrose argues, most matter has ended up in giant black holes. Very little entropy remains, and the next aeon can commence in perfect order. The second law guarantees that a vacuum cleaner does not actually decrease the overall disorder; at best, it just shifts it around. In fact, the machine creates far more entropy than it destroys (for example, by heating up the air in the room). A black hole, it turns out, is not different. Penrose’s assertion that black holes destroy entropy is flatly contradicted by “the generalized second law of thermodynamics”. (more)

How could such a big-shot make such a simple mistake? One should seriously consider the possibility that he isn’t saying what he appears to be saying, and in fact is saying something much more clever and insightful. But if so why wouldn’t he have devoted more effort to explaining, to avoid the misunderstanding. His book reads as if he didn’t even consider that this criticism would be offered. And that fact leads me to believe Penrose considers himself to be such a big shot that he didn’t even ask colleagues to read and criticize his book before publication. And that sort of isolation makes me more willing to believe that he did in fact just make a simple mistake.

The lesson: no matter how much better you think you are than the lowly incompetents that surround you, you’d still do well to ask for and listen to criticism.

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  • komponisto

    One should seriously consider the possibility that he isn’t saying what he appears to be saying, and in fact is saying something much more clever and insightful. But if so why wouldn’t he have devoted more effort to explaining, to avoid the misunderstanding. His book reads as if he didn’t even consider that this criticism would be offered.

    It is often quite difficult for the very smart to understand just how dumb most people are relative to them. This is especially true if most of their time is divided between (a) other smart people and (b) people who think they’re cool (but it can also be true even in other cases, where they’re in denial about their smartness due to social modesty).

    Looking at Penrose’s biography, it appears he’s been a high-status smart person all his life. As such, he probably takes it for granted that others can follow his thoughts, or if not will at least assume he’s saying something smart rather than something dumb.

    Another example:

    The Road to Reality
    is a wonderful book for students of mathematics and physics, but Penrose seems to have thought of it as a popularization.

  • http://don.geddis.org/ Don Geddis

    Your conclusion seems well supported by your analysis of this single, latest, example. But you can also establish a prior, by looking at Penrose’s career.

    His work on gravity (black holes), and geometry (tiling), suggests that he is brilliant, and sees things that others do not. That argues against your thesis.

    But then in 1989 he published “The Emperor’s New Mind”, and your conclusion is even more obvious in that book than in this latest one. He made a whole series of elementary mistakes there, in both computer science (Godel) and philosophy (quantum gravity as a “solution” to his puzzles).

    And he didn’t stop there. Penrose followed up with a series of books on the same subjects, never acknowledging the severe criticisms of his thoughts on these topics.

    So it’s pretty well established by now, over the last two decades, that Penrose — despite being brilliant — is far too arrogant about his own understanding, in fields where he makes novice mistakes.

    This prior suggests that your suspicion about his latest book is likely to be true. It’s not a one-time mistake. It’s a well-established pattern.

  • dWj

    I’ve heard a similar suggestion as to why the new Star Wars movies were (according to most fans) worse than the first ones; George Lucas wasn’t yet, in 1983, the mythic figure he became, and people were more willing to volunteer criticism. (I would think for Penrose that the problem is more likely to be a failure to seek criticism than a failure of others to offer it when given the chance.)

    I do wonder, though, whether he meant to be asserting that the second law of thermodynamics doesn’t apply, or at least not in this way. I recently found myself in an exchange in which I offered an idea that was counter to received wisdom, and somebody responded with a citation of received wisdom; it had not occurred to me to be explicit with “contrary to what everyone is taught in fifth grade…”. Penrose’s “error” seems basic enough that — without having read the book — I wonder whether he took for granted that it would be clear that his suggestion is a challenge to received wisdom, though perhaps one for which the arguments he presented were insufficient to convince people, even of its status as a speculative idea that might be worth considering.

    (Perhaps I’ll also note that I kind of expect a book dealing with the puzzle of the arrow of time to take the second law of thermodynamics less for granted than your average textbook.)

    • http://www.gwern.net/ gwern

      > I’ve heard a similar suggestion as to why the new Star Wars movies were (according to most fans) worse than the first ones; George Lucas wasn’t yet, in 1983, the mythic figure he became, and people were more willing to volunteer criticism.

      FWIW, I too believe that this is (part of) the reason the prequels were worse.

      If anyone is curious, _The Secret History of Star Wars_ discusses (using contemporary articles and interviews) how Lucas would distribute scripts and get feedback from tons of folks, but that Lucas began to stop doing this and had largely ceased by _Return of the Jedi_ (no accident that that is considered on par with the prequels).

  • Matt

    Aside from Penrose’s idea contradicting the second law doesn’t it also contradict research that information does get out of black holes? Isn’t that what Hawking lost a bet over?

  • Daublin

    Entropy in particular is commonly used by high-status physicists to either bash ideas of interlopers, or to justify some idea of their own. It’s easy to make sweeping, deep-sounding claims about entropy that are then quite complicated to analyze in detail. It’s perfect for status-bashing.

  • Robert Koslover

    Sometimes, very smart people make astoundingly basic mistakes. I once had the (very rare, for me) honor to present a lecture about a novel type of microwave antenna to a small group of some of the world’s most accomplished (no exaggeration) antenna scientists. You might guess that I was a bit nervous! At the end of my talk, one of them (and arguably the most accomplished among them all) asked me a question which appeared to include an assumption about antenna principles that was utterly, blatantly wrong, and at a trivially-elementary level of antenna science. I was so flabbergasted by the question that I simply couldn’t accept that I had heard or understood it correctly, so I actually responded (more or less) to that effect. The questioner looked perplexed but did not clarify or rephrase the question. Then, another world-class antenna expert in the same audience generously stepped in and answered his question, much as one would explain it to a freshman in an introductory antenna class. The questioner nodded and seemed to accept it. And thus, it became clear that my ears had not deceived me about what was being asked. That unquestionably-brilliant antenna scientist had, in fact, made a stunningly-elementary antenna-principles error in the process of formulating his question. To this day, I still can’t quite believe it.

    • http://williambswift.blogspot.com/ billswift

      Everyone, as far as I have been able to tell, has occasional “brain farts” where something that should be, and normally would be, incredibly obvious to him is overlooked. It seems to be similar to the “tip of the tongue” phenomenon. And it is another very good reason to have someone double-check your work. Or at least, if you can’t get someone to check it, set it aside for a few days or weeks before you review it yourself.

  • Doug

    I’m with Don Geddis. From reading the Emperor’s New Mind you can clearly see that Penrose’s thinking on a lot of big topics starts with a conclusion in mind than fits the facts to the predetermined conclusion.

  • http://timtyler.org/ Tim Tyler

    Re: “How could such a big-shot make such a simple mistake?” Er, hang on – isn’t Penrose’s fame built around mistakes? The Emperor’s New Mind was essentially one big fallacy – and that was before he got into the business with microtubules.

    • Constant

      Penrose no more built his reputation on Emperor’s New Mind than Stephen Hawking built his on A Brief History of Time. Possibly the most widely known, if not the most important, of his contributions is the Penrose tiling.

      • http://www.uweb.ucsb.edu/~criedel/ Jess Riedel

        I guess “importance” is a matter of taste, but his various general relativity theorems, especially the ones proving the inevitability of singularities, seem vastly more important to me. Granted, I’m a physicists, not a mathematician. But I don’t here many mathematicians talk about Penrose tilings, while the GR theorems of Hawking and Penrose are central to learning GR.

      • http://www.uweb.ucsb.edu/~criedel/ Jess Riedel

        Of course, I strongly agree with the point about Penrose’s latter dabblings in popular books having nothing to do with his fame as a mathematicians and physicist.

      • Constant

        Jess Riedel, we don’t disagree about importance. Whatever gave you the idea we did? I said “most widely known if not the most important”. Apparently you interpreted that to mean “the most important”, dropping the “not”.

      • http://timtyler.org/ Tim Tyler

        Checking Google NGrams, it looks as though the Emperor’s New Mind made Penrose: http://ngrams.googlelabs.com/graph?content=Roger+Penrose&year_start=1980

        A pity is was all wishful thinking.

      • http://www.uweb.ucsb.edu/~criedel/ Jess Riedel

        Constant: sorry, I can’t read.

        Tim Tyler: It’s not surprising that Penrose’s name shows up in more text that Google indexes after he publishes his popular books. That metric is a terrible thing with which to judge him as a good scientist or thinker to be listened to, which is what’s under discussion.

      • http://timtyler.org/ Tim Tyler

        I think the context may have got muddled. The original question was: “isn’t Penrose’s fame built around mistakes?” I think the graph shows that his rise to fame mostly happened when he wrote “The Emperor’s New Mind” – which is a tapestry of nonsense and mistakes – Q.E.D.

  • richard silliker

    Where was his editor and publisher?

  • http://zatavu.blogspot.com Troy Camplin

    The 2nd law of thermodynamics applies to closed systems, not to open systems. If the universe is an open system, then it does not apply — at least, in the sense it is usually taken to apply. Also, if information is the opposite of entropy, and information cannot be created or destroyed, then the universe must always remain in balance. If we look at the universe, it has crystalized out into ever-greater, ever-more-complex order. This had nothing to do with black holes (which Stephen Hawking already proved does not destroy information).

  • Peter

    “But not only did Penrose wave his arms pretty wildly on how there could be a metric along which metrics would disappear in approaching the vast-tiny border”

    I haven’t read the book so I can’t be sure this is what you are talking about, but it’s a pretty straightforward task in mathematics to put a metric on the space of metrics.

  • Anonymous

    What if the 2nd law of thermodynamics is actually wrong? I mean, what if it has… loopholes? >.<

    • Robert Koslover

      Sure, I’ll play!
      What if the law of conservation of momentum were wrong?
      What if the law of conservation of charge were wrong?
      What if special relativity were wrong?
      What if the CPT theorem were violated?
      (After all, why single out the 2nd law of thermodynamics?)

      • Anonymous

        Ok, good point. I’m looking forward to finding out if any of these theories/laws are falsified one day under special conditions. The 2nd law of thermodynamics seems to be special because it plays a big role in the possible very long-term survival of life in general.

  • http://www.uweb.ucsb.edu/~criedel/ Jess Riedel

    A black hole, it turns out, is not different. Penrose’s assertion that black holes destroy entropy is flatly contradicted by “the generalized second law of thermodynamics”.

    I’m not disagree with the idea that if Penrose was contradicting the beliefs of most of the physics community, he should be explicit instead of moseying over it. But for Busso to say his claim is obviously wrong because it “is flatly contradicted by “the generalized second law of thermodynamics” is like a 19th century physicist saying nuclear power is impossible because it contradicts the conservation of matter (an idea which had great experimental evidence to support it at the time).

    The generalized second law is just a conjecture about black holes (and, ultimately, a quantum theory of gravity) based mostly off of analogies! Seriously, anyone who knows basic general relativity and quantum mechanics can read the original papers of Bekenstein and Sorkin. They are very pretty and suggestive ideas, but hardly conclusive.

    Incidentally, Busso is no disinterested appraiser of Penrose. He’s a major proponent of the holographic principle, which is based off of the generalized second law and the rest of black hole thermodynamics, and which would be thrown out of Penrose was right (unlikely as that may be). I think it’s very disingenuous for Busso to dismiss Penrose, his intellectual opponent, by pretending that a speculative idea like the generalized second law is obviously true.

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  • JQ

    Not to be overly critical, but I think you mean, “you’d still DO well to ask for and listen to criticism.”

  • http://www.schieldenver.co.uk Book Publisher

    Well, I haven’t read the book so I can’t be sure this is what you are talking about, but it’s a pretty straightforward task in mathematics to put a metric on the space of metrics.