Updates

Some new items mostly updating older ones:

  • Natalie Wolchover has a very good article at Quanta, entitled A Fight for the Soul of Science, reporting on the recent Munich conference discussed here. David Gross sounds a little bit like John Horgan, emphasizing the problem of HEP physics getting too difficult, with an “End of Science” danger. I think he has the problem right:

    “The issue in confronting the next step,” said Gross, “is not one of ideology but strategy: What is the most useful way of doing science?”

    I hadn’t realized quite how radical Dawid is. He seems to have moved on from discussing theory “assessment” to theory “confirmation”. Even the most devoted string theorists like Gross may be unwilling to sign on to this, comfortable with the idea that string theory deserves a positive assessment, as a promising idea still worth working on, much less so with claims from Dawid that one can sensibly discuss string theory as a “confirmed” theory, one that belongs in our school textbooks.

    There was much discussion evidently of Bayesian confirmation theory, and Gross was enthusiastic about this

    Gross concurred, saying that, upon learning about Bayesian confirmation theory from Dawid’s book, he felt “somewhat like the Molière character who said, ‘Oh my God, I’ve been talking prose all my life!’”

    He may have become a bit less enthusiastic later when faced with Joe Polchinski’s Bayesian calculation showing a 94% probability confirming the multiverse.

    Sabine Hossenfelder and Carlo Rovelli both explained well the danger of such claims of non-empirical Bayesian confirmation of one’s ideas:

    The German physicist Sabine Hossenfelder, in her talk, argued that progress in fundamental physics very often comes from abandoning cherished prejudices (such as, perhaps, the assumption that the forces of nature must be unified). Echoing this point, Rovelli said “Dawid’s idea of non-empirical confirmation [forms] an obstacle to this possibility of progress, because it bases our credence on our own previous credences.” It “takes away one of the tools — maybe the soul itself — of scientific thinking,” he continued, “which is ‘do not trust your own thinking.’”

  • For more on the “non-empirical science” front, see Alan Lightman’s long piece in Harper’s on “Quantum Cosmologists” Sean Carroll, Alexander Vilenkin, James Hartle and Don Page. Lightman waxes poetic on the importance of “The need to ask the really big questions”, but unless I missed it, there’s nothing there about the need to provide any evidence for the answers that one comes up with. At least one of the four quantum cosmologists, Don Page, seems to see no particular distinction between theology and science.
  • On the Mochizuki front, there’s this report in Nature about the Oxford conference. On the question of what went wrong with the later talks

    But Conrad and many other participants say they found the later lectures indigestible. Kim counters that part of the difficulty lay in cultural differences: Japanese mathematicians have a more formal style of lecturing than do those in the West and they are not as used to being questioned by a testy audience, he says.

    I don’t think the “Japanese culture” explanation of the problem holds water. Of the three problematic speakers, one (Mok) is not Japanese at all (from Hong Kong), and the other two certainly understand that explaining mathematics to someone is about more than reading a lecture to an audience. It’s not plausible that the reason they didn’t have satisfactory answers to questions from the audience is their Japanese cultural background. For the case of Mochizuki himself, he grew up here in New York, went to prep school, undergraduate and graduate school in the US. The question of why following him is so difficult is a fascinating one, but I don’t think the answer to it has anything to do with his choice to move to Japan.

    A must-read detailed report on the situation is Brian Conrad’s, available here.

Update: For some other commentary on the Munich workshop and relevant issues, see Sabine Hossenfelder and my Columbia colleague Andrew Gelman (who I think, unlike anyone in the theoretical physics community, actually knows something about Bayesian methods).

Update: Fesenko has a comment at the Nature article, where he makes the claim: “There are no questions about the theory which are left unanswered.” I agree with my Columbia colleague David Hansen’s response to this, that this seems to be an absurd statement.

Update: There’s a very good report on the abc conjecture workshop from Kevin Hartnett at Quanta. His take on what happened agrees with others:

Kedlaya’s exposition of Frobenioids had provided the assembled mathematicians with their first real sense of how Mochizuki’s techniques might circle back to the original formulation of Szpiro’s conjecture. The next step was the essential one — to show how the reformulation in terms of Frobenioids made it possible to bring genuinely new and powerful techniques to bear on a potential proof. These techniques appear in Mochizuki’s four IUT theory papers, which were the subject of the last two days of the conference. The job of explaining those papers fell to Chung Pang Mok of Purdue University and Yuichiro Hoshi and Go Yamashita, both colleagues of Mochizuki’s at the Research Institute for Mathematical Sciences at Kyoto University. The three are among a small handful of people who have devoted intense effort to understanding Mochizuki’s IUT theory. By all accounts, their talks were impossible to follow.

There’s also a report now from Fesenko, available here. His take on this is that the problem wasn’t the talks, it was the audience:

Labor omnia vincit. Progress in understanding the talks correlated with preparation efforts for the workshop. There were participants who came unprepared but were active in asking questions, many of which were already answered in recommended surveys and some of which were rather puerile.

Unclear what the point of such remarks is, unless the goal is to make sure that many of the experts who attended the workshop won’t come to any more of them.

Update: The paragraph from Fesenko’s report on the workshop quoted about has been removed, replaced by

Без труда не выловишь и рыбку из пруда. Progress in understanding the talks correlated with preparation efforts for the workshop. Lack of reading of non-classical papers of the theory often correlated with the depth of asked questions.


Update
: Nature covers the Munich conference as Feuding physicists turn to philosophy for help.

Update
: The Fesenko report has been further edited, with the paragraph mentioned above now reading

Без труда не выловишь и рыбку из пруда. According to the feedback, progress in understanding the talks and quality of questions often correlated with preparation efforts for the workshop and reading of non-classical papers of the theory.

Update: Michael Harris’s take on the press coverage of the Oxford conference is here.

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70 Responses to Updates

  1. Peter Woit says:

    George Ellis,
    Apologies for the snideness. I wasn’t there so don’t know all that was discussed. Note that my remark was directed at theoretical physicists, not philosophers or others. From reading Wolchover’s report and others, my impression was that the main invocation of Bayesian confirmation from theorists was coming from Gross and Polchinski, using it in ways that I think are extremely hard to take seriously. While I’ve often seen a sophisticated use of ideas about probability, including Bayesian ones, in several areas of physics in the analysis of experimental data, I haven’t seen this at all in theorist’s work divorced from experiment. Quite possibly there are cosmologists or those who study quantum measurement theory who are capable of this, I don’t think the same is true of string theorists.

  2. Peter Woit says:

    Marko,
    You say that Dawid claims “his three arguments are the only sensible way one can assess a theory absent any observational evidence… there’s nothing else we can do.”

    I didn’t hear the talk, but I did read his book, and I don’t recall seeing a “no alternatives” to “no alternatives + two others” argument anywhere there. Rather it seemed to me that he was taking as his starting point a reading of arguments made by string theorists, trying to come up with a classification of those arguments. It seems to me that he was starting from the conclusion he wanted. If you instead started from the general question “what are good, justifiable ways of evaluating theoretical progress”, I think you’d end up with a different list.

    An obvious alternative to Dawid’s three that immediately comes to mind would be the criterion for progress “are these ideas moving away or towards successful contact with experiment as they develop”. This seems to me the most common way of evaluating theoretical ideas, which mostly start life unable to make contact with experiment, then either move towards being able to do so, or get abandoned as failures. In the case of string theory unification, the ideas started life with a program for contact with experiment, claims that they were nearly there. The history of the last thirty years has been one of moving in the wrong direction, headed towards zero possibility of any contact with experiment.

    Did this sort of thing come up at the workshop? I’d argue that there’s a reason this kind of criterion for confirmation is not being put forward by Dawid: it makes string theory look bad…

  3. vmarko says:

    Peter,

    I listened to the lecture, but didn’t read the book (and have no intention of doing so), so information that I have is kind of complementary to yours. 🙂

    Basically I agree with everything you said above, and it’s a subset of the reasons I have for disagreeing with Dawid’s criteria. And no, during the conference nobody has discussed the criterion of moving towards or away from experiment or any similar idea (I like your proposal, provided that you can give some operational way of estimating the notions “moving towards” and “moving away”).

    I also agree that Dawid was probably looking at what string theorists were doing when he was constructing his arguments. But Dawid’s position does *not* strike me as the one where he is deliberately cheering for ST. I agree that he was looking at a very skewed and biased sample of scientists, but I don’t think that he cherry-picked them intentionally. If anything, he didn’t take a good enough sample of HEP and QG theorists during his research, so one can blame him for constructing his criteria based on an unrepresentative sample of scientists. And I do think that is the case. But I also believe it was an error out of ignorance, not that he did it on purpose.

    Of course, I might be wrong, but that was the impression I got after listening to his lecture and talking to him in person. Maybe I’d have a different impression if I had read his book, I don’t know.

    Best, 🙂
    Marko

  4. Armin says:

    Peter,

    Just a quick observation: your apology makes it sound like you consider George Ellis a “philosopher or other”. Also, I think that referring to theoretical physicists in your remark without qualification is far too strong a claim.

  5. Peter Woit says:

    Armin,
    I think you’re misreading my comment here. My intent was purely to acknowledge that a snide remark wasn’t a great idea and to instead try to make clearer the thought behind it (which has nothing at all to do with Ellis).

  6. Laarbi says:

    Can anybody provide us with a link to the video of the Munich conference?

    Thank you!

  7. Peter Woit says:

    Laarbi,
    My understanding is that the talks were recorded, at some point (not yet) will be made available here
    http://www.whytrustatheory2015.philosophie.uni-muenchen.de/media/index.html

  8. Peter Woit says:

    Kartik Prabhu,
    Thanks! That article is quite good, but I don’t think the bottom line is any different than other reports from the conference:

    “The next step was the essential one — to show how the reformulation in terms of Frobenioids made it possible to bring genuinely new and powerful techniques to bear on a potential proof.These techniques appear in Mochizuki’s four IUT theory papers, which were the subject of the last two days of the conference. The job of explaining those papers fell to Chung Pang Mok of Purdue University and Yuichiro Hoshi and Go Yamashita, both colleagues of Mochizuki’s at the Research Institute for Mathematical Sciences at Kyoto University. The three are among a small handful of people who have devoted intense effort to understanding Mochizuki’s IUT theory. By all accounts, their talks were impossible to follow.”

    I’ll add a link to this to the posting. There is also a report on the conference from Fesenko,

    https://www.maths.nottingham.ac.uk/personal/ibf/files/iut-i-rep.html

    which blames the audience for what happened:

    “Labor omnia vincit. Progress in understanding the talks correlated with preparation efforts for the workshop. There were participants who came unprepared but were active in asking questions, many of which were already answered in recommended surveys and some of which were rather puerile.”

    I’m not sure what the point of such a comment from Fesenko is, unless he’s trying to ensure that most of the experts who showed up at this workshop won’t attend future ones.

  9. Daniel says:

    I wonder why people like Weinberg, t’Hooft and Wilczek were not invited…

  10. lun says:

    George Ellis – the deluge of hep-ph papers about the “750 GeV bump” shows the snarkiness is justified by quite a few sigmas since the hypothesis of knowledge by theoretical physicists of Bayesian probability has quite a low p-value. 🙂

  11. vmarko says:

    Daniel,

    “I wonder why people like Weinberg, t’Hooft and Wilczek were not invited”

    Actually, this question was asked during the conference (not for those three names in particular, but for someone else, I can’t remember now for who), and the response from the organizers (Dawid in particular) was that actually they were invited, but were unable or unwilling to appear. Again, I don’t know about Weinberg, t’ Hooft and Wilczek in particular — but apparently many more renowned scientists and philosophers were invited, but for one reason or another, didn’t show up. Unfortunately (but understandably) no names were spelled out, so…

    Best, 🙂
    Marko

  12. Pingback: Should scientists trust untestable ideas? | Uncommon Descent

  13. Daniel says:

    vmarko,

    Thanks for the info!

  14. DrDave says:

    ” This “no-alternatives” argument, colloquially known as “string theory is the only game in town,” boosts theorists’ confidence that few or no other possible unifications of the four fundamental forces exist, making it more likely that string theory is the right approach.”

    So, the only way to disprove string theory would be to come up with a a fake alternative which could not be tested and makes no predictions. How strange is that?

  15. Bayes’s theorem doesn’t work to say a theory has this-and-such probability is true. Giving any theory a probability only makes sense comparatively. Why? Well, here’s a longer argument:

    http://wmbriggs.com/post/17544/

  16. Rh L says:

    Peter,

    I think you’d love the newest edition of Fesenko’s comment (ca. December 27, 2015):

    “Без труда не выловишь и рыбку из пруда. Occasionally, a baby-like attitude to attend the workshop without reading any surveys or non-classical papers of the theory affected the quality of asked questions and progress in understanding the talks.”

  17. Peter Woit says:

    Rh L,
    It seems that Fesenko has been editing that text every day or so. I no longer see the paragraph you quote, but he has added this complaint:

    ” These papers contain a large variety of new ideas and concepts (listed in the letter to participants) and it is a rather naive question to ask to single out the most important idea/concept.”

    I think that’s a misunderstanding of the attitude of many of the experts there, who were trying to find a new, powerful, idea in Mochizuki’s formalism they could understand, because that is what would give them the insight needed to make some progress on understanding the proof. It’s not that there was an expectation that there is a single important new idea here, quite likely several are needed, but one has to start by finding and understanding a first one.

  18. David Hansen says:

    @Peter: And now that comment is gone in turn. What a joke.

  19. Paul D. says:

    Tom Hartsfield comes down against attempts to abandon empiricism for the sake of string theory:

    http://www.realclearscience.com/blog/2016/01/string_theory_has_failed_as_a_scientific_theory.html

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