Sunday, March 04, 2012

The Edge annual question 2012

With somewhat of a delay, here is my annual summary of the Edge annual question. In 2012 the smart people were asked

As every year half of the respondents used the opportunity to promote their own research. This year they may be forgiven, for they were likely drawn to their research because they found it elegant or beautiful. A notable exception is experimental psychologist Bruce Hood who nominated Fourier's theorem because "psychology ... is rarely elegant."

Some of his colleagues see this differently though. David M. Buss, for example thinks "Sexual Conflict Theory" is an elegant explanation for what he is concerned: "Men are known to feign long-term commitment, interest, or emotional involvement for the goal of casual sex, interfering with women's long-term mating strategy," he writes. He'd better learn string theory to explain everything.

Psychologist Mahzarin Banaji offers "Bounded Rationality," the insight that human beings are not "smart enough [to behave] in line with basic axioms of rationality." The inexistant rational person would say if the subject of your study doesn't behave as your axioms say, you should conclude that you've used the wrong axioms. More replies from the psychological side are that of Emily Pronin, who finds it beautiful that "Human beings are motivated to see themselves in a positive light," and that of Joel Gold who likes Freud's elegant discovery of the unconscious.

Nathan Myhrvold explains that the scientific method "it is the ultimate foundation for anything worthy of the name "explanation,"" and is, surprisingly, the only one to name the scientific method. The double helix and natural selection, as one could expect, appear various times.

Needless to say, the physicists had a large selection of answers to choose from. As Leonard Susskind wrote in his reply "That's a tough question for a theoretical physicist; theoretical physics is all about deep, elegant, beautiful explanations; and there are just so many to choose from." He chose to nominate Boltzmann's explanation of the second law of thermodynamics because his "favorites are explanations that that get a lot for a little." A good choice.

Anton Zeilinger names Einstein's 1905 proposal that light consists of energy quanta, Raphael Bousso on similar reasoning goes for quantum theory, and Satyajit Das for Heisenberg's uncertainty principle.

Steve Giddings and Roger Highfield nominate Einstein's insight that gravity is curvature of spacetime, Lee Smolin's favorite elegant explanation is the principle of inertia, and Sean Carroll, close by, names the universality of gravity. Stephon H. Alexander, always unpredictable, goes for particle creation in time dependent gravitational fields. (Which, incidentally, was the topic of my master's thesis.)

Lawrence M. Krauss goes for electromagnetism, Eric Weinstein favors the deep insight that quantum theory is "actually a natural and elegant self-assembling body of pure geometry that ha[s] fallen into an abysmal state of pedagogy putting it beyond mathematical recognition," Timo Hannay's favorite is QED, Laurence C. Smith goes for continuity equations, Lisa Randall nominates the Higgs mechanism, and Garrett Lisi names a theory of everything that does not yet exist - who knows what might have been on his mind.

Marcelo Gleiser and Bruce Parker nominate atomism. Gregory Benford and Peter Woit reasonably find beauty in the unreasonable effectiveness of mathematics, and Shing-tung Yau, (Co-author of The Shape of Inner Space) keeps it simple and elegant with "A Sphere."

Max Tegmark is as always entertaining:
"My favorite deep explanation is that our baby universe grew like a baby human — literally. Right after your conception, each of your cells doubled roughly daily, causing your total number of cells to increase day by day as 1, 2, 4, 8, 16, etc. Repeated doubling is a powerful process, so your Mom would have been in trouble if you'd kept doubling your weight every day until you were born... Crazy as it sounds, this is exactly what our baby universe did according to the inflation theory pioneered by Alan Guth and others..."
The reason to capitalize Mom is that it stands for God in this creation myth. And I guess the navel of the universe lies at MIT.

Jeremy Bernstein, interestingly enough, names the Planck scale as a limit to measurement of time (and space I want to add), which we recently discussed here. Bernstein however credits this insight to Freeman Dyson.

Freeman Dyson himself thinks it is elegant that general relativity remains unquantized and, repeating earlier statements of his, he "propose[s] as a hypothesis... that single gravitons may be unobservable by any conceivable apparatus." I very much like his reply, because I keep using a fairly old quote from Dyson on my slides to enter into an explanation why the detection of gravitons isn't equivalent to evidence for quantum gravity. So now I can use a newer quotation.

Frank Wilczek offers a very good answer: Simplicity, which he thinks of as the length of an algorithm: "Description length is actually a measure of complexity, but for our purposes that's just as good, since we can define simplicity as the opposite—or, numerically, the negative—of complexity." I like his answer because it touches on the question what we actually mean with elegance.

This underlying big question mark is raised also by Rebecca Newberger Goldstein: "Where do we get the idea — a fantastic idea if you stop and think about it — that the beauty of an explanation has anything to do with the likelihood of its being true?" An excellent point that we explored in my post "Is Physics cognitively biased?"

On that note, Frank Tipler favors parallel universes, Andrei Linde thinks "the inflationary multiverse" is a beautiful explanation for everything, and Martin Rees also nominates the multiverse.

Another noteworthy physicist's reply is that of Seth Lloyd, who made the effort to write up the demonstration SU(2) being a double cover of SO(3).

My award for the most bizarre reply goes to Dave Winer who thinks it is elegant that his computer screen "has the time in the upper-right corner."

The most interesting reply I found that from Barry C. Smith who summarizes it as "Lemons are Fast" and explains "When asked to put lemons on a scale between fast and slow almost everyone says 'fast', and we have no idea why." I'm not sure exactly what is elegant about this, but interesting it is without doubt.

For me the most insightful reply was that of Tania Lombrozo who writes:
"Metaphysical half-truths... realism, the existence of other minds, causation... These explanations are so broad and so simple that we let them operate in the background, constantly invoked but rarely scrutinized. As a result, most of us can't defend them and don't revise them. Metaphysical half-truths find a safe and happy home in most human minds.

[T]he depth, elegance, and beauty of our intuitive metaphysical explanations can make us appreciate them less rather than more. Like a constant hum, we forget that they are there."

And the shortest reply is that by Katinka Matson who nominates Occam's Razor.

My nomination for the most beautiful and elegant explanation would have been the variational principle (about whose elegance I wrote here), close to David Dalrymple's reply that named the principle of least action.

Anybody else has the impression that list is getting longer every year? Do they just write more or are there actually more names on the list?

The question that I would like to ask all the smart people is this: If everybody on the planet would read your reply (or have it read to) what would you want to tell them?


  1. I like the gauge principle where force interaction fields are introduced automatically by demanding a global symmetry to have a local validity.

    Nobody mentioned that?

    "to enter into an explanation why the detection of gravitons isn't equivalent to evidence for quantum gravity."

    What do you mean by that? Could you elaborate?

  2. Half the 'explanations' aren't explanations at all, they're just statements (debatable or otherwise) or even just things. If you can't phrase it in a form involving 'why' it isn't an explanation.

    BTW, did anyone mention the risk thermometer explanation of why making bicycle helmets compulsory increases the number of deaths and serious injuries to cyclists?

  3. Hi Giotis,

    Well, Eric Weinstein did. I could elaborate, but this isn't really the place. I wrote a whole paper on that here and several blogposts too (use the label Quantum Gravity). Best,


  4. Hi Bee,

    Thanks for the run down as it has me now want to read more of them in total. As for my own personal favourite I would have to agree with David Dalrymple as I can’t imagine any deeper explanation of what we find to be reality as to how it operates and yet it still being mysterious as to why. That is to admit yes we do have Feynman’s quantum expression of this with path integral, yet it’s simply a mathematical way to say with all possible histories considered it’s those of the least action which will most likely be realized. This makes it easier of course to calculate outcome, yet still fails to say as to where nature finds the time to have all these histories resolved when given none.

    “The laws of movement and of rest deduced from this principle being precisely the same as those observed in nature, we can admire the application of it to all phenomena. The movement of animals, the vegetative growth of plants ... are only its consequences; and the spectacle of the universe becomes so much the grander, so much more beautiful, the worthier of its Author, when one knows that a small number of laws, most wisely established, suffice for all movements.”

    -Pierre Louis Maupertuis (1746)



  5. A Foucault pendulum in a hermetically sealed vacuum bunker is elegant. How does it know?

    That the universe as a whole is irrotational is counter to everything we observe about large scale dynamics.

  6. The long acting range of electromagnetism and gravity suggests a connection, as Feynman pointed out. However little has come out of that theoretically because physics theorists continue to use the paradigm from the standard model that clusters the weak force, the strong force, and electromagnetism together.

    Physics should start thinking about a new mechanism where not only electromagnetic and gravititational forces are combined through long distances, but also that the strong force is also combined with them as entanglement over long distances. The obvious connection between all three would be the pathway paradigm within a more fundamental medium. Those pathways might create a force whose strength would be a result or the level of of order between two distant particles. The quantum vacuum energy is the obvious candidate for that fundamental intermediary medium.

  7. Great post but I'm a bit uncomfortable with all this 'smart people' stuff so beloved of The Edge - it's the same story with the book Brockman has recently edited.It's not just the elitism that bothers me, it's more that most of my heros in physics neither sought nor received fame, but their work is highly respected by those in the know (Think Arthur Jaffe or Julius Wess or my late father Lochlainn). Hurrah for the obscue ones!

  8. Hi Cormac,

    I think Brockman isn't trying to collect the best physicists alive. He is trying to collect some intellectuals, and his collection is also US-centered. To some extend it might be an attempt to gather some bright people in dark times and shine a light on them to say, look, we're not all overweight dummies who believe in creationism and that the sun goes around the earth. In any case, what I'm saying is, in my eyes this is really a club-of-people-Brockman-likes rather than an elite of something in particular. I think it's well done though. Best,


  9. Hi Bee,

    Where exactly in this paper you explain why the detection of gravitons isn't equivalent to evidence for quantum gravity?

  10. Hi Giotis,

    The whole paper is a summary of examples for evidence of quantum gravity that are not detections of gravitons. Best,


  11. OK I see...

    I misunderstood then. I thought you were saying that if somehow we confirm that gravitons exist this would not mean necessarily that gravity is quantized.

  12. Sorry for this misunderstanding. No, that's not what I meant. I meant, you don't need to detect a graviton to find evidence for quantum gravity. Much like you could argue that you don't need to detect a single photon to have evidence for quantum mechanics. I haven't made up my mind on Dyson's "hypothesis" that gravitons can't be detected at all. Sometimes I think he's right, then again I think he is wrong. Either way, I doubt anybody will detect a graviton within my lifetime.



  13. Hi Phil,

    Your comment makes me realize that nobody mentioned Feynman's path integral, which I think would have deserved a place among the elegant principles too. Best,


  14. My favorite deep explanation: Niels Bohr's formulation of quantum complementarity.

    My favorite elegant explanation: Occam's Razor.

    My favorite beautiful explanation: "De Rerum Natura" by Lucretius.

  15. Physics should start thinking about a new mechanism where not only electromagnetic and gravititational forces are combined through long distances, but also that the strong force is also combined with them as entanglement over long distances. The obvious connection between all three would be the pathway paradigm within a more fundamental medium. Those pathways might create a force whose strength would be a result or the level of of order between two distant particles. The quantum vacuum energy is the obvious candidate for that fundamental intermediary medium.

    Another way to think about the relative strengths of the different forces is in terms of the energy required to create order, i.e., to reverse entropy. If pathways are created within a medium the level of refinement and order not only would determine the effort to communicate via the pathway in terms of time and energy, but it would also effect the cost in terms of energy to create that pathway. Similar to the effort to create a superhighway versus a line in the dirt drawn
    with a stick.

    This is a good way of thinking about the strength of different forces and why such tremendous energy is encapsulated in the strong force. That is why perfect entanglement tends to only occur on the small scale. However I believe that incomplete and imperfect entanglement occurs all the time to each of us and then disappears like a puff of smoke as quickly as it appeared.

  16. Dense aether model is not deep, elegant, or beautiful explanation. It just works.


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