Tuesday, October 9, 2018

Lost in Math: How Beauty Leads Physics Astray I

In order to have some idea of what is going on in physics, I periodically read popular books on the subject. I read A Brief History of Time, by Steven Hawking, in 1988. Later, I read Brian Greene's The Elegant Universe. More recently, I read To Explain the World, by Steven Weinberg, and The Big Picture, by Sean Carroll. When I was growing up in the 1960's, physics was the preeminent science, and biology hadn't yet made its ascent. Einstein was alive until 1955, atomic weapons were perceived as a greater threat than they are now, Wernher von Braun, the original "rocket scientist," was working for NASA, Richard Feynman was still active, space exploration became a national priority under John F. Kennedy, and the standard model of particle physics was established. Physics had the aura of attracting the smartest people, and I thought that I should pay attention to what physicists had to say. With a slowdown in its progress, you don't hear as much about it now, except perhaps in cosmology, which is not a widely-followed subject.

Sabine Hossenfelder, a theoretical physicist, has written a unique and interesting critique of current practices in the field. She melds conventional popular science writing, such as interviews with top physicists, with her concerns about how research is being conducted and a blog-like openness about the bleak career prospects for physicists like herself. Her primary idea is that concepts such as beauty, elegance, symmetry and naturalness have subverted the scientific method in physics, whose practitioners increasingly create mathematical theories that have no obvious connection with empirical data. There is a dearth of new data, and this seems to have led to a kind of paralysis. The primary case in point is the failure of the Large Hadron Collider, operated by CERN near Geneva, to find interesting new particles other than the Higgs boson, which was first hypothesized in 1964 but not confirmed until 2013. Progress in the field of theoretical physics has been so slow that a researcher might easily spend an entire career without proving anything, perhaps working on a theory that ends up being abandoned. Moreover, as Hossenfelder interjects periodically, there isn't much job security except for a handful of rock-star physicists.

I like the fact that Hossenfelder's interviews read like real shop talk between physicists, but she engages in some deceptive oversimplification, in the sense that words such as "symmetry" and "naturalness" actually have specialized meanings that are more intelligible to PhD physicists than to lay readers. Books like this breeze past advanced mathematics in a way that might cause some readers to become ridiculously overconfident. Even so, as far as I've read (halfway), she has made a compelling case for some of the sociological factors affecting the behavior of the physicists in question, which mirrors what I have said about academics in other fields such as economics and creative writing. Academics in all fields are likely to continue the themes that they wrote about in their theses for the remainders of their careers, like broken records.

Speaking of music, Hossenfelder touches on some biological aspects of humans that show up in their preferences. Citing a 1975 study by physicists which finds that all popular music is similar with respect to maintaining a balance between predictability and unpredictability, her interpretation is that we like to be surprised, but not too much. This concept of humans preferring material that balances familiarity with novelty applies not only to music, but to all of the arts and even the sciences. To that I would add the psychological effects of advertising. I have long been puzzled why people pay attention to advertising. In this context, the answer is that the product being sold, whether a retail item or a politician, is unconsciously planted in people's brains as something that is familiar and safe, whether it is or not. Hossenfelder argues that the current generation of physicists, which grew up with the concepts of simplicity, naturalness and elegance, is having a hard time embracing real novelty, and that it has inadvertently sidelined the scientific method, which itself holds none of these prejudices.

There is another aspect of human behavior that I've been thinking about that Hossenfelder hasn't mentioned yet. This has to do with mate selection. Our conceptions of beauty are probably affected by our instincts regarding the identification of suitable mates. As I recall, a symmetrical face is preferable to an asymmetrical face, since it suggests genetic fitness. Similarly, there are universals in what constitutes the shape of a beautiful woman's face. And, of course, fertility goddesses are an indication of what people think a fertile woman's body might look like. I've only read about this anecdotally, but research has been done. Thus, it isn't a stretch to say that theories involving symmetry and curvature may literally appeal to physicists on the basis of their sexiness rather than on more objective scientific criteria. When you think about it, calling an idea or theory sexy when it has nothing to do with sex is really quite absurd.

Hossenfelder is quite a talented writer, and I like her dry, self-deprecating humor:

...I find a door that reads "Prof. Steven Weinberg." I peek in but the professor hasn't arrived yet. His secretary ignores me, and so I wait, watching my feet, until I hear steps in the corridor.

"I'm supposed to speak to a writer now," Weinberg says, and looks around, but there's only me. "Is that you?"

Always keen on new opportunities to feel entirely inadequate, I say yes, thinking I shouldn't be here, I should be at my desk, reading a paper, drafting a proposal, or at least writing a referee report. I shouldn't psychoanalyze a community that neither needs nor wants therapy. And I shouldn't pretend to be something I'm not.

Weinberg raises an eyebrow and points to his office.

His office, it turns out, is half the size of mine, an observation that vaporizes what little ambition I ever had to win a Nobel Prize. I don't have, of course, all those honorary titles on the wall. Neither do I have my own books to line up on my desk. Weinberg has now made it up to a dozen....

So I'm finding the book both informative and entertaining, and I'll make more comments when I've finished it.

No comments:

Post a Comment