Repeat After Me: Particle Physics Is Not All of Physics

The very last section of the book-in-progress (at least the draft that's with my editor right now...) is titled "Science Is Never Over," and talks about how there are a nearly infinite number of phenomena that you can investigate scientifically. The universe is a never-ending source of amazement and wonder, with surprisingly rich dynamics in the simplest of things. I mean, look at the thousands of words I've gotten out of talking about sticky tape...

This is why I sigh heavily whenever I see a title like Ashutosh Jogalekar's "Should Physicists Stop Looking for Fundamental Laws. This is, at least, a slightly different twist on the theme, but it's always the same story at the core: the search for the Ultimate Theory of Everything has run into some sort of snag (in this case, the latest round of multiverse speculation), and thus Physics is in crisis (in this case, it's turning into biology). Because, of course, high energy theoretical physics is all the physics there is.

Except it's not. If you look at the unit membership statistics for the American Physical Society, you'll see that the Division of Particles and Fields is fairly substantial-- around 3,500 members-- but only the second largest division in the APS. The largest is the Division of Condensed Matter Physics, with over 6,000 members, and my own home Division of Atomic, Molecular, and Optical Physics is not far behind the particle physicists, with just over 3,000 members.

And, in fact, that almost certainly overestimates the number of people working directly on a Theory of Everything. The fact is, the physicists whose work is genuinely in crisis as a result of recent developments (or, more accurately, the lack thereof) are a tiny minority of professional physicists. They're vastly overrepresented in the media, in large part because wildly speculative stuff about multiple universes is sexy and provides lots of opportunities for stoner-friendly CGI, but if they all got sucked into a black hole tomorrow (thus settling the "firewall" debate for good and all), physics as a whole would continue on with barely a hiccup.

I sort of hate to pick on Jogalekar about this, because his piece is better than a lot of the dreck that clogs this particular genre of pop-science. The biology analogy and the stuff about historical contingency is pretty original, and well written, like basically everything on that blog. If he doesn't have a book deal, somebody should give him one.

But the thing is, the vast majority of physicists are already comfortable taking the precise value of the electron charge as just one of those historical contingencies that you have to accept and get on with your day. Most of us are not actively and directly engaged in the search for ever more fundamental laws. The principles governing the systems I study were pretty well nailed down by 1950, and the core ideas of condensed matter are of similar vintage. And that doesn't stop the many thousands of members of DCMP and DAMOP from having rich and rewarding careers.

Physics will never be over, because science is never over. Even if we never again discover another testable fundamental principle, that's not a problem because we're not even close to exhausting the ones we already have. Theoretical particle physics has had a rough couple of decades, to be sure, but they're not the whole story, not by a long shot. And I wish more writers were more careful about recognizing that.

UPDATE: Some further discussion here.


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Chad: "This is, at least, a slightly different twist on the theme, but it’s always the same story at the core: the search for the Ultimate Theory of Everything has run into some sort of snag (in this case, the latest round of multiverse speculation), and thus Physics is in crisis (in this case, it’s turning into biology)."

This is deeply insulting to biology which is an empirical science unlike the multiverse bs.

I would argue that the last couple of years have seen major triumphs for theoretical particle physics. They found the Higgs boson, and they found the properties of the Higgs boson to be entirely consistent with the Standard Model. I wouldn't object to anyone calling that the biggest physics breakthrough of the 21st century (so far)--it certainly belongs in the top five.

It's true that theoretical particle physics has some issues. Many man-years of effort have been poured into the thus far fruitless search for a self-consistent theory of quantum gravity, and there is no evidence that we're any closer to solving that problem than we were when I first heard of the problem, mumblety-mumble years ago. But as you say, this affects only a minority of particle physicists, and the impact in other subfields is between minimal and nonexistent.

By Eric Lund (not verified) on 22 Jan 2014 #permalink

"there are a nearly infinite number of I fail to perceive how "nearly" operates here, even assuming Aleph_zero.

I have a problem with the "Fundamental Law" idea. There are certain things that scientific models have to be consistent with, but I think its us who are calling things fundamental.

There could be all sorts of "rules of nature" that work at different levels. Computational effort hierarchy rules, like the rules governing computability and things like Shannon's models of information transfer seem to be fundamental rules of nature with testable consequences. How many more things like that are there? and which iaremore fundamental? These are also rules that any physical model should have no disagreements against, and if they do I would consider that new physics on par or even more important than finding, say, super-partners of existing particles.

Amen to Chad's post and comments 1, 2, and 4.

I'm not sure I would count the experimental discovery of a particle whose existence was predicted in the 1960's as a recent triumph of theoretical physics...

Having your theory confirmed by experimental data is ALWAYS a triumph for theorists. However, I will grant that the triumph is more about the individuals than about current work.

OTOH, while the Standard Model goes back to the 1970's, people have continued to do lots of work on understanding it, refining its predictions to greater precision, understanding what sorts of observations could be used to clearly distinguish between the SM and other theories, etc. The fact that so many different types of experimental data can be clearly interpreted as supporting the SM is based in part on more recent work by theorists.

Well, the "crisis in physics" view comes somewhat out of the Rutherfordian view of the world: "It's either physics or stamp-collecting".

While you think you're doing physics, Chad, to a "Rutherfordian" perspective it's really stamp collecting. "The principles governing the systems I study were pretty well nailed down by 1950, and the core ideas of condensed matter are of similar vintage." So if you're not determining the core ideas, what are you doing? Stamp collecting: "We know how Cesium behaves in this system, but how about Rubidium?" There's less historical accident involvement than biology, but it's still stamp collecting to some extent.

It strikes me that, with the exception of a few logicians and phenomenologists with whom most of their own community disagree in this regard, particle physics is the only modernist academic enterprise left. Everyone else has gone post-modernist. Not only have we all gone to doing stamp collecting, we now believe that there cannot be such a thing as a central idea (though there can be connecting ideas), so only stamp collecting is possible.

By quasihumanist (not verified) on 22 Jan 2014 #permalink