Pointless particles
September 26, 2022 2:33 AM   Subscribe

'No one in physics dares say so, but the race to invent new particles is pointless' by astrophysicist Sabine Hossenfelder, writing in the Guardian.
posted by tavegyl (57 comments total) 18 users marked this as a favorite
 
We have particles at home.
posted by MetaFilter World Peace at 5:09 AM on September 26, 2022 [36 favorites]


The next time someone wants to complain about Star Trek making up particles, I'll cite this:
Since the 1980s, physicists have invented an entire particle zoo, whose inhabitants carry names like preons, sfermions, dyons, magnetic monopoles, simps, wimps, wimpzillas, axions, flaxions, erebons, accelerons, cornucopions , giant magnons, maximons, macros, wisps, fips, branons, skyrmions, chameleons, cuscutons, planckons and sterile neutrinos, to mention just a few. We even had a (luckily short-lived) fad of “unparticles”.
"Reversing the polarity of the plasma injectors" doesn't sound so dumb after all.
posted by Halloween Jack at 5:30 AM on September 26, 2022 [15 favorites]


Particles at home: [picture of plum-pudding model]
posted by phooky at 5:32 AM on September 26, 2022 [6 favorites]


Sounds like something an astrophysicist would say.
posted by polytope subirb enby-of-piano-dice at 5:51 AM on September 26, 2022 [1 favorite]


Particle Man

I’m hoping some actual physicists show up and share their thoughts on this. It could turn into a really interesting discussion.
posted by TedW at 5:52 AM on September 26, 2022 [2 favorites]


Compare and contrast pure research and applied science....
posted by seanmpuckett at 6:01 AM on September 26, 2022


paging PhysicsMatt
posted by lalochezia at 6:03 AM on September 26, 2022 [2 favorites]


oh the irony (emphasis mine below)

This procedure of inventing particles and then ruling them out has been going on so long that there are thousands of tenured professors with research groups who make a living from this

citation fucking needed.
posted by lalochezia at 6:05 AM on September 26, 2022 [7 favorites]


Um... maybe this is an uneducated opinion, but.. I thought they were discovered.. not invented?

Ok..
posted by VyanSelei at 6:06 AM on September 26, 2022 [1 favorite]


They have played us for absolute fools
posted by crocomancer at 6:08 AM on September 26, 2022 [8 favorites]


Um... maybe this is an uneducated opinion, but.. I thought they were discovered.. not invented?

The ones she's talking about are theorized in hopes that they might be discovered, but they haven't been found.

The thesis here is that it's relatively easy to theorize a particle and then spend time ruling it out, but not actually particularly useful: there are so many plausible ways to construct a particle on paper that you could spend forever just theorizing particles and ruling them out without ever actually expecting to find anything.
posted by BungaDunga at 6:20 AM on September 26, 2022 [11 favorites]


Not long before I went mad in 2000, it occurred to me that humanity was composed of morons interacting via the exchange of kōans.

I remember being quite pleased by that thought. Be careful with it, it might be dangerous.
posted by flabdablet at 6:22 AM on September 26, 2022 [16 favorites]


YouTube will not stop recommending me her videos, and there are a lot of them, and they all say "I'll tell you the secret thing that no one else will, that reveals all physics to be baloney!" It's VERY clickbaity, and I find she has a real Dr. Oz Only Physics vibe, but I don't know enough about physics to know whether that's fair. But my understanding is that we can't directly observe ANY quantum particles, and can only infer their existence by the way they interact with things, which a lot of them mostly don't. So theorizing the existence of a particle, and then checking the math to see if the world behaves as if that particle exists, is more or less what we do with ALL quantum particles, no? Again, I'm not a physicist, not even an amateur one, but I'm also a bit skeptical of Dr. Hossenfelder just because of the way she comes off in her videos...
posted by Sing Or Swim at 6:40 AM on September 26, 2022 [11 favorites]


I would like to take this opportunity to propose the Hossenfelderon, a quasi-particle whose effective action is evidenced by questioning the value of other theoretical particles.
posted by jabah at 7:07 AM on September 26, 2022 [4 favorites]


Are we going to rely on the same old overexposure to the same old boring particles to generate our new legions of superheroes?
posted by dances_with_sneetches at 7:14 AM on September 26, 2022 [3 favorites]


Seems I just read an astrophysicist saying that particle physics was one of the greatest boons to astrophysics.
posted by Goofyy at 7:41 AM on September 26, 2022


my understanding is that we can't directly observe ANY quantum particles, and can only infer their existence by the way they interact with things, which a lot of them mostly don't. So theorizing the existence of a particle, and then checking the math to see if the world behaves as if that particle exists, is more or less what we do with ALL quantum particles

Technically, seeing something interact with something else is what direct observation is. It's all quantum particles down at the bottom, when you see a detector go ping that's a particle interaction. She's talking about particles that have been theorized, hunted for, then ruled out.

I believe her argument is that these theorized particles aren't particularly well-motivated, and since the space of particles that could exist is large, you wouldn't expect most of them to ever pan out. So she's arguing that this method of generating hypotheses is a waste of time, like digging holes for treasure when you really don't have a good idea of where to look. That's why she likens it to "an army of typewriting monkeys"- not a particularly productive way to generate literature.
posted by BungaDunga at 7:44 AM on September 26, 2022 [4 favorites]


If we weren’t making up particles that turn out not to exist, we could be pretty certain we weren’t making up enough particles to catch the ones that do exist.
posted by jamjam at 7:54 AM on September 26, 2022 [1 favorite]


Can someone explain this to me? Like does math "prove" there might be particles and then scientists go out trying to find them through experiments?
posted by geoff. at 8:13 AM on September 26, 2022 [2 favorites]


I am but a poor and simple planetary astronomer, but this:

All experiments looking for those particles have come back empty-handed, in particular those that have looked for particles that make up dark matter, a type of matter that supposedly fills the universe and makes itself noticeable by its gravitational pull. However, we do not know that dark matter is indeed made of particles; and even if it is, to explain astrophysical observations one does not need to know details of the particles’ behaviour.

and this:

In some cases, the new particles’ task is to make a theory more aesthetically appealing, but in many cases their purpose is to fit statistical anomalies. Each time an anomaly is reported, particle physicists will quickly write hundreds of papers about how new particles allegedly explain the observation. This behaviour is so common they even have a name for it: “ambulance-chasing”, after the anecdotal strategy of lawyers to follow ambulances in the hope of finding new clients.

sound like... how you do science? You try to come up with explanations for observations that are consistent with the rest of the physics that we know. I suppose she's arguing that somehow, the bar is too low, and that the Wrong People are getting paid to look for the Wrong Explanations, but I would, at minimum, label this as a spicy take.
posted by BrashTech at 8:15 AM on September 26, 2022 [6 favorites]


I taught an undergrad course on dark matter and dark energy--am an astrophysicist (though teaching crowds out time for research!) I think some of Sabine's skepticism has in the past come from a good place. Superstring theory crowded out alternative approaches for decades and there is hardly any contact it makes with experiment. I need to rtfa as they say, but I'm pretty sure she has been especially skeptical recently of theories of particle dark matter.

Summary: we have evidence for dark matter from its gravitational influence. There's a minority position (called MOND for Modified Dynamics) that thinks there IS no (or little) dark matter. Instead we need to correct our law of gravity, general relativity. One version of MOND suggests just as pre-relativity physics broke down near light speed, that there's a special acceleration below with which the laws of gravity and motion need to be patched up or they'll give the illusion of dark matter.

MOND actually does a somewhat better job of describing how galaxies rotate, but the reason it's a minority view is:

1) The Bullet Cluster and similar structures. Collisions of entire galaxy clusters show that gravity (which causes "gravitational lenses") comes from a different place than the known mass of the cluster, which is in hot gas visible to X-ray telescopes. This is hard for MOND to explain.

2) The ripples in the Cosmic Microwave Background Radiation can be explained by a similar amount of dark matter, and are hard to explain with MOND

To better explain features of galaxies (where otherwise MOND has an edge) some are guessing at an entire "dark sector" of multiple particles. This might seem extravagant. Easy to compare with "epicycles", patching up a faulty theory by needless complexity. Yet... the alternative to epicycles, elliptical orbits, was itself chosen out of myriad other geometric shapes and introduced eccentricity and orientation parameters to be adjusted for each orbit as well.

Had we (Paul Dirac) not figured out antimatter, we would have missed out on about half of what's possible. It doesn't seem counter to good scientific practice to me to try out more possibilities when one is stuck. Make everything as simple as possible, but not more simple than possible. Sometimes nature itself is extravagant and sometimes it's hidden from us. Could too many hypotheses make it so that the correct one gets lost or its success is chalked up to luck? Sure, but if it's really right we'll end up with more and more successes in explaining different problems.

I asked my students at the end of the semester whether they preferred dark matter or MOND and they all preferred dark matter. They were mystified though that it hadn't turned up in direct detection experiments.

I quoted Sherlock Holmes to my students, that once one has eliminated the impossible, what remains, no matter how improbable, must be the truth.
posted by Schmucko at 8:16 AM on September 26, 2022 [25 favorites]


It's VERY clickbaity, and I find she has a real Dr. Oz Only Physics vibe

From the videos of hers that I’ve seen, I think she’s indeed quite skilled at generating clickbaity video titles and thumbnails, but overall she appears (to me) to be a genuine science communicator.

I’ve never seen any content that was genuinely wrong or misleading (although I’m more of an educated physics “enthusiast” than anything) so I think she’s just attempting to communicate some cutting edge, interesting ideas as widely as possible, which if you’re making YouTube videos means you need to game your titles and thumbnails for the almighty algorithm…
posted by Nutri-Matic Drinks Synthesizer at 8:18 AM on September 26, 2022 [8 favorites]



In the past, predictions for new particles were correct only when adding them solved a problem with the existing theories. For example, the currently accepted theory of elementary particles – the Standard Model – doesn’t require new particles; it works just fine the way it is. The Higgs boson, on the other hand, was required to solve a problem. The antiparticles that Paul Dirac predicted were likewise necessary to solve a problem, and so were the neutrinos that were predicted by Wolfgang Pauli. The modern new particles don’t solve any problems.

Back in MY day the theoretical particles solved problems and did stuff, and got jobs like a real particle would.
posted by shenkerism at 8:22 AM on September 26, 2022 [7 favorites]


sterile neutrinos - obviously these don't exist. At least, not anymore.
posted by piyushnz at 8:34 AM on September 26, 2022 [2 favorites]


Back in the hippie physics days, I remember somebody saying that blah blah Copenhagen Interpretation blah blah Niels Bohr blah blah… That only when the mathematics says particle X exists, do we discover particle X. There was the implied statement that until we can think about a particle that we can find it, meaning our thoughts sort of conjure it into existence. Maybe it was David Bohm, I don’t know. But epistemologically speaking, shouldn’t we have some clues as to what may be out there, before we can see it out there? Given that particle physics seems to have a math first, then experiment later approach, with the math giving us clues about what we might see, then proposing particles at least gives us something to look for. Or a way to see patterns in that onslaught of data points when particles collide. But… we should know enough that the time spent isn’t all wasted in designing unicorn traps and ghost detectors.
posted by njohnson23 at 9:02 AM on September 26, 2022 [1 favorite]


I'll dive in on this a bit: the default language particle theorists have been trained in for the past half century or so is quantum field theory. In this framework, when you propose a new piece of physics, it appears as a new particle. You stick in the relations among particles as symmetry groups. So if you sit down with some goal like, "can I unify these two things?" it's going to show up as introducing new particles and symmetry groups among them.

This approach began as anathema (Pauli introducing the neutrino speculatively was shocking), then was enormously successful for decades as the particle zoo was mapped out, and so you have a couple generations for whom this framework has been their entire professional lives. It's still producing some interesting work for modeling exotic condensed matter systems, so it's not fully tapped out. But most of the people Hossfelder is railing against don't have the background or training to try to put together alternative structures.
posted by madhadron at 9:55 AM on September 26, 2022 [8 favorites]


I feel like the validity of the question (maybe this kind of physics is crap?) leads into a kind of mid-life crisis-ish questioning of society. Remember a while ago, when Uber found out that a huge part of its advertising budget had been scammed, or when Facebook demanded everybody make videos and so lots of places hired videographers? And this is before we get to the telephone sanitising engineers or whatever.

Frankly we have to pay people to do something. It’s better to have all the intelligent people in one place so they can invent something like Velcro or the internet, rather than force them to stack pallets in the local supermarket. Of course, you could always question why we don’t just give them a stipend and say “please do smart things” but then you’re going to run into questions like “why does funding go to large institutions” and “why is this kind of hierarchical power structure constantly replicating itself” but these are questions outside the STEM/STEAM remit. Good luck with that; it’s very unpopular with large hierarchical organisations who have lots of funding.
posted by The River Ivel at 9:56 AM on September 26, 2022 [1 favorite]


The author seems to compare the confirmed survivor particles from the thirties to the sixties (neutrinos, antiparticles and the Higgs boson) with unconfirmed proposed particles. Perhaps it would be more symmetric and conserve everyone's energy to examine the alternative explanations proposed to address the problems that antiparticles, neutrinos and the Higgs mechanism/boson solved. I suspect there were many ideas at the time and there were also people complaining about those proposals. Wikipedia on the Higgs mechanism seems to say it took a few years to outcompete other explanations and become part of the standard model.

At least two of the proposed particles on the list are accepted as solving problems rather than just accounting for a statistical anomaly.

Wikipedia on sterile neutrinos:
Experimental results show that all produced and observed neutrinos have left-handed helicities (spin antiparallel to momentum), and all antineutrinos have right-handed helicities, within the margin of error.[3] In the massless limit, it means that only one of two possible chiralities is observed for either particle. These are the only helicities (and chiralities) allowed in the Standard Model of particle interactions; particles with the contrary helicities are explicitly excluded from the formulas.[9]

Recent experiments such as neutrino oscillation, however, have shown that neutrinos have a non-zero mass, which is not predicted by the Standard Model and suggests new, unknown physics.[10] This unexpected mass explains neutrinos with right-handed helicity and antineutrinos with left-handed helicity: Since they do not move at the speed of light, their helicity is not relativistic invariant (it is possible to move faster than them and observe the opposite helicity).[11] Yet all neutrinos have been observed with left-handed chirality, and all antineutrinos right-handed. (See Chirality (physics)#Chirality and helicity for the difference.)

Chirality is a fundamental property of particles and is relativistically invariant: It is the same regardless of the particle's speed and mass in every inertial reference frame.[12] However, a particle with mass that starts out with left-handed chirality can develop a right-handed component as it travels – unless it is massless, chirality is not conserved during the propagation of a free particle through space.

The question, thus, remains: Do neutrinos and antineutrinos differ only in their chirality? Or do exotic right-handed neutrinos and left-handed antineutrinos exist as separate particles from the common left-handed neutrinos and right-handed antineutrinos?
And axions:
An axion (/ˈæksiɒn/) is a hypothetical elementary particle postulated by the Peccei–Quinn theory in 1977 to resolve the strong CP problem in quantum chromodynamics (QCD). If axions exist and have low mass within a specific range, they are of interest as a possible component of cold dark matter.
This hits my clickbaity detectors as well.
posted by Emmy Noether at 10:33 AM on September 26, 2022 [2 favorites]


inhabitants carry names like [...] simps, wimps, wimpzillas

Same. :(
posted by Pyrogenesis at 10:35 AM on September 26, 2022 [7 favorites]


Everybody wants scientific studies that show surprising, counterintuitive insights and discoveries.

Nobody appreciates the scientific studies that show links don't exist, that A does not cause B, or merely reproduces the results of another study.
posted by AlSweigart at 10:42 AM on September 26, 2022 [4 favorites]


I agree with Emmy Noether (a safe bet when it comes to particle symmetries ;-) ) on neutrinos and axions being motivated. Before superstrings started to disappoint so many in not passing empirical tests and becoming more baroque with a "landscape" of universes, the idea of supersymmetric partners turning up seemed likely to many.

But neutrinos and antiparticles were out there to find even if we had lacked the insights of Dirac and Pauli.

In physics history, there's also the "who ordered that?" response to the discovery of the muon (comment over the shared Chinese food the physicists would go out for). Coherent theory didn't predict the "generations" of particles.

I think Hossenfelder is sincere but has an aesthetic bias here. Some scientist puts forward an idea and then another can modify it, or synthesize with another idea. It's messy and we don't know where it will lead. The investment of resources in theorizing is minimal though.
posted by Schmucko at 10:51 AM on September 26, 2022 [4 favorites]


I thought they were discovered.. not invented

does math "prove" there might be particles and then scientists go out trying to find them

in the 50s and 60s there was a real particle zoo . Hundreds of possible 'elementary ' particles were being 'discovered'
Nobody was happy with this. it seemed absurd.

A mathematical model proposing that the "elementary " particles were themselves a result of combinations of something more elemental.
The elegance and simplicity of Quarks meant that model was accepted .
Proof of the existence of the top quark took almost 30 years later.

So in a way .they were "invented" first.
posted by yyz at 10:53 AM on September 26, 2022 [3 favorites]


>The investment of resources in theorizing is minimal though.

Yeah--Part of what I was clumsily trying to say earlier is that the evidence of these particles is often extremely scant. We're looking we know not where for we know not what. The theoretical stuff is to give us an idea where to start. It's like saying 'well, if there was an animal we've never seen living here, would it live in a burrow? in a tree? what would it eat and where would we see its pawprints?' It's not as good as having the critter itself in a cat carrier, but it's not necessarily a bad place to start.
posted by Sing Or Swim at 11:19 AM on September 26, 2022 [4 favorites]


the bar is too low, and that the Wrong People are getting paid to look for the Wrong Explanations, but I would, at minimum, label this as a spicy take

We have a few cranks like this in genomics, who in my opinion seem more upset at grant monies being handed out to the Wrong People they don't like, than at the prospect of bad science being done.

I'm not a particle physicist, but I'd have to question the writer's thesis that experimental validation is being done that is statistically equivalent to looking for spiders on Mars.

I'd wager that the folks running the particle detectors and planning experiments are not idiots and have a good idea of the probabilities involved, scheduling equipment and analysis time on the basis of what is at least potentially discoverable, as well as interesting.

Filling in existing physics models is fine, but those models are incomplete. So if we have more data and more verified particles, new theoretical models will be more complete -- better, in other words. I don't immediately see how that's a bad thing.
posted by They sucked his brains out! at 1:16 PM on September 26, 2022 [2 favorites]


I would like to take this opportunity to propose the Hossenfelderon, a quasi-particle whose effective action is evidenced by questioning the value of other theoretical particles.

Is that in the same family as the mefion, which mediates the snark and grar forces?
posted by dephlogisticated at 1:17 PM on September 26, 2022 [4 favorites]


Forget it, Jake, it's Speed Force.
posted by Naberius at 1:35 PM on September 26, 2022 [2 favorites]


Hossenfelder is indeed a real and accomplished physicist, currently teaching at the Frankfurt Institute of Adanced Studies. She's not a crank, but is definitely something of a contrarian in her field. It's become her shtick, she's basically been re-writing the same article over and over for about a decade. Essentially, a big problem with physics from the human perspective is that it's messy. It has all kinds of weird exceptions, and deals with fundamentally quantities that seem arbitrarily incommensurate with each other. It's not orderly the way you'd expect a universe constructed by The Supreme Geometer to be. Like for example, why is the gravitational constant such an odd number: 6.674×10−11 m3⋅kg−1⋅s−2? If it's going to be fractional it seems like it ought to be an even 6.666 but it's off by a small amount. Now in the past, physicists have been able to use these little inconsistancies as clues to explore a deeper symmetry that existed. And that occasionally led them to finding new particles, even winning Nobel Prizes.

Hossenfelder's argument is that physicists have become too enamored of that same trick, namely, examining little unexplained inconsistencies and looking for new particles that explain away the inconsistency and find a deeper symmetry. It worked very well in the past, leading us to the entire particle zoo that we've discovered so far. But the easy gains are over, it's been years since any new fundamental particles have been discovered (the pentaquark may be "new" but not "fundamental" in this sense), and now she think this well of discovery is bone dry. She thinks faith in underlying symmetry has become less of a science and more of a religion. And, like other religions, the leaders are sucking up money that could be better spent elsewhere. And not only that, but there's been a brain drain of the most creative thinkers suckered into a quixotic quest for a Theory of Everything, in the same way that many great minds have been wasted getting caught up in the study of apocrypha and numerology. Maybe, she argues, it's all for naught; at a fundamental level the universe is simply messy and asymmetrical, and that's all there is to it.

Mind you, she has her own share of fringe ideas, so as much as she positions herself above the fray, nobody's immune.
posted by xigxag at 1:57 PM on September 26, 2022 [16 favorites]


Since the 1980s, physicists have invented an entire particle zoo, whose inhabitants carry names like preons, sfermions, dyons, magnetic monopoles, simps, wimps, wimpzillas, axions, flaxions, erebons, accelerons, cornucopions , giant magnons, maximons, macros, wisps, fips, branons, skyrmions, chameleons, cuscutons, planckons and sterile neutrinos, to mention just a few. We even had a (luckily short-lived) fad of “unparticles”.

A substance named "unobtanium" is about the most plausible thing in the entire movie Avatar.
posted by straight at 2:04 PM on September 26, 2022 [2 favorites]


Having followed her for years, I agree Hossenfelder is just a prickly contrarian and not a crank, but this op-ed seems very misguided, because the criticism is properly aimed at physicists, and writing for a general audience forces it to be oversimplified to the point where it can’t meaningfully convince anyone of anything they don’t already know. And yes, you might say “isn’t that just how science works?”

Anyway, of course the people actually doing particle experiments are not idiots. Her criticism is aimed at theorists, who are able to crank out endless papers about specific models that may check off the box of being testable in principle, but (a) may have dubious motivation to begin with (anomaly “ambulance chasing”), (b) are unlikely to ever be testable in practice, or (c) not really predictive because they have too many tunable parameters.

For instance, here is a paper posted to the arXiv today. It calculates a spectrum of gravitational waves that might be observable due to a phase transition in the early universe caused by a particular model of self-interacting dark matter with one particle and one field. In some of the model’s parameter space, the gravitational waves would be unobservable even in principle. And as far as I can tell, it doesn’t address questions like, how could we distinguish different dark sector models based on the observed GW spectrum, or any other observational evidence? (Disclaimer: not a physicist, might be dumping on these people’s work unfairly.)
posted by mubba at 4:09 PM on September 26, 2022 [2 favorites]


Relatedly:

Quanta had an interesting article about another response to the "crisis in particle physics" caused by the LHC not finding evidence of supersymmetry: "For three decades, researchers hunted in vain for new elementary particles that would have explained why nature looks the way it does. As physicists confront that failure, they’re reexamining a longstanding assumption: that big stuff consists of smaller stuff."
posted by BungaDunga at 4:51 PM on September 26, 2022 [1 favorite]


Mind you, she has her own share of fringe ideas, so as much as she positions herself above the fray, nobody's immune.

In fairness to Hossenfelder, that article by Kastrup seems to be criticizing a notion of superdeterminism that is not what Hossenfelder endorses, at least not as I understand it. Kastrup writes:
Let us use a metaphor to illustrate what we are being asked to believe. When I take a picture of some celestial body in the night sky—say, the moon—I can set my camera in a variety of different ways. I can, for instance, set aperture and exposure time to a variety of different values. What Hossenfelder is saying, in the context of this metaphor, is that there is some hidden and mysterious something about the moon that changes in response to what aperture or exposure I set on my camera. What the moon does up there in the sky somehow—we’re not told how—depends on how I set my camera here on the ground. This is superdeterminism in a nutshell and you be the judge of its plausibility.
In my understanding, that is a misrepresentation of Hossenfelder's position. Rather, Hossenfelder would argue that both the measured properties of the moon and the configuration you set on your camera depend in an unknown (possibly unknowable) way on some event(s) in their common past. And it is that joint history that explains why it appears as if setting a property on your camera determines a property of the moon at that moment. In fact, I find Kastrup's argument rather surprising, as I understand the goal of superdeterminism precisely to be avoiding the kind of spooky-action-at-a-distance in standard QM (such as seen with Bell's inequality and associated experiments) that Kastrup's metaphor seems to invoke. It is, if anything, the idea of "wavefunction collapse" in Copenhagen-style QM that leads to the idea of an observation made on the Earth having an immediate effect on a system on the Moon.

Anyway, that is to say that while Hossenfelder's superdeterminism definitely seems to be a minority position, and a pretty small minority as far as I can tell, I don't think it's "fringe" in the sense that Kastrup's article seems to suggest of being actually incoherent or unsupportable by the evidence. I'm just an amateur so I'm totally willing to concede there may be very good reasons to reject superdeterminism, but what Kastrup's attacking here doesn't actually seem to be superdeterminism as I understand it.

I do find Hossenfelder's YouTube video titles kind of clickbaity and sometimes I avoid them for that reason, but when I end up clicking through anyway, her arguments are usually actually quite sound, and her explanations unusually clear. I do think she tends to take overly extreme/simplistic positions on some things, even though I (as only an amateur whose opinion doesn't mean much) generally agree with her in principle.

In this case, while I think she's got a point about people taking mathematical flights of fancy too seriously, I think her characterization of theoretical particle physics as being overly obsessed with proposing new particles goes beyond simply uncharitable. Because of course the vast majority of new proposed particles won't turn out to exist. That's how science works. Most ideas are wrong. The question is, are they usefully wrong? Do they help contribute to a conversation about ideas that stimulates both experimentation and further model-building in ways that are productive? Hossenfelder would clearly say that in this case, the ideas being proposed within theoretical particle physics are not. Perhaps she's right, but just the fact that theoreticians are proposing a whole host of particles, most of which certainly don't exist, isn't itself evidence for that. Because it's not like each of these ideas is completely independent: they build on each other, they develop the field's understanding of the possibilities consistent with known quantum field theory.

Hossenfelder invokes the idea of infinite monkeys banging on typewriters, but particle physicists aren't just banging away at random. I'd suggest that it's more like a writer's room brainstorming for a TV show. Maybe the culture of the room is dysfunctional and isn't doing a good job of producing good ideas right now, and some good ideas aren't being considered because a few domineering personalities are controlling everyone's attention. (Or maybe not, I'm not a particle physicist, maybe things are going great and Hossenfelder's merely a contrarian without substance, though I don't have that impression.) But the fact that lots of ideas are being generated isn't itself a bad thing, and her Guardian essay seems to suggest that it is. I think what she really wants is for more diversity in the room, for ideas about alternative solutions than just introducing new particles to be given attention and resources as well. But I'm not sure that came across here.
posted by biogeo at 7:42 PM on September 26, 2022 [8 favorites]


Hossenfelder's big bugbear is 30 years of physics departments funding people theorizing supersymmetry and string theories that only seem to get more complex and less provable without a collider with a diameter of a planetary orbit. And now with discussion of the next two generations of particle accelerators going into hundreds of billions of dollars - and the LHC having proved *nothing* the theorists thought of, activity disproving a wide swath of scientific literature and leaving SUSY on a theoretical deathbed - she's campaigning against $100 billion being spent on a next-gen particle accelerator that we really don't have any specific expectations of other than "more energy=better science." At least the LCH did what was expected of it and found the (or *A*) Higgs, but that was a widely expected result of the Standard model. There's no other slam-dunk discoveries expected in the range of energies expected to be achieved - it's not quite "throwing shit at the wall and seeing what sticks" but it's not far off.

She's concerned that, after spending $100 billion on a new collider, nothing will happen, and (a) that $100 billion could have funded a lot of other experiments and (b) the purses won't open for the $200 billion accelerator that will be needed to achieve electron volts with one more exponent in the scientific notation, or for other experiments in physics that will be tainted by association with a $100 billion boondoggle giving billions to physics organizations that have been infiltrated to the highest levels by SUSY/String Theory true believers.

I don't have the scientific background to have a valid opinion about how correct she is, but I've seen enough of her videos and read enough of her articles to know that's her ultimate practical concern.
posted by phibetakafka at 8:08 PM on September 26, 2022 [15 favorites]


I think what she really wants is for more diversity in the room, for ideas about alternative solutions than just introducing new particles to be given attention and resources as well. But I'm not sure that came across here.

This is precisely how I read it, much more narrowly than many of the interpretations here. I understood her complaint to be about a one-size-fits-all solution, rather than a general complaint about uselessness of hypotheses because most of them don't pan out. I suck at coming up with analogies, but it's like as if for anything observed in nature biologists would always postulate a new gene, rather than also looking at ontogenetic and epigenetic factors, novel gene expressions, particular genetic contexts or whatever.
posted by Pyrogenesis at 10:36 PM on September 26, 2022 [3 favorites]


What the moon does up there in the sky somehow—we’re not told how—depends on how I set my camera here on the ground. This is superdeterminism in a nutshell

It's certainly a nutshell, but I detect no superdeterminism inside it.

Maybe I've got my camera set wrong.
posted by flabdablet at 1:19 AM on September 27, 2022


I liked the article, I thought it was hilarious and entertaining for a lay reader. I also think Hossenfelder makes a clear and understandable argument, she's saying that theoretical particle physics has literally zero scientific results to show, and that the cause for this is because the discipline as a whole is effectively using a bad scientific strategy of "particle reductionism" and the concern is that it is bad theoretical thinking. She concludes what's needed is a more fundamental theoretical approach rather than this piecemeal, Kuhnian-paradigmatic social process that's led to scientific stagnation in a professional discipline. Sounds new.
posted by polymodus at 2:37 AM on September 27, 2022 [2 favorites]


Since the 1980s, physicists have invented an entire particle zoo, whose inhabitants carry names like preons, sfermions, dyons, magnetic monopoles, simps, wimps, wimpzillas, axions, flaxions, erebons, accelerons, cornucopions , giant magnons, maximons, macros, wisps, fips, branons, skyrmions, chameleons, cuscutons, planckons and sterile neutrinos, to mention just a few. We even had a (luckily short-lived) fad of “unparticles”.

Science that sounds like shitposting
posted by obliterati at 10:06 AM on September 27, 2022 [1 favorite]


Physicist Peter Woit discusses the Hossenfelder article and what points he disagrees with. Sabine responds in the comments (she's a regular on his blog).
posted by indexy at 10:51 AM on September 27, 2022 [5 favorites]


Peter Woit’s blog is well worth following by the way — he’s also somewhat of a contrarian, being the author of the 2006 anti-string-theory-hype book Not Even Wrong, but the blog has plenty of non-contrarian posts about physics and math. I believe the commenter just below Sabine Hossenfelder is the Peter Shor, who invented the first quantum factoring algorithm, and other well known names like John Baez and John Preskill are also regulars.
posted by mubba at 3:34 PM on September 27, 2022


Sabine Hossenfelder just put up a more detailed blog post that is written more for scientists than the general public. With the additional context I find her argument pretty convincing as someone who cares a lot about the philosophy of science but doesn't have much background in theoretical physics. She does sound pretty irritated and I can see why other physicists would find her tone/style to be dismissive.
posted by JZig at 10:48 PM on September 27, 2022 [2 favorites]


> It's still producing some interesting work for modeling exotic condensed matter systems, so it's not fully tapped out.

where it's at!
Physics Duo Finds Magic in Two Dimensions - "In exploring a family of two-dimensional crystals, a husband-and-wife team is uncovering a potent variety of new electron behaviors."[1,2]

also btw :P posted by kliuless at 1:56 AM on September 28, 2022


Posits are not really a new kind of number. More a different kind of lossy encoding of real numbers allowing to control precision and use more efficiently the range of values afforded by 64 bits (same 8 bytes used to represent IEEE754 double precision floats).

And Hossenfelder is not just a cranky contrarian with a massive axe to grind. She's also an effective and hilarious writer. In Lost in Math she slaughters a number of sacred cows just by interviewing them and letting them speak.
posted by kandinski at 5:50 AM on September 28, 2022 [1 favorite]


Hossenfelder's new blog statement really pinpoints a general thing that I often dislike seeing in public disagreements. Calling someone a contrarian is a sort of ad hominem that is different than her accusation that the physicists are incentivized to publish or perish. The latter is structural criticism, the former is a personal attack. It's so detrimental to free inquiry and science. Anyone who has been in a position of dissent can understand how stinging and patronizing being told one's disagreeable stance is contrarianism. So it's impressive to see Hossenfelder's actions and responses when confronted by this. She could still be wrong or deeply mistaken, but the scientific profession does itself an intellectual disservice by casually spreading attacks on character and motives.
posted by polymodus at 5:59 AM on September 28, 2022 [1 favorite]


Reading Sabine's blog post. Some responses to her have bordered on the nasty, but I don't think "contrarian" is such an insult; if she is pointing to systemic problems she's still promoting herself as immune to those pressures and the mainstream as ditching real scientific motivations in favor of ill-gotten monetary gains.

I really liked her book Lost In Math, though I disagreed with some of her conclusions, and I think it was because it was structured around interviews with OTHER scientists, some mavericks, others more conventionally minded or even founders of the current order.

I think there's something a little off in the contrast between her criticism of the field as not being empirically successful but multiplying hard to confirm hypotheses, and her taking on the "measurement problem" in quantum physics with Superdeterminism (I'm still not sure exactly what that is, but there are countless interpretations of QM or reformulations that deal with the measurement problem: many worlds, consistent histories, quantum logic, transactional interpretation, objective state reduction, Bohmian theories, or as someone linked above, giving up on Unitarity.) The measurement problem has been notorious in its wishy-washy multiplication of guesses that are either untestable or have been refuted.

Maybe the problem, that we haven't made the progress in physics we used to, is not really about us humans and the way we do physics. Maybe it's about nature, what's out there, unifying quantum and gravity, explaining our signals of dark matter and energy, maybe the answer is just a larger leap from what we have now to work with than we've had in the past 100 years. Maybe there's something complicated and subtle and hard to guess out there. Maybe faced with these unknowns, there's no reliable method. Throwing things at the wall to see what sticks, experimenting blindly at higher energies, are not reliable methods but maybe there are none now.
posted by Schmucko at 8:20 AM on September 28, 2022


Counterpoint: Particle Physics Is Doing Just Fine by particle physicists Chana Prescod-Weinstein and Tim M.P. Tait.
posted by heatherlogan at 8:40 AM on September 28, 2022 [2 favorites]


The whole particle zoo comment - it is lumping in proposed tweaks to the standard model motivated by actual observations with cutesy names for trying to classify what sort of stuff might make galaxies spin like they have more stuff in them with those esoteric and very difficult to test predictions of string theory, and possibly a few other things.

It is very much rhetorically motivated and not scientifically motivated.

And it bothers me, because it's appealing to people going "technobabble, big words, ha-hah!" and not offering any education or enlightenment about physics.

So first off, the search for dark matter, the high energy physicists doing particle accelerator research, and string theory are all very different subfields in practice.

The standard model high energy physics part is trying to get a handle on everything that makes up the universe on a fundamental level, and does take a rather huge resource investment. Not only because particle accelerators that produce energies we haven't thoroughly investigated are huge and expensive, but also because it takes veritable armies of grad students and researches to do all the math to predict to the right accuracy what the current standard model does predict should happen when you messily smash two particles together at extremely high speeds.

It's trying to coax out the fundamental secrets of the universe at the very smallest levels and it is hard. Your options are to spend a lot of work chipping away at a very hard problem, or give up on understanding. I mean there is a legitimate debate that I'm not qualified to argue on about how much money should be spend on engineering and construction to make a larger particle accelerator vs. how much should be spent on theorists and computation time to make better use of the data we already have, but it's going to be an extraordinary undertaking to learn more either way. And most of it won't be grand discoveries, just a ton of fiddly moving and shuffling of jigsaw pieces and incremental maybe-progress at the edges until finally someone can step back and say "ahah!" and a bunch of stuff comes together to be a deeper understanding.

The field of dark matter on the other hand, is a lot more observational and focused on answering a specific question. In the late 60's, early 70's, an astronomer named Vera Rubin did a thorough investigation of the velocity of starts in spiral galaxies, and found something that we'd had inklings of before. Stars at the edges of spiral galaxies move too fast to be held in their orbits by the gravity from mass of the matter we can observe in these galaxies.

The theory that so far best fits observations is that there is more stuff there that we can't see - "dark matter." Literally just stuff we can't see. Now it's possible that it's not stuff but that we just don't understand gravity very well. But the things you have to do to make a theory of gravity that fits all the subsequent observations means you have to add a lot of variables you could tweak to perhaps fit near any observation, so it's not very falsifiable. Which is the exact sort of thing this article is complaining about some of these particles being!

So a lot of the effort has gone into dark matter research: saying, so if this effect is caused by stuff, what sort of stuff is it? A lot of the sillier words "simps" "wimps" "machos" are just broad stroke categorizations of properties "stuff" could have so we can narrow down what we're looking for. It doesn't really have anything directly to do with the named particles from particle physics, except that dark matter might turn out to be made of particles we already know about.

MACHOs - MAssive Compact Halo Objects: dark matter is small, dense, not very shiny rocks (pretty well ruled out by this point)
WIMPs - weakly interacting massive particles: dark matter is made of particles with mass that don't interact with light or normal matter much
SIMPs - Strongly Interacting Massive particles: WIMPs that can bump into each other, just not stuff we can see
Wimpzillas - WIMPs, but each one, is like, really heavy
etc.

Generally speaking, the approach is to make some assumptions about what dark matter is. Then we can figure out how either prove/disprove that particular property and narrow down the options for what dark matter could be. Yes it generates a lot of silly names, but it is a coherent strategy.

There's also an experimental side, which involves building detectors that are so shielded from everything we know about, they just might detect some of this weakly interacting dark matter, and we might be able to get some idea what it is.

Now in my experience string theory has a lot more cultural cachet than actual research investment. It seemed to be more that one person who might be a crazy or a genius and we don't know, but all they're asking for is a piece of paper, a pencil, and a room, and maybe they'll come up with something, or math that can be used somewhere else. So why not have a couple around? It's relatively cheap compared to experiments, especially, say, a particle accelerator. Sure, maybe you might call it pure mathematics at this point than applied mathematics, but so what? It's a small investment to maintain a diversity of approaches. Which I think is what this article wants to argue for?

And the ambulance chasing comments. My experience during the faster than light neutrino anomaly that turned out to be a loose cable time was that most of those anomaly papers aren't really serious attempts at inflating publication count. It's just people taking a break from doing their main job of doing some seriously detailed and tedious calculations to indulge an unlikely "what if?" and do some quick back of the envelope calculations about the implications of what happens if something that is almost certainly a measurement error turns out not to be.

I mean on very rare occasions, like discovering the cosmic microwave background, something that seems like its almost certainly a problem with the equipment turns out not to be, and things do get a lot more interesting!

So that argument reads to me as a lot more "stop having fun, folks!" rather than a meaningful criticism of misallocation of resources. And I don't know, maybe those comments are pointed at a specific person that doesn't do a whole lot of work otherwise. But in general it's people who love doing math taking a quick break from doing math to do slightly different math.

All in all, the article doesn't leave me with any sort of idea of what a better approach might look like.
posted by Zalzidrax at 10:22 AM on September 28, 2022 [7 favorites]


On the dark matter side, I think Sabine Hossenfelder's arguments are likely to become outdated soon.

I've been actively engaged with the US High Energy Physics community's Snowmass process (described in this article, for instance) -- Chanda Prescod-Weinstein and Tim Tait are both involved in that as well, as it turns out. Basically, we're trying to figure out what the most compelling ways to make progress in fundamental physics over the next decades might be.

One thing that's become clear to me from the Snowmass discussions is that most of the best-motivated possibilities for dark matter -- including both axion and WIMP models -- would not have been detectable with the experiments that have been done so far, but should cause signals that can be detected by new dark matter searches that will be going on in the coming decade.

If none of those possibilities pan out, the answer must be something more exotic (and the theorists will continue to speculate -- that's their job!).

It's also clear from the white papers developed for Snowmass that the exact nature of dark matter will affect a variety of astrophysical observations -- which makes astrophysical studies a useful probe of what the dark matter might be...
posted by janewman at 8:28 PM on September 28, 2022 [2 favorites]


All in all, the article doesn't leave me with any sort of idea of what a better approach might look like.

Have there been ML-assisted approaches to theoretical physics? Particle accelerators generate absolutely massive amounts of data, which would otherwise seem like a goldmine for that direction.
posted by They sucked his brains out! at 9:52 AM on September 29, 2022


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