alt Hacker NewsFundamental physics is dying? [video]
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John Carlos Baez thinks Sabine has a point.
https://mathstodon.xyz/@johncarlosbaez/113285631281744111
>Despite the silly clickbait title of this video, Sabine says a lot of interesting stuff in it: her criticism of claimed deviations from Lorentz invariance in loop quantum gravity is about as good as you'll get from anyone who hasn't actually worked on loop quantum gravity. I worked on it for about 10 years, and the situation is even a bit worse than she makes it sound.
I'm not hot on what fundamental physics looks like now or in the future, but there's an attitude that Sabine promotes that I see echoed in a lot of comments here which feeds into problems with research.
I don't think the work put into studying fundamentals was "a waste of time" thus far. It's dangerous to label experiments and ideas that were acted on in good faith as the best options at the time but didn't yield positive results as missteps.
Scientists need to be allowed to do work like this without fear because to do so otherwise leads to perverse incentives and you end up with things like lots of studies that can't be reproduced because of p-hacking or worse.
Arguing bad faith after the fact is awfully hard without real evidence and if you're going to discount anyone with enthusiasm for their research proposal based on enthusiasm alone you're not going to be left with a healthy program. I don't blame anyone who supported things like supersymmetry as an example for something which hasn't panned out. we're still left with a major mystery and big questions and it says we need to rethink things in more difficult directions.
My understanding of the situation (which may be wrong, in which case please let me know) is that physics is stuck at a local optimum.
There are two obvious ways to get out
(1) Surprising physical observations, or
(2) Mathematical advances
Way (1) is what kicked off quantum mechanics. Way (2) is what kicked off Newtonian mechanics.
I see string theorists and loop quantum gravity people as working on (2). Their models are mathematically interesting and aren't totally understood from a mathematical perspective. But they're different enough that studying them may break the impasse.
I see (1) as largely limited by the budgets and technology needed to build things like particle accelerators and spacecraft.
For (2) you have to decide whether to only explore mathematics that defines physical reality, or whether to also allow exploration of non-physical systems. For example, you might explore a universe that is almost physical but has time machines. Restricting the search space to only physically realistic systems is a significant constraint, so there's a debate to be be had about how much weight to give it.
This might be too weird to be true, but when I heard that Geoff Hinton got the Nobel prize for Physics, I wondered if the prize committee was having trouble finding "real" physicists who had made fundamental advances....
This is not meant to knock Prof Hinton. These are his own words:
“I’m not a physicist, I have very high respect for physics,” Hinton said. “I dropped out of physics after my first year at university because I couldn’t do the complicated math. So, getting an award in physics was very surprising to me. I’m very pleased that the Nobel committee recognised that there’s been huge progress in the area of artificial neural networks.”
If LQG turns out to be unworkable, we're back at string theory as the only renomalizable description of quantum gravity.
Quantum gravity research amounts to one professor per university faculty on average. Even in the worst case this would not be the crisis of unmet expectations it is made out to be... QG researchers are very brave because they are risking everything on the possibility that existing data constrains quantum gravity in a way that hasn't yet been understood. I doubt there is even a single person making that gamble unaware that the Planck energy density is something like 20 orders of magnitude above present-day experiments.
The fundamental reason for this is simple. Humans are prone to cognitive dissonance. Meaning, we do absurd things to avoid painful thoughts. And anything that questions our sense of identity, is a painful thought.
So if my self-image is, "I've advanced our understanding of the fundamental nature of reality," then the idea that my contributions weren't useful becomes painful. So we avoid thinking it, challenge people who question our past contributions, and so on.
The natural result of this cognitive dissonance is a feeling of undue certainty in our speculations. After all certainty is merely a belief that one idea is easy to believe and its opposites are hard to believe. We imagine that our certitudes are based on fact. But they more easily arise from cognitive biases.
And this is how a group of intelligent and usually rational people descend into theology whose internal contradictions can't be acknowledged.
I think the problem is more fundamental. Newtonian mechanics is a science based on observation. Mathematics is just used to build a model that describes _how_ the reality behaves, not why.
Now Einstein is very special, because he proved that our human perception of space and time is wrong. When we think about the allegory of the cave, we got a glimpse of the reality we couldnt see before.
Nowadays every phyiscist wants to be the next einstein that uses mathematics to show us something about reality. The problem is that einstein had good reasons for his ideas. The constant speed of light didn't really work with maxwells equations. The model at that time didn't correctly describe the observations and the maths he used to solve that is rather elegant and simple.
You know how some people seem knowledgeable until they talk about your field? Well for me (molecular biology and genomics) this never happens with Sabine.
So, even though much of this is over my head, I grant her much credence.
FWIW.
Her choice of background for this video and the matching imprint on her blouse gives us maybe a hint that "fundamental" physics is too broad a field to actually die :-) I.e., there are ongoing and deep puzzles e.g., in dark matter / dark energy where observational data keep accumulating and at some point a critical mass (pun) of evidence may reshape our ideas about how the universe fundamentally works. The new ideas need have nothing in common with pre-existing mind sets of how things work.
Now about the string theory / quantum gravity furore, after decades of work by arguably extremely bright people its pretty clear that Nature in the current juncture is not giving us enough clues to proceed. This should not be stressful - Nature is not a Hollywood production studio that needs to churn gee-wow "experiences" every season. But Sayre's law applies rather well [1] "In any dispute the intensity of feeling is inversely proportional to the value of the issues at stake.". What is at stake here is the ego of a few individuals that assumed otherwise (i.e., that a post-Einstein revolution is imminent) and the (relatively minor in the scheme of things) research funding of this particular niche of physics.
Theoretical physics is not the only domain bouncing regularly between "hypes" and "winters", as the recent Nobel prize for Physics clearly demonstrates.
I know that this will probably be down-voted to death but I don't like these hyperbolic takes. I know that Sabine did use this title for click-bate purposes that she is now mostly doing YouTube videos (she had horrible experience that unfortunately not rare in scientific community [1]). I understand that the field of particle physics which is the corner stone in fundamental physics is not showing the great advances that it used to have a couple of decades ago. But I think people really don't understand that the field is still advancing and although these advances are less catchy to be reported in mainstream (and don't get traction if posted on HN) it is not dead or dying.
There is a reason why we had a particle data group updating the PDG [2] each two years (you can order physical copies for free but please don't do if you don't need one). People were writing about that since after the big discovery of Higgs boson (that was 12 years ago). We still have a lot of measurement and puzzles that is less about unification theory that people usually would talk about. Theory people are coming up with all different ideas even if some are not testable now but that job of theorist is mainly come up with ideas and help bridge the gap later.
I would suggest everyone interested in this topic to read the electroweak current chapter of the book called "How experiments End" [3] to understand a historical example to how we approached the standard model when it was first proposed. Most of the particle physicists will not work on supersymmetry, string theory and these catchy theories that people will hear about. Most of the work is advancing and answering (and raise questions) piece by piece. Here is an example of interesting results that help us answer some questions [4]. Also I'm not saying that the field had its own problems and can improve on many aspects. I'm just against these extreme and hot takes that claims it is in a crisis or dying.
for people who posted the comment from John Carlos, I like this toot/tweet/comment by Sven Geier [5] which was what John replied.
Disclaimer: I'm a particle physicist and have a skin in the game.
[1]https://www.youtube.com/watch?v=LKiBlGDfRU8
[3] https://press.uchicago.edu/ucp/books/book/chicago/H/bo596942...
[4] https://www.symmetrymagazine.org/article/new-results-from-th...
I think in this an other videos, what she says is "they are not even wrong" and she does have a point there.
As a non-physicist, it’s hard to understand if she has a point or not.
Any physicists care to weigh in?
Sabine is often right, but I think she's wrong here about Lorentz invariance being a problem, or at least a problem in the way she's saying.
Lorentz transformations are never going to length-contract the underlying fabric of space/spacetime. Relativistic length contractions contract moving objects, not the underlying spacetime.
In fact it's a strange and basic misunderstanding to have.
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This seems like a narrow view given that there are plenty of unanswered questions in chaos theory, etc. but physicists who think about quantum stuff typically don't like to consider the other physics Revolution of the 20th century as equivalent to theirs.
Physicist here.. I will not give Sabine more YouTube views, justifying clickbait titles. Below is just my opinion. There are certainly issues in theoretical physics. I think particularly string theory was a massive waste of effort in physics and to some degree illustration of failure of the whole system. Despite that most of other physics I would say in sensible shape, it is just harder to make progress given that we have to push to higher energies, more accurate measurements etc. The question whether there will be major advance in fundamental physics to some degree depends on new discoveries. Many people are pushing, but it is not guaranteed.
long ago i coin: scientific physics
an analogy with astrology and astronomy fits perfectly.
Remember those great men who did groundbreaking work that completely changed the fabric of society? Consensus my a, their work is self evident. If you need someone to tell you something is a great accomplishment it apparently isn't obvious.
If there is no revolution triggered by [say] relativity theory it doesn't qualify for the list of great discoveries. You need people to tell you how great it is.
funny as hell
I'm way too late for this to be meaningful, but here's what I think! tl;dr -- gravity is the problem, we should focus on experiments and observations for a while, bring in some better mathematics, and continue the long range program of developing quantum theories that include or even produce GR.
I'm just a physics enthusiast. When I became interested in physics, I was initially a sort of partisan in the "realist" camp -- pro Einstein, anti Bohr; liked Verlinde's entropic gravity, distrusted the graviton -- but have come full circle to the opposite view. GR has massive explanatory and predictive power, and an extremely satisfying aesthetic quality, but obviously breaks down behind the curtain of a black hole's event horizon, where we cannot make observations. I say obviously because it predicts a singularity, which is just another way of saying it makes no prediction at all. On the other hand, many of my complaints about QM I now look at as unanswered questions, opportunities for inquiry. QM is based 100% on experimental observations. The theory came together in a rather ad hoc fashion at the beginning of the last century, but as it was more carefully studied theoretically and experimentally, also proved to be highly predictive, even more that GR. Yes there are big ugly, outstanding questions -- measurement collapse, the transition from microscopic quantum behavior to macroscopic classical behavior, the intractability of all but the simplest calculations -- but those are huge areas of knowledge that the future will gradually (or suddenly) fill in, as our understanding moves forward.
So, gravity, not QM, is the problem. We should start with the axioms of quantum mechanics, and look for ways to observe where QM and GR can be measured at the same time. LIGO offers opportunities like this, as the sensitivity of the instrument is well within the quantum regime. Continued study of QCD could make a testable prediction for what exists inside of a black hole. Or continue to study the very fine transitions between energy levels in the nucleus. Mathematically, maybe the Langlands program, with its rather weird, Fourier-like sums of L functions will allow us to model non-linear behavior.
And yes, string theory sort of "jumped the shark" at some point. I'm sure Ed Witten regrets saying that other pursuits were a waste of time. But the thing is, the string theory program is centered on QM, and has shown that QM can naturally produce GR, given certain unrealistic assumptions. That's mathematical progress.
I knew from the title it's gonna be Sabine Hossenfelder. Her videos are just clickbait at this point.
Is this Dang turning titles into Betteridge questions again? The original does not have a question mark.
> What's even more insane is that the only two people I can think of who have pushed back against this are Peter Woit and Eric Weinstein, and both of them are trying to sell you their own theory of everything
Sabine forgot Stephen.
https://writings.stephenwolfram.com/2021/11/the-concept-of-t...
If you want to reply to https://news.ycombinator.com/item?id=41811140 or say something Sabine-adjacent, please do it here.
(This is so https://news.ycombinator.com/item?id=41808143 doesn't get too offtopic)
i love sabine. she's speaking the lived experience of quite a few of us who lost faith in the academy.
I've said this before in not the same words, and I am always downvoted here on hackernews: people need to understand theory of knowledge before they understand science. Physics and physicists are the worst offenders.
I have a pet conspiracy theory for why there has been so little progress in physics for so long. The invention of the nuclear bomb scared a lot of people, it made them scared of physics. What else might physicists turn up that could change the world in dramatic ways? Anti-gravity? Ray guns? Other dimensions? Travel to other worlds? All bad for business, no one is going to buy your airplanes or air craft carriers if they can buy an anti-gravity machine. So physics was suppressed by both business and government. Physicists were given "safe" work to do (ITER, quants) that would occupy them and keep them from exploring wild stuff. Grant financing was controlled so that only safe research would be conducted. It would be fairly invisible to the world, just a few high level decisions would determine how the funding was directed. I get the impression that if this was indeed a conscious decision that it's starting to fall apart as younger generations take over and become frustrated with the direction of physics. They weren't there when the A-bomb was invented, and nuclear weapons have not been on peoples minds much for a long time, most people have not lived in a time when one was used. So they see interesting topics and want to explore them and encounter resistance from more established scientists. It's a conspiracy theory because it would involve some buy-in from a fair number of physicists to make it work, but a lot of physicists when I was getting my BA in physics were very loudly saying "never again" about atomic weapons and felt it had tarnished the whole profession. It's very difficult to say what humanity would be capable of handling in terms of radical new inventions. Anti-gravity could solve many large problems, but it might make it even easier to destroy Earth. Once new knowledge exists it is hard to suppress it. Stopping it from from ever existing seems easier. I guess we'll find out if physics has been suppressed if the dam breaks and new ideas start proliferating. The nature of the new physics would be a big clue as to whether research in it was suppressed. I'm reminded of Elon Musk, he seems to have had really radical success in some very stagnant industries, just by trying instead of accepting limits, and being able to fund his ideas himself.
Theoretical physics are theoretical; that seems to be the crux of her problem. And in that light it makes sense that she's become an influencer who makes content instead of someone who devotes most of their time to advancing the science. Yes, oftentimes people will be paid to work on problems, and they'll end up in a cul-de-sac. That will be the case for the majority of the field in the case of something like quantum physics. But if we pay enough of these people to sit in rooms and work on problems, maybe one of them will figure something out. That's how science progresses.
For the context, the video this is a follow up to is helpful (they're both short) - https://www.youtube.com/watch?v=ZlHvW6k2bcM