FeaturedB Sabine Hossenfelder and Beauty in Physics

1. Jul 12, 2018

Staff: Mentor

From the article:
https://motherboard.vice.com/en_us/...ists-are-misled-by-outdated-notions-of-beauty

2. Jul 12, 2018

Dr. Courtney

Picking which theory is right is always a matter for experiment.

Picking which theory is more worthy to try an experiment on is not an endeavor that science has provided a clear path on.

The culture of science has evolved from highly capitalist in the 16th-19th centuries (whoever could pay for it did the experiments they wanted to do) to highly socialist in the 20th-21st centuries (the expense and scale of much science leads to an elite deciding how to spend government money on which ideas to develop and test.)

We simply do not have a clear set of principles to know how to develop theories how to pick more promising theories before the experiments are done. Beauty in a theory is no more an objective criteria than beauty in a woman or a building or a landscape. Simplicity is similarly challenging to define objectively.

Nice article, thanks for posting the link.

3. Jul 13, 2018

romsofia

I think a good article to read if you haven't already is: https://arxiv.org/pdf/1710.07663.pdf

Especially the section on "The role of theory":
“The truth is, the Science of Nature has been already too long made only a work of the Brain and the Fancy: It is now high time that it should return to the plainness and soundness of Observations on material and obvious things.” These words are not the latest attack against the abstractness of modern theoretical physics or the inability of string theory to find a criterion for empirical falsifiability. No, these words are by Robert Hooke and date 1665 [52], when times were changing in England and a new approach to science was emerging: a radically different use of abstract mathematics in formulating physical theories. Only one year later, in the annus mirabilis 1666, Isaac Newton, who had no sympathy for Hooke – sincerely reciprocated by Hooke – started to revolutionise physics by making use of calculus in his formulation of mechanics and gravitation. A masterpiece of a work of the Brain."

But some things on the article in OP:

I honestly don't like the approach in the article in OP. It seems foolish to me to assume that people are looking for "beauty" and the author seems to be coming at the issue with a whole bunch of hindsight. The one quote I dislike the most is: "My conclusion from this long line of null results is that when physics tries to rectify a perceived lack of beauty, we waste time on problems that aren’t really problems."

Throughout history, people take the wrong roads, but if you never allow them to take the road, how do you know it's wrong? Only through hindsight can the author state that they aren't "really problems".

I do research in QG, and I dislike where the field is going as well. We haven't found SUSY, but they keep changing their goals in order to protect the idea behind it. But there is logic behind it all. They take the quantum fields to be very fundamental because the logic behind that formalism has been so accurate in experiments. So the "beauty" behind them IS WORKING, so it isn't foolish to think that logic would keep working.

I'm not sure what particular approach Sabine Hossenfelder takes to solving the quantum gravity problem, but I think it's ignorant to say that supersymmetry isn't a "real problem".

4. Jul 13, 2018

Dr. Courtney

Do you really mean allow? Or do you mean "pay for"? I've never heard a suggestion that a scientist in the US or west would not be allowed to pursue any idea as long as they arranged their own funding. Usually, the complaint is closer to demanding money for the pursuits from the government treasury - money taken from the taxpayer at threat of legal action.

5. Jul 13, 2018

stevendaryl

Staff Emeritus
I'm not sure whether I agree with her about this. It is true that all the various elegant and beautiful approaches to go beyond the standard model (string theory, supersymmetry, loop quantum gravity, Grand Unified Theories) have not produced anything much. But is it because the researchers were driven by the desire for beauty? It seems to me that the successes of foundational physics were also driven by similar desires to unify and streamline our laws of physics. Combining the laws of magnetism and electrical forces into a single topic of electromagnetism was the sort of unification activity that seems to have fizzled out recently. So was General Relativity. So was quark theory and QCD. Her point might be that these efforts were guided by experimental results, so there was a twin motivation, aesthetic and experimental. I would not say, though, that the experimental motivation was the only thing. In GR for instance, Einstein's motivation was to unify SR and gravity theory. It was a matter of pursuing coherence, rather than addressing experimental puzzles (there certainly were empirical consequences to GR, but they were not what motivated Einstein).

The real reason, in my opinion, that work in foundational physics has slowed recently is basically because of the lack of ideas for experimental evidence that goes beyond the predictions of the standard model. In some sense, as ugly as it is in some ways, the standard model is just too good. It agrees too well with experiment. You need experimental puzzles to solve to advance science.

Now, I do think that cosmology, as opposed to particle physics, does have a lot of observational puzzles to solve. But unless the solution connects with something experimental (which I think of as different from observational, in the sense that in an experiment, you can choose the setup, while in observations you have to take what the universe gives you), it's hard to see how a theory can go beyond the "guessing" stage.

6. Jul 13, 2018

Dr. Courtney

You have some very nice insights there. Thanks for sharing. Great contribution.

I wonder how absolutely you mean the following statements:

You need experimental puzzles to solve to advance science.

Do you mean that new experimental puzzles are an absolutely firm requirement (science cannot possibly advance without them)? Or do you mean that advancing science will be much harder and take much longer without them?

But unless the solution connects with something experimental (which I think of as different from observational, in the sense that in an experiment, you can choose the setup, while in observations you have to take what the universe gives you), it's hard to see how a theory can go beyond the "guessing" stage.

I think I get your meaning, but clarification would be helpful. My view (and experience) is that eventually observation will provide what is needed for the testing of new theories/hypotheses but it may take lots longer and require greater patience and possibly expense. If one waits long enough and is clever enough, eventually the universe will give what is needed through observation to test many theories. In many ways the observation of black holes colliding provided an onservational test of GR in ways where it is hard (at least for me) to conceive of an experimental test. But the observational approach required building a sensitive detector and waiting.

7. Jul 13, 2018

Staff Emeritus
Counter-example: the Higgs mechanism.

8. Jul 13, 2018

Staff Emeritus
If Hossenfelder would then turn around and argue "But it's been 6 years since the Higgs", I might then turn around and point out that in those years, she published 11 papers with a maximum of 14 citations, while the LHC experiments have published 1000 papers with a maximum of 1000 citations for non-Higgs results. If I were feeling uncharitable, I might even question whether she has correctly identified who has a lack of progress.

9. Jul 13, 2018

Staff: Mentor

In my view, that much optimism is too much.

For example, I suspect that we will never be able to resolve which QM interpretation is correct, or what happened before the "origin" of the universe, Yet we have many scientists studying those things as a career. I just met a post doc at Dartmouth who is planning on spending the rest of his life on MWI. My reaction was, "What a waste of taxpayer money. He will likely never contribute anything to the state of the art in an entire lifetime."

I recognize that you said, "If one waits long enough" and that is unbounded. In the future, we will have better methods and better tools and there is no defined upper limit to "better." But those might come from advancements in other areas like electronics, rather than from MWI scientists. Therefore the prudent policy would be to table some of those science investigations for several centuries until technology makes it possible to succeed.

I say the same thing to people on the engineering side who insist that technology will inevitably produce FTL travel given sufficient advancements.

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10. Jul 13, 2018

stevendaryl

Staff Emeritus
I might agree that research on quantum interpretations or MWI is unlikely to produce anything. However, that research is certainly not a significant waste of research dollars. Theorizing at your desk is a LOT cheaper than building huge experiments. LHC, for instance, cost $13.25 billion to build, and then there's operating costs, computing costs to interpret the data, etc. 11. Jul 13, 2018 PeterDonis Staff: Mentor That was just a confirmation of the Standard Model. It did not provide support for any of the "beyond the standard model" ideas that have been proposed over the last 40 years. 12. Jul 13, 2018 stevendaryl Staff Emeritus The one experimental detail that seems like a tiny bit of departure from the standard model is the discovery of a small neutrino mass (I assume that the nonzero mass is pretty much accepted now?) But that's actually a trivial (I think?) modification of the standard model to accommodate nonzero neutrino mass. 13. Jul 13, 2018 anorlunda Staff: Mentor That's a very strange outlook on "significant waste." It is unlikely to produce anything but other stuff is more expensive. Where's Senator Fulbright when we need him? If it was only a handful of MWI researchers, I wouldn't object, but there is no defined upper limit to the number of scientists worldwide who expect taxpayer financing for the same thing. How many QM interpretation researchers do we finance in the world today, 103? 104? 14. Jul 13, 2018 stevendaryl Staff Emeritus How else would you measure whether research is a waste of money? You compare how much money it costs to the likelihood of getting something valuable out of it. I think that Senator Fulbright was a little ridiculous in his criticism of research. He highlighted research that sounded silly, regardless of whether (A) it cost a lot of money, or (B) there was scientific reason to think that the research was worthwhile. I don't think he made any kind of careful cost/benefit study for research dollars. I think that it is only a handful of people who do MWI research. 15. Jul 13, 2018 Dr. Courtney I agree completely with your comments on MWI (and QM interpretations more generally) and questions of what happened before the origin of the universe. But I tend to be skeptical regarding whether these questions are even within the realm of science at all (the realm of science requiring testability). My comments about waiting long enough should be constrained to ideas where there is strong and clear testability to begin with. It was insightful of you to point out questions that I regard to be on the fringe of testability to begin with. For me, it depends on what you mean by "table." I agree that we should with hold public funding for ideas where the testability is decades or centuries in the future. However, I would strongly disagree with attempts to stifle thought and development of ideas where the proponents are able to find the funding independently of government. And I would also not prohibit "incidental" government funding like what a tenured professor does with his research time (unfunded other than salary) or publication costs like arXiv expenses and the like. I can appreciate that theorizing at one's desk is cheaper than huge experiments, but my value judgements would tend to reduce spending on theoretical ideas that I regard to be on the fringe of testability: string theory, MWI, pre-origin issues, etc. Theory grad students aren't much cheaper than experiment grad students, and computational needs of theory tend to be much more expensive than experiment (at least in atomic physics, blast physics, and ballistics where I have the most experience on both sides.) I'd relegate public funding on theories on the fringe of testability to faculty salaries, minimal publication expenses, and "borrowed" computing time on otherwise idle machines. 16. Jul 13, 2018 PeterDonis Staff: Mentor As I understand it, yes, it is--basically you just add the right-handed neutrino singlet. AFAIK the only reason that wasn't included in the original Standard Model was that there was no experimental evidence for neutrino mass. 17. Jul 13, 2018 stevendaryl Staff Emeritus I'm looking, and I can't find a pie chart breaking down the number of researchers in the various fields of physics, but I do know that nobody at my university worked on interpretations of quantum mechanics.  I should say, rather, that nobody was funded to work on interpretations of quantum mechanics. Some people (such as me, actually) worked on it in our spare time. 18. Jul 13, 2018 fresh_42 Staff: Mentor I wouldn't measure it at all. To me this is a very, very American point of view, always having a return on invest in mind. We value a thing called "freedom of research" here, which basically means, that we leave it to the researchers how they spend their time. Surely, things are different if you will occupy telescope time or accelerator time. But what happens on your desk is basically completely unregulated. Beside the research, university professors here have to teach for a certain weekly amount of time, and if they want to have a break from it, which is usually for half a year, sometimes a year if the attendance of a foreign university or the participation in some research groups are the reason, they will have to back up this request. However, the obstacles are negligible, a well written request usually will do. 19. Jul 13, 2018 stevendaryl Staff Emeritus Hmm. If you're going to spend money, surely you have to have some way of judging what's worth spending money on, right? You can't just leave a bowl with$10 million in it, and a sign saying: "If you need money to support your research, just take what you need."

20. Jul 13, 2018

Staff: Mentor

Sure. But neither MWI nor QM interpretations need that bowl. They are both very theoretical, as math is, where my insights are basically from. What you need is a good library and maybe some money for new journals and research results. I explicitly excluded e.g. telescope time. But the "taxpayers'" money regarding MWI is simply financing the chair.

My point was the importance of "freedom of research" as we believe, that a close connection between research and funding will influence the results. Medical research is a good example for that. Therefore, we're no friends of such money related considerations.

Last edited: Jul 13, 2018