Sabine Hossenfelder and Beauty in Physics

[Vanadium 50]

I thought the original SM had massless neutrinos, and the discovery of oscillations forced the change to massive ones.

That's the retcon. In the 80's and early 90's, most people would have said neutrinos probably have a small [Dirac] mass. Then as soon as neutrino oscillations were discovered, the SM was retconned to require massless neutrinos. (By the way, it was 41 years between the prediction of neutrino oscillations and their discovery)

, but whether experiments can probe the regime where the hypothesis being considered (such as SUSY) predicts that something new should be found

I don't disagree with this, but it's a bit unfair of Hossenfelder to limit herself to predictions intended to give large signals in early LHC running, and then declaring failure when they don't come to pass. I am no fan of SUSY, but it is not difficult to come up with models that stabilize the Higgs mass, yet need more data to produce a visible signal at the LHC.

I also think the very premise is unfair. If Hossenfelder has a better approach, she should publish it. But "you're doing it wrong! You're doing it wrong!" is not helpful.

 

[PeterDonis]

In the 80's and early 90's, most people would have said neutrinos probably have a small [Dirac] mass. Then as soon as neutrino oscillations were discovered, the SM was retconned to require massless neutrinos.

So by "massless" you mean "zero Dirac mass", so that neutrino mass is generated by a different mechanism?

 

[gmax137]

retconned

Well I learned a new word today. At first I thought this was a typo. [/tangent]

 

[Vanadium 50]

o by "massless" you mean "zero Dirac mass", so that neutrino mass is generated by a different mechanism?

No, I mean that masslessness of the neutrinos did not become part of the SM until late in the game - near or after when they were discovered to be massive.

 

[PeterDonis]

I mean that masslessness of the neutrinos did not become part of the SM until late in the game

I'm not sure that's true. As I understand it, the original SM only had the left-handed neutrino, and it was massless (you need both left-handed and right-handed to have a Dirac mass term, and there was no other mass mechanism for the neutrino).

 

[stevendaryl]

Well I learned a new word today. At first I thought this was a typo. [/tangent]

It's from comic books (or similar long-running fictional stories, such as TV series of movie series). At some point, there is a plot development that contradicts what was previously said about the fictitious characters or their fictitious history, so the history is just changed to accommodate the new plot development. Sometimes in the comics, the authors explain the contradiction by invoking a parallel world where things happened differently. Other times, they just hope readers won't notice, or at least, won't complain too much.

 

[Vanadium 50]

I'm not sure that's true. As I understand it, the original SM only had the left-handed neutrino

And what I am saying is that nobody in 1990 was saying that.

 

[PeterDonis]

nobody in 1990 was saying that

The original Standard Model dates from the 1970s. What particular significance does 1990 have?

 

[PeterDonis]

The original Standard Model dates from the 1970s. What particular significance does 1990 have?

To expand on this a bit: when I say the original SM, to the best of my understanding, had massless neutrinos, I am talking about the 1970s SM, the one that combined original quantum chromodynamics with the Weinberg-Salam electroweak theory. As I understand it, this model gave masses to the W and Z bosons via the Higgs mechanism, and to the quarks and electron-series leptons by having both left-handed and right-handed spinor fields for them with a Dirac mass term put in by hand. But there were no right-handed neutrinos so neutrinos were massless in this model.

When experimental evidence for neutrino masses appeared, as I understand it, this SM was extended by adding right-handed neutrinos in order to allow the neutrinos to have masses; but other mechanisms were also proposed.

 

[stevendaryl]

To expand on this a bit: when I say the original SM, to the best of my understanding, had massless neutrinos, I am talking about the 1970s SM, the one that combined original quantum chromodynamics with the Weinberg-Salam electroweak theory. As I understand it, this model gave masses to the W and Z bosons via the Higgs mechanism, and to the quarks and electron-series leptons by having both left-handed and right-handed spinor fields for them with a Dirac mass term put in by hand. But there were no right-handed neutrinos so neutrinos were massless in this model.

When experimental evidence for neutrino masses appeared, as I understand it, this SM was extended by adding right-handed neutrinos in order to allow the neutrinos to have masses; but other mechanisms were also proposed.

I thought that in the electroweak model, the only mass that electrons had was via the Higgs mechanism. So there is no Dirac mass (what takes its place is the coupling term between the electron and the Higgs, which is nonzero after symmetry-breaking). (Or is that term still considered a "Dirac mass"?)

 

[PeterDonis]

I thought that in the electroweak model, the only mass that electrons had was via the Higgs mechanism.

I think that in the original model, the electron and quark masses were actually Yukawa mass terms from the interaction with the Higgs. But they look just like Dirac mass terms once you give the Higgs a nonzero constant vacuum expectation value.

 

[Vanadium 50]

In the 80's and early 90's, most people would have said neutrinos probably have a small [Dirac] mass.

The original Standard Model dates from the 1970s. What particular significance does 1990 have?

It was before the discovery of neutrino oscillations. Other than that, it's a description of a period in time. If I said "bell bottoms and hot pants were popular in the 70's", there is no answer to "why the 70's" other than that's when it happened. (And, of course, there is no rational explanation why they were popular at all)

If you look at textbooks at the time describing the SM, say Halzen and Martin or Griffiths, you will not see statements like "neutrinos are massless". You will instead see statements like "neutrinos are ultrarelativistic". If you look at the SN1987a papers, like Arnett and Rosner, same story. If you go back to Weinberg's "A Model of Leptons", arguably the birth of the SM, he barely discusses neutrinos, but he most certainly does not claim they are massless. The 1978 review article of Bilenky and Pontecorvo jumps right into what is known about neutrino masses and mixing without so much as a nod at the supposed masslessness of the neutrinos in the SM. If you go earlier, say Perkin's 1972 text, he actually comes right out and writes that neutrino velocities are approximately c - not exactly c as one would have for a massive particle.

It wasn't until after neutrino oscillations were seen that people started saying "Neutrinos are massless in the SM" about the time that neutrino masses were discovered.

 

[PeterDonis]

If you look at textbooks at the time describing the SM, say Halzen and Martin or Griffiths, you will not see statements like "neutrinos are massless". You will instead see statements like "neutrinos are ultrarelativistic". If you look at the SN1987a papers, like Arnett and Rosner, same story. If you go back to Weinberg's "A Model of Leptons", arguably the birth of the SM, he barely discusses neutrinos, but he most certainly does not claim they are massless. The 1978 review article of Bilenky and Pontecorvo jumps right into what is known about neutrino masses and mixing without so much as a nod at the supposed masslessness of the neutrinos in the SM. If you go earlier, say Perkin's 1972 text, he actually comes right out and writes that neutrino velocities are approximately c - not exactly c as one would have for a massive particle.

Hm, interesting. I'm curious whether any of the textbooks or review articles actually write down the fields they are using, or a Lagrangian, and if so, whether the fields or the Lagrangian they write down allow a nonzero mass for neutrinos.

I was able to find a copy of Weinberg's 1967 paper online. He specifically writes down a left-handed doublet (neutrino and electron) and one right-handed singlet (electron), and says those are the only lepton fields he's using. That means he is using a model in which the neutrino has to be massless, because you need both left- and right-handed fields (as the electron has in his model) for a nonzero mass. He doesn't explicitly say that the neutrino in his model is massless, but I don't see how the math he gives can lead to any other conclusion.

In short, I'm trying to understand whether the apparent failure you describe of many references to say that the neutrino in the original SM was massless was because the original SM actually allowed a nonzero neutrino mass, or simply because the references were sloppy and didn't actually take the time to explore or discuss the actual consequences of the underlying math for neutrino mass.

 

[TeethWhitener]

It's nowhere near this many. US-DOE supports maybe 200-300 theorists in total. The number supported to work primarily on quantum interpretations is, as far as I can tell, zero. If someone is funded to do some other thing and they write a paper on interpretations nobody is going to complain, but if that's all they are doing? No way.

This is really important to keep in mind. There's a significant misconception as to what gets funded. It's like the surveys where people estimate NASA's annual budget as ~20% of the total federal budget.

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.

[edit] 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.

Here's a (somewhat) detailed breakdown: https://www.aip.org/fyi/federal-science-budget-tracker/FY2018
See, in particular, the DOD breakdown. All basic research (denoted 6.1, or technology readiness level 1--see here for a definition of DOD technology readiness levels) done by DOD totals to ~$2B, versus the total R&D budget at ~$88B.

 

[Vanadium 50]

I'm trying to understand whether the apparent failure you describe of many references to say that the neutrino in the original SM was massless was because the original SM actually allowed a nonzero neutrino mass, or simply because the references were sloppy and didn't actually take the time to explore or discuss the actual consequences of the underlying math for neutrino mass.

Neither, I think. The modern language of Weyl fields wasn't popular back then (Griffiths specifically warns against it) and the (1+γ₅) terms were viewed as projection operators rather than fields in their own right. That is, the W coupled to the left-handed components of fields rather than left-handed fields. In this view, there is (or at least can be) a non-interacting right-handed component to the neutrino.

 

[PeterDonis]

Neither, I think. The modern language of Weyl fields wasn't popular back then (Griffiths specifically warns against it) and the (1+γ5) terms were viewed as projection operators rather than fields in their own right. That is, the W coupled to the left-handed components of fields rather than left-handed fields. In this view, there is (or at least can be) a non-interacting right-handed component to the neutrino.

Ok, thanks, this is good background that I wasn't aware of.

 

[martinbn]

I tried to read her book but I couldn't. It was a bit boring and I had the constant impression that she tries a bit too hard to be witty all the time, which seemed to me forced and was very tiring. I am not saying that the book isn't worth it, it's just not for me. I also still don't know what the main thesis is.

 

[Android Neox]

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

I wouldn't call multiverse interpretation "beautiful". Everett was kicked out of physics for proposing Many Worlds. The only reason multiverse models exist is because they are the only models that are consistent with quantum entanglement, Bell's Inequality, and non-simultaneity.

 

[Lish Lash]

I would argue that "beauty" is such a culturally loaded term that it is inappropriate to apply it to a field as rigorously objective as physics. Beauty is not only an intrinsically subjective term, it is entangled with intimately personal associations of pleasure and sexual attraction, activities often dismissed as inessential. It seems covertly provocative to apply a term with such connotations to intellectual pursuits of knowledge. I think "elegance" is a more genuine characterization of the esthetic inclinations of scientific intuition.

 

[fresh_42]

I would argue that "beauty" is such a culturally loaded term that it is inappropriate to apply it to a field as rigorously objective as physics. Beauty is not only an intrinsically subjective term, it is entangled with intimately personal associations of pleasure and sexual attraction, activities often dismissed as inessential. It seems covertly provocative to apply a term with such connotations to intellectual pursuits of knowledge. I think "elegance" is a more genuine characterization of the esthetic inclinations of scientific intuition.

This is quibbling. I don't think that beauty is a subjective term. There is such a thing as classic beauty, and you know it if you see it. The point is that uneducated people use this term as well, and for them it is highly subjective and emotional, but this is not the beauty scientists speak of. Why does Beethoven's 9-th work on the entire globe, or Chopin? Why are Michelangelo's sculptures beautiful? These are in the category which is meant here, not someone's favorite color, food or body shape.

Whether you call this elegance is just a workaround of the fact, that many people simply don't have a sense of beauty. You may call this sad, but I think it is true. If scientists speak of beauty, they usually mean the incredible simplicity of many natural phenomenons, or how slim some proofs are, or how a few equations reveal deep insights. There is an inherent beauty in most theories and it can neither be discussed, nor is it a matter of opinion. Galois' theory is beautiful. The only question about it is whether people are able to see it or not. If they don't, then the reason is a lack of understanding, not a lack of beauty.

 

[PeterDonis]

I don't think that beauty is a subjective term. There is such a thing as classic beauty, and you know it if you see it.

I think you're on very shaky ground here. First, "you know it if you see it" is pretty much the classic definition of "subjective". Second, I'm not sure how much agreement there is among scientists and mathematicians about what specific theories, models, proofs, etc. count as "beautiful".

The only question about it is whether people are able to see it or not.

But if they can't see it, and it's defined as "you know it if you see it", how can it possibly be objective?

 

[fresh_42]

Yes, 'You know it if you see it' might have been too bold, as my definition constraints the set of people I mean by 'you'. It is a rather snobbish and certainly political incorrect way to see it, because I couple it to education. However, it is not shaky ground, as I don't want to defend it, neither make it mass compatible. It is my personal opinion, and I declared it as such. It doesn't demand to be 'provable' as I don't have the desire to convince people.

I cannot run the 100 meter under, say 20 seconds, so I am not an athlete. The beauty of science can't be seen by the majority of people, but this doesn't mean there wasn't athletes who can run the 100 meter under 10 seconds.

 

[Lish Lash]

If scientists speak of beauty, they usually mean the incredible simplicity of many natural phenomenons, or how slim some proofs are, or how a few equations reveal deep insights.

While I agree with your characterization of scientists, those are examples of what I (and I believe most dictionaries) would describe as "elegance". You may insist on conflating that term with more fashionably publicized forms of "beauty", but it's a distinction I think we do recognize when we see it.

 

[PeterDonis]

'You know it if you see it' might have been too bold

My issue isn't that it is "too bold", it's that it is subjective, when you specifically tried to claim it wasn't.

If, for example, you argued that General Relativity is "beautiful" because it takes a very simple field equation derived from a very simple Lagrangian and extracts from it a huge variety of detailed quantitative predictions that have been confirmed experimentally to many decimal places, that would be an objective criterion for "beauty" (and one I would tend to agree with). But that criterion, or anything like it, is very different from "you know it when you see it".

For the criterion I just described, I would agree with @Lish Lash that "elegance" is a better word for it than "beauty", but that's a matter of personal preference; the criterion itself is objective. The problem with "you know it when you see it" is that it isn't.

The beauty of science can't be seen by the majority of people, but this doesn't mean there wasn't athletes who can run the 100 meter under 10 seconds.

And if the criterion of "beauty in science" is something like what I described above, there is no problem. Certainly the fraction of people who can understand why GR is beautiful in the above sense is small, just as the fraction of people who can run 100 meters in under 10 seconds is small, but that doesn't make either one any less true or objective.

The problem with "you know it when you see it" is that if you then turn around and say that, well, some people just can't see it, you are undermining your own criterion; it becomes useless.

 

[fresh_42]

The problem with "you know it when you see it" is that if you then turn around and say that, well, some people just can't see it, you are undermining your own criterion; it becomes useless.

Maybe "bold" was the wrong word. It was what the dictionary gave me for the word I was looking for. "You know it if you see it" shouldn't be the definition, rather emphasizing that people who can see it will recognize it as such, in the same sense as people around the world apparently agree that the final chorus in Bethoven's 9-th is beautiful. There is no objective criterion either, nevertheless there are dozens of flash mob videos from around the world which support this point of view.

And to find GR (or my example Galois' theory) beautiful, you first have to understand it. I don't think that this sense of beauty can be measured in bytes as in CS: the shorter the more beautiful. This would be too short in either meaning. And that's my difficulty here and why I only expressed my personal point of view: there is no objective scale, but this does not automatically make it subjective. It depends on whether you're able to see it, i.e. whether you really understood GR. GR is beautiful despite the fact that the rubber sheet isn't accurate. It's beauty doesn't come from the numbers 21 or 18 (I don't remember the exact number of equations, resp. free parameters, which is why I've chosen Galois theory as example).

 

[PeterDonis]

"You know it if you see it" shouldn't be the definition, rather emphasizing that people who can see it will recognize it as such

Ok, fair enough.

It depends on whether you're able to see it, i.e. whether you really understood GR.

Yes, but there are objective criteria for whether people have really understood GR. Can they calculate its predictions for themselves, and have their calculations match the ones that GR experts have already done and which have been extensively confirmed by experiment?

You are basically saying that anyone who meets those objective criteria will find GR beautiful. I'm not sure that's true--at least, I'm not as sure as you seem to be. But I think that it's more likely that anyone who meets those objective criteria will agree that GR is simple and elegant, in the sense I described in my previous post.

there is no objective scale, but this does not automatically make it subjective

I agree. There is no objective scale for "simple and elegant" as I described it, yes. And that does not automatically make that criterion subjective. I think the key is that the criterion has to involve something that can be reasonably objectively measured and agreed on--even if people can't agree on where exactly the boundary lines of categories like "simple and elegant" or "beautiful" are in terms of the objective measures, we can all agree on what the objective measures themselves say in particular cases.

For example, we could argue over how simple a Lagrangian needs to be to qualify as "simple and elegant", but we can all agree, for example, that the Einstein-Hilbert GR Lagrangian is the unique one that has no higher than second derivatives of the metric and minimal coupling between gravity and matter. Similarly, we could argue over how "simple" Galois theory is, but we can all agree that it provides simple insights that resolve a lot of questions (such as why fifth degree and higher polynomials aren't solvable using radicals) that seem intractable without it.

 

[fresh_42]

You are basically saying that anyone who meets those objective criteria will find GR beautiful. I'm not sure that's true--at least, I'm not as sure as you seem to be.

Yes, but this is as if you asked whether a rose is beautiful. I'm not especially a fan of roses, but I accept them as beautiful. I won't discuss this judgement. Anybody who has a different opinion is - to me - just an ignorant. Since I don't want to spread this view, I don't have a problem with people of different opinion. I simply don't take them serious about this topic. Again, a personal attitude, no definition of a hidden truth of the concept of beauty. It is my personal definition.

I remember a talk at a dinner table about the old question: invented or discovered. To me, these two subjects are related, as they come down to the question: what is nature and what is human? I admit to be a Platonist here. I said then as an example, that - again in my opinion - all these things are discovered, even music. I mentioned Tchaikovsky's 6-th as an example, where music tells a story (about death) which everybody can understand, so it cannot be invented. I'm not sure how many scientists would follow this strict point of view, but at least one mathemarician understood what I meant. From that and similar discussions, e.g. about applied versus abstract mathematics, I conclude that at least many scientists share the same awareness of beauty.

Another example, I think, is the standard model. Its simplicity, beside its reliability, seems to be so convincing, that many, if not most attempts to find a unifying model are simply extensions of it: bigger groups (dimensions), graded Lie algebras.

At the hearts of our models is usually Noether and we find it difficult to leave the concept of Lagrangians. To me this is a sign of an inherent beauty, and it can be seen once we dug deep enough to this core. A certain Lagrangian might be ugly, the principle is not.

 

[stevendaryl]

I think you're on very shaky ground here. First, "you know it if you see it" is pretty much the classic definition of "subjective". Second, I'm not sure how much agreement there is among scientists and mathematicians about what specific theories, models, proofs, etc. count as "beautiful".

But if they can't see it, and it's defined as "you know it if you see it", how can it possibly be objective?

I'm not sure that I agree with the claim that beauty is objective, but the fact that not everyone can detect a quality doesn't mean that the quality is subjective. For example, those with red/green color blindness can't tell the difference between red apples and green apples, but that doesn't mean that the difference is subjective.

 

[PeterDonis]

the fact that not everyone can detect a quality doesn't mean that the quality is subjective

I agree with this as a general statement. But if the specific definition of the quality is "you know it when you see it", then if someone doesn't see it, it isn't there--i.e., it's subjective.

However, @fresh_42 has clarified that he didn't mean "you know it when you see it" as a definition, but as an illustration; his reasons for thinking that "beauty" by his definition is objective actually seem pretty similar to my reasons for thinking that "simple and elegant" is objective. See posts #60, #61, and #62.

 

[Auto-Didact]

I also think the very premise is unfair. If Hossenfelder has a better approach, she should publish it. But "you're doing it wrong! You're doing it wrong!" is not helpful.

Actually saying 'stop doing it' is helpful in itself, especially in the chosen formats of public articles and popular books. The argument is that theoretical physics in foundations has not produced any spectacularly successful work after the Standard Model. The duration of this stagnation has even been dubbed a 'crisis in physics' precisely because this has never before occurred in theoretical physics for such a length of time since Newton; the problem is even worse considering there are more physicists alive today than in all of history combined since Newton.

Sociologically speaking, in the last 30 or so years there has been a strong popularising influence in the public domain. Most of this comes from influential scientists promoting MWI, SUSY, the multiverse and so on. This has an effect on the chosen career paths of a significant amount of young science students. Hossenfelder's book, as well as Woit's 'Not Even Wrong' and Smolin's 'The Trouble With Physics', form an opposing voice to unbalanced considerations aesthetic arguments in physics, which has become more and more popularized since Dirac, eventually peaking during the 80s, 90s and 00s. They argue that these unsuccessful theories of physics and their proponents have become dominant in science without experiment and that they continue to have a stable, ideological hold over physics, against which one must actively resist and fight against if theoretical physics is to return its previously healthy state.

Moreover, this has also led to many interested laymen, especially academics and scientists outside physics, to having accepted these models as scientific on the same level as actual canonical theories in physics. These academics, especially the more vocal ones, tend to have influence over university boards and connections across faculties, in other words, some role in selecting who will or will not get hired from the perspective and what ideas will or will not get funded from shared university funds; the recognizability and public familiarity of their ideas plays a significant role in these choices.

I suspect that Hossenfelder et al. realize that the adventure of science is not only an academic endeavor, but because of how science has become institutionalised, it is also a battle for the heart of the public. Given enough weapons and ammo, the public will eventually themselves start questioning theorists more strongly, this actually does occur seeing students are also part of the public; when this happens and these theorists are unable to properly account for why they haven't made any actually large lasting contributions to physics like their predecessors have, things will start to change in a democratic fashion i.e. their funding will get cut and redirected to other competing theories. In other words, science will finally self correct.

It is also important to mention that forcing a student to conform to some PhD topic tends to make him too familiar with some set of techniques and the associated mode of thinking, which biases his thinking onwards; this severely constrains his possible theoretical point of views. The hope is then that the aforementioned self-correction of the science will lead to a healthier theoretical milieu, one in which a theorist with a different, more productive point of view, will have the opportunity to arise naturally as has happened in the past since Newton, without getting screamed down by proponents of a dominant competing theory to which he is forced to conform to from pretty much the start of his career or risk career suicide, as is the situation today.

 

[bhobba]

I wouldn't call multiverse interpretation "beautiful". Everett was kicked out of physics for proposing Many Worlds. The only reason multiverse models exist is because they are the only models that are consistent with quantum entanglement, Bell's Inequality, and non-simultaneity.

That's all wrong. Everett was not kicked out of physics, he was just the type of guy that liked solving problems - it didn't worry him that much what they were - he just decided to work on stuff for government instead.

The quantum formalism all by itself explains entanglement, Bell and all that. I have zero idea what you mean by non-simultaneity in QM. Standard QM does however obey the Galilean transformations.

Thanks
Bill

 

[gleem]

Didn't (doesn't) Lee Smolin also have a problem with the direction of theoretical physics in his book "The Trouble with Physics" Publish some eight years ago.

 

[gerald V]

I am surprised that Hossenfelder thinks that physics is mislead by the search for beauty. Actually, most of the current theories - inflation in particular - could hardly be more ugly. I have to accept such pragmatism, but hope that most of it will not be the last word.

To me it appears that physicist share the fate of all humans, namely that they are unable to learn from history. History of science teaches
that always those pre-judgements turned out as fallacious which had been regarded as most beyond dispute, supported by an intimate combination of experimental evidence and philosophical perception.

 

[Crass_Oscillator]

I find it baffling that anybody would suggest that beauty is anything but subjective. In quantum transport for instance, one can go the route of second quantization along with all of the associated dazzling Feynman diagrams and abstract representations, followed by conventional Green function methods, or for a number of other quantum kinetic approaches which are more crude or simple, where applicable (I confess that I like Wigner functions as, under the proper circumstances, I can look at the equation of motion cock-eyed until it looks like a Boltzmann equation, which is tractable to pleasing and comparatively simple Monte Carlo approaches).

By virtue of my different biases (applications to electronics in my case), my definition of beauty changed. If theoretical physicists are all clustering around the same biases (i.e. same standard of beauty) without progress in 40 years, Hossenfelder may have a point.

 

[bhobba]

I find it baffling that anybody would suggest that beauty is anything but subjective.

Of course in a statistical sense it is subjective ie there would be plenty of people who do not understand a theory well enough to really decide, they just have some pop sci idea of the theory or the general 'loose' ideas taught at HS, who would not say so, despite their source almost certainly saying it is.

The issue is however when you pick a genuinely beautiful theory such as GR, by which is meant just about all exposed to it's full technicalities, think GR is beautiful. In fact I do not know of anyone that does not (again of people that understand its technicalities). I think they generally hold views more along the lines of Chandrasekhar:
http://adsabs.harvard.edu/full/1984JApA...5...3C

That's the strange thing about theories generally considered beautiful. I would define a beautiful theory as one held as such, by an overwhelming majority of physicists, no physicist would care to argue it. Another characteristic is the theory is more or less inevitable from that beauty and is confirmed without revision by experiment.

Why some theories are like that I do not know, its a great mystery IMHO, but it seems to be the way some theories are.

Added Later:
One of the things I really enjoy is seeing a theory that on the surface looks ugly, what can be done to make it more like GR. I personally have nearly reached that point with QM - but not quite - close though.

Thanks
Bill