Sabine Hossenfelder: There are areas where physics blurs into religion
theguardian.com
theguardian.com
It's in biology where you still have ample low hanging fruit in terms of experiments. I feel if you're a brilliant physics grad in 2022, don't waste your time on string theory - apply some of that knowledge to chemistry and biology
I wonder how much contact you have with the world of research in theoretical physics that lead you to this conclusion. More to the point: do you have any, or is this person your only source of information?
Do you know that phenomenon where you think you're learning good information from a source, until that source talks about a subject you're an expert in and you realize they have no idea what they're talking about? That's how I feel every time I see Sabine hossenfelder on HN. I have a PhD in theoretical physics in a string-adjacent field[1], and my view is that this person has had negative net contribution to physics. First by contributing zero from poor research, and second by detracting by spreading the impression amongst the general population that experts aren't really experts, they don't know what they're talking about, are stupid or corrupt etc etc. Seems to be the theme of the 2020s that the most incompetent of any field become financially the most successful by making a business out of writing about how their colleagues are ignorant.
[1] my experience interacting with the kinds of muppets that are fans of Sabine is that at this point you'll have learned the argument that "well of course you think that way, that's because you're in the system and benefit from its rotting, being a PhD in X". If that's what you think about me, don't bother even responding. In reality I've left the academia for industry and am doing 10x better financially than any of my ex-colleagues - I benefit nothing from the effort I make in trying to communicate what is really going on here.
... said Stadler to Waldorf.
Her main point to me, which she is quite good at repeating, is roughly that just because the maths works out, doesn't mean it's physically real. I think this is a very healthy caveat which is all too often neglected in popular science reporting.
"That's right!, and we're doing 10x times better up here in our box than you muppets down there on the stage!"
You can't know that, even if the math technically works. Maybe we are, maybe we aren't, it's really about what you choose to believe.
What makes string theory particularly poor, in your opinion?
There are a very small handful of anomalies which aren't adequately explained by the standard model, but string theorists didn't base their models around resolving these questions. They sought a grand, unified, simple theory out of a philosophical (religious?) belief that one ought to exist.
And generally speaking we have good reason to believe the universe operates on a simplistic rule set that evolves in complex ways because finding a simple equation at the heart of complex interactions is pretty much the history of physics.
Well, Paul Dirac for one did predict the antimatter counterpart of the electron because of mathematical beauty, didn't he?
She is (was) a physics researcher, perhaps a mediocre one, most are. But saying she has no idea what she's talking about requires some justification.
Specifically, what do you disagree with her about?
Why would you say "was" - she's still a fellow at FIAS and lists herself as a researcher on her own website. Conversely, her only publication in the last decade with more than 100 citations was her popular science book aimed at non-physicists and most of the things before that were borderline hack stuff, basically going back to Milgrom's theory with very little content that would justify moving this research from fringe to mainstream [1]. She definitely hasn't established herself as an authority on foundations of quantum mechanics or string theory, which she has taken a liking to discredit. So the commenter above was not wrong.
[1] https://scholar.google.com/citations?user=NaQZcyYAAAAJ&hl=en
If you were a research fellow in virology or immunology, and you had read and understood the relevant papers, then I would listen to you, yes. That doesn't mean I would take what you said as the final word.
How would you know that if I hadn't published papers on the relevant topics and only published in adjacent, non-mainstream topics?
And yes, the bar for string theory is high. Not every research fellow in theoretical physics would be qualified to comment here - quite the opposite actually. In the same way any honest theoretical plasma physicist will refuse to comment on quantum computing papers. Inside academia it is well known that you often can't even expect people to create qualified comments across neighbouring offices inside departments. Regardless, there are quite a few qualified people in this area. If someone with caliber like Susskind, Gross, 't Hooft, Witten or from the respected younger generation came out and said it's all a hoax, you can bet everyone would listen. And they have come out with specific critique, but you'll find it very different from the likes of Hossenfelder and it is usually not discussed in popsci literature. Noone in the field cares about people who haven't even shown they understand it, let alone contributed to it.
> How would you know that if I hadn't published papers on the relevant topics
No, that not the question. You don't get to assume that people are incompetent until they've presented incontrovertible evidence to the contrary. You're the one making ad hominem arguments, the burden of proof is on you.
What? Have you even read OP's article? A direct quote from the article has her saying this physics research is "religion masquerading as science under the guise of mathematics." If that's not insinuating a hoax I then don't know what is.
IMHO religions are just religions. As much as you can't scientifically prove the existence of god, you can't disprove it either. It's not necessarily a hoax.
Leaving aside the setting of ridiculously high bars for the moment, that level of evidence would be different depending on who is observing. A car mechanic is going to be able to spot clear evidence of incompetence in another car mechanic long before it’s apparent to a layperson observer.
Sure, it's not experimental physics, but as long as it's _bound by reality_ somehow, it's still science.
So the way a good physicist operates is to say "fine, I can't do the experiment, but let me see what is allowed by current experimental bounds". This is good. It's also an idea as old as science itself.
In contrast it's tremendously ironic that physics poopooers like Sabine and that other peter woit guy typically choose to work on special-relativity-violating theories, which are immediately outside of the bounds that the experiments we do have impose. Do you understand what I'm saying? This person is claiming "we can't directly probe a string therefore string theory is religion", but then she works on something which is worse than religion - something which we know is experimentally disproven. (I'm talking about the loop quantum gravities, and entropic gravities and so on and on - they're all inconsistent with one of the most toughroughly experimentally tested laws, special relativity). If they weren't so good at convincing the public that no one knows anything, their tragedy would be comic.
Not sure what you are referring to here. If it is her work on theories involving a minimal length scale: Heisenberg and Planck also hypothesized about minimal length scales. Hardly controversial even if difficult to combine with Lorenz invariance.
Experimental testability is important in physics. It doesn't mean anyone doing something not directly testable is a hack, but I think it's good people have been raising the issue more recently.
So it’s good science to color within the lines not try to redraw them through new experiments we CAN conduct.
I don’t know; sounds like sheer laziness and lack of true creativity if you can only play inside a decades old sandbox.
Along with the entitled tone and “I’m doing 10x better in industry than colleagues in academia” kind of feels like you’re doing it for bragging rights not science.
How do we know who's an expert here? Peer review is only as good as your peers. Genuine question.
It looks like Beyond Standard Model physics is becoming increasingly more abstract, increasingly less mathematically well-defined*, and not getting any closer to physically testable. So I don't know how to judge who's an expert.
* - What are the equations of M-Theory?
That's a fair question.
Let me give you a rule of thumb. I must emphasize you can't take it _too_ seriously. But it seems to hold quite well that in hard sciences, not just physics, looking from the inside, you notice that the ones who talk to the media are normally the bottom of the barrel. This makes a lot of sense. If your goal is to learn about the fundamental building blocks of the universe, writing blog posts the societal aspects of science doesn't help you with that. Real scientists spend their time doing science. There's very few exceptions to this. In fact right now I can think of a single person who's a world class researcher _and_ a prolific blogger; Terrence Tao, but he's a mathematician.
My point is, you can't judge who's the expert based on the quality of the science produced because you don't have the expertise for that. But believe you me, if someone spends a lot of time doing things other than research, they're probably not the best.
Right, sorry, I forgot that the only thing of importance that people have to contribute are Nobel prize winning papers. You know, lecturing, writing textbooks, writing standard scientific papers, peer reviews, all of these things aren't contributions. Obviously no-one should engage with the media unless they have won a Nobel and have decided they have no major papers left in them. In fact at that point, if they were real scientists, they'd just realise their time was up and walk off to perish on the tundra like the elderly inuits used to so they don't take up any more precious resources from the real scientists.
There is a commonality in your argument, at least from where I'm standing, with the logic of the 'proper binmen' people or the ascetics -- only those who suffer in silence away from society are truly the 'holy physicists'.
https://www.theguardian.com/news/2022/nov/15/who-remembers-p...
It's ironic that you express the following sentiment:
> If your goal is to learn about the fundamental building blocks of the universe, writing blog posts the societal aspects of science doesn't help you with that. Real scientists spend their time doing science. There's very few exceptions to this. In fact right now I can think of a single person who's a world class researcher _and_ a prolific blogger;
when, just yesterday, the highest ranked post on the site was this:
https://news.ycombinator.com/item?id=33750825
about this essay:
> My point is, you can't judge who's the expert based on the quality of the science produced because you don't have the expertise for that.
But you do have the expertise / knowledge / chuzpah to say that Mr Tao is a world class researcher? Sorta contradicktory, no?
However, reviewing Sabine's cosmology papers to assess her arguments that theory research is poorly incentivised would be nonsensical anyway, so why even bother?
(To make my position clear, I actually don't agree with Sabine's angle that theory research is overvalued, but I do agree it focuses weirdly on some topics. I do read contemporary papers outside of what's presented via pop sci. But that should not be the content of your response if you are as credentialed as you say)
Something that stuck with me was an article[1] describing how certain fields of medicine had languished, whereas others had made dramatic strides forward during the same period. For example, psychology is basically 90% hogwash. Meanwhile, the study of the the brain's biochemistry and therapeutic medication-based remedies for many common brain dysfunctions have made huge strides forward in recent decades.
Back in the mid 20th century, the only treatment for most brain-related problems was "talk to a psychiatrist". This generally did nothing except help psychiatrists rack up billable hours.
When medications eliminated the "need" for one-on-one therapy sessions, how do you think it went, trying to convince psychiatrists that their entire lucrative field is a giant waste of time?
Yeah.
Precisely how you think it went.
Similarly, when I was at University around the late 1990s, the entire field of AI research revolved around only logic. As in, some person or a few people had decided that the path to general intelligence was to be via "fuzzy logic", or "predicate logic", or "probabilistic logic", or... well... some kind of logic at any rate. We had to learn LISP, Prolog, and Boolean algebra, and so on.
That entire path was a giant waste of time, but... none of it was wrong. Not one bit. They were correct, confidently making slow but steady progress, and they weren't even going in the wrong direction! They were advancing AI! Just... very slowly, and with no chance at achieving the modern miracles of AI such a text-to-image generation. (DALL*E, Imagen, Stable Diffusion, etc...)
Let's circle back to Sabine's criticism of theoretical physics.
They're the same.
They're confident that they're correct because they're not wrong!
Sabine doesn't argue that they're wrong. I also don't believe physicists are wrong, and I've even studied physics to a graduate level, agreeing with at least 99% of it.
What I believe is that theoretical physics specifically has gone down a parallel path that leads to a dead end.
The path leads in the right direction, and every step along it leads to forward progress.
The issue is that there are people that simply refuse to believe that maybe, just maybe, we're all stuck in a dead end.
Quantum Mechanics researchers especially love to point to a small number of successes such as the precision numerical calculations related to the anomalous magnetic dipole moment of the electron as proof that they're on the right path. This is cheerfully ignoring the minor detail that the equivalent calculation for the muon has a 3.5 standard deviation error when compared to reality. Oops. Just ignore that. We're on the right path, remember, because the step we took with the electron was forward!
This is the problem.
I remember my professors being so earnest about AI and logic, and how "one day", there will be intelligent robots programmed in Prolog.
I also remember my Quantum Mechanics lessons where the professor very earnestly told me that microscopic systems change magically only when you look at them, which is patent nonsense, but is repeated to this day, just like Freud's idiocy is still taught to psychiatrists decades after much of their profession has been largely superseded by therapeutic drugs.
[1] I wish I could dig it up, but I read it over a decade ago. The gist is pretty clear though, in that not all "sciences" are equal, and small branches even within the same larger field are often dramatically more effective and/or correct due to "cultural" reasons, or a better approach. The article listed many examples, but the criticism of certain areas of medicine and psychology were the most scathing. For a similar rant, see Richard Feynman's take on the topic: http://people.cs.uchicago.edu/~ravenben/cargocult.html
The opposite of what you write is true. Physicists are eager to see where theory doesn't fit reality, that might even lead to a nobel price. Even statistical fluctuations are sometimes hyped as breakthrough experiments.
The point is that people point to the equivalent result for the electron as evidence that the existing theory is correct, when it gets only one correct out of the three leptons.
There is no guarantee that the "new" thing will be another step along the same path as the existing theory.
I very strongly suspect that we'll need to backtrack a bit, perhaps a lot, and then walk along another parallel path to get to that new thing.
It might look very similar, but the subtle differences can make all the difference in allowing forward progress.
I've also been pretty frustrated by Copenhagen interpretation orthodoxy, but decoherence and open quantum systems generally has made great strides as a subfield in recent times. People are thinking about it better than ever.
I’ll take him and Sabine, and my 24 yo masters in elastic structures, over your entitled screed any day.
This reminds me of the power grid. Practically any news article or video is woefully ignorant and a LOT of studies that get put on here have a mountain of assumptions that render their conclusions as far less firm than the readers on here understand. There are some experts on HN in this area, but a lot of folks just blindly parroting stuff they don't understand.
In science, laymen most often don't know what a result looks like.
But the layman's belief that a YouTube video is sufficient background to reject the work of scientists... that's on them. They should know that a video, or even several videos, is not enough. We should all be able to recognize Mount Stupid.
Which is why the other thing the videos never mention: you won't expect experimental results from any of the competing theories, either.
This isn't a serious scientific debate. It's a few scientists annoyed that they're getting less funding, and accusing the string theory people of exactly the same things they do.
There is a genuine scientific debate here, and a lot of real problems. None of which they make videos about.
Note in particular that "millions" is probably right, and it's pocket change compared to the LHC -- which is NOT a string theory experiment. Its energies are well within the standard model, which is the problem. There is no practical way for us to get outside that range. String theory persists because it's pencil and paper and grad students, and doesn't cost that much.
An argument could be made for shutting down the LHC and sending the money to soil science or lupus or something else more likely to produce results. But the string theory arguments being conducted via YouTube are abysmal science.
And the fact that we’ve gone from “the layman couldn’t possibly understand the science” to “it doesn’t cost that much any way” is telling. How about a good reason to keep doing this type of research at all?
I left physics in 2008 in part because I was in the same boat as you and had gotten disillusioned with both string theory and particle physics. Now I kinda wish I had stuck it out and focused on more practical, less hyped-up areas.
I feel like this isn't at all what most religious people are doing and that you're presenting some kind of strawman to make them seem alien and dumb
There's really roughly two camps, one which is very much questioning the existence of God and are actually busy trying to find the answer to the existence question by finding evidence. Sometimes in scripture, sometimes in others or in nature. Often these people are actually somewhat open to counter arguments. These people are generally somewhat equivalent of physicists with a pet theory they're trying to pursue, develop and prove, say string theorists.
The other camp believes strongly, and isn't so much involved with whether or not God exists, but instead they deal with the details. They might think about how the trinity works, talk about trying to reach the youth, working on helping people in their local community, etc. These people are kind of the equivalent of physicists who work within the existing framework of established physics. Whether that's through applied physics or by say trying to analyze the composition of some star.
Granted, this might be a cultural thing and there a cultures where the beliefs are less practical and more intense, including intense studies of holy books. But most people around me that are religious don't do that. It's just been my experience.
There are many ways of understanding the world; rational thinking is only one of them. Note however, that the kind of theology that organized religion is usually known for is a kind of, perhaps misguided, rational thinking. The real core of religious thought is closer to direct theophany.
(Note that a genuinely rational account of theophany and such is quite possible, but only at a meta level. The way you directly engage with such things is what leads to the distinction I'm referencing here.)
I don't know anything about religious thought. Not that it doesn't exist, but I don't know anything about it. Like I said, the way I see it, most people find value in it for practical everyday life. And the older I got, the more I understood it -- life is definitely easier if you are convinced of something and don't question it. But in that view it's mostly for the earthly things, and less for the religious thought.
The sciences have the experimental part, which is a method made possible by the kind of phenomena you observe. As far as religion is concerned, I don't want to oversimplify, as I think we run the risk of lumping everything together, as there are different interpretations as to what a religion is.
He doesn't really speak about personal feelings, but more about the frontiers of a personal investigation.
SCIENCE AND RELIGION [Edge.org, 2007]: https://www.edge.org/conversation/werner_heisenberg-science-...
Science is doing what works, and you can't tell what works if you rely on theories that aren't testable. (What does it even mean for an untestable theory to work?)
But...
What if some theories that aren't testable eventually lead to theories that are testable and useful? How do we know when to abandon a chain of inquiry? What about theories that are technically possible to test, but currently impractical? Do we stop developing them until the technology to test them exists, or might further work reveal easier tests?
For a long time, physicists were fairly ruthless about abandoning work that didn't quickly lead to something that could be tested experimentally, but not always (e.g. Bohmian mechanics was pursued quite ardently even though it's predictions do not differ from standard quantum mechanics.) In the last few decades, as we've increasingly searched for things like grand unifying theories that might bridge the chasms between fields, we've begun to tolerate an increasing amount of work that is not founded in anything testable. The key developments that will tie a field back into reality often seem just around the corner but never appear.
It boils down to a question of how we allocate resources. Work done on untestable theories that never become testable is wasted, so where do we draw the line?
The history of physics is such that this almost never happened. In fact I'm struggling to think of an example in which it did, though I'm sure there are some examples somewhere.
The few things I can think of are stuff like antimatter, which popped out of the theory and weren't taken seriously until they were unexpectedly confirmed by experiment.
On the other hand as you mention the history of physics is littered with theories and frameworks pushing beyond the experimental frontier, only to be discarded. String theory being only the most recent example.
That’s a fine but important point. The Big Bang is still the simplest cosmological origin story we have that fits the evidence, and I don’t think Sabine is denying it. Nor does she deny multiverse theories which have even less of a leg to stand on. The case of multiverse theory is even worse as there are no testable predictions which come from them.
If you want someone with a stronger track record in research, but with essentially the same message, there is Lee Smolin and his book "The Trouble with Physics".
(1) Google Scholar lists a person's publications in the order of the most cited first [1]. Hossenfelder's 2 most cited articles [2,3] try to figure out the implications of the idea of what if there is a minimum length scale in nature. (Like the speed of light is maximum possible speed. What is there is a minimum possible length, i.e. what if nature has a resolution, like computer graphics?)
[1] https://scholar.google.com/citations?user=NaQZcyYAAAAJ
[2] https://link.springer.com/article/10.12942/lrr-2013-2
[3] https://www.sciencedirect.com/science/article/pii/S037026930...
Is her work significant? I will check out your book recommendation.
What I found most lacking was a viable path forward, an alternative to all this nay-saying. She had a section in the end with bullet points on what to do and not do, but it was quite brief and generic.
I had a short but interesting exchange on Twitter with Dr. Tony Padilla who has spoken about the case for string theory on Numberphile [2]. He stands at the opposite end of the spectrum of course, and it's worth listening to what he has to say as well.
Being a non-expert with just a casual interest in the inner workings of the universe, I am eagerly awaiting whatever the next breakthrough brings for our understanding of the cosmos, but I have to say that string theory and susy have seemed to over-promise and under-deliver with little prospect in sight, and perhaps at the detriment of a more fundamental or foundational approach. Indeed, the question of what is time has always bothered me, so I'm picking up Carlo Rivelli's book on this next [3].
[1] https://www.basicbooks.com/titles/sabine-hossenfelder/lost-i...
[2] https://www.youtube.com/watch?v=Q8ccXzM3x8A
[3] https://www.penguin.co.uk/books/301539/the-order-of-time-by-...
We need more Sabine Hossenfelders. Too bad natural hierarchies seek to excommunicate such people.
There is an attraction to having “real” knowledge that everybody else is full of manure, i know some people whose small children have found conspiracy youtube and are struggling at dinner conversation over every “well actually”.
If "low morale" is really the bottleneck then we aren't getting any science done anyway.
And as an aside, I don't believe in group / peer based "science". There's a few geniuses (often not credited) that define the entire thing while everyone else seems to practically be in marketing by comparison.
Science can be a group institution, but educational institutes are far from it.
Criticism and disbelief are the bedrock of Science, and calling people that don't flock to still-unproven claims "science deniers" is very dystopian. There's also entire groups of phenomena that "hard" / popular science conveniently ignores. They all fall under Science by definition, but not under science-the-religion.
Interesting counter-mainstream ideas are important and valuable - but I don’t hear about any of them from Hossenfelder’s writing, and it’s all about how broken “the system” is. Everything I watch or read from her leaves me deeply suspicious.
Anyone from the other side could make the same argument (and they often do).
If you're trying to name a "us versus them" then there's just one big mainstream entity, the rest is fragmented. So it's not really a "red flag" because opposition is by definition not a coherent group.
A fairly serious accusation to make, which you did little to nothing to back up.
* http://backreaction.blogspot.com/p/talk-to-physicist_27.html
* https://aeon.co/ideas/what-i-learned-as-a-hired-consultant-f...
It is kind of a natural progression of abstraction by defining physical objects, in the end you arrive at some endpoint like the “universe”. So, you wonder: “Hmm, in order to study it properly I need more than one. Let me see if there is some viable way to propose it. Which new predictions am I getting? Does it a better job than … ” etc
The same holds true for other frontiers like exobiology, consciousness etc. where one can easily wind up in woo-woo territory.
Hossenfelder mentions Penrose. Another prominent figure who pops up frequently is Stephen Wolfram with the means of financing himself. They are making bold claims which are most likely - surprise, surprise - false. But because the chances are astronomically or cosmologically low it is seen as somehow this high-stake game in reputation. Since there is only a tiny fractions of scientists with a lot of chips (say Noble Prize), when they get on the table the crowd cheers on.
So, unfortunately most play safe in the long term. One such strategy was/is to hide the “trouble” behind ever more sophisticated mathematical abstractions which at least undoubtedly require extraordinary and disciplined mind to be even able to grasp. Ever since Lee Smolin called bs on that I feel that string theorists, now, appear more humble, careful in their presentation and acknowledge the pitfalls. As an popular example Sean Carrol comes to my mind.
To put it constructively: level the playing field and measure your position with the same standard as you evaluate others. The more powerful, diverse and precise shots in the dark in terms of viable theories we get to test the better the chances.
The first principle is that you must not fool yourself—and you are the easiest person to fool. So you have to be very careful about that. After you’ve not fooled yourself, it’s easy not to fool other scientists. You just have to be honest in a conventional way after that.
All this to say, both the current state of our attempts to reach the next frontier of human knowledge (string theory, say) and Sabine's criticisms follow age old traditions of back and forth in science. Both are needed, the former to make actual progress and the later to keep the bad ideas in check.
Having said that, I personally detest the particular populist-with-lack-of-nuance approach Sabine (and others like her) take. I like Sean Carroll's books [2] and his Mindscape podcast [3] for a more nuanced view. For instance, his recent podcast with Raphael Bousso [4] is such a nice overview of the current state of the art Physics. On string theory:
String theory, I think, has given us from my perspective, as far as I can tell, the only consistent candidates for theories of quantum gravity that are in any sense complete. In particular, it has led to the discovery of the AdS/CFT correspondence. That is a lot of letters. But what it means is that there’s a certain class of universes, unfortunately, not including the one that we seem to be living in, but still a very rich set of space times worlds that you can imagine, for which we have a complete quantum theory of gravity. Or at least it could be wrong. We haven’t tested it experimentally. But it’s a very significant statement that you have a theory which is complete in itself, it’s not missing anything. You could put it on a computer and run it, you can calculate things with it. And so that I would say is, from the physics perspective, the number one thing that has come out of String theory, there’s a lot of beautiful mathematical results, and many other applications that the theory has had.
[1] https://www.goodreads.com/book/show/19395553-our-mathematica...
[2] https://www.preposterousuniverse.com/books-courses/
[3] https://www.preposterousuniverse.com/podcast/
[4] https://www.preposterousuniverse.com/podcast/2022/11/21/218-...
Not arguing against the point you are making, just highlighting a silly turn of phrase. Who ever encountered a nuanced populist?
One can hope :)
Sure, there are many examples of scientists clinging on to old ideas too long, but eventually when enough evidence is marshaled by someone to overturn the old model, they are heralded and given honors.
That is all to say: frontier physics is utterly unlike religion, where so may claim to KNOW the truth, where the most tenuous claims are literally gospel, where there is little desire admit counter-evidence.
But they're vastly outweighed by the PhDs working in String Theory which is going on 50 years now with nothing really to show for it experimentally. And they do claim that they know the truth, and they defend their PhDs, and their grants and grad students, with rationalizations that aren't testable and don't admit any evidence. It very much seems like a religion.
Nobody has patched the holes in the theories that I mentioned, but almost nobody works on them, so the problems become self-fulfilling. And it just isn't that easy these days to have a single Einstein come along and upend the apple cart with a handful of rapid fire papers.
There's frontier theologists too that are very open to evidence from all sorts of angles. Yes, most religious people aren't trying to hit new ground, but most scientists (and physics loving laymen) aren't either. Most physicists work within established models, just like most religious people
Theology is never more than rearranging the deck chairs.
You might not approve of them since there's no objective way to measure the validity of religions/religious doctrines, but they're there.
Some of the more successful ones in relatively recent times are for example Martin Luther, Joseph Smith, etc.
You mean when the old guard retires and dies, like Planck said.
That is a good distinction to make, singling out the people who are truly at the frontier of understanding. As you say, they are far less likely to be certain of their findings.
However, I would say it makes sense to draw a similar distinction in terms of religious thinkers, because they're certainly not all the same. If one were to ask those at the religious frontier of understanding, one might well find an analogous lack of certainty as to what is going on.
String theory in particular has had a testability problem from the very beginning. https://www.math.columbia.edu/~woit/wordpress/?p=533
All current observations are also consistent with quark stars. We don't know what the quark degeneracy pressure is, so there's no current way to differentiate.
This is not correct. There is a maximum mass limit for any object supported by quark degeneracy pressure, regardless of the equation of state. That is a fundamental fact about relativistic degeneracy that has the same general consequence for any kind of degeneracy pressure (it was originally discovered by Chandrasekhar when he discovered the maximum mass limit for white dwarfs that is now named after him). What the exact limit is depends on how stiff the equation of state is, but even the stiffest equation of state leads to a mass limit of about 3 solar masses. We know of plenty of compact objects that are far more massive than that.
No one knows the actual quark degeneracy pressure, so no one knows if stars collapse to black holes or if they get stopped.
Because we have these objects with huge masses but we can't see them, and such objects have to be compact. Objects with those masses that do not emit huge amounts of light that make them easily visible (i.e., that are not stars) can't not be compact. They either have to be held up by degeneracy pressure, which means they are either white dwarfs or neutron stars/quark stars, or they have undergone complete gravitational collapse and are black holes. All of those objects are compact, and there are no other possibilities.
> No one knows the actual quark degeneracy pressure, so no one knows if stars collapse to black holes or if they get stopped.
This is not correct. I have already explained why: the maximum mass limit. That limit applies regardless of what the actual quark degeneracy pressure turns out to be in an actual gravitational collapse. It is a fundamental fact about relativistic degeneracy.
You have not explained sufficiently about the maximum mass limit, there are plenty of suns that are enormously massive, but they're not black holes because heat is keeping the density from increasing.
The same thing would happen with a quark star or a strange star, the degeneracy pressure would keep it from ever becoming a black hole, at least until the pressure was overcome but we don't know what that pressure is.
What I'm saying is we cannot distinguish between a black hole and a quark star, not with our present observations.
Yes, I have: I said it applies to objects supported by degeneracy pressure. Ordinary stars are not; as you note, they are supported by thermal pressure. But thermal pressure never lasts forever; eventually any star will stop being able to produce heat and will collapse until it is either supported by degeneracy pressure, or forms a black hole. The maximum mass limit is a limit on the first alternative.
Also, as I said, an object supported by thermal pressure will be easily visible since it will emit lots of radiation. The objects that we believe are black holes are not doing that, so they can't be supported by thermal pressure anyway.
> The same thing would happen with a quark star or a strange star, the degeneracy pressure would keep it from ever becoming a black hole
Not if it is over the maximum mass limit. Sorry, but you are simply wrong as regards what the actual physics says. For the gory details, look up the Harrison-Wakano-Wheeler equation of state, or consult the classic textbook by Shapiro and Teukolsky.
> at least until the pressure was overcome but we don't know what that pressure is.
The whole point of the maximum mass limit is that any pressure, no matter how large, will be overcome if an object is over the limit. That's why we don't need to know what the actual pressure is.
> What I'm saying is we cannot distinguish between a black hole and a quark star, not with our present observations.
And what you are saying is wrong. See above.
LIGO has been able to confirm theoretical properties of the event horizon. The EHT has imaged a black hole, which effectively images the event horizon.
> All current observations are also consistent with quark stars.
Is there a reference for that?
What specific properties has LIGO confirmed about the event horizon? It is not quite clear to me how the gravitational waves of two merging bodies would be different between a merger of normal stellar objects and black holes.
> The EHT has imaged a black hole, which effectively images the event horizon.
The EHT image is mostly an accretion disk. I think accretion disks can also form around things that are not black holes. If something were of the sufficient density, I believe it could make the same image without having an event horizon. I am no astrophysicist though so maybe that image would force the density to be sufficiently high to make a black hole.
No "normal stellar object" can be more compact than 9/8 of the Schwarzschild radius for its mass. (This is a result known as Buchdahl's Theorem, first discovered in the 1930s.) Gravitational wave emission when objects of that size or larger merge is much less energetic compared to the total mass involved than the merger of black holes, which merge at the Schwarzschild radius; also the predicted waveforms are different, because there is actual matter (nonzero stress-energy) present when normal stellar objects merge, whereas black holes are vacuum (zero stress-energy).
Hawking's area theorem is one: https://news.cornell.edu/stories/2021/07/hawkings-black-hole...
> It is not quite clear to me how the gravitational waves of two merging bodies would be different between a merger of normal stellar objects and black holes.
I'm not sure one can be so loose here. LIGO uses detailed models of black hole and neutron star mergers to match the signals against. What are "normal stellar objects" that would yield the same magnitude of gravitational waves emitted during a merge as black holes and neutron stars?
> The EHT image is mostly an accretion disk. I think accretion disks can also form around things that are not black holes.
There's also a huge hole in the middle of the accretion disk. What other object, other than a black hole, has such a large accretion disk but yet no emitted radiation?
Gravitational waves are a prediction of GR but not of quark stars, so GR explains more of the available evidence than quark stars alone.
I don't know where you're getting that from. Gravitational waves can be emitted by any system with a time-varying quadrupole moment. Mergers of quark stars would certainly qualify. Even a single quark star that was wobbly enough would.
Quark stars have plenty of mass, why would you think they would not generate gravitational waves? I don't understand what you could be thinking of.
In fact a black hole would make things more complicated because of the infinite time dilation.
If anything gravitational waves are evidence for extraordinarily massive objects, but against black hole singularities with their problematic infinite time dilation.
This is way too simplistic. Gravitational waves are waves of propagating spacetime curvature. They can certainly be produced by "mass", i.e., by objects with nonzero stress-energy, as long as those objects (or mergers of such objects) have time-varying quadrupole moments. But they can also be produced by objects like black holes (or mergers of such objects), which have zero stress-energy and are made purely of spacetime curvature.
> a black hole would make things more complicated because of the infinite time dilation
There is no such thing. The effect you are talking about is an artifact of a particular choice of coordinates and has no physical meaning. It certainly does not prevent black hole mergers from emitting gravitational waves.
From the point of view of Earth black holes can never merge because it would take an infinite amount of time to do so.
I do not care about the point of view of the black hole itself, or the point of view of an object falling into the black hole.
And it most definitely has physical meaning, and while gravitational waves could be emitted, they can never actually get to the merger.
The gravitational waves would essentially slow down and fade out if it was a black hole.
And since that is not what we see, I do not find the data compelling for black holes, but rather for ultra massive objects.
This is not correct. What is correct is that from Earth you cannot see events on or inside the horizon of a black hole (or of a merger). But the fact that you cannot see those events does not mean they don't happen or that you cannot have indirect evidence for them, any more than the fact that you cannot see objects over your horizon on Earth itself means that objects can't travel there.
> I do not care about the point of view of the black hole itself, or the point of view of an object falling into the black hole.
Nothing I am saying has anything to do with any "point of view". I am stating invariant facts about the spacetime geometry and events in it.
> it most definitely has physical meaning
No "point of view" has physical meaning. "Points of view" are mathematical conveniences that we humans use for calculations. They are not physical things.
> while gravitational waves could be emitted, they can never actually get to the merger.
> The gravitational waves would essentially slow down and fade out if it was a black hole.
Neither of these claims correctly reflect what GR predicts for black holes and black hole mergers. What GR predicts matches observations.
In a different reality, i.e. in a different point of view, it may have happened. And this is not a contradiction, it is merely the way the universe works.
And not only what can we not see beyond the event horizon, as things approached the event horizon they slow down tremendously. Even at quite a distance they slow down so much that our lifetime is insufficient to see them change.
In our lifetime it is impossible to see black holes merge because the time dilation is sufficient to slow that down to imperceptibility.
Sorry, but this is simply wrong as a description of what the actual theory of relativity says. So is the rest of your post. I've already explained why.
Using the mathematics of a physics theory to deny a tautological(?) statement seems to get at the very issue that Sabine is raising in the original article. Alternatively, you're literally arguing that the mathematics of the theory of relativity bears no meaning in reality. (i.e. "The effect you are talking about is an artifact of a particular choice of coordinates and has no physical meaning.") I'm not sure whether your statement is true, but if it is, it seems to prove Sabine's point...
Maybe it does to you, but it isn't a tautology. It's a false claim. See below.
> Is there a substantial difference between "from our point of view" and "as far as we are concerned ... in reality" under the theory of relativity?
Yes. A "point of view" in relativity (by which is meant something like a coordinate chart or a reference frame) might not be capable of describing all of reality. So you cannot infer, just from the fact that a "point of view" does not contain some particular event, that that event is not part of reality. Before you can draw that inference, you first have to show that the "point of view" in question is capable of describing all of reality (which in relativity means all of whatever spacetime manifold you are dealing with).
The "point of view" the GP is trying to use is not capable of describing all of the spacetime manifold we are dealing with. So it does not justify the claim the GP is making, that any event not described by that point of view cannot be part of the spacetime manifold.
> Using the mathematics of a physics theory to deny a tautological(?) statement
Is not what I am doing. I am using the mathematics of relativity to correct a wrong claim by someone who (apparently) doesn't understand that mathematics properly. Everything I am saying is basic general relativity and can be found in any GR textbook.
Doesn't have anything to do with the mistake the poster I have been responding to has been making. Sabine is talking about people who understand a given theoretical model but aren't willing to give it up when it either fails a test against experiment, or is shown to be in principle untestable by experiment. The poster I have been responding to does not understand the theoretical model being discussed, so is in a different position from the people Sabine is criticizing.
> Alternatively, you're literally arguing that the mathematics of the theory of relativity bears no meaning in reality.
I am arguing no such thing. I am simply making clear that, like any physical theory, GR has parts of its math that represent physically meaningful parts of reality, and parts of its math that represent human conventions that make calculations easier but have no physical meaning. Coordinate charts/reference frames, which is what the poster I have been responding to means by "point of view", are in the latter category. But invariants--quantities that are the same regardless of any choice of coordinates or reference frame--are also part of the math of GR, and those do have physical meaning.
I'm probably an order of magnitude less intelligent than her, but her arguments seem extremely reasonable to me. She seem to me to be a bridge from the PBS, pop-science mentality to more serious considerations.
Also, she's a fox. :-)
There is one important difference, though. Religions say that all this has a purpose: the one great consciousness wants to understand itself. Science, on the other hand, believes in chaos.
There are some questions science just doesn't answer and doesn't need to. We might never get the tools to peer past the boundaries of space and time, so speculation made by scientists in those areas is still kind of religious or at least not science. Religion can simply say God created everything last Thursday as if it had always been, and science has no refutation for that and doesn't need one.
Therefore I disagree with your analysis just because currently you can make that analogous comparison. There's probably always something like that because social discourse will spread current science to religion and vice versa, but they do not really need to compete. Also science has a chance of solving it's split but religion and philosophy will bang on about consciousness forever.
The God of Christianity is a concept that is there if you believe in him, and is not there if you don’t. To prove his existence is meaningless. It provides the same struggle as trying to prove that Cassiopeia exists, or what it means at an atomic level to touch an object, or whether complex multicellular organisms are one single being or a colony of many beings.