[dieselgate]

> The thing is, we are wrong, but this stuff is useful to make predictions

I understand where you're coming from but this is a very cynical take. String theory is a strawman compared to the empirical "discoveries" of items like black holes or the Higgs boson.

[ColdStream]

I think it is similar to the 'All models are wrong but some are useful' adage.

There is reality and there is the math at which we point at it with. The pointing will never be reality but that doesn't mean it is useless.

In the same way you cannot blow the wind with the word 'Fan'. But the concept of a fan is very useful.

[jambalaya8]

Aye, but we only sorta kinda "know" what things like black holes might be. We have models that make sense to us based on our understanding of science, and we think our instruments can faithfully report on what they can be with measurements we believe we are making correctly, but we have no clue what we don't know, and no real way to prove it, just theorize, and sort of bundle up what we believe is data supporting it.

[mmooss]

> we have no clue what we don't know

We have very good ideas about it, including the issue described in the OP. We also don't know how gravity and the other forces work together. We don't know where other life is in the universe. We don't know how to travel to other stars. We don't know what is under the surface of Europa (but we'll soon find out).

And we have a very good idea of what we know because our theories, based on our observations, predict things accurately.

The original upthread comment and followup seem like taking some philosophical questions to logical extremes.

[jeremyjh]

There are so many observations that fit the theory at this point, that we know there is a supermassive black hole in the center of our galaxy just as well as we knew the earth orbited the sun before the voyager flight.

[jambalaya8]

Well, not really. We can hypothesize there is certainly something _very_weird_ going on in the center, and we kinda know weird things happen at super-densities, and we can conjecture based on our understandings of things like gravity and celestial collapses, but any new black holes or even ones we know of that might have occured won't be in our timeframe, and we can never actually witness one even if it were (short of it suddenly happening to our own glowy ball of gas, but there'd hardly be a you to witness it)...

People like Wheeler and Hawking came up with theories and people basically sought to prove or disprove them, but maybe we have a limited capacity to think outside of those boxes. Like, who really knows, maybe the big bang had similarities... who knows how being close to a black hole really affects stuff like space-time curvature.

[ButlerianJihad]

> People like Wheeler and Hawking came up with theories and people basically sought to prove or disprove them

Basically, except that theories aren't "proven".

[jambalaya8]

I can totally prove 'theories' of mechanics (including planetary mechanics) using calculus-based physics, given a writing instrument and some notepaper; prior to centuries of that then-evolving thing we now take for granted (math, in its advanced forms, including multivariable calculus, differential equations, polar geometry, modern trigonometry, modern algebra (the grad-level stuff), that would not be possible. Though, likely since as long as humans have walked the planet, they had seen 'proof' with their own eyes (collision physics, metabolism, bulldings not falling down randomly).

But stuff like black holes, special relativity, etc, are like phenotype vs genotype: the former you can witness and deduce, and prove, and witness the proof. The latter, you can witness instruments, hypothesise, use math, use instruments, deduce... you aren't really witnessing the stellar event though; you are merely witnessing instruments and playing matching games.

Humans will probably never ever be able to measure or witness what would really happen if you tossed a Cabbage Patch Kid into a black hole, no less an exoplanet or whatever. We will almost certainly never be conscious and anywhere near an accretion disk, nor even have cameras that can show us them, nor be able to toss that Cabbage Patch Doll in. Yes, we can hypothesise and 'sorta prove' there is a whole lotta denseness going on, but our ability to really understand it IS somewhat limited to numbers.

Theories are theories until proven multiple times. But even when we prove them, that doesn't always mean the theories we built around them are also right. For instance, maybe there are things that can seem like supermassive black holes that are something else entirely.

[ButlerianJihad]

> planetary mechanics

There may be a language-barrier issue here, because you've already used an uncommon term. You also put 'theories' in quotes, as if they are not actually called theories? Are you thinking of theorems in mathematics?

https://en.wikipedia.org/wiki/Theoretical_physics#Physical_t...

  A physical theory is, at its core, a mathematical model of some set of physical phenomena. It gets judged on two main grounds: how well its predictions match what we already observe, and whether it can successfully predict new things that can then be tested...

  It is also worth being clear about what a physical theory is not. A mathematical proof establishes the truth of a conclusion given certain axioms, and that is that. A physical theory, however well-supported, remains permanently open to revision by future observations. That is not a weakness. It is the defining feature of a science that is actually trying to describe the world rather than merely exploring abstract structures.[6]

> I can totally prove 'theories' of mechanics

I don't think you can. We know that orbits and ephemera can be calculated to a high degree of accuracy, and there's abundant evidence of that. But even here, the three-body problem exists, and perturbation theory is actually a theory. If you extrapolate your pencil-and-paper calculations for the orbit of Europa, for example, 3,000 years into the future, you'd have discrepancies. Our formulas are not proofs but approximations, even still.

Proofs can be written for purely mathematical aspects--even the math in theoretical models--but a mathematical proof is guaranteeing the equation and the soundness of the mathematics; it is proving a theorem, not "proving a theory".

  In mathematics and formal logic, a theorem is a statement that has been proven, or can be proven.[a][2][3] The proof of a theorem is a logical argument that uses the inference rules of a deductive system to establish that the theorem is a logical consequence of the axioms and previously proved theorems.

https://en.wikipedia.org/wiki/Mathematical_proof

> phenotype vs genotype

I don't see that. GPS actually takes into account both special relativity and general relativity, in different ways, and thereby confirming predictions made by these theories.

"Black hole" is simply a conventional name we've given to a prediction arising from general relativity. General relativity has been a robust theory, with predictions confirmed, and with no significant falsified predictions.

> Theories are theories until proven multiple times.

This makes no sense at all.

> But even when we prove them, that doesn't always mean the theories we built around them are also right.

You've doubled down on the nonsensical. We've lost the plot here.

[oersted]

Well, it seems that the question still remains somewhat open. There are theories that fit the data as well or better than the black-hole model.

My naive intuition is that this is mostly just physicist publishing papers and throwing some exotic ideas out (we still don't know enough about dark matter), and that the black-hole model will remain as the consensus. But it's not as unquestionable as you say it is.

> An alternative to the black hole (BH) scenario has been recently proposed in terms of a supermassive compact object composed of self-gravitating fermionic dark matter (DM).

https://academic.oup.com/mnras/article/546/1/staf1854/843111...

> Sagittarius A* Might Not Be a Black Hole

https://youtu.be/7tRww03EKlk?si=0XcJ1yw-gPj1IzQW

[jambalaya8]

I am one of those people that feel that dark matter is not something humans should be studying too much. Just like hadrons, wormholes, and those people interested in creating lab-based little black holes. It strikes me as naive and dangerous to assume all physics is meant to be studied. Just because we know splitting atoms can make really big explosions, for instance, doesn't mean it might not have had other effects on the fabric of the universe we lack the mental facilities, advanced knowledge, or context to fathom.

[jambalaya8]

Still remembering how many people bought into m-branes and p-branes.

[jeremyjh]

Black holes are simply a consequence of GR, which has made more successful predictions than just about any physical theory. Did M-branes make any successful predictions?

[blooalien]

"The more you know, the more you realize you don’t know." — Aristotle

[shusaku]

The more you know, the more you realize you don’t know to whom you should ascribe a quote.

[blooalien]

@shusaku> "The more you know, the more you realize you don’t know to whom you should ascribe a quote."

Well, so far I see variants of this particular quote from Aristotle, Einstein, and Voltaire. Someone else probably said it earlier than any of 'em probably, but I honestly don't care enough to dig any deeper than this. Besides, half the time I've dug deeper into Mark Twain or Albert Einstein quotes (just for a couple really common examples) I find that they're attributed with saying a thing they never actually said anyhow, so... :shrug:

https://motivane.com/quote/more-you-know-more-you-dont-know/

https://www.goodreads.com/quotes/620163-the-more-i-learn-the...

https://wiseopinions.substack.com/p/voltaires-paradox-about-...

[odyssey7]

Could have learned a thing from Socrates.

[BobbyTables2]

and Donald Rumsfeld (;->

[CuriouslyC]

The Higgs and black holes are quite different. We've basically observed Higgs according to how we've defined them, while we've only observed phenomena consistent with black holes as we hypothesize them. Singularities are the result of theories based on (ironically named) real numbers, it's entirely possible that what we call black holes are really dark stars formed from exotic matter that can only exist in hyper-extreme conditions, like a leveled up neutron star.

[i_no_can_eat]

The difference is that we have theorerically sound formation scenarious for black holes under very broad conditions, and we have absolutely no model for a formation scenario of such an exotic dark star.

[mr_toad]

Observations keep poking holes in those hypotheses (I’m not sure they even count as theories). We keep finding black holes with anomalous masses, or black holes that formed too early.

Part of the problem is that we have very little observational data. But another big problem is that our best ideas, based on general relativity are known to be incompatible with quantum mechanics.

[i_no_can_eat]

My comment was specifically about those alternative "dark stars" hypothesis. Is there one with a formation scenario?

[CuriouslyC]

That's gated by a constructivist replacement for general relativity and a deeper understanding of heavy quarks. Science marches on.

[gtowey]

The thing is we have a lot of models which make very accurate predictions most of the time, which are useful for doing some impressive science.

But we have no accepted theory of what is actually happening behind the math. What we have is that in 1925 most theoretical physicists decided that we have already uncovered the most fundamental structures of the universe and further investigation into how or why things are the way they are is fruitless. This view has dominated for the last 100 years. Physics has been focused only on modeling and testing, but nobody knows exactly what the models are telling us about the universe.

I agree with the above poster that this is wrong and we may yet learn that our models are only very close to reality, but the actual mechanics are different. At least I think more research should be pointed in this direction.

[exmadscientist]

> in 1925 most theoretical physicists decided that we [are done]

No. Just... no. Even advancing that fifty years to 1975, the Standard Model reigns not because people want it to reign, but because no one can knock it off its throne. There is no better idea that can explain more than the Standard Model can. It's not a conspiracy.

(I did used to joke with my students that progress in physics stopped around 1975, which is around when LSD got banned, so there might well be a lack of ideas. But I'll leave that one to the reader!)

[podocarp]

From my understanding of the parent I think he's not saying that nothing is trying to replace the standard model etc. But instead nobody is trying to explain the standard model (or whatever).

For example, wavefunction collapse. You can see the wikipedia page for all its interpretations. There's no such page for Newtonian dynamics (even though gravity is also spooky action at a distance) and classical EM (you're telling me there's more of these fields everywhere I can't see).

I think it's simply because classical experiments are a primary source and quantum experiments are a secondary source of information. The classical case you just see and know the result. Quantum experiments you're always looking at some medium that detects or measures or whatever the original interaction. So you're only interrogating the detector, not the original particles or interaction. So of course we're stuck with an interpretation problem. It's the same problem with news. The primary sources are always 100% certain what happened because they saw it. The secondary source will allow for more interpretation because they have heard from multiple primary sources, etc.

[mr_toad]

> Quantum experiments you're always looking at some medium that detects or measures or whatever the original interaction. So you're only interrogating the detector, not the original particles or interaction.

Exactly, waveform collapse is a philosophical question, it’s not an actual problem for the theory.

[oersted]

I'm reticent of falling into this endless conversation again, but it's a bit addictive.

I believe the point is that the Standard Model is still built on Quantum Field Theory, but looking into what's really going on under quantum mechanics is a bit taboo and very few people are spending time on it.

Frankly, I acknowledge that I am an outsider and that surely my perspective is far too naive and simplistic, I'm sure the reality in the field is far more nuanced. But still, I'm in good company when I question what's going on, like Einstein and many other prominent physicists have.

It is true that the end of the conversation was just "shut up and calculate", which is wise on some level, but it also implies that the mathematical model is the end-truth and you should unquestionably just build on it. There is a consensus that the mathematical model of quantum theory is really what is mechanistically happening, and that the wave function is a real physical thing.

But one can also argue that it is merely a probabilistic theory that, yes, describes the probability distributions of what will happen extremely accurately, but still is a partial answer and it doesn't actually predict what will happen. In every other context, we use probability to describe processes that we don't have a complete model for. It is a bit presumptuous to think that in quantum mechanics probabilities are somehow fundamental and not emerging from more deterministic underlying phenomena.

You can have a theory that says that there's an equal likelyhood of getting heads or tails on a coin, and that theory can reflect the statistics extremely accurately. But that is obviously not the end of the story, there are deeper mechanics determining if you get heads or tails at each given time, it is not fundamentally random, you just don't fully understand what's going on yet.

[HappMacDonald]

But the real litmus test is and always has been "can a theory predict the results of empirical measurements (such as controlled experiments) more accurately than its competitors".

The Danish-interpretation quantum physicists might urge you to shut up and calculate, but what we lack is any model capable of both describing why and how the wave function collapses and simultaneously offering more accurate predictions than QM does. The most well known low hanging fruit being: describing events in noticeably curved spacetime (or put in other words, in situations where the effects of gravity are non-trivial) because we don't even need a better model to know that QM breaks there, QM itself will happily tell us that much by piling on infinities and singularities that can no longer be canceled via renormalization.

So the take home is less "shut up and calculate" and more "don't waste their time with speculation about underlying mechanics until it can also offer more accurate predictions, and until then redirect your energies back to calculating: making use out of the tool we already have at least".

If nothing else, familiarity with the tool that does work up to a certain standard is more likely to lead someone to the next big step than hanging back in the wings of Newton and Aristotle with layperson intuitions about macroscopic objects in terrestrial gravity.

[oersted]

Of course, but such a theory doesn't pop out of nowhere. Like in any technical field, new paradigms are always inferior to the incumbent on key metrics, and need room to be nurtured for long periods.

My perception is that there's a cultural issue suppressing the investigation of the causes of quantum mechanics, making it much harder for a better theory to flourish.

It's also really-really hard. If you take my earlier example, the probabilistic theory of the coin-flip is worlds apart in terms of complexity from a real understanding of the forces acting on the coin when it's flipped. It's a massive gap to jump over, you have to come at it from another easier and longer path, like it was done with classical physics.

[exmadscientist]

Yes, this, exactly.

The moment someone has a theory that's experimentally testable somehow (somehow possible, anyway), there will be plenty of interest. There has never been such a theory to date.

Until that arrives, it's all just hot air.

[inigyou]

A new theory could also explain known observations using fewer assumptions. The standard model has a lot of odd things baked into it - why these specific quarks and leptons? Why no right-handed neutrinos? Most simply, why does each particle have the rest mass it does? And why is there a Higgs field that's very similar to the field of condensation of Cooper pairs in a normal superconductor, but with more dimensions?

Solving just one "why" question might earn you a Nobel prize.