askchapo

Theoretical physics academia is very cultish. This really isn't an exaggeration. The job of theoretical physicists is to speculate. They have the expertise to justify speculation, and they publish their speculations into journals for their peers to criticism. Yet, despite that, there is an expectation that you are only allowed to speculate on certain things, part of the "reasonable discourse," and other areas of speculation are considered incredibly taboo. This is what I mean by it is cultish.

For example, it is considered part of the "reasonable discourse" to believe general relativity is wrong and is ultimately an approximation for a "deeper" theory we have yet to discover, almost certainly one where gravity is explained not by the curvature of spacetime but by force-carrying particles, those being gravitons. This is part of the motivation for String Theory, as a candidate for gravitons naturally follows from the logic of the theory.

It is, however, extremely taboo in academia to suggest that quantum mechanics might be wrong, at least incomplete. The physicist David Albert talked about how he wanted to do his PhD thesis on an alternative theoretical model which would underlie quantum mechanics, and he was just about kicked out of the PhD program for it. The only reason he wasn't booted was because one of his professors took pity on him and convinced the others to allow the professor to assign Albert a thesis for him to work on.

The philosopher Tim Maudlin has discussed this in length, how physics departments tended to boot people out who questioned the fundamentality of quantum mechanics, and sometimes those physicists would come over to the philosophy department since it was the only place they could get a job. Even the physicist John Bell talked about how his colleagues seemed to sweep under the rug alternative models to quantum mechanics, saying it was bizarre how people kept publishing "impossibility proofs" that an alternative realist model was impossible even though he was holding one his hands by David Bohm which nobody seemed to ever mention.

I kind of encountered this myself when I posted some papers for discussion on a physics forum and found myself immediately banned. I messaged the moderators and asked why I was banned, and I was told that one of the peer-reviewed papers I referenced, one of the authors, that being the theoretical physicist Robert Spekkens, had also at another time published an alternative model to quantum mechanics. The moderator told me that they themselves are a physicist in academia and all his colleagues agree that people like Spekkens are a "pariah" that they are just waiting for them to die off and should not be taken seriously.

That is the state of modern physics academia. Even if you have done all the hard work to get a PhD, even if you engage properly by publishing your papers into respectable peer-reviewed journals, you will still be treated as equivalent to a know-nothing crackpot physicist if you dare put forward a model where quantum mechanics is not fundamental. But be sure to put forward a model where general relativity is no fundamental all day every day.

Likely one of the reasons for the stagnation in physics is the obsessive focus on speculative models trying to replace general relativity without any models questioning the fundamentality of quantum mechanics. There are a lot of interesting things out there proposed by some niche physicists which never get deeply explored.

For example, the physicist Hrvoje Nikoli´c showed you can fit the predictions of relativistic quantum mechanics to a theory of point particles moving deterministically in 3D space with well-defined values at all times in an absolute spacetime by introducing an additional structure to special relativity known as a preferred foliation. The physicist Ilja Schmelzer's also showed you can reformulate general relativity with a preferred foliation and it gives you a very different picture, such as one where black holes are replaced by "frozen stars." Nikoli´c has further showed that there can be a rational reason to believe in this additional structure, because it naturally emerges out of presuming space is discretized, which also solves issues with hard to deal with infinities and opens the way for potentially new empirical predictions as such a model would deviate from Lorentz invariance under certain cases.

Much of what these people tell the public and even students is just mythology as well. Like, the mythology that Einstein's special relativity is one of the most proven theories ever, and was a necessity after the Michelson-Morley experiment, even though when Einstein presented his theory in 1905, it was mathematically equivalent to a theory Lorentz proposed in 1904 and made all the same empirical predictions. There were no new predictions made by Einstein's special relativity, so the idea it can even be said to be "proven" makes no sense because any experiment to verify it would also verify Lorentz's theory.

This also plays into the mythology around Bell's theorem. It is usually stated that Bell's theorem rules out local realism, where realism is just object permanence, the idea that particles have values even when you're not looking (realism doesn't imply determinism, that is a misconception; a realist model can also be a stochastic model). Since special relativity is supposedly "proven," we can't question locality, so therefore we must throw out realism, and then you get all this mythology about how quantum mechanics forces us to believe in weird things like "object reality doesn't exist" or whatever crackpot nonsense they keep publishing in peer-reviewed journals. Special relativity was, again, never proven, and so swapping it out for a theory with a preferred foliation similar to Lorentz's changes none of the predictions, yet allows you to fit it to a realist model, a simple model of point particles moving in 3D space with well-defined positions at all times.

Models like these are intriguing but never broadly studied because they go against the "reasonable discourse." You get a few niche physicists occasionally who study such alternative models, but often they have to form their own alternative organizations to even get them any funding.

Theoretical physics has a problem where the most famous scientist ever was a theoretical physicist, so people have high expectations for it to churn out new mind-bending ideas to write pop sci articles about, but mainstream theoretical physics has come to some deeply unsatisfying answers, so only weirdo fringe theories like string theory get pop sci attention.

The real thing is still the standard model, which is a catalog of sub-atomic particles that everything is made of, and their interactions.

One of the main things they're up to now is figuring out dark matter. There's a dozen ways you can measure how much mass there is out there in space, and they all agree that there's way more than we can account for with stars. We really don't know wtf the other stuff is, and all the candidates have problems. More gravity measurements will probably help. The actual work-end of that is telescopes.

You're right to be sceptical and again right to point out, that the distinction between theoretical and experimental physics is unique among the sciences. There's a good reason and a bad reason. The good reason is, that physics needs so much math, that math can't always keep up. Theoretical physics sometimes delivers the math to experimental physics that's needed to model real experimental findings.

The bad reason is that some fields of physics, like particle physics, have been stagnating for about fifty years. Many important experiments have been done since than, but they only confirmed the standard model and didn't produce any big surprises. And for what open questions exist, theoretical physics didn't produce any new models or theories that could be tested in praxis (or mostly even in principle). That's the second reason why theoretical physics split from experimental physics. The models in development diverged from the models in use and the two stopped being linked by experimental results.

However, that's only true for some subfields (particle physics and foundations). In quantum computing, quantum mechanics, solid state physics, cosmology, fluid mechanics and other fields, theory and experiment continue to work hand in hand and produce amazing results. And even in particle physics, things are not that black and white and new ideas are being tried out.

Respectfully, even most geology falls into the realms of the theoretical. We have theories of how a sandstone gorge is formed, but no one has been doing the measurements for long enough to know for sure. We have simply created a model that fits the observed phenomena available to us and have created theoretical abstractions based on that model.

Otherwise, theoretical physics relies on a creation of predictions that could be mathematically true, based on inferred extrapolation of the current, contradictory, models but ultimately haven't actually been able to square enough circles in the field of experimental physics to be widely taken as whole scientific.

For example, there are aspects of string theory, such as long distance quantum pairing, that have been shown to be true experimentally, however, overall experimental data does not demonstrate to a statistically significant degree that the actual reason for this phenomena is because the universe works through a string theory model, there are too many other things that fit other, contradictory theoretical models.

So my understanding from people who have been in physics either making YouTube videos or just talking to me:

The headlines are usually over-sensationalized. String theory especially, to this day, hasn't made an experimental prediction irrc. In fact string theory specifically I don't think CAN be tested because of how it's laid out? It's got math to it but not a whole lot you can check. Doesn't make it bad I guess but it just hasn't produced results (yet... maybe).

But theoretical physics works very well and you can have it because physics is just math. So much fucking math. But just math none-the-less.

What makes theoretical physics valuable, then, is that it guides experimental physics.

Good example: Einstein did a lot of math and figured out the universe /should/ bend with gravity. And you could check that by seeing if light bends with gravity. Then they figured out "okay if we look at Venus next to the sun, it should look like it's in the wrong place according to the math we have now, but it should look like the right place according to the math Einstein did" and BAM it did. The sun bent the light coming from Venus.

If Einstein didn't do the theoretical work, not very likely anyone would've thought to potentially damage a telescope by looking at Venus next to the sun when they could just look at it any other time... Or something like that. Mightve been Mercury or a comet or something.

So anyways: if the theoretical physics can explain all existing observations and it can predict new observations, then all that math can be used for new theoretical work to tell scientists to look at things they usually wouldn't bother with because some NERD did a lot more math and saw something kinda funny.

There are definitely theoretical parts of other studies too like that, but physics gets its own very very very definite Theoretical section because it's literally just a bunch of math problems to begin with. You still need to confirm that your math is right through observation, but it's still math ultimately.

from what i remember during my bachelors degree in physics, theres two main things going on:

• Proving more of the Standard Model. The standard model governs pretty much all particle physics. So far a lot of it is proven experimentally. But there are still things that are predicted, but not yet verified. This is stuff that the Hadron collider and CERN are doing

• Reconciling General relativity and quantum mechanics. At large scales, GR is pretty much proven. At small scales, QM is pretty proven. But both theories are incompatible with the other. Dunno much about this personally. They're looking for a Grand Unified Theory.

String theory is just bunk science, don't need to really investigate it any further.

String theory is just some math* that people like that got hyped up, and it's a fringe view in modern physics because it doesn't have the ability to predict anything that other theories can't. Angela Collier is a theoretical physicist who posts lots of youtube videos about her field and other subjects, including a weird one about string theory where she's playing the Binding of Isaac for some reason while complaining about how string theory destroyed the reputation of theoretical physics in the popular imagination.

Geology seems like it could be a good point of comparison because a lot of geology is based on things that we can't exactly demonstrate in experiments because it takes place over millions of years, but there are a lot of more directly testable things that we do know and we can synthesize those conclusions to draw conclusions about things that can't be directly tested.

*Theoretical physics in general has lots of math but more popular views also present testable hypotheses.

there are lots of observations about the universe which are interesting For example, magnets light and electricity seem to be interlinked by a set of relationships. Theoretical physics is about developing frameworks (sets of equations usually now) that match all experimental data and explain those relationships. Or answer puzzles/propose conditions under which experiments might illuminate them like why do magnets not have monopoles?

A lot of theoretical physics outside of the headlines is computational stuff, models for predicting material properties of things that don't exist yet for example.

Physics is a large domain, so this is like asking how modern medicine works. You should be as baffled about acetaminophen, according to your reasoning, as you are about dark matter.

As with all sciences, physics is speculation and analysis based on empirical data. When our speculative theories cease to line up with the data, then we speculate some more, sometimes in radically new ways. This was the case when quantum mechanics came about, to solve problems like the UV catastrophe which were not explainable with classical mechanics.

Carefully constructed models on what should exist, and how those things should behave if they exist, then experiments that show these things behaving as predicted, therefore validating the model. It's an inductive process like dialectics. You move between theory and praxis, updating theory and adjusting action. Though this kind of paints a picture that all science is experimental when it's not and yet is equally valid. Like lots of stuff in geology can't be observed directly due to time scales or ran as a experiment. In a way there's more experimental data supporting the wave-particle duality of light than experiments supporting plate tectonics. It becomes just thinking about stuff really hard, and looking at stuff very closely to make sure you're observing it the right way. Make predictions about what you should find next if you're correct.

I dunno. You hear about experiments from time to time where the collide some hardons and count neutrinos or something.

It's mostly just math innit? Like, we notice that the arms of spiral galaxies are spinning faster than we would predict under the Standard Model's gravity math, so there must be some other thing happening. That's where you get dark matter.

Or we notice that the universe is expanding faster than the Standard Model's cosmic inflation math would predict, so there must be some other thing that's making it faster. That's where you get dark energy.

But it's all just math.

It's a scam meant to keep academics employed. It's all unfalsifiable but it leads to money and prestige for its followers. There's your answer.
This explains most of the soft sciences, frankly. "We must protect our phoney-baloney jobs!"

At the risk of oversimplifying, the experimental branch of a field tries things to see what happens, while the theoretical branch takes those observations about the world and tries to explain why it's like that. They don't call it theoretical geology, because there's essentially no such thing as experimental geology, so it's redundant. (Ain't nobody got time to run an experiment that lasts a few million years, or funding to buy a test planet.) Geologists can mostly only try to explain what we can see about the Earth. In physics, it's the difference between bashing particles together to measure what flies off, versus figuring out why those particular things flew off.

They properly ought to be complementary, with the theorists coming up with new hypotheses for the experimentalists to test.

Depending on the area they build giant race tracks and crash particles into each other and see what happens. That's pretty cool. They once had a weasel to clean the machine but they stopped retaining their services when they pooped in it