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Why the foundations of physics have not progressed for 40 years

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Re: Why the foundations of physics have not progressed for 40 years

#291

Post by [deleted] »

SiempreViernes wrote: post #247
jfengel wrote: post #200

Earlier quoted context omitted.

It sounds like that only because scientists reformulate their models in terms that people are familiar with. Actual physicists don't work in terms of the gamma correction factor; they work in tensor fields that don't look anything like conventional arithmetic. But they can pare all that down to something expressed in terms people are familiar with. And that has the bonus purpose of helping them understand why the fam…

Don't worry about it, I think you're talking to a NN stuck in a local optima around the term "overfit".

[deleted]

Re: Why the foundations of physics have not progressed for 40 years

#292

Post by nonbel »

ChrisLomont wrote: post #279
nonbel wrote: post #222

Earlier quoted context omitted.

Matter/anti-matter asymmetry is expected to be present. It is a basic feature of individual random walk instances using symmetrical laws that about half will be dominated by matter and the other half dominated by antimatter for long periods of time (although the "universe" may pass through pure energy states as it switches between the two). While there is a balance on average and in the long run, there is not for ind…

>Matter/anti-matter asymmetry is expected to be present. It is a basic feature of individual random walk It may be the cause, but it is not known to be the cause. And it's not a random walk; black holes accumulate charge from pairs, making future radiation not symmetric. My understanding is that people have probed this for some time and it's still inconclusive if it can generate the observed imbalance. Here's [1] a 1…

Nice link, thanks.

Re: Why the foundations of physics have not progressed for 40 years

#293

Post by K0SM0S »

jiggawatts wrote: post #283
K0SM0S wrote: post #272

Earlier quoted context omitted.

I 100% agree with you in all respects — I don't come from a physics background but I hear you loud and clear. I think the 'why' is deep and psycho-historical in nature: - we're exiting the "industrial" mindset where everyone is the same making the same products, to a wider topology of knowledge and skills (more and wider horizontals, more and bigger verticals, 'average' profiles become 'scattered'). This clearly driv…

GA is just "strongly typed" vector algebra. It recognises and embraces the inalienable fact that areas and volumes are fundamentally different to vectors and scalars. The reason Physics "went wrong" is that in 3D space (only!) the mathematics of areas and vectors is coincidentally isomorphic, so it's possible to cheat and use only vectors and scalars and then everything "works". Similarly, volumes and scalars are eas…

Wow, thanks so much for all this. I've yet to digest it fully but it's a terrific intro, I love how you worded some of this. You should consider teaching! :)

I can't elaborate much, so just a few "mind blown" moments for posterity:

> GA is just "strongly typed" vector algebra.

That's one hell of $1B slogan, at least around these parts! :) Shut up and take my money.

> in 3D space (only!) the mathematics of areas and vectors is coincidentally isomorphic, so it's possible to cheat and use only vectors and scalars and then everything "works".

I never realized that... there's indeed a lot of confusion in my mind between those concepts. I fail to see how "different" they're supposed to be, I guess really need to go back to sane basic in that regard.

> Geometric Algebra has various subsets that are also closed algebras in their own right.

Just wow. I love this. I actually need this.

> GA has no such restrictions and the same formulas work in all dimensions, including high-dimensional or with degenerate metrics. Problems from classical geometry such as finding tangent lines to circles can be trivially extended to finding tangent hyperplanes to hyperspheres, even for very complex problems.

So that is the real kicker for me, because it fits my problem space so well. I'm exploring highly-dimensional models (basically letting complexity arise from the dimensionality of rather simple/elementary objects, rather than trying to shoehorn complex functions in low-dimensional space in hope of pretty much randomly finding "better fits" — it's a strong desire to not interpret the data before the fact, to remove bias from modeling itself).

There's interesting research around geometric deep learning as well, which seems largely informed by physics as well, and this is sort of the logical conclusion of that for big datasets.

I think industrial use may rise greatly based on this first take. But it's always a generational thing with culture — it takes ~25 years give or take for those who "grew up with it" to finally become the majority of the workforce and sway things their way. Same with politics — looking at you, academia. As you said, "but by this point they're so used to wiring up breadboards manually that it's too late to teach them how to do anything properly."

> It's nuts.

Yeah, it'll take time, never mind how infuriating in the meantime. But good on you, spreading the word about GA is exactly how we move forward, one post, one topic at a time. Eventually, we get there.

Re: Why the foundations of physics have not progressed for 40 years

#294

Post by goatlover »

lmm wrote: post #278
cletus wrote: post #164

Does anyone else feel like the abstractions and models in physics have gone passed the point where the casual outsider (even a technically and scientifically minded one) can no longer intuitively understand it? Because that's how I feel. There are so many things I just don't understand now like: 1. I originally thought the Heisenberg Uncertainty principle was a natural consequence of using particles (photos) for meas…

> 1. I originally thought the Heisenberg Uncertainty principle was a natural consequence of using particles (photos) for measurement. Instead however it seems to be a fundamental property of the universe, which I only learned after finding out most of the mass of hadrons comes from the relativistic motion of quarks and it explains why hadrons don't collapse to a point. > 2. What does it even mean to create more space…

> We're getting further and further away from everyday experience, and so more and more of the fundamentals of reality have to be understood from mathematical first principles rather than everyday intuition.

How much of that is an insistence on thinking of things in terms of fundamental particles and definitive properties instead of fields and packets of energy? I guess the question is that what the mathematical models are really about, and whether we're just having a hard time shrugging off Greek atomism and 19th century materialism when it comes to intuition?

Intuition could be built on top of a solid understanding of fields, backed by the math. The difficult part is connecting that to the classical world of our size that we experience.

Re: Why the foundations of physics have not progressed for 40 years

#295

Post by goatlover »

Koshkin wrote: post #280
paganel wrote: post #233

Earlier quoted context omitted.

I may be in the wrong here, but afaik mathematics has not "re-invented" itself after WW2, to take it a step further, I fail to see how we're doing different mathematics compared to what Newton and Leibniz have put on the table. Even if we look at the "greatest" post-WW2 maths result, Fermat's Theory, I don't see any new reality-related insights that it has brought us, and I'll go another step further and I say that e…

First off, mathematics did actually reinvent itself in the late 1940s, with the discovery of Category Theory, which, despite being sometimes called “abstract nonsense”, has found its way into theoretical physics. Further, there is nothing mystical at all in any of the concepts of the modern physics - not more anyway than in the concept of, say, the atom. It is actually math that should be credited with the removal of…

> there is nothing mystical at all in any of the concepts of the modern physics

Nothing mystical, but there certainly are deep questions, which is why we have the various interpretations of QM.

Re: Why the foundations of physics have not progressed for 40 years

#296

Post by guerrilla »

bordercases wrote: post #113
Psyladine wrote: post #76

Earlier quoted context omitted.

>Like a psychologist, thus, the philosopher of physics succeeds by eventually making themselves superfluous. Yes, my doctor too has a thankless job of treating disease & injury in me, where once he succeeds, he has no purpose in life.

His purpose is the next patient! A better analogy is "once my doctor successfully advocates for better health habits and I achieve them, they are purposeless."

I believe that was the point, phrased in sarcasm. Philosophers move on to the next thing after they hand problems to science.

Re: Why the foundations of physics have not progressed for 40 years

#297

Post by guerrilla »

philbarr wrote: post #19
MiroF wrote: post #4

Earlier quoted context omitted.

Great series to all who haven't read it!

It is a really good series, even if it is a bit like reading a sci-fi story whilst being beaten over the head with a physics textbook.

That's the best part!

Re: Why the foundations of physics have not progressed for 40 years

#298

Post by lmm »

goatlover wrote: post #294
lmm wrote: post #278

Earlier quoted context omitted.

> 1. I originally thought the Heisenberg Uncertainty principle was a natural consequence of using particles (photos) for measurement. Instead however it seems to be a fundamental property of the universe, which I only learned after finding out most of the mass of hadrons comes from the relativistic motion of quarks and it explains why hadrons don't collapse to a point. > 2. What does it even mean to create more space…

> We're getting further and further away from everyday experience, and so more and more of the fundamentals of reality have to be understood from mathematical first principles rather than everyday intuition. How much of that is an insistence on thinking of things in terms of fundamental particles and definitive properties instead of fields and packets of energy? I guess the question is that what the mathematical mode…

> How much of that is an insistence on thinking of things in terms of fundamental particles and definitive properties instead of fields and packets of energy? I guess the question is that what the mathematical models are really about, and whether we're just having a hard time shrugging off Greek atomism and 19th century materialism when it comes to intuition?

I don't think it's "Greek atomism and 19th century materialism" to imagine a world made of persistent physical objects in well-defined positions. That's the entirety of everyday life.

Re: Why the foundations of physics have not progressed for 40 years

#299

Post by nablaoperator »

brutt wrote: post #196
nablaoperator wrote: post #185

Earlier quoted context omitted.

Try not to be discouraged, it's okay to talk about physics. But try to use the right language for it - mathematics. In online forums, physical ideas or questions are often described in words, which is subject to so much imagination that it can be considered philosophy, but not physics. It's almost pointless to talk without mathematical support. Words are words and have no special meaning. In the example above: A bett…

So what need to be changed in properties of Nature to switch EM with Right Hand Rule into EM with Left Hand Rule? Can you explain this using a formula? Where we can expect to see EM with LHR? Can we see it in our Laniakea? Or at opposite side of Shapley Attractor - Dipole Repeller? Or at perpendicular one? Do we have void between RHR and LHR? Can we cross it? What is nature of EM? Is it because of nonlinear trajector…

I can't take you seriously anymore.

Re: Why the foundations of physics have not progressed for 40 years

#300

Post by pas »

effie wrote: post #234
cletus wrote: post #164

Does anyone else feel like the abstractions and models in physics have gone passed the point where the casual outsider (even a technically and scientifically minded one) can no longer intuitively understand it? Because that's how I feel. There are so many things I just don't understand now like: 1. I originally thought the Heisenberg Uncertainty principle was a natural consequence of using particles (photos) for meas…

Yes. First, intuition depends on your experience. If you never studied physics, most things will be nonintuitive (heavy bodies don't fall faster than light ones? really?) Second, modern 20th century physics education (courses, textbooks) suffered sustained corruption of methodology by scientific authorities, where the quest for understanding was renounced in favor of "modelling" and "prediction" (e.g. authors of orth…

Hm. Comparing paradigm shifts with model based realism is not really valid criticism of either, yet understandable.

The folks who just added one more term to the old stuff to make it predict better - let's call them the old guard necessarily did it to point out that old models can become slightly new ones too. Even if in the long run they will be seen as the evil holdouts.

Yet at the same time we know that just whipping up a new fancy maths model won't solve anything in itself. New models need to make new testable predictions.

And then even new models require lengthy fine tuning, which requires costly experiments.

Alas textbooks are very often terrible, but not because they emphasize predictions and models over "understanding" - but usually because they omit to elaborate on how to select the better of two models, how paradigm shifts happen, how anomalies are ever present - and thus make practical model selection even harder. Plus they regularly fuck up the math explanation part, exactly because they use terrible language and models.

Finally, it's always data that cleans up the mess. Either practical usefulness - engineering, applied science. Quantum experiments, q-bits, and so on. And on the high-energy end cosmology and astronomy.

Anyone harking about how the crisis is about politics usually wants to allocate more money to theorists, so we will finally get breakthrough theories. Yeah, great, we already have a lot of those, but without data we don't know which one to take seriously.

Furthermore pouring money into theory is a nice idea, and comparatively cheap (compared to a new collider), but that won't solve the very pragmatic employment question for the collider builders. (Who are out of luck anyway, because the era of building bigger underground circles seems to be over. But they would gladly build anything, but they won't make good theorists, even if pundits' articles seem to imply there's a simple slider between theory and experimentation.)

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