Has Physics Lost Its Way? | Hacker News Reader

Has Physics Lost Its Way?

nytimes.com

56 pointspseudolus38 comments

I think this book [1] makes a similar argument, but in more concise and direct terms. The gist of the argument is theoretical physicists have wasted too much time and effort trying to come up with elegant math and grand theories that sound plausible but can't be tested or, when they can, fail the test. And rather than acknowledging that, the field as a whole keeps digging in without making much progress.

[1] https://www.goodreads.com/book/show/36341728-lost-in-math

And there are also at least two other somewhat older books in the same general vein: Not Even Wrong and The Trouble with Physics. To the comments in a couple of other posts, it's not clear to me why one would write yet another book on this topic unless they're also proposing useful alternative approaches.

I wonder if it is the same thing that stalled AI research for decades? After the initial burst of hacks that seemed really impressive (ELIZA for example), the field focused on finding formal mathematical solutions to the problems and effectively stalled for 30+ years. It's only in the past few years with a shift to doing statistical things on large sets of data--something that feels a lot more like the hacky original efforts--that it feels like we're making any progress again.

This is from a outsider's point of view so it may be completely wrong. But I did try to take an AI course in the late 90s and it was so far divorced from computer hardware that I joked it should have been in the math department.

Neural nets had been in development since the 80s. The hardware became powerful enough to take advantage of the research quite recently.

AI today is still pretty divorced from hardware-level details, unless you’re working directly with GPU code. When I took a machine learning course, it was much more math than coding

CS has historically been associated with the math department at many schools. At many others, it's in the engineering school but that's by no means universal.

I don't really see any disconnect between CS and math.

As with most of what Sabine writes, the book is very one-sided, in that it gives the reader the impression that a free-thinking person can only come to one reasonable conclusion, i.e. complete agreement with the book. It also gives the false impression that the field is much more single-minded than it actually is.

And honestly, even if you do agree with the book in every detail, "just make correct predictions, bro" is not at all helpful advice for actual physicists. There is a massive set of possible predictions, only a tiny fraction will be right, and everybody is already incentivized to look as hard as possible for that tiny fraction, in as many different ways as possible. You might as well show up at a floundering startup's office, lean back in a comfy chair, and say "just make more money, bro".

Sabine acts as if the correct approach is obvious, but on the very rare occasions where she actually does mention what ideas she thinks are promising, they're just as contrived or difficult to test as everybody else's, and often more so.

great comment, also something unrelated looking at your website I was hoping to find some notes about how to write in latex I have seen some submissions at HN but I think you could give some awesome tips

IANAP but my understanding is we've reached a point where it's very difficult to test anything in physics. Eg, we've picked all the low-hanging fruit and everything left is something that requires large expenditures to test (more powerful particle colliders, etc).

Is there some alternative direction available where testing and verification are easier and cheaper?

This is the right question, although I don't know if there is a happy answer. If we need ever more expensive experiments to learn anything, progress is going to become very slow.

Maybe that's why there is so much math; math is cheap. And there is always the hope of coming up with something testable.

>Is there some alternative direction available where testing and verification are easier and cheaper?

A plurality of physicists now work in condensed matter. See e.g.

https://physicstoday.scitation.org/doi/10.1063/PT.3.4110

>when they can, fail the test

I'm not seeing why this is a bad thing. Every new idea we learn to test for, even if we test it and it comes back false, advances our knowledge and understanding.

Could it just be the case we are so far from our everyday experiences of the natural world that advancing further in our understanding requires taking small steps?

> wasted too much time and effort trying to come up with elegant math and grand theories that sound plausible but can't be tested

Einstein did not believe the gravitational waves he predicted could ever be detected. Or so I recall. But stuff like many-worlds interpretation appears fundamentally untestable (add same disclaimer here).

This book is quite good. Suggesting we follow the historical trend where advances in physics almost always reduce the number of magic numbers in the model. https://www.amazon.com/Mathematical-Reality-Space-Time-Illus...

Reading this review, I can't tell what Lindley hoped to contribute with this book or why Al-Khalili found it noteworthy enough for a NYTimes book review (which itself is so brief that it doesn't seem to say much beyond something like "despite the claim to the contrary, Physics is more than math, and maybe in the future we'll be able to test some of the untested ideas that came from mathematical beauty.")

What am I missing here?

Personally, I think that the criticism of physics being driven too much by mathematics is exactly wrong. The most sensible approach to quantum gravity yet came out of Wheeler's group. It's a really obvious approach: I came up with the basic idea independently, then looked up Gravitation to see if it was technically possible, and learnt that the authors thought of that 50 years before I did.

But it was abandoned, because no one could do the maths.

So I think we're waiting for another Laplace and Euler, to solve the Wheeler-de Witt equation.

My experience in school was the best professors were in the physics department. I learned a lot in those classes. I never asked, "Is this useful?" Of course, it has been very useful, especially in understanding engineering problems.

The physics professors worked hard at teaching their classes, and they all supported graduate students. I think that is sufficient. I don't care if some of their research gives mathematical results that are not testable. That is what we call research. I will back those professors every time.

That is my opinion.

Are you saying that those professors who i dont doubt are good and supportive, beside teaching generate some junk because academia requires them? Maybe something is broken

No, I do not believe those physics professors would publish any "junk". I expect some research reaches a dead end. However, those professors seemed much too driven by the pursuit of knowledge to waste their time on useless research.

Though the math is beyond me, theoretical physics is pretty much all math. The math being developed may or may not be useful eventually, but it adds to the knowledge base. I think "is this testable?" is the wrong wrong question to ask.

All the hang-wringing about elegant mathematics misses the point. An elegant theory is one that captures a lot of complexity with a minimal description. That some small number of assumptions goes on to describe a multitude of phenomena is the mark of a good theory. Given the choice between an elegant theory and an inelegant one that describes the same data, the elegant one is more likely to be true.

If there are problems with modern physics, its not that we're spending time looking for elegant theories.

Totally agree that in general the endless naval gazing in physics (multi-verse / string theory etc) seems like a colossal waste of time.

Another good interview on this topic:

https://blogs.scientificamerican.com/cross-check/physicist-g...

It seems unfair to criticize some physicists for the fact that they haven’t subjected their theories to experiment, when we know that testing certain theories would require access to vast levels of energy that the human race doesn’t yet have at its disposal (and may never have).

No but I think it's fair to criticize any physicist who establishes a theory to be beyond testability and continues work on it, or who works on another physicists theory that is established to be beyond testability.

Especially if they are using public money, because public monies need to be accountable.

>it's fair to criticize any physicist who establishes a theory to be beyond testability and continues work on it

Would the same apply to people who further explore questions like P = NP and what happens if it is true or false or what happens if the Riemann hypothesis is true? Sometimes digging more into something that doesn't seem testable results in a finding that is testable or into knowledge that helps advance a related field.

I think the deeper question is, how do we make sure that public money is spent in a justifiable fashion. And when it comes to science that is a hard question to answer, especially if one considers that science works a bit differently than the way the average voter thinks about things when it comes to notion such as proven or disproven.

It might apply if P=NP or the Riemann hypothesis were remotely the same thing. An open mathematical conjecture has uncertainty about whether effort into cracking it will produce fruit. That's entirely different from a physical theory where it certainly cannot be tested.

Any physical theory that cannot be tested is a mathematical theory that can produce results useful in other places.

In general all of theoretical physics is mathematics that takes inspiration from experiments, and takes shortcuts when proving theorems:).

Establishing a theoretical framework only for it to be proved with experimental evidence centuries later is actually common. As some other poster said, it still adds to the knowledge base.

Our current society is way to focused on short-term gains, mostly because of profit imperatives. Yet it is becoming increasingly obvious that being short-sighted will eventually doom us all. Coronaviruses were an obscure family of viruses no one but a handful of niche researchers were interested about until it became the most important thing in the world. As for climate change...

That's not true at all. Coronaviruses are 20% of common colds and were an active, non-niche field of research at least since I was in grad school for biochemistry back in the early aughts.

That's fair, I have to keep reminding myself that "the early aughts" are not less than 10 years ago.

One problem is that some string theorists think this situation means that this type of physics should simply abandon empirical testability as a criterion for evaluating the truthfulness of theory.

I think it is entirely fair to criticize the value of theories that cannot be tested in the forseeable future.

Isn't this what Eric Weinstein is on about in his podcast as series The Portal?

Academia lost its way, not Physics.

Many words in the English language have more than one meaning. One of the common meanings of the term "physics" is the academic physics community. Did you really not know that?

Actually, the snarky poster was correct.

US Academics is about grant-seeking and ass-kissing foremost (and living in your car), not whatever the discipline at hand is.

Physics itself is oblivious to that.

Anyone have a non-paywall copy?

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