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It’s time to admit quantum theory has reached a dead end

nautil.us

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Re: It’s time to admit quantum theory has reached a dead end

#191

Post by somenameforme »

chii wrote: post #74
jiggawatts wrote: post #4

Earlier quoted context omitted.

To me, this always felt like programmers excusing abhorrent code with "but it works". Quantum theory isn't. It's not a single, cohesive, consistent theory.[1] There is no recipe you can apply, it's just a bunch of guessworks and heuristics that happen to produce the numerically correct equations if you keep trying long enough. This isn't secret or some sort of external criticism, you'll find this front-and-centre in…

> because approaches like this often have virtually no explanatory power. the famous feynman have produced a response to this train of thought - usually from the laymen - where they demand an "explanatory theory". The answer is usually "don't know"; why gravity work the way it does? - don't know, but we can calculate orbits to great precision; why does photons or electrons travel the way it does? - don't know, but we…

Confounding variables are a strong argument against this. Give me two sets of data that have no causal relationship, and it's very possible (if not likely) I will be able to demonstrate not only a causal relationship but also observational predictability through the existence of confounding variables. Let me use ML models and this becomes trivial.

Do school names determine how good a school will be? Of course not. However, schools have names which tend to be reused: cultural icons, scientists, etc.. And schools in low performing areas are going to have a different distribution of chosen names than schools in high performing areas. So you can create a model that will not only demonstrate this but also offer legitimate observational predictability that a school's name will, on average, determine how well it will do.

The only way you could really refute this hypothesis is by understanding the true confounding variable, or by running some huge scale multiple decades long experiment where you changed the names of new schools and measured the performance difference. That experiment is clearly not really practicable, so all you're left with is understanding.

And this is really where the risk is. If we ever begin to build upon something that is unsound then it risks everything from that point onward being also invalid. At best everything collapses and you realize you must have made a mistake. At worse, you simply end up adding endless epicycles until at some point everything starts to completely stall out muddled in its own invalid fundamentals and irreconcilable complexity.

Re: It’s time to admit quantum theory has reached a dead end

#192

Post by Dylan16807 »

Zamicol wrote: post #186
CorrectHorseBat wrote: post #180

Earlier quoted context omitted.

>All computers require a clock to function. Why would our universe be any different? Clocks are not required at all, even for digital computers. They only make designing computers a lot simpler.

Clockless computers don't have a global clock but they still have components that "tick".

Depending on the design, no more than abacus has components that "tick". And I'd never say an abacus requires a clock to function.

If even a single bit gets hung up in a straightforward clockless design, everything else waits for it.

None of that is really visible to something inside the computer, though. The OP is describing calculation steps, not clock cycles.

Re: It’s time to admit quantum theory has reached a dead end

#193

Post by jerrysievert »

colordrops wrote: post #179
adriand wrote: post #115

Earlier quoted context omitted.

I read somewhere that quantum mechanics is the most tested of all scientific theories. And it has been shown to be right, every time. Hawking espoused this idea he called “model dependent realism”. The idea is that every human understanding of reality is model-dependent, that is, it is not “reality” that we truly understand (we can’t) but rather in every case we have some model of reality that is useful in particular…

Apparently Hawking coined this term in 2010. Robert Anton Wilson coined a similar term, "Model Agnosticism", all the way back in 1977 in his book Cosmic Trigger: "The Copenhagen Interpretation is sometimes called "model agnosticism" and holds that any grid we use to organize our experience of the world is a model of the world and should not be confused with the world itself. Alfred Korzybski, the semanticist, tried t…

he expanded on that quite a bit in quantum psychology (1990), giving an expanded treatise on the software of the mind and how it maps our interpretation of reality.

quite a good read if you liked his previous works.

Re: It’s time to admit quantum theory has reached a dead end

#194

Post by konschubert »

japanuspus wrote: post #190
shoyer wrote: post #73

As former quantum physicist, I find it little troubling to read "quantum theory has reached a dead end" in specific reference to the interpretation of quantum mechanics. Most quantum physicists could not care less about how quantum mechanics is interpreted when it makes highly accurate quantitative predictions, and there are still plenty of interesting open problems for quantum theory (e.g., related to the practical…

As a former quantum physicist who has just decided to go back into quantum computing, this was my take as well: Introductory quantum physics courses may still include wave-function collapse and all that nonsense, but I have not met many physicists who use this as a mental model. To be a bit more specific as to how _decoherence_ solves this, one way to see it is that classicality (i.e. observables having specific valu…

Okay, cool, I’m 100% with you.

But could we then please stop teaching the collapse nonsense to first year students?

The logical inconsistencies of the collapse interpretation are an insult to their intellect.

Re: It’s time to admit quantum theory has reached a dead end

#195

Post by dorgo »

adriand wrote: post #115
shoyer wrote: post #73

As former quantum physicist, I find it little troubling to read "quantum theory has reached a dead end" in specific reference to the interpretation of quantum mechanics. Most quantum physicists could not care less about how quantum mechanics is interpreted when it makes highly accurate quantitative predictions, and there are still plenty of interesting open problems for quantum theory (e.g., related to the practical…

I read somewhere that quantum mechanics is the most tested of all scientific theories. And it has been shown to be right, every time. Hawking espoused this idea he called “model dependent realism”. The idea is that every human understanding of reality is model-dependent, that is, it is not “reality” that we truly understand (we can’t) but rather in every case we have some model of reality that is useful in particular…

> it is not “reality” that we truly understand (we can’t)

Yes, we can only describe with models what can be observed. But it is a bad excuse for ignoring contradictions in (or between) models.

Re: It’s time to admit quantum theory has reached a dead end

#196

Post by alar44 »

dekhn wrote: post #119
alar44 wrote: post #85

Earlier quoted context omitted.

Right, my point is that it's as solved as it can really be as far as human understanding is concerned. There are too many variables at play to have any sort of elegant solution like Ohm's law or calculating an orbit. The best we can do is find different/more efficient/novel methods to calculate it. Am I wrong?

The problem is ill-posed, not that we lack a solution.

Can you elaborate on why it's ill-posed?

Re: It’s time to admit quantum theory has reached a dead end

#197

Post by luc4sdreyer »

japanuspus wrote: post #190
shoyer wrote: post #73

As former quantum physicist, I find it little troubling to read "quantum theory has reached a dead end" in specific reference to the interpretation of quantum mechanics. Most quantum physicists could not care less about how quantum mechanics is interpreted when it makes highly accurate quantitative predictions, and there are still plenty of interesting open problems for quantum theory (e.g., related to the practical…

As a former quantum physicist who has just decided to go back into quantum computing, this was my take as well: Introductory quantum physics courses may still include wave-function collapse and all that nonsense, but I have not met many physicists who use this as a mental model. To be a bit more specific as to how _decoherence_ solves this, one way to see it is that classicality (i.e. observables having specific valu…

> in the limit of near-infinite degrees of freedom.

Can you explain or express this in a simpler way? Is it almost like saying macroscopic?

Re: It’s time to admit quantum theory has reached a dead end

#198

Post by po »

drujensen wrote: post #169

As former amateur physicist, who read a couple books over the years :) To me it's quite simple. We haven't detected what is causing the waves that the particle of light is riding on. The particle of light is like a surf board, riding a wave and will always hit the shore in the interference pattern. Einstein and Bohr were both right. What has been the wrong assumption over the years is that the light is generating the…

> The particle of light is like a surf board, riding a wave and will always hit the shore in the interference pattern.

This is exactly Bohm's Pilot Wave theory that the article talks about. It has been debunked to some extent but I believe the debunking is still somewhat controversial for proponents. There are neat macro-level simulations of it called "Walking Droplets" if you search for them.

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

https://www.pml.unc.edu/walking-drops

Re: It’s time to admit quantum theory has reached a dead end

#199

Post by dr_dshiv »

wahern wrote: post #96
dr_dshiv wrote: post #84

Earlier quoted context omitted.

Nothing. His model actually fit the data worse than epicycles. He just thought it was a more sensible approach that matched the Pythagorean opinion. It wasn’t until Kepler that a geocentric model involving ellipses actually was more predictive. Might be worth returning to the Pythagorean interpretation (which Bohr discussed): All is number. The world is made of math, not stuff.

> It wasn’t until Kepler that a geocentric model involving ellipses actually was more predictive. You mean heliocentric?

Thanks, my bad.

Re: It’s time to admit quantum theory has reached a dead end

#200

Post by jiggawatts »

chii wrote: post #74
jiggawatts wrote: post #4

Earlier quoted context omitted.

To me, this always felt like programmers excusing abhorrent code with "but it works". Quantum theory isn't. It's not a single, cohesive, consistent theory.[1] There is no recipe you can apply, it's just a bunch of guessworks and heuristics that happen to produce the numerically correct equations if you keep trying long enough. This isn't secret or some sort of external criticism, you'll find this front-and-centre in…

> because approaches like this often have virtually no explanatory power. the famous feynman have produced a response to this train of thought - usually from the laymen - where they demand an "explanatory theory". The answer is usually "don't know"; why gravity work the way it does? - don't know, but we can calculate orbits to great precision; why does photons or electrons travel the way it does? - don't know, but we…

"don't know" -- that doesn't mean we can't know, it just means we don't currently have an explanation. If you had asked similar fundamental questions about the "why" of beetle species a few centuries ago, even the most prolific beetle collector in the world would have answered "don't know".

"The laymen demands an explanatory theory" -- and so do scientists! Why do you assume scientists are somehow "above" explanations, and are content in ignorance?

"explanation _is_ the maths." -- People had good rules of thumb for evolution (such as dog breeding practices), and Gregor Mendel could have come up with his mathematical rules for selection before Darwin published his explanatory theory of natural selection. That doesn't mean that it's worthless to try to aim for an explanatory theory of QM instead of a purely numerical / observational one.

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