The present phase of stagnation in the foundations of physics is not normal • Hacker News Board

Re: The present phase of stagnation in the foundations of physics is not normal

#71

Post by naasking » Tue, Nov 20, 2018, 7:32 PM UTC

andrepd wrote: post #53

tbabb wrote: post #14

While I don't like this ~guy's~ woman's disdainful, superior tone, I do think his complaint has merit. Physics is notoriously bad at having curiosity about strange, unconventional, or truly novel ideas. I just finished reading What is Real? by Adam Becker-- a history of modern physics-- and am astonished at how aggressively physicists resisted and suppressed "unconventional" interpretations of quantum mechanics (like…

>Physics is notoriously bad at having curiosity about strange, unconventional, or truly novel ideas. Physics of today would be unrecognisable to a scientist at the start of the 20th century. Indeed the physics of 1935 would be unrecognisable to a scientist at the start of the 20th century. Our understanding progressed enormously AND it did so because people put forward radical theories in complete rupture with the es…

> Physics, indeed all science, studies observable reality. Any "deep" questions about why or about things not measurable, quantifiable, or empirically observable, are by definition outside the scope of science.

This is wrong. Scientific theories provide predictive power, yes, but they should also provide explanatory power.

Which is to say, they should describe a model of the world because this is how we devise experiments, and experiments are clearly critical for science.

Two theories with equivalent predictive power but unequal explanatory power are not equally good theories.

Re: The present phase of stagnation in the foundations of physics is not normal

#72

Post by naasking » Tue, Nov 20, 2018, 7:34 PM UTC

andrepd wrote: post #69

tbabb wrote: post #60

Earlier quoted context omitted.

> There is nothing "obviously wrong" about the standard Copenhagen interpretation Can you tell me how to calculate whether a system of particles will cause another system of particles to collapse or not? Can you tell me under what circumstances a system of particles will evolve unitarily or not? Can you shade the region of the spacetime diagram of EPR where the wavefunction is collapsed? How about in a delayed choice…

>Can you tell me how to calculate whether a system of particles will cause another system of particles to collapse or not? You appear to be somewhat mistaken. Copenhagen interpretation does not postulate any specific explanation or mechanism for wave-function collapse, merely that "upon measurement, the wave-function collapses into an eigenstate of the observable being measured". This, of course, is a physically veri…

> This, of course, is a physically verified phenomenon

No it's not. There are interpretations in which collapse does not exist, so these experiments are not measuring what you think they're measuring unless you already assume the conclusion.

Also, your view on other interpretations of QM are outdated. Arguably one of the more famous results on quantum mechanics, Bell's theorem, would have never existed if not for Bohmian mechanics.

Don't discount the value of explanatory power. The fact that other interpretations provide far more explanatory power than Copenhagen makes them far more valuable. Many important results in quantum foundations would have never happened if everyone were a Copenhagenist.

Re: The present phase of stagnation in the foundations of physics is not normal

#73

Post by phkahler » Tue, Nov 20, 2018, 7:34 PM UTC

tylermw wrote: post #3

Love this comment left on the post by Peter Shor (of Shor's algorithm--the algorithm that kicked off the quantum computing frenzy). I assume it's him and not an imposter. "It's not just that scientists don't want to move their butts, although that's undoubtedly part of it. It's also that they can't. In today's university funding system, you need grants (well, maybe you don't truly need them once you have tenure, but…

>> And if you submit a proposal that says "I'm going to go off and work on this crazy idea, and maybe there's a one in a thousand chance that I'll discover some of the secrets of the universe, and a 99.9% chance that I'll come up with bubkes," you get turned down.

That's just people being chicken. You know someone got to research why wombat poop comes out in cubes:

https://gizmodo.com/we-finally-know-how-wombats-produce-thei...

I could spend a couple hours giving physicists off-the-wall ideas that have some degree of plausibility. All worth exploring rigorously IMHO.

Re: The present phase of stagnation in the foundations of physics is not normal

#74

Post by trainingaccount » Tue, Nov 20, 2018, 7:36 PM UTC

tbabb wrote: post #60

andrepd wrote: post #53

Earlier quoted context omitted.

>Physics is notoriously bad at having curiosity about strange, unconventional, or truly novel ideas. Physics of today would be unrecognisable to a scientist at the start of the 20th century. Indeed the physics of 1935 would be unrecognisable to a scientist at the start of the 20th century. Our understanding progressed enormously AND it did so because people put forward radical theories in complete rupture with the es…

> There is nothing "obviously wrong" about the standard Copenhagen interpretation Can you tell me how to calculate whether a system of particles will cause another system of particles to collapse or not? Can you tell me under what circumstances a system of particles will evolve unitarily or not? Can you shade the region of the spacetime diagram of EPR where the wavefunction is collapsed? How about in a delayed choice…

Also, all the non-MW interpretations say "and then choose a random outcome" without any clue as to how randomness might occur. MWI can propose an actual mechanism for randomness: sampling a space of alternatives, aka the Sleeping Beauty approach. To me this is pretty close to a knockdown argument in favour of MWI.

Re: The present phase of stagnation in the foundations of physics is not normal

#75

Post by trainingaccount » Tue, Nov 20, 2018, 7:37 PM UTC

andrepd wrote: post #69

tbabb wrote: post #60

Earlier quoted context omitted.

> There is nothing "obviously wrong" about the standard Copenhagen interpretation Can you tell me how to calculate whether a system of particles will cause another system of particles to collapse or not? Can you tell me under what circumstances a system of particles will evolve unitarily or not? Can you shade the region of the spacetime diagram of EPR where the wavefunction is collapsed? How about in a delayed choice…

>Can you tell me how to calculate whether a system of particles will cause another system of particles to collapse or not? You appear to be somewhat mistaken. Copenhagen interpretation does not postulate any specific explanation or mechanism for wave-function collapse, merely that "upon measurement, the wave-function collapses into an eigenstate of the observable being measured". This, of course, is a physically veri…

You really want to look into the delayed choice eraser... it's mind blowing.

Re: The present phase of stagnation in the foundations of physics is not normal

#76

Post by selestify » Tue, Nov 20, 2018, 7:46 PM UTC

FakeComments wrote: post #67

andrepd wrote: post #53

Earlier quoted context omitted.

>Physics is notoriously bad at having curiosity about strange, unconventional, or truly novel ideas. Physics of today would be unrecognisable to a scientist at the start of the 20th century. Indeed the physics of 1935 would be unrecognisable to a scientist at the start of the 20th century. Our understanding progressed enormously AND it did so because people put forward radical theories in complete rupture with the es…

> There is nothing "obviously wrong" about the standard Copenhagen interpretation. Copenhagen interpretation showed up when they were faced with a choice between preserving locality or determinancy. They chose wrong — we know now QM is non-local, and that the underlying justification for the Copenhagen model is an extraneous philosophical proposition. But much like an extra dependency in a software project, no one wa…

Copenhagen does not require nonlocality

Re: The present phase of stagnation in the foundations of physics is not normal

#77

Post by teilo » Tue, Nov 20, 2018, 7:47 PM UTC

tree_of_item wrote: post #49

teilo wrote: post #42

Earlier quoted context omitted.

How do you take someone seriously who says, "Mathematics, so useful a tool in the past, cannot describe this situation. The only way to describe this system is by using the system itself; there are no shortcuts. Math, philosophy, reason and order are inapplicable because they are only rules-based approximations of a chaotic state." That's tantamount to saying that his theory is not based on data, logic, or even sound…

I take it seriously because it echoes a sentiment I've seen expressed previously. If you're interested, I believe this post outlines the idea: https://blog.stephenwolfram.com/2018/11/logic-explainability... The tl;dr is that physics is not necessarily explainable, however much you want it to be. So it's very possible that the underlying phenomena of reality is simply out of reach of theories (i.e. it's incompressible…

Nonsense. It’s just a rehash of the old steady state model. Further, any theory which itself claims to be unproveable, is a religious sentiment masquerading as science, and is a waste of mental effort.

Wolfram’s article is irrelevant to this discussion. It is a question of empistemology.

Re: The present phase of stagnation in the foundations of physics is not normal

#78

Post by T-A » Tue, Nov 20, 2018, 7:49 PM UTC

jsweojtj wrote: post #50

walrus1066 wrote: post #27

I think this is excessively harsh. The only guarantees made about the LHC were, that it would prove or disprove the existence of the Higgs Boson. Believe me, experimental physicists are desperate to find the slightest deviation from the standard model. I spent 2 years on one such 'stab in the dark' rare decay analysis! The SM's predictions have been tested to a rigor unparalleled in history. It predicts stuff like ma…

It does not predict the fine structure constant, that is an input into the model.

https://en.wikipedia.org/wiki/Fine-structure_constant#Measur...

Re: The present phase of stagnation in the foundations of physics is not normal

#79

Post by TheOtherHobbes » Tue, Nov 20, 2018, 7:50 PM UTC

andrepd wrote: post #48

YeGoblynQueenne wrote: post #20

Earlier quoted context omitted.

>> What irritated me about it was the assumption that, if most of your predictions are correct, your model is almost entirely correct, and just needs to be tweaked a bit. Haha, no. We wish. Epicycles worked very well and were highly accurate, because, as Fourier analysis later showed, any smooth curve can be approximated to arbitrary accuracy with a sufficient number of epicycles. However, they fell out of favour wit…

>A theory can explain observations even perfectly well and still be wrong- because the frame of reference is wrong. The worse thing is that you can't figure that out until you've figured out what the correct frame of reference is, and looked at your obsrevations in a new light. Well strictly speaking, it wasn't wrong . It explained the observations perfectly well. What a heliocentric description brought was a simpler…

It was wrong in the sense that epicycles are an entirely imaginary math artefact, and reality works on different principles.

Revolutions happen when a new mental model - or frame of reference, or whatever you want to call it - can generate new kinds of math.

The old model is certainly wrong in the sense that it's not a good picture of how reality actually works.

If you really want to, you can still use epicycles for certain kinds of problem, just as you can use Newtonian physics for basic mechanics.

But this is engineering, not physics. These theories are useless for frontier research. They're absolutely wrong in the sense that their lack of completeness means they cannot be used to generate theory[n+1].

Re: The present phase of stagnation in the foundations of physics is not normal

#80

Post by anonymousDan » Tue, Nov 20, 2018, 7:51 PM UTC

tylermw wrote: post #3

Love this comment left on the post by Peter Shor (of Shor's algorithm--the algorithm that kicked off the quantum computing frenzy). I assume it's him and not an imposter. "It's not just that scientists don't want to move their butts, although that's undoubtedly part of it. It's also that they can't. In today's university funding system, you need grants (well, maybe you don't truly need them once you have tenure, but…

One slightly cynical strategy I've heard is that your next grant proposal should be for the work you've already completed, giving you time to come up with the idea for the one after :)