# Is it really true that physicists can't agree on fundamental questions of quantum mechanics?
**URL:** https://boards.straightdope.com/t/is-it-really-true-that-physicists-cant-agree-on-fundamental-questions-of-quantum-mechanics/648308
**Category:** Factual Questions
**Created:** [January 25, 2013, 10:38am UTC](https://boards.straightdope.com/t/is-it-really-true-that-physicists-cant-agree-on-fundamental-questions-of-quantum-mechanics/648308 "2013-01-25T10:38:05Z")
**Posts on this page:** 20
**Page:** 1
### Author:  [@deltasigma](https://boards.straightdope.com/u/deltasigma)
#### Post date: [January 25, 2013, 10:38am UTC](https://boards.straightdope.com/t/is-it-really-true-that-physicists-cant-agree-on-fundamental-questions-of-quantum-mechanics/648308/1 "2013-01-25T10:38:05Z")
In a [paper in pre-print on arXiv](http://phys.org/news/2013-01-survey-physicists-fundamental-quantum-mechanics.html), three physics surveyed their colleagues at a conference in 2011 and the level of disagreement apparently was notable.
The example given in the [Phys.org](http://Phys.org) article is regarding whether Bohr’s view of QM was accurate. 30% agreed that it is or is likely, another 30% said it’s not or is unlikely and 30% weren’t sure. Apparently 10% didn’t respond, or at least that’s what I surmise.
I’m sure another article will be published after the paper comes out, if it indeed does. But in the meantime, what are the thoughts of our resident QM cognoscenti?
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### Author:  [@jackdavinci](https://boards.straightdope.com/u/jackdavinci)
#### Post date: [January 25, 2013, 11:37am UTC](https://boards.straightdope.com/t/is-it-really-true-that-physicists-cant-agree-on-fundamental-questions-of-quantum-mechanics/648308/2 "2013-01-25T11:37:28Z")
My impression is that they agree on the results, equations, etc but don’t agree on the interpretation of what is going on behind the scenes / what it all really means. And there are some that think the various interpretations are equivalent. Until someone comes up with a way to actually test which interpretation is correct, there’s plenty of room for debate. The only test I’ve seen involves suicide so…
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### Author:  [@njtt](https://boards.straightdope.com/u/njtt)
#### Post date: [January 25, 2013, 11:38am UTC](https://boards.straightdope.com/t/is-it-really-true-that-physicists-cant-agree-on-fundamental-questions-of-quantum-mechanics/648308/3 "2013-01-25T11:38:14Z")
Apparently this poll was conducted by Jerry Seinfeld. I see that one of teh questions was: “ **What about quantum information?** ”
Is that crazy, or what?
¬¬¬¬¬¬¬
The details here maybe of interest, although the poll seems to have been conducted in an amateurish way, but it is not news that physicists do not agree about the foundations of quantum mechanics.
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### Author:  [@leahcim](https://boards.straightdope.com/u/leahcim)
#### Post date: [January 25, 2013, 11:55am UTC](https://boards.straightdope.com/t/is-it-really-true-that-physicists-cant-agree-on-fundamental-questions-of-quantum-mechanics/648308/4 "2013-01-25T11:55:09Z")
Reading the actual survey questions, the paper should probably be entitled “A Case Study in Improper Design of Multiple-Choice Surveys”. The paper states, about the question on Bohr:
> [@](#):
>
> Just as with the previous question about Einstein’s view of quantum mechanics, we did not elaborate on the specifics of what we meant by “Bohr’s view.” Bohr, of course, has become associated with a variety of positions, and it is likely that in responding to the question, each participant had a slightly different set of ideas and slogans in mind.
With similar disclaimers for other questions. One can hardly take seriously the results of a survey where respondents aren’t necessarily agreeing or disagreeing with the same thing in their minds.
That being said, the topics discussed in the survey are topics that aren’t well study-able by experiment. All physicists know how to “work the math” of QM and get the predictions out unambiguously, and those predictions a borne out by experiment. The questions are about what reality “working the math” is representing, and since the interpretations can not be tested by experiment, no consensus can be driven.
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### Author:  [@Derleth](https://boards.straightdope.com/u/Derleth)
#### Post date: [January 25, 2013, 12:07pm UTC](https://boards.straightdope.com/t/is-it-really-true-that-physicists-cant-agree-on-fundamental-questions-of-quantum-mechanics/648308/5 "2013-01-25T12:07:38Z")
> [@jackdavinci](#):
>
> The only test I’ve seen involves suicide so…
"Though all these bras and kets I see,
QM holds its mystery.
No-one knows what’s really there.
Or even if black holes have hair!
CHORUS:
All interpretations
Leave us with big questions
So you can take or leave them as you please!
Bell inequalities will show
There are things we cannot know.
Or do they point to spooky acts?
Or are the loophole theories facts?
CHORUS
A brave man once requested me
to answer questions that are key
‘is it to be or not to be’
and I replied ‘oh why ask me?’
All interpretations
Leave us with big questions
So you can take or leave them as you please!"
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### Author:  [@iamnotbatman](https://boards.straightdope.com/u/iamnotbatman)
#### Post date: [January 25, 2013, 12:23pm UTC](https://boards.straightdope.com/t/is-it-really-true-that-physicists-cant-agree-on-fundamental-questions-of-quantum-mechanics/648308/6 "2013-01-25T12:23:05Z")
Yes it is true, and it is an embarrassment. [Here](http://www.youtube.com/watch?v=ZacggH9wB7Y) Sean Carroll does a really good job of explaining all of this. Having gone through a graduate program in physics, I can tell you that interpretations of QM are not often discussed. Many physics PhD’s have never thought particularly hard about the subject.
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### Author:  [@Chronos](https://boards.straightdope.com/u/Chronos)
#### Post date: [January 25, 2013, 5:13pm UTC](https://boards.straightdope.com/t/is-it-really-true-that-physicists-cant-agree-on-fundamental-questions-of-quantum-mechanics/648308/7 "2013-01-25T17:13:16Z")
> [@](#):
>
> Many physics PhD’s have never thought particularly hard about the subject.
No, we haven’t, and why should we? We’re scientists, and hence prefer to think about scientific matters. Leave that one for the philosophers and theologians.
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### Author:  [@zoid](https://boards.straightdope.com/u/zoid)
#### Post date: [January 25, 2013, 5:42pm UTC](https://boards.straightdope.com/t/is-it-really-true-that-physicists-cant-agree-on-fundamental-questions-of-quantum-mechanics/648308/8 "2013-01-25T17:42:09Z")
> [@iamnotbatman](#):
>
> Yes it is true, and it is an embarrassment. [Here](http://www.youtube.com/watch?v=ZacggH9wB7Y) Sean Carroll does a really good job of explaining all of this. Having gone through a graduate program in physics, I can tell you that interpretations of QM are not often discussed. Many physics PhD’s have never thought particularly hard about the subject.
Why is it an embarrassment? Even scientists can have differing opinions about matters that aren’t clearly settled.
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### Author:  [@The\_Hamster\_King](https://boards.straightdope.com/u/The_Hamster_King)
#### Post date: [January 25, 2013, 6:28pm UTC](https://boards.straightdope.com/t/is-it-really-true-that-physicists-cant-agree-on-fundamental-questions-of-quantum-mechanics/648308/9 "2013-01-25T18:28:31Z")
Metaphysics is predicated on an error – namely that understanding is about knowing what something IS rather that what it DOES.
Quantum mechanics says what the universe DOES, not what it IS. Expecting science (or any mechanism of knowledge production) to answer ontological questions is a fruitless question. Our understanding of the universe will always, inevitably be functional, not metaphysical, because that’s how understanding works.
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### Author:  [@deltasigma](https://boards.straightdope.com/u/deltasigma)
#### Post date: [January 25, 2013, 7:21pm UTC](https://boards.straightdope.com/t/is-it-really-true-that-physicists-cant-agree-on-fundamental-questions-of-quantum-mechanics/648308/10 "2013-01-25T19:21:23Z")
I know this will get us off topic and land this in GD, but . . . WTF. Here goes.
There is also the issue of epistemology. How do we distinguish between knowledge and belief. Does QM constitute ‘knowledge’ of the universe if all it does is allow us to make useful predictions but tells us nothing of it’s actual nature? And if not, then aren’t we all really nihilists at heart?
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### Author:  [@The\_Hamster\_King](https://boards.straightdope.com/u/The_Hamster_King)
#### Post date: [January 25, 2013, 7:43pm UTC](https://boards.straightdope.com/t/is-it-really-true-that-physicists-cant-agree-on-fundamental-questions-of-quantum-mechanics/648308/11 "2013-01-25T19:43:30Z")
> [@deltasigma](#):
>
> Does QM constitute ‘knowledge’ of the universe if all it does is allow us to make useful predictions but tells us nothing of it’s actual nature?
Can you give me even a single example of a case where we have knowledge of something’s “actual nature”?
All knowledge is functional, not ontological. It makes predictions, it doesn’t tell us what things are. Expecting QM to provide ontological answers about the universe is a misunderstanding of how knowledge works.
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### Author:  [@deltasigma](https://boards.straightdope.com/u/deltasigma)
#### Post date: [January 25, 2013, 7:48pm UTC](https://boards.straightdope.com/t/is-it-really-true-that-physicists-cant-agree-on-fundamental-questions-of-quantum-mechanics/648308/12 "2013-01-25T19:48:56Z")
> [@The\_Hamster\_King](#):
>
> Can you give me even a single example of a case where we have knowledge of something’s “actual nature”?
>
> All knowledge is functional, not ontological. It makes predictions, it doesn’t tell us what things are. Expecting QM to provide ontological answers about the universe is a misunderstanding of how knowledge works.
So the only knowledge you can have is superficial? I think most people will find that a bit unsatisfying.
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### Author:  [@njtt](https://boards.straightdope.com/u/njtt)
#### Post date: [January 25, 2013, 7:58pm UTC](https://boards.straightdope.com/t/is-it-really-true-that-physicists-cant-agree-on-fundamental-questions-of-quantum-mechanics/648308/13 "2013-01-25T19:58:00Z")
> [@The\_Hamster\_King](#):
>
> Metaphysics is predicated on an error – namely that understanding is about knowing what something IS rather that what it DOES.
>
> Quantum mechanics says what the universe DOES, not what it IS. Expecting science (or any mechanism of knowledge production) to answer ontological questions is a fruitless question. Our understanding of the universe will always, inevitably be functional, not metaphysical, because that’s how understanding works.
Why don’t we have these sorts of issues with all other scientific theories then? Why is it only quantum mechanics that freaks people, including physicists, out?
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### Author:  [@The\_Hamster\_King](https://boards.straightdope.com/u/The_Hamster_King)
#### Post date: [January 25, 2013, 8:02pm UTC](https://boards.straightdope.com/t/is-it-really-true-that-physicists-cant-agree-on-fundamental-questions-of-quantum-mechanics/648308/14 "2013-01-25T20:02:34Z")
> [@deltasigma](#):
>
> So the only knowledge you can have is superficial? I think most people will find that a bit unsatisfying.
The question is not what is satisfying. The question is what is possible. The universe has no obligation to be satisfying.
And I’m not sure why you’re calling functional knowledge “superficial”.
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### Author:  [@The\_Hamster\_King](https://boards.straightdope.com/u/The_Hamster_King)
#### Post date: [January 25, 2013, 8:16pm UTC](https://boards.straightdope.com/t/is-it-really-true-that-physicists-cant-agree-on-fundamental-questions-of-quantum-mechanics/648308/15 "2013-01-25T20:16:03Z")
> [@njtt](#):
>
> Why don’t we have these sorts of issues with all other scientific theories then? Why is it only quantum mechanics that freaks people, including physicists, out?
Because most other sciences don’t collide with “folk physics”.
We all have a basic, functional understanding of how the world works that gets us through the day. The world is a big 3-D space populated with objects that have specific properties. There’s a car over there. The car is green and weighs a lot. If I step in front of it while its moving it will knock me down. This is the basic human umwelt we use to navigate reality on a day-to-day basis.
However, this folk physics is a mental construct. It was a useful way to solve survival problems on the African veldt 200,000 years ago. It’s not what the universe really is. But it’s so baked into how our brains work that it seems metaphysically unassailable.
Most sciences work quite nicely within the folk physics framework. We can do chemistry by thinking of molecules as little objects that jiggle around in 3-D space and link up with each other. So it doesn’t cause the sort of intellectual crisis that QM does.
What QM and relativity do is show us the limits of our human umwelt. The universe isn’t really a 3-D box filled with objects. Time and space are malleable. Objects act like wave functions smeared through the entire universe. We can write equations that make functional predictions within these alternate frameworks, but they clearly describe an understanding that lies outside our intuitive sense of how the universe is structured.
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### Author:  [@Tom\_Tildrum](https://boards.straightdope.com/u/Tom_Tildrum)
#### Post date: [January 25, 2013, 8:19pm UTC](https://boards.straightdope.com/t/is-it-really-true-that-physicists-cant-agree-on-fundamental-questions-of-quantum-mechanics/648308/16 "2013-01-25T20:19:21Z")
> [@The\_Hamster\_King](#):
>
> What QM and relativity do is show us the limits of our human umwelt.
I think the question we laypeople are asking might then be reformulated as, “why do physicists believe this represents such a limit?” Or to put it perhaps a slightly different way, why is metaphysical to ask, “what causes a wave function to collapse,” as opposed to a question like “what causes the Earth to revolve around the Sun”?
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### Author:  [@The\_Hamster\_King](https://boards.straightdope.com/u/The_Hamster_King)
#### Post date: [January 25, 2013, 10:26pm UTC](https://boards.straightdope.com/t/is-it-really-true-that-physicists-cant-agree-on-fundamental-questions-of-quantum-mechanics/648308/17 "2013-01-25T22:26:05Z")
> [@Tom\_Tildrum](#):
>
> Or to put it perhaps a slightly different way, why is metaphysical to ask, “what causes a wave function to collapse,” as opposed to a question like “what causes the Earth to revolve around the Sun”?
It’s not. But any answer to “What causes a wave function to collapse?” will be yet another functional description. It will better describe how the wave function behaves, and that increased understanding may let us make better predictions about how the universe behaves. But it won’t be any closer to saying what the universe is.
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### Author:  [@deltasigma](https://boards.straightdope.com/u/deltasigma)
#### Post date: [January 25, 2013, 10:42pm UTC](https://boards.straightdope.com/t/is-it-really-true-that-physicists-cant-agree-on-fundamental-questions-of-quantum-mechanics/648308/18 "2013-01-25T22:42:26Z")
I should point out that ‘collapsing the wave function’ presumes a certain interpretation of QM
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### Author:  [@Pasta](https://boards.straightdope.com/u/Pasta)
#### Post date: [January 25, 2013, 11:18pm UTC](https://boards.straightdope.com/t/is-it-really-true-that-physicists-cant-agree-on-fundamental-questions-of-quantum-mechanics/648308/19 "2013-01-25T23:18:04Z")
My minor contribution here: that survey is terrible. My own response to almost every question would be “This question is ill-defined and/or unanswerably vague, but I’m sitting at this conference and you gave me this survey, so I’ll humor you and check one of the boxes based on whatever whim strikes me.”
The survey notwithstanding, this is indeed something most physicists don’t spend a lot of mental cycles on.
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### Author:  [@njtt](https://boards.straightdope.com/u/njtt)
#### Post date: [January 25, 2013, 11:38pm UTC](https://boards.straightdope.com/t/is-it-really-true-that-physicists-cant-agree-on-fundamental-questions-of-quantum-mechanics/648308/20 "2013-01-25T23:38:26Z")
> [@The\_Hamster\_King](#):
>
> It’s not. But any answer to “What causes a wave function to collapse?” will be yet another functional description. It will better describe how the wave function behaves, and that increased understanding may let us make better predictions about how the universe behaves. But it won’t be any closer to saying what the universe is.
Well, frankly, you were the one who made this an issue of what the universe _is_ rather than what it _does_. If you admit that “What causes a wave function to collapse?” is a legitimate question, even if any answer can only be “functional,” you have admitted that there is a lot we don’t understand about the foundations of quantum mechanics.
Anyway, your distinction between metaphysics and “functional” science just seems to be warmed over Logical Positivism, a philosophical program that is pretty much universally agreed to have been an abysmal failure.
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