# Philosophical implications of quantum mechanics (warning: long confusing OP) **URL:** \ **Category:** Great Debates\ **Created:** [November 2, 2001, 10:20pm UTC](https://boards.straightdope.com/t/philosophical-implications-of-quantum-mechanics-warning-long-confusing-op/91210 "2001-11-02T22:20:50Z")\ **Posts on this page:** 9\ **Page:** 2
**Author:** ![g8rguy](https://avatars.discourse-cdn.com/v4/letter/g/7cd45c/32.png) [@g8rguy](https://boards.straightdope.com/u/g8rguy)\ **Post date:** [November 7, 2001, 7:26am UTC](https://boards.straightdope.com/t/philosophical-implications-of-quantum-mechanics-warning-long-confusing-op/91210/21 "2001-11-07T07:26:57Z")
> [@](#): > > It sounds like we’re closer together on this than I thought at first. Well, that’s a relief. I’d hate to think I’m a **total** nutjob! 🙂 > [@](#): > > Yes, the wave function changes, but this doesn’t bother me since I think of the wave function as representing _the information I possess about the system_. Of course, when I make a new measurement, the information I possess changes. Ah. It sounds like I do ascribe more meaning to it than you do, and therein lies the heart of any disagreement between us. > [@](#): > > And I agree with you - it _does_ bother me that we have no mechanical model that works for QM, which is why I think these discussions are worthwhile. My “so what?” was facetious; I’d like to have a deeper understanding of the processes described by QM, too. My feeling is that such an understanding might follow the lines of gauge invariance. A vector potential is not physical, since a gauge transformation changes the potential without changing the physics, but certain quantities that are calculated from the potential _are_ physically meaningful (e.g. electric field, integral around a loop). So in QM, maybe we can find a mechanical model that isn’t relativistically invariant, but the non-invariance, like a gauge transformation, never shows up in physically relevant quantities. If anyone knows how to do this, please let me know. 🙂 When I figure it out, you’ll be the first to know… 😉 **dierson** , the reason I don’t think outside the box is that what I’m trying to describe is stuff inside the box. Sure, I agree with you that I can define t[sub]0[/sub] to be whatever I want, that I can take t → -t in my equations, etc etc, but I must have **something** to describe the evolution in time (artificial construct or not) because that’s the goal to begin with! Oh, and **erl** , if you’re still following this, don’t despair; I’m still thinking about what you’ve said (you have an interesting perspective on things!), but haven’t had much free time to devote to the boards this week. I swear I’ll get back to you as soon as I can. Finally, **Ben** , the reference you want is, for example: Townsend, _A Modern Approach to Quantum Mechanics_, University Science Books, etc etc etc. ---
**Author:** ![elucidator](https://avatars.discourse-cdn.com/v4/letter/e/8edcca/32.png) [@elucidator](https://boards.straightdope.com/u/elucidator)\ **Post date:** [November 7, 2001, 7:31am UTC](https://boards.straightdope.com/t/philosophical-implications-of-quantum-mechanics-warning-long-confusing-op/91210/22 "2001-11-07T07:31:44Z")
Schrodinger’s cat died for your sins! ---
**Author:** ![ambushed](https://avatars.discourse-cdn.com/v4/letter/a/3bc359/32.png) [@ambushed](https://boards.straightdope.com/u/ambushed)\ **Post date:** [November 7, 2001, 7:47am UTC](https://boards.straightdope.com/t/philosophical-implications-of-quantum-mechanics-warning-long-confusing-op/91210/23 "2001-11-07T07:47:47Z")
Do many particle and quantum physicists still talk about the hopelessly outdated idea of a “collapse of the wave function”?? **Sheesh!** I thought such mental masochism was a long dead relic of the misty (and confusing) past. I’ve read papers which say that the majority of quantum physicists long ago dumped the old Copenhagen nonsense with its mind-bending talk of collapse and instead embraced MWI or TI or time-reversal! Why go out of your way and seek to _multiply_ metaphysical problems when other interpretations have no need of such? ---
**Author:** ![erislover](https://avatars.discourse-cdn.com/v4/letter/e/71e660/32.png) [@erislover](https://boards.straightdope.com/u/erislover)\ **Post date:** [November 7, 2001, 3:33pm UTC](https://boards.straightdope.com/t/philosophical-implications-of-quantum-mechanics-warning-long-confusing-op/91210/24 "2001-11-07T15:33:41Z")
Hopelessly antiquated belief? 'Tis to laugh, **ambushed**. We have a model built which explains the experiments we get. That model includes waveform collapse. What is the problem here? I have never particularly liked MQM models which try to brush off waveform collapse. Seems to push Occam’s Razor aside for nebulous philosophical gain. I think the experiments which demonstrate the vacuum potential are enough to seal it for me, but then, the nay-sayers to MQM don’t really offer me anything more than, “But it _can’t_ be waveform collapse!” Why not? **FriendRob** , I would be interested in hearing your understanding of light polarization experiments, where two sheets of polarity-blocking material are placed apart from each other, and no light makes it through (predictably, since any that made it through the first isn’t “lined up” with the second). And yet, doing our different experiment, when we add a piece of polarization material inbetween the other two, we _do_ get an output! No light should pass through the first and the second, or the second and the third, or the first and the third, and yet light goes all the way through. How do you explain that without actual manifested wavefunctions? It seems impossible to me. I am also particular interested in your interpretation of electron scattering experiments where single electrons are “fired” at the scattering crystal one-at-a-time, and where we still see the interference pattern. I don’t mean to be a dick about it if it seems like I am, I am really interested in hearing your ideas about the simple experiments which seem, _to me_, to conclusively demonstrate the waveform state of nature. If there isn’t the waveform then I am assuming that we are back to “classical” waves and particles? Or is everything corpuscular? ---
**Author:** ![DSeid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dseid/32/20194_2.png) [@DSeid](https://boards.straightdope.com/u/DSeid)\ **Post date:** [November 7, 2001, 7:29pm UTC](https://boards.straightdope.com/t/philosophical-implications-of-quantum-mechanics-warning-long-confusing-op/91210/25 "2001-11-07T19:29:08Z")
erislover, re the wave polarization experiments … one way would be to assume some movement in higher dimensioned space ---
**Author:** ![dierson](https://avatars.discourse-cdn.com/v4/letter/d/7feea3/32.png) [@dierson](https://boards.straightdope.com/u/dierson)\ **Post date:** [November 7, 2001, 10:32pm UTC](https://boards.straightdope.com/t/philosophical-implications-of-quantum-mechanics-warning-long-confusing-op/91210/26 "2001-11-07T22:32:18Z")
hey, you know what? physics is more of a hobby for me…but I enjoy it! I am not a professional teacher however, there are others that can explain why time doesn’t exist better than I… For instance this book The End of Time by Julian Barbour ( [http://www.sciencenewsbooks.org/endoftime.html](http://www.sciencenewsbooks.org/endoftime.html) ) seems to elucidate the theory well…here is an interview with Barbour [http://www.takethepursuit.com/learning/other/timeexist.html](http://www.takethepursuit.com/learning/other/timeexist.html) ---
**Author:** ![g8rguy](https://avatars.discourse-cdn.com/v4/letter/g/7cd45c/32.png) [@g8rguy](https://boards.straightdope.com/u/g8rguy)\ **Post date:** [November 8, 2001, 5:25am UTC](https://boards.straightdope.com/t/philosophical-implications-of-quantum-mechanics-warning-long-confusing-op/91210/27 "2001-11-08T05:25:10Z")
> [@](#): > > \*Originally posted by ambushed \* > \*\*Do many particle and quantum physicists still talk about the hopelessly outdated idea of a “collapse of the wave function”?? > > **Sheesh!** I thought such mental masochism was a long dead relic of the misty (and confusing) past. > > I’ve read papers which say that the majority of quantum physicists long ago dumped the old Copenhagen nonsense with its mind-bending talk of collapse and instead embraced MWI or TI or time-reversal! > > Why go out of your way and seek to _multiply_ metaphysical problems when other interpretations have no need of such? \*\* Curious. My beef with the Copenhagen interpretation is indeed that it’s so metaphysically unappealing (I assume you’ve gathered that by now). But don’t you find the idea of something like the many worlds approach to be just as awful? I mean, to suggest that a new universe is born every time a new measurement is made seems hopelessly extravagant to me! ---
**Author:** ![FriendRob](https://avatars.discourse-cdn.com/v4/letter/f/ecc23a/32.png) [@FriendRob](https://boards.straightdope.com/u/FriendRob)\ **Post date:** [November 8, 2001, 3:01pm UTC](https://boards.straightdope.com/t/philosophical-implications-of-quantum-mechanics-warning-long-confusing-op/91210/28 "2001-11-08T15:01:23Z")
> [@](#): > > \*Originally posted by erislover \* > \*\* > **FriendRob** , I would be interested in hearing your understanding of light polarization experiments, where two sheets of polarity-blocking material are placed apart from each other, and no light makes it through (predictably, since any that made it through the first isn’t “lined up” with the second). And yet, doing our different experiment, when we add a piece of polarization material inbetween the other two, we _do_ get an output! No light should pass through the first and the second, or the second and the third, or the first and the third, and yet light goes all the way through. > > How do you explain that without actual manifested wavefunctions? It seems impossible to me. > > I am also particular interested in your interpretation of electron scattering experiments where single electrons are “fired” at the scattering crystal one-at-a-time, and where we still see the interference pattern. > \*\* Let me tackle the electron scattering first, since that gives a good illustration of “my” QM philosophy (of course I don’t claim credit for it). QM describes not individual experiments, but collections of experiments. A “quantum state” is defined by an experimental **procedure** that yields well-defined probabilities for all measurable quantities. This only makes sense in reference to a collection of experiments - if you only do it once, probabilities are meaningless. So, take a crystal, and a beam of electrons - this is the procedure. QM tells you the probability of detecting a scattered electron at a particular angle of measurement. It matters not a whit whether the beam is continuous, or “one electron at a time”. But the **probabilistic** nature of the QM prediction means it is telling you about the result of many measurements on many electrons - not about the result of any single experiment. The wave function summarizes my knowledge about **a large collection of experiments** , not just one. I use it to calculate with, but don’t ascribe **physical** existence to it. Briefly, same thing with photon polarization: experimental set-up #1 yields no photons, set-up #2 yields photons; two different setups, two different wavefunctions, two different probability distributions for the outcome. BTW, one philosophical consequence of this approach is that it doesn’t make any sense to talk about “the wave function of the Universe”. We don’t get a collection of Universes to do experiments on, we just get one. So, no wave function. > [@](#): > > I don’t mean to be a dick about it if it seems like I am, I am really interested in hearing your ideas about the simple > experiments which seem, to me, to conclusively demonstrate the waveform state of nature. Not at all. Nothing like a good debate to clarify one’s ideas. > [@](#): > > If there isn’t the > waveform then I am assuming that we are back to “classical” waves and particles? Or is everything corpuscular? This is where the difficulty is, philosophically at least. QM gives us **no** _mechanical_ model of the subatomic/atomic world. Classical waves don’t work. Classical particles don’t work. Thinking of the wave function as a “real” wave doesn’t work. QM tells us everything we can know about a system, but doesn’t tell us anything about what’s “really” going on. As Feynman said (approximately), “I have danced with Nature and tried to woo her, but she won’t let you peek under her veil.” (Hey! Maybe I’ve found a sig!) ---
**Author:** ![erislover](https://avatars.discourse-cdn.com/v4/letter/e/71e660/32.png) [@erislover](https://boards.straightdope.com/u/erislover)\ **Post date:** [November 8, 2001, 6:25pm UTC](https://boards.straightdope.com/t/philosophical-implications-of-quantum-mechanics-warning-long-confusing-op/91210/29 "2001-11-08T18:25:20Z")
Unless I am reading that wrong, **FriendRob** , it seems you’ve just stated that everything _is_ corpuscular but we can only understand it by “making up” probability functions. In other words: the universe _really is doing something._ Is that correct? I don’t see how that accounts for electron interference patterns… Something I’m missing… [Previous page](https://boards.straightdope.com/t/philosophical-implications-of-quantum-mechanics-warning-long-confusing-op/91210.md?page=1)