# serious physics problem **URL:** \ **Category:** Great Debates\ **Created:** [May 6, 2004, 2:07pm UTC](https://boards.straightdope.com/t/serious-physics-problem/243819 "2004-05-06T14:07:29Z")\ **Posts on this page:** 17\ **Page:** 2
**Author:** ![SentientMeat](https://avatars.discourse-cdn.com/v4/letter/s/43a26b/32.png) [@SentientMeat](https://boards.straightdope.com/u/SentientMeat)\ **Post date:** [May 7, 2004, 10:07am UTC](https://boards.straightdope.com/t/serious-physics-problem/243819/21 "2004-05-07T10:07:39Z")
**JT** : > [@](#): > > If you claim that the human brain is just a complex computing machine, then your argument is self-defeating. However, if you are not limited to that claim, then your argument is not self-defeating. In other words, this is only a problem for those who insist on a purely mechanistic human brain – not for those who reject that tenet. How so? **Both** a computer-brain _and_ a “soul with free will” (or whatever entity you replace the computer-brain with) can be faulty, its logic “really” being nonsense, the validity of its reasoning being entirely questionable. Logic in **both** might be illusory, agreed? I have plenty of reasons to question the mechanistic-brain model, but plenty _more_ to question the _non_-mechanistic model since I believe it introduces unnecessary entities. I repeat my question: **Why do you feel that a nonmechanistic brain is _more_ satisfactory?** Does it merely make you “feel happier”? What entity do you feel it is _necessary to introduce_ in an Ockham’s Razor sense, and why? ---
**Author:** ![Frankenstein\_Monster](https://avatars.discourse-cdn.com/v4/letter/f/ccd318/32.png) [@Frankenstein\_Monster](https://boards.straightdope.com/u/Frankenstein_Monster)\ **Post date:** [May 7, 2004, 10:26am UTC](https://boards.straightdope.com/t/serious-physics-problem/243819/22 "2004-05-07T10:26:30Z")
> [@CalMeacham](#): > > It’s not merely that we can’t know the position and momentum to arbitrary accuracy simultaneously. It’s that a particle cannot have a precisely defined position and momentum simultaneously, … Not necessarily. This is but one particular interpretation of Quantum Mechanics (I believe this is called the Copenhagen Interpretation). QM allows other interpretations. And people have come up with them. > [@jshore](#): > > And, it should be noted that some people have tried to propose so-called “hidden variables” theories to explain things like the two-slit experiment, basically proposing that the particle has chosen a definite state but it just remains hidden from us. However, such theories lead to concrete predictions, such as certain inequalities, as Einstein and two other scientists pointed out (“EPR paradox”) and many experimental tests have now shown, I think fairly convincingly (although people always like to try to dream up new loopholes), that the inequalities implied by the hidden variable theories are not satisfied in the real world. It has been proven that QM predicts phenomena that can’t be explained by **local** hidden variables theories. (And those phenomena have subsequently been observed in actual experiments.) OK, so nobody has mentioned [Bohm’s interpretation of Quantum Mechanics](http://plato.stanford.edu/entries/qm-bohm/) yet. This is an interpretation of Quantum Mechanics that is fully deterministic. Meaning that all the particles in a system _do_ have fully determined positions and momenta at all times. Yet it is completely consistent with traditional QM. (It is in fact an extension of QM.) Of course, it is still true that there _do exist_ strange phenomena in the real world. So you do have to accept certain non-intuitive realities - especially the way subatomic particles are “connected,” sometimes even at a distance. In [this thread](http://boards.straightdope.com/sdmb/showthread.php?p=4768513) there was also an interesting discussion about one strange QM phenomenon and its interpretations. ---
**Author:** ![dhsapiens](https://avatars.discourse-cdn.com/v4/letter/d/bbce88/32.png) [@dhsapiens](https://boards.straightdope.com/u/dhsapiens)\ **Post date:** [May 7, 2004, 5:36pm UTC](https://boards.straightdope.com/t/serious-physics-problem/243819/23 "2004-05-07T17:36:19Z")
So here is a synopsis of what I have learned so far. 1. In the actual Universe, you can’t really identify BOTH the momentum AND the position of certain particles at the same time. This is not some sort of pie in the sky theory, it actually works; i.e., the problems with absolute zero as kindly provided by Calmeacham. Can anyone else give an example? 2. Einstein’s “hidden variable” thing has been squished. There is no “hidden variable”. It’s all really just random unless we can somehow explain how tiny particles communicate with one another across great distances (and as I now understand it, this may vaguely be what String Theory is proposing). My problem is that I still don’t understand what “random” fundamentally means to a physicist. How can we reconcile the idea that all things behave in accordance with physical laws (i.e., everything that exists has a physical nature and is thus constrained in its actions in a specific way) with the idea of randomness? Do physicists believe that causality does not exist on the quantum scale? Why or why not? So, can String Theory provide the “hidden variable”? What is “random” sensu stricto? Thank you. ---
**Author:** ![II\_Gyan\_II](https://avatars.discourse-cdn.com/v4/letter/i/bbe5ce/32.png) [@II\_Gyan\_II](https://boards.straightdope.com/u/II_Gyan_II)\ **Post date:** [May 7, 2004, 6:30pm UTC](https://boards.straightdope.com/t/serious-physics-problem/243819/24 "2004-05-07T18:30:27Z")
> [@JThunder](#): > > If it’s true, then we have no reason to trust human logic – including the logic which tells us to trust our logic. Agreed. Including the logic that tells us not to trust our logic. Ultimately, thinking is a just framework to organise our intuitions. > [@CalMeacham](#): > > I think you still don’t quite understand. Although a lot of people make the Uncertainty Principle into an issue of our disturbing the system, or of our ability to know position and momentum to a given degree, it cuts deeper than that. It’s not merely that we can’t know the position and momentum to arbitrary accuracy simultaneously. It’s that a particle cannot have a precisely defined position and momentum simultaneously, even if no sentientt being is trying to measure it. Unless you happen to be God (or a non-sentient being), I’m not sure how you or any human can come to that conclusion. My _intuition_ is that since the world _seems_ to work within the structures that we call “rules”, rule-based structures permeate throughout all scales and modes of awareness. > [@scotandrsn](#): > > Now let’s suppose that the electron has a definite position and velocity beyond our ability to percieve. The properties of the electron are present only at a specific place at a specific time. > > That would mean that the way in which two atoms interacted chemically would be dependent upon what part of their orbit the electrons were in at the time of interaction. Chemistry would be a complete crapshoot, because there would be no way to get consistent observations of interactions. But in fact it this is not the case. Whoa!! What? This feels awfully similar to the essence of Intelligent Design argument, that certain structures or frameworks **require** conditions A,B or C in order to work. You would have to be smart enough to know that a completely deterministic framework necessarily won’t be able to produce certain emergent higher-order logic, in order to make such a claim. I don’t think any human has achieved that level of insight. ---
**Author:** ![II\_Gyan\_II](https://avatars.discourse-cdn.com/v4/letter/i/bbe5ce/32.png) [@II\_Gyan\_II](https://boards.straightdope.com/u/II_Gyan_II)\ **Post date:** [May 7, 2004, 6:44pm UTC](https://boards.straightdope.com/t/serious-physics-problem/243819/25 "2004-05-07T18:44:14Z")
> [@scotandrsn](#): > > The fallacy in the OP is the assumption that, below any ability of ours to percieve, that determinism reign’s supreme. > > This is not the case. > > … > > Remember that the electron shell is the only thing about the atom that really takes up any appreciable volume. The “shape” of the atom, thus the shape of any molecule that atom might be a part of, and thus the shape and properties of any material those molecules make up, is completely determined by the electron’s orbit. > > Now let’s suppose that the electron has a definite position and velocity beyond our ability to percieve. The properties of the electron are present only at a specific place at a specific time. > > … > > Uncertainty at the sub-atomic level is _vital_ to certainty at the macroscopic level. It is only because of this built in uncertainty that the universe looks anything like it does. Having reread your post, you are conflating two issues here. Even ignoring my argument in the above post, what your illustration simply shows is that **our model/conception** of the atomic and sub-atomic level universe is {imprecise,approximate}/inaccurate. It could be that our understanding is correct. But by the nature of the subject domain and the method of science, we have no way of knowing so. It does not follow from your argument that determinism doesn’t apply. ---
**Author:** ![Frankenstein\_Monster](https://avatars.discourse-cdn.com/v4/letter/f/ccd318/32.png) [@Frankenstein\_Monster](https://boards.straightdope.com/u/Frankenstein_Monster)\ **Post date:** [May 8, 2004, 1:25pm UTC](https://boards.straightdope.com/t/serious-physics-problem/243819/26 "2004-05-08T13:25:35Z")
[nitpick] > [@dhsapiens](#): > > 1. Einstein’s “hidden variable” thing has been squished. There is no “hidden variable”. It’s all really just random unless we can somehow explain how tiny particles communicate with one another across great distances … 1. “communicate” is too strong. No super-luminal communication has yet been proven to happen nor shown to be possible. I’m not sure, but in fact it might have been disproven. “Connected” (non-locality) is, on the other hand, what’s been experimentally proven to happen, as I understand it. 2. “Somehow explain”… that’s a valid question. I’m not denying that. On the other hand, do we have to “somehow explain” why the speed of light is the same in all frames of reference? It’s counter-intuituve, but it’s just reality. [/nitpick] > [@dhsapiens](#): > > My problem is that I still don’t understand what “random” fundamentally means to a physicist. How can we reconcile the idea that all things behave in accordance with physical laws (i.e., everything that exists has a physical nature and is thus constrained in its actions in a specific way) with the idea of randomness? I’m not a physicist; and I would be just as interested to hear a physicist’s take on this. Meanwhile, my take: 1. I’m not convinced that any Quantum Mechanics is required to explain the brain or the sensation of free will or the phenomenon of daily-life, macroscopic randomness. I think the function of brain can be sufficiently explained by classical mechanics and chemistry. (Although, to be sure, Chemistry in turn is an application of QM.) 2. I believe it has not been proven that nature is nondeterministic. QM still leaves open the possibilty that nature isn’t random at all. Therefore the question of randomness in QM is not necessarily different than randomness in ordinary statistical mechanics. [This](http://logica.rug.ac.be/censs2002/abstracts/Flichman.htm) seems to be a discussion of randomness in statistical mechanics, is this the kind of argument you’re looking for? ---
**Author:** ![II\_Gyan\_II](https://avatars.discourse-cdn.com/v4/letter/i/bbe5ce/32.png) [@II\_Gyan\_II](https://boards.straightdope.com/u/II_Gyan_II)\ **Post date:** [May 8, 2004, 2:47pm UTC](https://boards.straightdope.com/t/serious-physics-problem/243819/27 "2004-05-08T14:47:24Z")
> [@dhsapiens](#): > > 1. Einstein’s “hidden variable” thing has been squished. There is no “hidden variable”. It’s all really just random unless we can somehow explain how tiny particles communicate with one another across great distances (and as I now understand it, this may vaguely be what String Theory is proposing). Not [exactly](http://www.nature.com/nsu/nsu_pf/030106/030106-6.html). ---
**Author:** ![scotandrsn](https://avatars.discourse-cdn.com/v4/letter/s/a4c791/32.png) [@scotandrsn](https://boards.straightdope.com/u/scotandrsn)\ **Post date:** [May 8, 2004, 5:38pm UTC](https://boards.straightdope.com/t/serious-physics-problem/243819/28 "2004-05-08T17:38:47Z")
> [@II Gyan II](#): > > Whoa!! What? > > This feels awfully similar to the essence of Intelligent Design argument, that certain structures or frameworks **require** conditions A,B or C in order to work. You would have to be smart enough to know that a completely deterministic framework necessarily won’t be able to produce certain emergent higher-order logic, in order to make such a claim. I don’t think any human has achieved that level of insight. Not ID at all. I spit on that nonsense. Take water for example. One of the things we know about water is that it is an electromagnetically polarized molecule. That is, the probability of the electrons (with their associated negative electrical charge) being at a certain point in the molecule is greater than that of their being at another point in the molecule. Now if I could reasonably think of the electrons in this particular situation as being discrete particles with a distinct location and momentum that were merely beyond my ability to observe with instruments, then I should be able to divine where the electrons are at any given nanosecond by putting a water molecule in a situation where effects of the changing polarity (due to the position and momentum of the electrons) could be observed on that time scale, and watch what happens. But this is not how water behaves in the real world. The molecule remains polarized in exactly the same way at all times. The probabilistic model serves to explain the real-world phenomenon better than the discrete particle model. Although the discrete particle model works sufficiently to explain other phenomena of the electron, it can not be extended to cover all situations. ---
**Author:** ![dhsapiens](https://avatars.discourse-cdn.com/v4/letter/d/bbce88/32.png) [@dhsapiens](https://boards.straightdope.com/u/dhsapiens)\ **Post date:** [May 8, 2004, 5:58pm UTC](https://boards.straightdope.com/t/serious-physics-problem/243819/29 "2004-05-08T17:58:21Z")
Gyan suggests that the “hidden variable” argument has not been squished, but the link provided does not support this suggestion. The physicist in question HAS published a report on a “deeper layer” of reality on the quantum scale. But he isn’t talking about anything of Einsteinean relevance. The Copenhagen Interpretation holds that there are UNKNOWABLE things about the way that quantum mechanics work. To say that something is UNKNOWABLE is a bold statement, but then again they have done some convincing experiments to show that they might be right. This remarkable t’Hooft guy is saying well, it might still be unknowable, but that’s just because when you’re talking things on the Planck Scale (uber tiny), conditions change so darned fast. But it doesn’t mean that Planck-level laws aren’t in effect - and t’Hooft believes that “complete information” exists on that scale. That’s the bottom line. When we get a monstrous Planck-level microscope going, we will be able to see whether or not nature is wholly deterministic. And if fundamental particles are wholly deterministic, then so is everything else, by an inexorable link of cause and effect. If there can be a “middle ground” between Bell’s theorem/convincing correlative experiments demonstrating that particles are communicating with one another across great distances (string theory) and quantum determinism, then this is probably the right answer. ---
**Author:** ![II\_Gyan\_II](https://avatars.discourse-cdn.com/v4/letter/i/bbe5ce/32.png) [@II\_Gyan\_II](https://boards.straightdope.com/u/II_Gyan_II)\ **Post date:** [May 8, 2004, 5:58pm UTC](https://boards.straightdope.com/t/serious-physics-problem/243819/30 "2004-05-08T17:58:32Z")
> [@scotandrsn](#): > > Take water for example. One of the things we know about water is that it is an electromagnetically polarized molecule. That is, the probability of the electrons (with their associated negative electrical charge) being at a certain point in the molecule is greater than that of their being at another point in the molecule. You’ve missed the point. You’ve saying that if model A is assumed to be the underlying state (idealised point particles), a deterministic framework fails, so determinism is false. I’m saying that it’s not necessary that model A is the only possible model that could serve to fulfill a deterministic paradigm. And one can’t prove that model A is the only possible model, unless one comes up with an argument by logical contradiction. So far, no one has done that. A more fundamental point that you missed is that you are assuming that for a certain given set of simple deterministic rules, you can’t produce complex emergent higher-order logic (i.e. chemistry would be “crapshoot”). The study of cellular automata and fractals should be enough of a practical proof against that notion. ---
**Author:** ![II\_Gyan\_II](https://avatars.discourse-cdn.com/v4/letter/i/bbe5ce/32.png) [@II\_Gyan\_II](https://boards.straightdope.com/u/II_Gyan_II)\ **Post date:** [May 8, 2004, 6:02pm UTC](https://boards.straightdope.com/t/serious-physics-problem/243819/31 "2004-05-08T18:02:50Z")
> [@dhsapiens](#): > > Gyan suggests that the “hidden variable” argument has not been squished What??? I suggested no such thing. OK, now that I reread my post, you assumed that I was addressing all of your quoted statement. I was just addressing “_It’s all really just random unless we can somehow explain how…_” BTW, this statement is wrong. I expect we agree that the real nature of reality is independent of our grasp of it. So, even if we can’t explain it, we don’t know if things are “really random”. ---
**Author:** ![scotandrsn](https://avatars.discourse-cdn.com/v4/letter/s/a4c791/32.png) [@scotandrsn](https://boards.straightdope.com/u/scotandrsn)\ **Post date:** [May 10, 2004, 11:28am UTC](https://boards.straightdope.com/t/serious-physics-problem/243819/32 "2004-05-10T11:28:22Z")
> [@II Gyan II](#): > > You’ve missed the point. You’ve saying that if model A is assumed to be the underlying state (idealised point particles), a deterministic framework fails, so determinism is false. I’m saying that it’s not necessary that model A is the only possible model that could serve to fulfill a deterministic paradigm. And one can’t prove that model A is the only possible model, unless one comes up with an argument by logical contradiction. So far, no one has done that. Ladies and gentlemen, II Gyan II has a new deterministic model of quantum theory! Enlighten us… (I can’t address the rest of your post, because it has nothing whatsoever to do with anything I was talking about. Did you forget to quote someone else’s post?) ---
**Author:** ![Frankenstein\_Monster](https://avatars.discourse-cdn.com/v4/letter/f/ccd318/32.png) [@Frankenstein\_Monster](https://boards.straightdope.com/u/Frankenstein_Monster)\ **Post date:** [May 10, 2004, 12:28pm UTC](https://boards.straightdope.com/t/serious-physics-problem/243819/33 "2004-05-10T12:28:37Z")
> [@scotandrsn](#): > > Ladies and gentlemen, II Gyan II has a new deterministic model of quantum theory! Enlighten us… drumrolls… [http://plato.stanford.edu/entries/qm-bohm/](http://plato.stanford.edu/entries/qm-bohm/) bang! ---
**Author:** ![scotandrsn](https://avatars.discourse-cdn.com/v4/letter/s/a4c791/32.png) [@scotandrsn](https://boards.straightdope.com/u/scotandrsn)\ **Post date:** [May 10, 2004, 12:47pm UTC](https://boards.straightdope.com/t/serious-physics-problem/243819/34 "2004-05-10T12:47:50Z")
> [@Frankenstein Monster](#): > > drumrolls… > > [http://plato.stanford.edu/entries/qm-bohm/](http://plato.stanford.edu/entries/qm-bohm/) > > bang! My introduction to Bohm was through the notorious pseudo-scientific shitfest, “The Holographic Universe” by Michael Talbot. Whether justified or not, Talbot used Bohm as an introduction to his supposed “proof” of Weekly World News-type paranormal activity. Bohm suffered in my estimation because of this association, and I confess to a serious inability to discuss him objectively. I leave this for others to argue. ---
**Author:** ![Frankenstein\_Monster](https://avatars.discourse-cdn.com/v4/letter/f/ccd318/32.png) [@Frankenstein\_Monster](https://boards.straightdope.com/u/Frankenstein_Monster)\ **Post date:** [May 10, 2004, 1:08pm UTC](https://boards.straightdope.com/t/serious-physics-problem/243819/35 "2004-05-10T13:08:18Z")
I guess _all_ of Quantum Mechanics has been used in all manner of [shitfest](http://www.drizzle.com/~jwalsh/sokal/) at one time or another. ---
**Author:** ![II\_Gyan\_II](https://avatars.discourse-cdn.com/v4/letter/i/bbe5ce/32.png) [@II\_Gyan\_II](https://boards.straightdope.com/u/II_Gyan_II)\ **Post date:** [May 10, 2004, 4:17pm UTC](https://boards.straightdope.com/t/serious-physics-problem/243819/36 "2004-05-10T16:17:08Z")
> [@scotandrsn](#): > > Ladies and gentlemen, II Gyan II has a new deterministic model of quantum theory! If you think that’s what I conveyed in my post, you need to work on your English comprehension. Also, by your lack of reference, I assume you didn’t read the Nature link I posted in #27. ---
**Author:** ![erislover](https://avatars.discourse-cdn.com/v4/letter/e/71e660/32.png) [@erislover](https://boards.straightdope.com/u/erislover)\ **Post date:** [May 11, 2004, 11:48am UTC](https://boards.straightdope.com/t/serious-physics-problem/243819/37 "2004-05-11T11:48:39Z")
**scotandrsn** , the mathematics of hidden variable theories are not contradicted by experiment, as far as I know or have heard, provided you do not carry along other theories’ assumptions. I think it is terrible to have a perfectly good and competing theory be left out of popular imagination. Also, there’s a crank for every subject. Don’t let that ruin the subject. 🙂 [Previous page](https://boards.straightdope.com/t/serious-physics-problem/243819.md?page=1)