Connectionists: Physics and Psychology (and the C-word)

Tue Jan 28 15:49:00 EST 2014

Randy,  I just skimmed your screed against physics and while I agree 
that most physicists don't pay attention to the foundations of quantum 
mechanics and I sympathize with your angst, I still must disagree with 
some of your assertions.

It is not true that only entangled photons can demonstrate nonlocality. 
Once two massive particles are outside of their respective light cones, 
they are no longer causally related by the speed-of-light.  If you have 
two measuring devices setup very far apart and you can keep the two 
particles coherent then they will violate Bell's inequalities.  The fact 
that it took them a long time to get to the space-like separation is 
irrelevant.  All that matters is once they are far enough apart they are 
causally separated but Bell's inequalities will still be violated.  I 
also believe that Alain Aspect's experiments show photon entanglement.

QED is manifestly Lorentz covariant so photons do travel at the speed of 
light in the theory.    Also, the Langrangian for all quantum field 
theories have the same form as Maxwell's equations that you like so 
much.  I also don't really follow what you are so distrubed about with 
regards to the locality of photons.  The normal modes of photons are 
indeed pure Fourier modes but the photons that you know and love come in 
wave packets, which imparts locality to them.  I'm not sure why this 
bothers you.

I think you also impart some advantage to semi-classical calculations 
over QM that don't seem warranted.  All calculations in QFT are 
perturbational and there are basically two small parameters you can use 
- the coupling constant, e.g. alpha, or Planck's constant hbar.  A 
semi-classical calculation (also called a loop expansion) just uses 
small hbar.  The agreement to experiments like the Lamb shift or 
electron-photon scattering, etc do improve as you go to higher order in 
the loop expansion.

As mathematics, Quantum mechanics is beautifully self-consistent and 
rather simple.  All you need is unitary transformation of a state 
function in Hilbert space together with the Born rule.  You may find 
that distasteful as a representation of reality but I find that much 
more satisfying than our confusing nonlinear classical world.  I think 
the biggest puzzle in quantum mechanics is the origin of the Born rule.  
Why is the L2 norm squared of the amplitude probability?

Anyway, I had no idea you were thinking about these things.

cheers,
Carson

On 1/28/14 2:12 PM, Randall O'Reilly wrote:
> I’m glad to hear this counterpoint to all this physics envy — I took a deep dive into the current state of theory in quantum physics a while back, and was pretty shocked at what a mess it is!  Sure, it works (“shut up and calculate” is a mantra) but from a conceptual level, there are some pretty serious unresolved issues, which don’t seem to be very widely appreciated in the lay press, with all those rah-rah unified theory books.
>
> The core issue is relevant for the discussion here: physics does NOT actually have anything approaching a “mechanistic” model — it is all a descriptive calculational tool.  In other words, you can compute the right answers, but this is clearly not how “nature computes physics”.  Indeed, the notion of finding such a mechanistic model is considered naive and has long since been abandoned.
>
> Translating this to our field: the Bayesians have won, and nobody cares about how neurons actually work!  As long as you can compute the “behavioral” outcome of experiments (to high precision for sure), the underlying hardware is irrelevant.  And those calculations seem a lot like the epicycles: you need to compute more and more terms in infinite sums to reach ever-closer approximations to the truth, with the seemingly arbitrary renormalization procedure added in to make sure everything converges.  Do we think that nature is using the same technique?
>
> Anyway, I wrote up a critique and submitted it to a physics journal: http://arxiv.org/abs/1109.0880
> Not surprisingly, the paper was not accepted, but the review did not undermine any of the major claims of the paper, and just reiterated the “standard” lines about the whole entanglement issue, denying the validity of the various papers cited raising serious questions about this.
>
> I did make some friends in the “alternative” physics community from that paper, and I am currently (very slowly) working on a “neural network” inspired model of quantum physics, described here:  http://grey.colorado.edu/WELD/index.php/WELDBook/Main — in this model, everything emerges from interacting wave equations, just like we think everything in the brain emerges from interacting neurons..
>
> - Randy
>
> On Jan 28, 2014, at 8:03 AM, Kaare Mikkelsen <mikkelsen.kaare at gmail.com> wrote:
>
>> Speaking as another physicist trying to bridge the gap between physics and neuroscience I must also say that how the most abstract ideas from quantum mechanics could meaningfully (read: scientifically) be applied to macroscopic neuroscience, given our present level of understanding of either field, is beyond me. To me, it is at the point where the connection is impossible to prove or disprove, but seems very unlikely. I do not see how valid scientific results can come in that direction, seeing as there is no theory, no reasonable path towards a theory, and absolutely no way of measuring anything.
>>
>> --------------------------------------------------------------------
>> Kaare Mikkelsen, M. Sc.
>> Institut for Fysik og Astronomi
>> Ny Munkegade 120
>> 8000
>> Aarhus C
>> Lok.: 1520-629
>> Tlf.: 87 15 56 37
>> --------------------------------------------------------------------
>>
>>
>> On 28 January 2014 15:32, Richard Loosemore <rloosemore at susaro.com> wrote:
>> On 1/27/14, 11:30 PM, Brian J Mingus wrote:
>> Consciousness is also such a bag of worms that we can't rule out that qualia owes its totally non-obvious and a priori unpredicted existence to concepts derived from quantum mechanics, such as nested observers, or entanglement.
>>
>> As far as I know, my litmus test for a model is the only way to tell whether low-level quantum effects are required: if the model, which has not been exposed to a corpus containing consciousness philosophy, then goes on to independently recreate consciousness philosophy, despite the fact that it is composed of (for example) point neurons, then we can be sure that low-level quantum mechanical details are not important.
>>
>> Note, however, that such a model might still rely on nested observers or entanglement. I'll let a quantum physicist chime in on that - although I will note that according to news articles I've read that we keep managing to entangle larger and larger objects - up to the size of molecules at this time, IIRC.
>>
>>
>> Brian Mingus
>> http://grey.colorado.edu/mingus
>>
>> Speaking as someone is both a physicist and a cognitive scientist, AND someone who has written papers resolving that whole C-word issue, I can tell you that the quantum story isn't nearly enough clear in the minds of physicists, yet, so how it can be applied to the C question is beyond me.  Frankly, it does NOT apply:  saying anything about observers and entanglement does not at any point touch the kind of statements that involve talk about qualia etc.   So let's let that sleeping dog lie.... (?).
>>
>> As for using the methods/standards of physics over here in cog sci ..... I think it best to listen to George Bernard Shaw on this one:  "Never do unto others as you would they do unto you:  their tastes may not be the same."
>>
>> Our tastes (requirements/constraints/issues) are quite different, so what happens elsewhere cannot be directly, slavishly imported.
>>
>>
>> Richard Loosemore
>>
>> Wells College
>> Aurora NY
>> USA
>>
>>
>

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