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

[Randall O'Reilly]

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.
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> 
> 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
> 
>