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Article 1747 of comp.ai.philosophy:
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>From: dow@nova1.stanford.edu (Keith Dow)
Newsgroups: comp.ai.philosophy
Subject: Re: Physical limits when programming neurons and minds
Message-ID: <1991Nov29.164139.1588@morrow.stanford.edu>
Date: 29 Nov 91 16:41:39 GMT
References: <43772@mimsy.umd.edu> <288@tdatirv.UUCP> <57751@netnews.upenn.edu>
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>In article <288@tdatirv.UUCP>, sarima@tdatirv (Stanley Friesen) writes:
>>This also is my main problem with the 'anti-AI' crowd.  I have yet to see
>>any properly defined, verifiable definitions of some property possessed by
>>neurons that is not, or cannot, be programmed into a digital computer.
>
>I have yet to see every physical property of a neuron programmed.  I
>have yet to see any evidence that this is possible.




>From a physicists perspective, the brain is just a solution of
Schroedinger's equation.  Whether you know the boundary conditions and
have the computing power necesary to solve the equation is a problem 
for engineers.  





>  The work of Pour-El
>and Richards has shown that certain physically plausible PDEs do not
>have computable solutions, so until we have an incrediblely greater
>amount of knowledge of the physics of neurons, the belief that every
>property of neurons is programmable is at best tentative.


This physics of every phenomena larger than a proton is well understood.
Therefore every propety of a neuron is programmable.  People may or may 
not have the talent necesary to do it.  That is a completely seperate
issue.





>But for the sake of argument, let's assume that neurons can be digitally
>simulated.  Even with that much conceded, you still have a leap of faith:
>
>>If every property of a neuron is programmable, then so is intelligence.
>
>This does not follow in the least.  If our brains exploit quantum
>cryptography to get an internal sense of privacy, then short of a
>revolution in physics, there is no way you can simulate our minds
>on a digital computer.  There may indeed then be a different way
>to get digital intelligence, but it will not be found via the above
>implication.

The above is not true at all.  Schroedinger's equation is a second order
partial differential equation.  The solutions are completely
deterministic.  You can stick it on a computer and solve it.  Just
because we may not be able to solve it for a particular case at the
present time does not mean it can't be solved in the future.


stuff deleted

>In other words, Gell-Mann and Hartle are suggesting that a particular
>quantum mechanical configuration is an essential part of our minds.
>And so Bell's inequality may prevent any digital computation from
>ever being a simulation of our minds.

Ton's of quantum mechanics problems have been solved on computers.  The
results have been verified many times with experiments.  So what is the
problem?  

Long range correlations can be handled on a computer.  So Bell's 
inequality is no big deal.   Physicists agree on at least two things.
They don't understand quantum mechanics. They don't need to
understand quantum mechanics because all they have to do is calculate
what happens next.  And they know how to calculate what happens next
using quantum mechanics.

cheers


