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From: rar@ZOOKS.ADS.COM (Bob Riemenschneider)
Newsgroups: comp.ai
Subject: Re: Chinese Room Argument
Message-ID: <8903140108.AA04394@zooks.ads.com>
Date: 14 Mar 89 01:08:32 GMT
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Mike Coffin presents what seems to me a pretty poor argument for the
possibility of "understanding through symbol pushing".

=>   1) I have in my possesion a system that seems to understand and think:
=>      my brain.  (My wife might argue about that...)
=>   2) The brain (and the rest of the body) is made up of physical parts:
=>      electrons, atoms, molecules, cells, organs, etc.
=>   3) I see no reason, in principle, that such parts can't be simulated
=>      to any desired precision, given powerful enough computers.  Not
=>      necessarily Turing machines; we may need random bits.

Mike: 

So far, so good.  You haven't shown that *only* the physical properties of
the brain are relevant to understanding, that (say) divine intervention
isn't required, but I'm inclined to believe that replacing a brain by a
physically identical object wouldn't affect understanding.

=>   4) Given such simulators, I see no reason, in principle, that I can't
=>      begin replacing my biological parts with simulated parts.
=>      Obviously I will need some chemical peripherals to interface the
=>      two systems.

I can see lots of reasons why it might be impossible to perform such
"replacement".  For instance, suppose that relatively fine physical structure
turns out to be relevant to intelligence--i.e., that simulation at the 
electron level turns out to be required.  So you pick some electron to
be replaced, and simulate it on your computer.  You then remove the electron,
only to realize that hooking the simulation in doesn't make sense.  A
simulation of an electron doesn't have the right physical properties to
influence other electrons in the same way that an electron does.  E.g.,
the remaining electrons have to "feel" the same electrical repulsion 
that they would if the electron hadn't been removed.  Electrons repel
electrons, simulated electrons simulated-repel simulated electrons, but
simulated electrons do not repel actual electrons any more than simulations
of hurricanes blow down actual trees.

This sort of bit-by-bit replacement argument only works if the replacement
pieces have the right causal powers.  But we don't know what causal powers
are relevant to understanding.  That's part of the problem.

=>   5) Given that the simulations are accurate enough, I see no reason that
=>      at some point in the process of replacement I will cease to
=>      understand: e.g., that with 23.999% of my brain simulated, I understand,
=>      but with 24.000% I cease understanding.

Even if everything followed to this point, this at most shows that either
understanding isn't lost, or it's implausible to regard understanding as an 
all-or-nothing thing.  ("I see no reason to believe that at some point in
the process of pulling out hairs I will become bald.")  But, there's good
reason to say understanding isn't all-or-nothing anyway.

By the way, if I recall correctly, Searle believes that simulation of
intelligence is possible, and so is creation of an artifact that understands.
He's trying to show that true understanding will not through an extension
of certain programming techniques, so your whole argument doesn't have
much relevance to the conclusions that were supposed to be drawn from
the Chinese Room.

							-- rar