Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!mnetor!uunet!husc6!uwvax!uwslh!lishka
From: lishka@uwslh.UUCP (Christopher Lishka)
Newsgroups: comp.ai
Subject: Re: The success of AI (misunderstandings)
Message-ID: <280@uwslh.UUCP>
Date: Fri, 23-Oct-87 13:59:07 EST
Article-I.D.: uwslh.280
Posted: Fri Oct 23 13:59:07 1987
Date-Received: Sun, 25-Oct-87 16:46:41 EST
References: <213@PT.CS.CMU.EDU>
Reply-To: lishka@uwslh.UUCP (Christopher Lishka)
Organization: U of Wisconsin-Madison, State Hygiene Lab
Lines: 98

In article <213@PT.CS.CMU.EDU> spe@spice.cs.cmu.edu (Sean Engelson) writes:
>
>A couple of clarifications in response to recent posts:
>
>(b) I did not state that we could simulate the human body and brain at
>this point in time.  However, we could at some point, presumably, get
>to the point where we know precisely how the body is constructed, and
>construct a simulation of the physical processes that occur.  This is
>reasonable because the human body is finite in extent, and thus there
>is a finite amount of information to discover, thus it can be
>discovered in finite (although possibly very large) time.  This is why
>I say that computers are not a less-powerful model of computation than
>the human brain, as the one can simulate the other.  By 'as powerful'
>I mean that the same computations may be performed by both; in the
>same sense that a serial computer is as powerful as a parallel one, as
>the one can simulate the other, although with a great loss of efficiency.
>

I have some questions of Mr. Engelson (forgive me is I misspelled your
name in my last posting), that others on the net might answer also:

How do we know that a computer and a human are "as powerful" as each
other?  How do we know that the same computations can be performed on
each "entity?"  Referring back to the biological sciences (esp.
Neurobiology), it would seem that there is so much that is *not* known
that coming to conclusions about abstract things such as how a human
body computes (especially billions of computations that we are not
aware of) is a bit naive at this point.  It seems like so many
mistakes that were made in the past about the human body and mind: the
brain as complex plumbing, the brain as a rather large telphone
network, etc.  Can the assumption that the two are equal in their
power to compute really be made based on what humans know (and do not
know) about their own functioning? Just a thought (maybe I am looking
at this the wrong way...).

By the same reasoning as above, is the analogy between serial and
parallel computers (and a computer and human body) really a good one?
The differences between any computer and a human body (based on the
little we do know) is staggering.  In theory, things appear to be the
same.  But computers do not have hormones, neurotransmitters, internal
messengers, complex channels, etc. for each of their "basic"
constituents (which I am assuming are cells).  Now, theoretically they
may not be necessary.  In constructing a model, it is easy to overlook
what can be implemented and what is easy to implement.  But
practically the mechanisms may be necessary.  I don't know.  No one
else knows.  But I do know that my Professor of Neurobiology (whom I
think is a good source) as well as the Grad. Students I have spoken
with *all* warn me to beware of these oversights, because the small
details are what do make the difference.  If these messenger molecules
and different neurotransmitters and sodium/potassium/calcium channels
and electrical vs. chemical channels were totally useless, why have
they survived millions of years of evolution?  Are we then only
super-parallel processors when compared to parallel-processing
computers, just as parallel-processing computers are to serial
computers? 

>(c) No, it would not be neccesary to simulate the physical world in
>our hypothetical super-computer.  We could simulate the actions of the
>sensory inputs by filtering such things as movie-camera output,
>tactile sensors, etc., through a simulation of human sensory organs.
>We know that that is theoretically possible through the same line of
>reasoning as above.

Is this reasonable?  Could we raise a human being properly be hooking
his retinal receptors to wires, his aural receptors to wires, his
tongue connections to a computer simulation, etc.?  Would we get a
*normal* person?  Personally, I don't think so, but then I don't know;
noone knows.  And until someone such as Hitler comes along, the
question will probably remain unanswered.  Now, I feel this applies to
computers because we would, in effect, be doing the same thing (given
that we could artificially create a model of a human in a computer).
You would still need to simulate the real world in the images that you
gave the machine.  The images would need to respond to the machine.
When the machine wanted to move, all of the images and artificial
senses would need to reflect that.  When the machine tried wanted to
ask a question while standing on its head, twiddling it fingers,
chewing gum, and computing pi to the fourth power, could the images
and artificial senses fed to it effectively simulate that?  (I know,
it probably wouldn't have a head or do those things, so just insert
any funny little thing that a "child" computer-modelled human would do
at once.)  Again, no small feat.  Is this really possible in the
future?


>Sean Philip Engelson			I have no opinions.  

Just some thoughts of mine (the above are NOT intended to be flames).
I feel is a very interesting discussion, but in the end hinges on
one's personal beliefs and philosophies (but then, what doesn't ;-)
The usual disclaimer applies (including the bit about the cockatiels).

					-Chris


-- 
Chris Lishka                    /lishka@uwslh.uucp
Wisconsin State Lab of Hygiene <-lishka%uwslh.uucp@rsch.wisc.edu
"What, me, serious? Get real!"  \{seismo, harvard,topaz,...}!uwvax!uwslh!lishka