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Article 4277 of comp.ai.philosophy:
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>From: daryl@oracorp.com
Newsgroups: comp.ai.philosophy
Subject: Re: Definition of understanding
Message-ID: <1992Mar5.141610.20612@oracorp.com>
Date: 5 Mar 92 14:16:10 GMT
Organization: ORA Corporation
Lines: 54

michael@psych.toronto.edu (Michael Gemar) writes:

[About a system for calculating potential energy in springs]

> You then say, "Aha, but the *system* that calculates potential energy
> in a spring does [understand about springs]!" However, someone who
> knows electrostatics says, "But wait!  That's also the formula for
> calculating the electrostatic energy *in a capacitor*.  Simply
> *interpret* k as C (capacitance) and as V (potential across the
> capacitor plates)."  *Now* what does the system "understand"?  Only
> pendulums?  Only capacitors?  Pendulums *and* capacitors?  I'd vote
> for neither, myself.

Michael, I agree with your point here, but I don't see how it uncovers
a difference between the situation for computers and the situation for
human beings. You are supposing that there are two subjects: springs
and capacitors, that are exactly isomorphic (when we restrict our
attention to dynamics, anyway). Every statement about the one subject
can be interpreted as a statement about the other. Before you take
this as evidence of a fundamental difference between computers and
people, you should consider how (and if) *people* avoid this
difficulty.

Suppose that there are two situations a human being can find him or
herself in: A and B. They are different situations, but, by an amazing
coincidence (1) all sensory clues to the human are identical for A and
B, (2) all "sensible" behavior on the part of the human in situations
A and B are identical. (By (1), I mean more than simply that the
immediate sensory clues are the same. The immediate sensory clues for
(a) it being night-time, and (b) being in a dark, sealed room are the
same, but there are very different sensory clues in the past and
future. By saying that the sensory clues for situation A and B are
identical, I mean that all that all sensory clues leading up to A are
identical with those for B, and also that all sensory clues following
A are identical with those for B.) If there could possibly be
situations A and B that are *exactly* isomorphic in this sense, then
would it make sense to say that a human "understands" that he or she
is in situation A? Would it make sense to say that the human
"understands" what to do?

Now, you might object that there *couldn't* be two situations in the
real world that are so completely isomorphic. In that case, a
Turing-Test passing computer would similarly not be subject to your
argument from isomorphism. However, if there could be such situations,
then I would like to know why your argument doesn't also apply to
humans to show that *they* don't really understand.

In my opinion, the problem of pinning down reference is real, and it
*doesn't* get solved, either by humans or by programs; the best we can
ever hope for is some kind of "understanding modulo isomorphism".

Daryl McCullough
ORA Corp.
Ithaca, NY


