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From: roelw@cs.vu.nl
Newsgroups: comp.ai
Subject: Chinese room argument
Message-ID: <2139@star.cs.vu.nl>
Date: 9 Mar 89 13:52:17 GMT
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In article <3399@uhccux.uhcc.hawaii.edu> lee@uhccux.uhcc.hawaii.edu (Greg Lee) writes:

> suppose I exchanged the denotations of your
> (complex of) symbols for 'red' and 'green'.  You might have
> a traffic accident.  Isn't that relevant?  Your computations
> wouldn't change, but their appropriateness would.

Let's not suppose what is to be argued, that my (or anyone else's) thinking
is a symbol-manipulating process. So let's do a few other thought experiments
instead:

1. Do the experiment with a symbol-manipulating robot. To be specific, take a
universal Turing machine (UTM) and put on its tape (a) a description of a
particular TM who behaves as a traffic participant and (b) a description of the
input to this TM. Now change the denotation of the symbols on the tape of this
UTM, e.g. let the symbol "red" denote green and let "green" denote red.
There is of course no difference to the computation of the UTM.

2. Put the UTM in a box equiped with video cameras, wheels and a motor and let
it drive in the street. Again there is no difference to its computation if you
interpret "green" as red etc. (You may put any other symbol-manipulating device
in a box with the same result.)

The general result is that a symbol-manipulating device is not affected by the
denotation you or anyone else give to the symbols it manipulates.

Of course, it is a different matter if the programmer wrote "green" where s/he
should have written "red". The robot will probably cause a traffic accident by
that.

3. Talk with someone, using the word "green" to mean red and "red" to mean
green, without the other person's knowing about this change in denotation. S/he
quickly will find something weird about your conversation; the worst possible
outcome would be that s/he thinks you are nuts; the best outcome would be that
you agree to use words, say "reen" and "gred", to stand for what you both agree
to be red and green.

What this shows, I think, is that the denotation of public symbols is publicly
known and that if you make a private change in what is conventionally denoted 
by a symbol, you will get social problems. Conventions about what the 
denotations of symbols are, are not (merely) in the head of one individual but
are social institutions. 

This leads to Harnad's question:

> Philosophers
> have made two kinds of nondemonstrative conjectures about "swapping."
> One was about swapping experiences (the "inverted spectrum" conjecture:
> could someone among us pass indistinguishably even though whenever
> he saw or spoke of what we refer to as "green" he actually saw what we
> refer to as "red" and vice versa). The second "swapping" conjecture is
> about meaning: Could the meanings of some (or all) of the words in a
> natural language be coherently swapped or permuted while leaving ALL
> behavior and discourse unchanged? (This is Quine's celebrated thesis of
> the "underdetermination of radical translation.")

> I feel logical and intuitive pulls in both directions in both cases.

I think that logically, it is possible that we will never notice the swapping,
as long as we talk about domains where swapping has not occurred. If you swap 
the denotation of "red" and "green", and we proceed talking about politics, I 
may not notice anything. Until of course you mention the Red party in Germany, 
where I would talk about the Green party in Germany. There is no *proof* that
you have not swapped denotations, but I think it is crucial that we could sort
out a difference when we encounter one -actually, that we would recognize a
difference as denotation swap to begin with.


Roel Wieringa