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From: roelw@cs.vu.nl
Newsgroups: comp.ai
Subject: Chinese room argument
Message-ID: <2056@star.cs.vu.nl>
Date: 20 Feb 89 12:22:15 GMT
Sender: roelw@cs.vu.nl
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Organization: VU Informatica, Amsterdam
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As I understand it, the Chinese room argument is based on the simple and
fundamental fact that computers (and, in general, Turing machines) manipulate
symbols on the basis of their form only. What the meaning of these symbols is,
if they have any, is irrelevant for the rules of manipulation.
  The same fundamental idea is the foundation of formal semantics explained
in any textbook on logic: define a language L as a set of meaningless symbols,
and independently of that define an interpretation function from L to a 
mathematical structure S which assigns meaning to the words (or formulas, or
sentences, or terms, etc.) in this language. Constants are assigned elements 
of $S$, predicates are assigned sets of tuples, etc. This leads to the 
definition of truth of a word (or formula etc.) in $S$ with respect to I.
  We can now add a derivation relation |- over F(L) x L which formalizes the 
idea that { w1, ..., wn } implies w. Interesting questions to ask about
|- are whether it preserves truth, allows one to derive all true formulas, etc.
  A computer must somehow implement |-. Because |- is defined over formulas 
independently of the meaning of the formulas w.r.t an S or an I, but is defined
on the basis of the syntactic structure of the formulas only, the computer
manipulates the symbols independently of their meaning as well.
  With respect to the person in the Chinese room manipulating symbols, the
people outside the room may have no idea what the strings of karakters mean
either (in which case there is no I) or they may have different ideas about 
what the correct I is (in which case there are different possible I's) or they
may switch interpretation functions; all of this does not affect the process
in the room one bit. There is no way the process in the room has access to the
meaning of the symbols it manipulates; this is built into the experiment from
the start.
  This implies that Harnad is right in saying that the argument works only for
symbol-manipulating processes.
  So far there should be no disagreement. The problems begin when we start to
figure out what to conclude from this argument. Conclusions which are 
warranted, I think, but are also relatively uninteresting,  are that 
computers manipulate symbols according to their syntactic structure, and that 
we may vary the interpretation of the symbols manipulated. All interesting 
conclusions contain a term not contained in the argument above, such as 
"understanding." To be able to conclude that a symbol-manipulating process cannot implement understanding (or, stronger even, that it cannot *simulate* 
understanding) we need an extra premiss connecting the term *understanding* 
with the concept of symbol-manipulation based on syntactic structure. There 
are two standpoints, which seem to divide people into two groups which do not 
understand each other (this recursive structure of the problem is not totally 
accidental).
  1. Understanding cannot be realized in a symbol-manipulating process;
  2. Understanding can be realized by a symbol-manipulating process.
A major reason for 1. is that in order to understand a word (sentence etc.) 
in a language, we must know its meaning, which is precisely what a Turing 
machine is not able to do. A major reason advanced for 2. is that, as a matter
of fact, our understanding is realized in symbol-manipulation; as far as I 
know there has been no evidence for this empirical claim.
  This puts the evidence in favor of claim 1, although I realize that 1 has not
been *proved*. Outside mathematics very little can be proved, although we may 
show things by repeatable experiments, or argue them from plausible principles,
or, as happens too often, make our point by shouting it, or by deriding 
people with opther viewpoints, burn books by writers we don't like, etc. It 
seems to me futile to expect it to be *proven*, using a plausible definition 
of "understanding", that understanding a sentence cannot be realized without 
knowing the meaning of the words. Perhaps those who require a proof of this 
think these things must be proved precisely because they think that thinking 
is a symbol-manipulating process.

I would like to ask both people in favor of 1 and in favor of 2 why they 
think it is so important to believe 1 or 2; the debate sometimes resembles a 
religious discussion. It obviously matters a lot to people whether 1 or 2 is 
believed. What difference does it make?

Roel Wieringa
Vrije Universiteit
de Boelelaan 1081
1081 HV Amsterdam.
uucp: roelw@cs.vu.nl