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From: cam@castle.ed.ac.uk (Chris Malcolm)
Subject: CR denies computer addition? (was Re: Penrose and Searle)
References: <JMC.94Nov22011226@white.wisdom.weizmann.ac.il> <Czu5zD.Dto@festival.ed.ac.uk> <Czzosp.Br5@cogsci.ed.ac.uk>
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Date: Fri, 2 Dec 1994 04:42:35 GMT
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Xref: glinda.oz.cs.cmu.edu sci.skeptic:96877 comp.ai.philosophy:23024 sci.philosophy.meta:15231

In article <Czzosp.Br5@cogsci.ed.ac.uk> jeff@aiai.ed.ac.uk (Jeff Dalton) writes:
>In article <Czu5zD.Dto@festival.ed.ac.uk> cam@castle.ed.ac.uk (Chris Malcolm) writes:
>>In article <JMC.94Nov22011226@white.wisdom.weizmann.ac.il> jmc@white.wisdom.weizmann.ac.il (McCarthy John) writes:

>>>Imagine that the procedure that the man in the Chinese room were performing
>>>unbeknownst to him were simulating an abacus rather than translating Chinese.
>>>Would the Searle argument then prove that a machine can't do arithmetic?

>>Yes. The interesting point is that we are (nearly all of us) happy to
>>extend the meaing of "add" to include what calculators do, but not (so
>>many of us) to extend "understanding" to computers which get the
>>behaviour right.

>Bull.

>>In principle you are quite right. The Chinese Room argument implies
>>that calculators do not add numbers,

>No it doesn't.

There is a strong interpretation of "understand", adopted by Searle,
which necessarily includes the subjective feel of understanding. The
CR argues that a computer running a program wouldn't have this. There
is a weak interpretation of "understand", in which the possession of
understanding is certified by the right behaviour. This is often (not
quite correctly) considered to the Turing Test view. Searle denies
that this is a valid interpretation of "understand". There is a
middling interpretation which views understanding as getting the
behaviour right by means of the right kind of internal machinery. This
is (for example) the interpretation supposed by Brian Smith's
Knowledge Representation Hypothesis.

There are three corresponding interpretations of "semantics",
"intentionality", and so on. While Brentano quite clearly meant the
strong version in "Brentano's thesis" (that "intentionality is the
ineliminable mark of the mental") it is often cited today in support
of the two weaker versions.  An appropriately modified CR argument can
be used to argue that just running the right program can't produce the
strong version of these either.

Although Searle originally intended his CR argument to show that
running the right program couldn't cause strong understanding, in
counter to Schank's claim that script systems displayed a minimal form
of understanding, it is not clear that Schank meant to claim strong
understanding in the first place. Searle offers as a corollary of the
CR argument that you can't get semantics from (nothing but) syntax. Of
course all that the CR justifies is the denial of strong semantics.
However, there has been a long debate in AI and computer science about
whether one can get weak or middle-strength semantics from syntax, and
Searle's CR is often loosely taken as a contribution to this debate.
It is possible (I'd need to check back carefully) that Searle himself
does this.  Others certainly do. For example, Harnad provides an
avoidance of the middle-strength denial of semantics from syntax by
"robotic functionalism" via categorical perception as a means of
symbol grounding.

Similarly there is a strong, middling, and weak interpretation of
addition. My point was that many people who take the strong
interpretation of understanding are happy to adopt the weak
interpretation of addition, in which case there is no problem with
computers adding, but there is one with computers understanding (by
means of running programs). But if one adopts the strong intepretation
of addition, then a suitably modified CR proves that running the right
program won't do it.

I can't see any logical grounds for adopting the strong interpretation
of "understand" and the weak of "addition" as the "proper"
interpretations. It seems as arbitrary a choice as that which allows
planes to fly but not submarines to swim. It is certainly sanctioned
by popular usage in philosophical writing that "understanding" be
interpreted strongly, "semantics" middlingly, and "addition" weakly.
But I don't think this contingent linguistic fact constitutes a
consistent philosophical view. If one adopts the strong interpretation
of understanding then I can see no good reason for failing to adopt
the strong interpretation of addition, and so arguing Searlishly that
although getting the bit strings to come out right is the right
behaviour, it crucially misses the subjective perception of number.
-- 
Chris Malcolm    cam@uk.ac.ed.aifh          +44 (0)31 650 3085
Department of Artificial Intelligence,    Edinburgh University
5 Forrest Hill, Edinburgh, EH1 2QL, UK                DoD #205
"The mind reigns, but does not govern" -- Paul Valery
