Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!watmath!clyde!caip!princeton!mind!harnad
From: harnad@mind.UUCP (Stevan Harnad)
Newsgroups: net.ai,net.cog-eng
Subject: Re: Searle, Turing, Symbols, Categories (Question not comment)
Message-ID: <160@mind.UUCP>
Date: Thu, 2-Oct-86 12:05:28 EDT
Article-I.D.: mind.160
Posted: Thu Oct  2 12:05:28 1986
Date-Received: Sat, 4-Oct-86 05:46:32 EDT
References: <158@mind.UUCP> <150@cwrudg.UUCP>
Organization: Cognitive Science, Princeton University
Lines: 59
Keywords: Robotics, Symbol-Crunching, Category Representation,Analog Representation, Induction
Xref: watmath net.ai:3741 net.cog-eng:760
Summary: On the robot version of the turing test and on symbolic and nonsymbolic computation


In his commentary-not-reply to my <158@mind.UUCP>, Richard Rush
<150@cwrudge.UUCP> asks:

(1)
>     I never heard of the "robot version" of the Turing Test,
>     could someone please fill me in?

He also asks (in connection with my "transducer/effector" argument)
about the analog/symbolic distinction:

(2)
>     I know I claimed no commentary, but it seems that this argument
>     depends heavily on the meaning of the term "symbol". This could
>     be a problem that only arises when one attempts to implement some
>     of the stranger possibilities for symbolic entities. 

In reply to (1): The linguistic version of the turing test (turing's
original version) is restricted to linguistic interactions:
Language-in/Language-out. The robotic version requires the candidate
system to operate on objects in the world. In both cases the (turing)
criterion is whether the system can PERFORM indistinguishably from a human
being. (The original version was proposed largely so that your
judgment would not be prejudiced by the system's nonhuman appearance.)

On my argument the distinction between the two versions is critical,
because the linguistic version can (in principle) be accomplished by
nothing but symbols-in/symbols-out (and symbols in between) whereas
the robotic version necessarily calls for non-symbolic processes
(transducer, effector, analog and A/D). This may represent a
substantive functional limitation on the symbol-manipulative approach
to the modeling of mind (what Searle calls "Strong AI").

In reply to (2): I don't know what "some of the stranger possibilities
for symbolic entities" are. I take symbol-manipulation to be
syntactic: Symbols are arbitrary tokens manipulated in accordance with
certain formal rules on the basis of their form rather than their meaning.
That's symbolic computation, whether it's done by computer or by
paper-and-pencil. The interpretations of the symbols (and indeed of
the manipulations and their outcomes) are ours, and are not part of
the computation. Informal and figurative meanings of "symbol" have
little to do with this technical concept.

Symbols as arbitrary syntactic tokens in a formal system can be
contrasted with other kinds of objects. The ones I singled out in my
papers were "icons" or analogs of physical objects, as they occur in
the proximal physical input/output in transduction, as they occur in
the A-side of A/D and D/A transformations, and as they may function in
any part of a hybrid system to the extent that their functional role
is not merely formal and syntactic (i.e., to the extent that their
form is not arbitrary and dependent on convention and interpretation
to link it to the objects they "stand for," but rather, the link is
one of physical resemblance and causality).

The category-representation paper proposes an architecture for such a
hybrid system.

Stevan Harnad
princeton!mind!harnad