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From: harnad@mind.UUCP (Stevan Harnad)
Newsgroups: net.ai,net.cog-eng
Subject: Re: Searle, Turing, Symbols, Categories
Message-ID: <112@mind.UUCP>
Date: Sat, 1-Nov-86 15:02:08 EST
Article-I.D.: mind.112
Posted: Sat Nov  1 15:02:08 1986
Date-Received: Tue, 4-Nov-86 00:35:58 EST
References: <158@mind.UUCP> <150@cwrudg.UUCP> <160@mind.UUCP> <2495@utai.UUCP> <759@bcsaic.UUCP>
Organization: Cognitive Science, Princeton University
Lines: 65
Summary: Modeling subtotal modules is inadequate
Xref: mnetor net.ai:1272 net.cog-eng:326


michaelm@bcsaic.UUCP (michael maxwell) writes:

>	I guess what I had in mind for the revised Turing test was not using
>	language at all--maybe I should have eliminated the sound link (and
>	writing). What in the way people behave (facial expressions, body
>	language etc.) would cue us to the idea the one is a human and the other
>	a robot?  What if you showed pictures to the examinees--perhaps
>	beautiful scenes, and revolting ones? This is more a test for emotions
>	than for mind (Mr. Spock would probably fail). But I think that a lot of
>	what we think of as human is tied up in this nonverbal/ emotional level.

The modularity issue looms large again. I don't believe there's an
independent module for affective expression in human beings. It's all
-- to use a trendy though inadequate expression -- "cognitively
penetrable." There's also the issue of the TOTALITY of the Total
Turing Test, which was intended to remedy the underdetermination of
toy models/modules: It's not enough just to get a model to mimic our
facial expressions. That could all be LITERALLY done with mirrors
(and, say, some delayed feedback and some scrambling and
recombining), and I'm sure it could fool people, at least for a while.
I simply conjecture that this could not be done for the TOTALITY of
our performance capacity using only more of the same kinds of tricks
(analog OR symbolic).

The capacity to manipulate objects in the world in all the ways
we can and do do it (which happens to include naming and describing
them, i.e., linguistic acts) is a lot taller order than mimicking exclusively
our nonverbal expressive behavior. There may be (in an unfortunate mixed
metaphor) many more ways to skin (toy) parts of the theoretical cat than
all of it.

Three final points: (1) Your proposal seems to equivocate between the (more
important) formal functional component of the Total Turing Test (i.e., how do
we get a model to exhibit all of our performance capacities, be they
verbal or nonverbal?) and (2) the informal, intuitive component (i.e., will it
be indistinguishable in all relevant respects from a person, TO a
person?). The motto would be: If you use something short of the Total
Turing Test, you may be able to fool some people some of the time, but not
all of the time. (2) There's nothing wrong in principle with a
nonverbal, even a nonhuman turing test; I think (higher) animals pass this
easily all the time, with virtually the same validity as humans, as
far as I'm concerned. But this version can't rely exclusively on
affective expression modules either. (3) Finally, as I've argued earlier,
all attempts to "capture" qualitative experience -- not just emotion,
but any conscious experience, such as what it's LIKE to see red or
to believe X -- amounts to an unprofitable red herring in this
enterprise. The whole point of the Total Turing Test is that
performance-indistinguishability IS your only basis for infer that
anyone but you has a mind (i.e., has emotions, etc.). In the paper I
dubbed this "methodological epiphenomenalism as aresearch strategy in
cognitive science."

By the way, you prejudged the question the way you put it. A perfectly
noncommittal but monistic way of putting it would be: "What in the way
ROBOTS behave would cue us to the idea that one robot had a mind and
another did not?" This leaves it appropriately open for continuing
research just exactly which causal physical devices (= "robots"), whether
natural or artificial, do or do not have minds.


Stevan Harnad
{allegra, bellcore, seismo, rutgers, packard}  !princeton!mind!harnad
harnad%mind@princeton.csnet
(609)-921-7771