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Article 5904 of comp.ai.philosophy:
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>From: rickert@mp.cs.niu.edu (Neil Rickert)
Subject: Re: Grounding: Virtual vs. Real
Message-ID: <1992May26.022413.14151@mp.cs.niu.edu>
Organization: Northern Illinois University
References: <1992May25.214006.29965@Princeton.EDU>
Date: Tue, 26 May 1992 02:24:13 GMT
Lines: 79

In article <1992May25.214006.29965@Princeton.EDU> harnad@phoenix.Princeton.EDU (Stevan Harnad) writes:
>There still seems to be some confusion about the critical role of
>transduction in symbol grounding, and about how it is that a robot with
>TTT-capacity could be grounded if all its [REAL] transducers ever
>received as input were computer generated stimulation. I hope this
>analogy will help:

[long discussion of TTT, virtual reality, etc, removed for brevity]

  Well you certainly resolved much of the confusion as to what you meant.
But it is not at all clear to me that TTT does anything.

  More specifically, it seems that instead of asking "Is strong AI possible"
we must as "is TTT possible."  Instead of asking "does TT imply understanding"
we must ask "does TT imply TTT."  In other words, I don't see what all of this
achieves other than a change in terminology.

>As I keep stressing, thinking, unlike flying, is unobservable (except
>by the one doing the thinking). Hence it is a HYPOTHESIS that a

  Yes, you have stressed this several times.  But stressing it does not
make it true.  The nuclear fusion in the center of stars is unobservable,
but produces a great deal of supporting evidence from which scientists
infer its existence.  I put it to you that the same is true of thinking -
namely although not directly observable, it produces a great deal of
supporting evidence.  The TT is based on the assumption that you can
infer thinking from a sufficient amount of supporting evidence.  Nobody
will deny that such an inference does not provide absolute certainty,
just as there cannot be absolute certainty that there is fusion in the
core of alpha centauri.

>One scaled down candidate, however, can already be rejected as not
>having the requisite capacity, and that is a purely computational one,
>even TT-scale, waiting only to be hooked up to some trivial transducers
>so it can DEMONSTRATE its capacity.

  I think you are using the method of "proof be exhaustion" - namely if you
repeat your statement often enough, those who disagree will become exhausted.

>                                    That system would have TTT capacity
>in about the same sense that a single cell might, if only it were
>connected to the rest of the brain and body;

  Terrible analogy.  It is not the same thing at all.

 You said, earlier in your discussion:

>Now here is the analogy with the TTT-robot: If the robot REALLY has the
>capacity to pass the TTT, that capacity is not lost if it never gets to
>use it, or if it uses it only in a simulated environment. Nor
>does such a robot, in a simulated environment, turn into just a
>computer ("in a vat") in a virtual world. Its TTT capacity (like the
>plane's) is not only intact, but actually being used even when its
>senses are stimulated by computer-generated input (just as yours is,
>when you play a video game).

 But if you unplug the transducers of your TTT-robot, and in their place
plug in connections to a computer producing the virtual reality input,
you have exactly the situation you have just denied is possible.  How
can it be that whether input comes from a transducer or from a computer
changes anything at all, if the input does not change?

>The only way to get confused here is to make the mistake that when the
>input to the candidate is computer-generated rather than real, then the
>candidate may as well just be a computer too! The reality of the
>transduction should be a partial reminder that this is not all there is
>to it; the plane analogy should help too.

 I guess this is the mistake you will believe I am making.  But the plane
analogy certainly does not help.  For the fact is that aircraft designers
often use numerical models of wind tunnel tests, and they claim that for
some purposes these pure computer simulations give them more and better
information than does a test in a real wind tunnel.

-- 
=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=
  Neil W. Rickert, Computer Science               <rickert@cs.niu.edu>
  Northern Illinois Univ.
  DeKalb, IL 60115                                   +1-815-753-6940


