From newshub.ccs.yorku.ca!ists!helios.physics.utoronto.ca!news-server.csri.toronto.edu!psych.toronto.edu!christo Mon May 25 14:06:30 EDT 1992
Article 5773 of comp.ai.philosophy:
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>From: christo@psych.toronto.edu (Christopher Green)
Subject: Re: Grounding: Real vs. Virtual (formerly "on meaning")
Organization: Department of Psychology, University of Toronto
References: <1992May19.003821.9450@Princeton.EDU> <1992May19.221021.1619@psych.toronto.edu> <1992May20.030811.13711@mp.cs.niu.edu>
Message-ID: <1992May20.150243.25894@psych.toronto.edu>
Keywords: symbol, analog, Turing Test, robotics
Date: Wed, 20 May 1992 15:02:43 GMT

In article <1992May20.030811.13711@mp.cs.niu.edu> rickert@mp.cs.niu.edu (Neil Rickert) writes:
>
>  How can a human be raised in a completely virtual reality?  What is
>a virtual hunger pang?  What is a virtual runny nose?  How much
>excitement will there be in a virtual adrenaline rush?  How can a
>human learn to speak if he can neither hear his own voice nor feel the
>movement of his facial muscles?
>
>  I could go on, but I think you get the point.  There is a large amount
>of physical reality which is determined by the genes.  Can a brain live in
>a test tube, isolated from its physical reality, and still learn and
>develop normally?
>
Interesting point, but the practical difficulties are not really the key to
the philosophical question.  In principle, you could have a "brain-in-a-vat".
And, if you did, Harnad's proposal implies that such a brain would have no
real semantics because, I take it, these things and feelings it thought it
was having would all be the result of artificial stimulation (I suspect
there're problems with this phrase, but I'll let someone else take them up).
That is, it would never see a cat, but only the image of a cat. Thus, its
tokening of "cat" owuld not refer to cats.  It would never feel a scratch 
on its arm, but only the "image" of a scratch on its arm. 

My intuitions do not guide me clearly on this point. What do you think
Stevan? Is this an implication that you embrace?

-- 
Christopher D. Green                christo@psych.toronto.edu
Psychology Department               cgreen@lake.scar.utoronto.ca
University of Toronto
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