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Article 5946 of comp.ai.philosophy:
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>From: markrose@spss.com (Mark Rosenfelder)
Newsgroups: comp.ai.philosophy
Subject: Re: Grounding: Virtual vs. Real
Message-ID: <1992May27.183408.4868@spss.com>
Date: 27 May 92 18:34:08 GMT
Article-I.D.: spss.1992May27.183408.4868
References: <1992May25.214006.29965@Princeton.EDU> <1992May26.022413.14151@mp.cs.niu.edu>
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In article <1992May26.022413.14151@mp.cs.niu.edu> rickert@mp.cs.niu.edu 
(Neil Rickert) writes (quoting Stevan Harnad):
>>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?

I think it's part of Harnad's point that the transducers are not *attached*
to a thinking system, whose input is the transducers' output; they are 
*part* of the thinking system, whose input is physical (the transducers'
input).  In Harnad's view, adding or removing transducers *doesn't* change
anything... for the internal calculating engine, which he doesn't consider
intelligent.  The robot as a whole-- engine + transducers (perhaps + other '
non-computational elements)-- *is* intelligent; but removing its transducers
creates a different system.  Perhaps a diagram would help.

                                /------ thinking system ----------------------
+---------+                                          /-- nonthinking system --
| real or | physical   physical +------------+ symbolic symbolic+------------+
| virtual | facts  -->  inputs  | TRANSDUCER | output --> input | CALCULATOR |  
| reality |                     +------------+                  +------------+
+---------+
                  versus
                                                     /-- nonthinking system --
+---------+  symbolic                                  symbolic +------------+
| virtual |   output      ----------------------->       input  | CALCULATOR |
| reality |                                                     +------------+
+---------+


