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Article 2493 of comp.ai.philosophy:
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Newsgroups: comp.ai.philosophy
Subject: Re: Edelman's non-computability non-argument
Message-ID: <1992Jan4.152226.3327@csc.canterbury.ac.nz>
>From: chisnall@cosc.canterbury.ac.nz (The Technicolour Throw-up)
Date: 4 Jan 92 15:22:25 +1300
Reply-To: chisnall@cosc.canterbury.ac.nz
References: <61325@netnews.upenn.edu>
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Organization: Computer Science,University of Canterbury,New Zealand
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>From article <61325@netnews.upenn.edu>, by weemba@libra.wistar.upenn.edu (Matthew P Wiener):
> In article <1992Jan2.143651.3317@csc.canterbury.ac.nz>, chisnall@cosc (The Technicolour Throw-up) writes:
>>Could you elaborate on Edelman's reasoning?  I can understand using
>>interactions with an outside world as an argument against real life
>>predictability but how does he get non-computability?
> 
> There's nothing to elaborate. He just points out that Turing machine
> computability is rather narrowly defined, and his model makes enough
> of a role of the outside world that he thinks it hopeless to reduce
> his model to a Turing machine.

I'm still not sure what relevance this "outside world" has to computability
irrespective of the extent to which it is used by his model.  What's wrong
with using a transducer machine with the same power as a TM (e.g. a PDA with
2 stacks) as the model?  He's right that TM's are narrowly defined here -
TM's aren't transducers and are therefore inappropriate for dealing with an
external world.

> I haven't the foggiest clue as to how to truly model the outside world.

For starters you need to use transducer machines.  Surely this is obvious.
Or have I missed some point?
--
Just my two rubber ningis worth.
Name: Michael Chisnall          email: chisnall@cosc.canterbury.ac.nz


