From newshub.ccs.yorku.ca!ists!helios.physics.utoronto.ca!news-server.ecf!utgpu!cs.utexas.edu!uunet!tdatirv!sarima Sun May 31 19:04:20 EDT 1992
Article 5927 of comp.ai.philosophy:
Path: newshub.ccs.yorku.ca!ists!helios.physics.utoronto.ca!news-server.ecf!utgpu!cs.utexas.edu!uunet!tdatirv!sarima
>From: sarima@tdatirv.UUCP (Stanley Friesen)
Newsgroups: comp.ai.philosophy
Subject: Re: penrose
Message-ID: <31@tdatirv.UUCP>
Date: 26 May 92 19:29:43 GMT
References: <2524@ucl-cs.uucp> <1992May1.025230.8835@news.media.mit.edu> <1992May6.220605.26774@unixg.ubc.ca> <1992May8.015202.10792@news.media.mit.edu> <1992May18.194416.27171@hellgate.utah.edu> <27@tdatirv.UUCP> <atten.706786286@groucho.phil.ruu.nl>
Reply-To: sarima@tdatirv.UUCP (Stanley Friesen)
Organization: Teradata Corp., Irvine
Lines: 37

In article <atten.706786286@groucho.phil.ruu.nl> atten@phil.ruu.nl (Mark van Atten) writes:
|sarima@tdatirv.UUCP (Stanley Friesen) writes:
|>Right, but why assume *human* *thought* is complete (in this sense)?
|>Is ti really certain that we can *always* jump the rails, so to speak,
|>and arrive at the truth.
|
|>This is what Penrose' argument requires, and I find it extremely unlikely.
|
|No, Penrose's argument does not require that we can *always* jump the rails,
|he just argues that there is at least one case where we can (i.e. Goedel's
|argument). 

Except, in that case his conclusions do not follow.  It is possible to
construct a TM that can recognise the Goedel sentences in a formal system
from any of a given countable subset of possible formal systems.

Thus, just recognizing *one* example of the Goedel sentence, or even any finite
list of examples, does *not* prove that our minds are not TM's (or like
TM's in some sense).

Furthermore, since every human is different, it can be argued that we would
each implement a slightly different TM, so we could each have a different
range of recognition.


Note, our minds differ from a mathematical TM in that we routinely use the
partial outputs, rather than the post-termination outputs, and there does
not seem to be a normal STOP instruction in the input tape (I do not know
of many people who have died of 'brain failure').

Now, is this enough to make theoretical TM results invalid for human minds?
I don't know.
-- 
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sarima@teradata.com				(Stanley Friesen)
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uunet!tdatirv!sarima


