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Article 2832 of comp.ai.philosophy:
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>From: jeff@aiai.ed.ac.uk (Jeff Dalton)
Newsgroups: comp.ai.philosophy
Subject: Re: Table-lookup Chinese speaker
Message-ID: <6003@skye.ed.ac.uk>
Date: 17 Jan 92 18:04:30 GMT
References: <1992Jan15.181213.29101@oracorp.com> <1992Jan16.180846.7095@spss.com>
Reply-To: jeff@aiai.UUCP (Jeff Dalton)
Organization: AIAI, University of Edinburgh, Scotland
Lines: 24

In article <1992Jan16.180846.7095@spss.com> markrose@spss.com (Mark Rosenfelder) writes:
>In article <1992Jan15.181213.29101@oracorp.com> daryl@oracorp.com writes:
>>I thought that it would be uncontroversial. By whatever criterion you
>>use for "sensible conversations", the fact that the conversations are
>>only finite in length immediately implies that there exists a finite
>>state machine that has only sensible conversations. 

>You can restrict the database as narrowly as you want (say "conversations
>with Daryl McCullough which pass the Turing test") without avoiding the
>problem.  There must exist some conversation C in the database, which
>is the ONLY conversation which begins with the sequence s1, s2, ... sn,
>where these are particular statements.  (This claim must be true if the
>database is finite.)
>
>The computer has just uttered statement sn.  If you utter statement s(n+1),
>all is well-- the computer can still proceed with conversation C.
>But if you utter any other statement, (e.g. t) it has failed the Turing test,
>because it has no entry in the database of passing conversations which
>begins with s1, s2, ..., sn, t.

Your argument is in effect a proof that there are infinitely many
sensible conversations.  But that is not so unless they can be
arbitrarily long (though still finite).  But they can't be arbitrarily
long, because we're supposing they take no longer than one lifetime.


