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Article 1690 of comp.ai.philosophy:
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>From: jeff@aiai.ed.ac.uk (Jeff Dalton)
Newsgroups: comp.ai.philosophy
Subject: Re: Daniel Dennett
Message-ID: <5729@skye.ed.ac.uk>
Date: 27 Nov 91 20:43:51 GMT
References: <1991Nov23.214707.1663@cc.gatech.edu> <39701@dime.cs.umass.edu> <centaur.691029638@cc.gatech.edu> <39729@dime.cs.umass.edu> <centaur.691103968@cc.gatech.edu>
Reply-To: jeff@aiai.UUCP (Jeff Dalton)
Organization: AIAI, University of Edinburgh, Scotland
Lines: 27

In article <centaur.691103968@cc.gatech.edu> centaur@terminus.gatech.edu (Anthony G. Francis) writes:

   First of all, we can't construct a FSA for the _memory_ subsystem,
   because of the physical constraints of this universe. Essentially,
   my point is that Turing Machines require unbounded amounts of
   storage, and for a vast collection of problems, actual physical
   storage is sufficient for an implementation of a Turing Machine to
   solve those problems. A direct implementation of a FSA for that
   same set of problems, however, is _impossible_.

But the physically realizable Turing machines can all be treated
as theoretical FSAs for many purposes.  If a physically realizable
TM can "understand" in the Chinese Room sense, then the program
involved is equivalent to some (perhaps theoretical) FSA.  So if
_no_ FSA is capable of the required processes, neither is any
physically realizable TM.  If, on the other hand, some FSAs are
capable, the question for physically realizable TMs is still open.

   So, the alternatives that I see are to simply restrict our
   discussions to theoretical machines, in which case Turing Machines
   are more powerful, or to restrict ourselves to machines with space
   constraints, in which case Turing Machines are more powerful.

I have suggested another alternative above, namely to consider
theoretical FSAs as representatives of physically realizable TMs.

-- jd


