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Article 4589 of comp.ai.philosophy:
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>From: orourke@unix1.cs.umass.edu (Joseph O'Rourke)
Newsgroups: comp.ai.philosophy,sci.philosophy.tech
Subject: Re: A rock implements every FSA
Message-ID: <45094@dime.cs.umass.edu>
Date: 19 Mar 92 00:00:49 GMT
References: <1992Mar17.224156.9177@bronze.ucs.indiana.edu> <1992Mar17.231452.9979@husc3.harvard.edu> <1992Mar18.045939.3084@bronze.ucs.indiana.edu> <1992Mar18.095140.9984@husc3.harvard.edu>
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Reply-To: orourke@sophia.smith.edu (Joseph O'Rourke)
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In article <1992Mar18.095140.9984@husc3.harvard.edu> 
	zeleny@zariski.harvard.edu (Mikhail Zeleny) writes:

 >In article <1992Mar18.045939.3084@bronze.ucs.indiana.edu>
 >	chalmers@bronze.ucs.indiana.edu (David Chalmers) writes: 

    >>At best, it [Putnam's rock] implements a "trace" of a particular run
    >>of the FSA, as Joseph O'Rourke nicely put it.

Thanks :-).

 >This is easy: first, you interpret the states of Putnam's automaton as
 >ordered pairs <state, input> of a FSA (cf. the relevant comments on p.124);
 >follow this by running through enough input/state combinations to exhaust
 >the finite combinatorial possibilities afforded by the machine's table.
 >Finally, you do the mapping.  In this way, there will be no counterfactual
 >possibilities left unaccounted for.

There was an objection to your [MZ's] extension of Putnam's rock theorem
to handle I/O by Anthony Francis based on the need for inputs of unbounded
length.  But it is clear from Putnam's description (p.124) that he is
imagining that the I/O is not actually present, but rather talks of
an automaton that behaves "as if" they were.  So I don't see that Francis's
point kills your idea.
	To rephrase Mikhail Zeleny's idea (which goes beyond what is
present in Putnam's book):  if we list out all possible traces that
the FSA could make on any input, string them end-to-end, and map
those lists of traces to the rock's physical states, then all possibile
state transitions of the FSA are "realized" in the rock.  It seems to
me that this is right.  (It also may not be precisely what MZ had in
mind.)
	But it is only right by a significant weakening of what it
means to "realize" or "implement" an FSA.  Since Putnam doesn't seem
to define the key notion of "realization" (at least I couldn't find
it in the Appendix or book proper), it is not easy to claim this 
is a departure from what he had in mind.  But according to this new,
implied definition of realization, a rock not only realizes every
FSA, it also realizes every sonnet written by Shakespeare.  For
one could string out the symbols in a sonnet end-to-end and map them
onto physical states of the rock.  In other words, a rock realizes
every FSA only in a very uninteresting sense of realization.
	Incidentally, I think it is possible to quibble with Putnam
on other grounds, in particular, his physical assumptions.  But since
his theorem is rather weak when all the important terms are explicated,
it is not worth attacking his physics.


