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Article 4700 of comp.ai.philosophy:
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>From: orourke@unix1.cs.umass.edu (Joseph O'Rourke)
Newsgroups: sci.philosophy.tech,comp.ai.philosophy
Subject: Re: A rock implements every FSA
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Date: 24 Mar 92 22:17:24 GMT
References: <1992Mar24.025128.9379@bronze.ucs.indiana.edu> <1992Mar24.042009.12510@organpipe.uug.arizona.edu> <1992Mar24.051654.18747@bronze.ucs.indiana.edu> <1992Mar24.112548.10215@husc3.harvard.edu>
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In article <1992Mar24.112548.10215@husc3.harvard.edu> 
	zeleny@zariski.harvard.edu (Mikhail Zeleny) writes:

 >...as I've said earlier, all
 >that remains to be done is to 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.  Just string all possible traces
 >together in a sequential order.  Given the original context of determining
 >the theoretical validity of functionalism, the requisite bound on input
 >length is easily obtained on the basis of temporal limitations on the
 >length of human life.

First, I think that the need for truncating traces to a finite length
is a serious flaw, in spite of your justification for this move.  It
means that the rock doesn't realize the FSA: it realizes some other
FSA which is equivalent on inputs of length < n.
	But that aside, my second objection is that your scheme does
not have the desirable feature that the rock behaves in different
ways depending upon the input, as does the FSA it is supposedly
realizing.  Because you have absorbed the inputs into states, which
are spread out over time, the sense of a machine responding to variable
inputs is totally lost.  Let's face it:  your rock doesn't realize or
implement the FSA in an interesting sense.  It just sits there, whereas
the FSA is active: it responds to the input.  I can't believe this
nearly vacuous sense of realization has any philosophical implications.
	What seems to be needed is a mapping of FSA states to the rock
so that some physical parameter (say temperature) corresponds to the 
FSA input.  I have thought about this a bit, but haven't seen a
way to rescue Putnam.  If your patch is his only savings, the force
is gone.


