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Article 4514 of comp.ai.philosophy:
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>From: orourke@unix1.cs.umass.edu (Joseph O'Rourke)
Newsgroups: comp.ai.philosophy
Subject: Re: A rock implements every FSA
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Date: 17 Mar 92 21:40:02 GMT
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In article <1992Mar17.014500.8635@bronze.ucs.indiana.edu> 
	chalmers@bronze.ucs.indiana.edu (David Chalmers) writes:

  >[...](I'd hate to see it become folk wisdom that a rock
  >implements any FSA, just through the claim being repeated enough
  >times):

It is not completely clear to me what Putnam himself thinks of his
"theorem."  (It is odd, isn't it, that he calls it a "theorem"?  I
feel this is a weakening of the force of the word "theorem.")  In
"Representation and Reality," he treats it more like "a rock 'implements'
any FSA," with emphasis on the scare quotes around 'implements.'  He
uses it mainly as a tool in his argument against functionalism.

  >My problems with Putnam's "proof" are roughly
  >
  >1. He sets it up so that the rock does indeed go through some actual
  >sequence of states ABABAB... during a given time interval.  But an
  >FSA must also satisfy counterfactuals [...]
  >
  >2. An FSA certainly must satisfy counterfactuals of the form "if
  >in state S, input I had come in, then it would have transited to
  >state T", for all counterfactual inputs I.  [...] As far as I can tell, 
  >the required counterfactual sensitivity is entirely lacking.

Putnam is well aware of the counterfactuals objection, and devotes pages
96-105 of his book to refuting it.  But the refutation is curious.  He
focuses exclusively on David Lewis's theory, which is perhaps not
inappropriate since (a) Lewis wrote a paper in direct response to
Putnam (a paper which I have not read), and (b) Lewis is Mr. Counterfactual
if anyone is.
	Putnam characterizes Lewis's theory of causality as having two
main points (p. 96):

	(1) Counterfactuals:  if "A caused B," then "if A had not been
	the case, then B would not have occurred."

	(2) The states cannot be arbitrary disjunctions (as in Putnam's
	"proof"), but rather must satisfy some criteria of "naturalness."

Putnam then argues that Lewis's theory does not hold up in various
(to me) nebulous ways.  But I think the upshot is that, if you (David
Chalmers) want to reject Putnam's rock-theorem, then you have to be
prepared to offer a theory of causality more robust than Lewis's possible
worlds theory; or you have to find reason to reject his rebuttal of Lewis.
To just say "counterfactual sensitivity is lacking" is not enough:
Putnam well knows this.
	Of course, what I mean by "you have to" is: if you were to try to
publish your theory in a reputable journal of philosophy.  And this
may not be your goal at all.


