From newshub.ccs.yorku.ca!ists!helios.physics.utoronto.ca!news-server.ecf!utgpu!cs.utexas.edu!qt.cs.utexas.edu!zaphod.mps.ohio-state.edu!sol.ctr.columbia.edu!bronze!chalmers Wed Apr 22 12:03:58 EDT 1992
Article 5140 of comp.ai.philosophy:
Xref: newshub.ccs.yorku.ca comp.ai.philosophy:5140 sci.philosophy.tech:2565
Newsgroups: comp.ai.philosophy,sci.philosophy.tech
Path: newshub.ccs.yorku.ca!ists!helios.physics.utoronto.ca!news-server.ecf!utgpu!cs.utexas.edu!qt.cs.utexas.edu!zaphod.mps.ohio-state.edu!sol.ctr.columbia.edu!bronze!chalmers
>From: chalmers@bronze.ucs.indiana.edu (David Chalmers)
Subject: Re: A rock implements every FSA
Message-ID: <1992Apr17.222658.1055@bronze.ucs.indiana.edu>
Organization: Indiana University
References: <1992Apr17.142040.11231@husc3.harvard.edu> <1992Apr17.202258.20091@bronze.ucs.indiana.edu> <1992Apr17.211851.18106@sophia.smith.edu>
Date: Fri, 17 Apr 92 22:26:58 GMT
Lines: 77

In article <1992Apr17.211851.18106@sophia.smith.edu> orourke@sophia.smith.edu (Joseph O'Rourke) writes:
>In article <1992Apr17.202258.20091@bronze.ucs.indiana.edu> 
>	chalmers@bronze.ucs.indiana.edu (David Chalmers) writes:
>
> >Personally, I find bizarre the idea that such blatantly contingent
> >facts as the law of gravity or the mass of an electron could be
> >metaphysically necessary.  
>
>This is an interesting point to me, and I would like to know where
>Kripke discusses it.  I couldn't find it in Naming & Necessity, but
>I haven't read that cover-to-cover since I passed the age of reason :-).

At the very end of the book version, p. 164.

  The third lecture suggests that a good deal of what contemporary
  philosophy regards as mere physical necessity is actually
  necessary tout court.  The question of how far this can be pushed
  is one I leave for further work.

>It seems what is or is not contingent depends on the status of
>accepted physics.  Isn't it possible that the law of gravity must
>hold in any existent universe, that it follows inexorably from the
>existence of *any* matter?

Well, on the face of it it's just blatantly false that the law of
gravity must hold in any existent universe.  I can coherently
conceive of a world in which there's no gravitational force,
or in which the gravitational constant is different, or...

Most of the instances of physical necessity turning out to be
metaphysical necessity can actually be interpreted as cases of
conceptual necessity -- it's just that in certain cases, a posteriori
discoveries can actually determine constraints on the application
of a concept.  So it turns out to be conceptually necessary (though
a posteriori) that water is H20.  But this is not so much finding
out something new about the metaphysical structure of the cosmos
as finding out something new about the semantics of the term
"water".

It's not impossible that other contingent-seeming facts might
turn out to be necessary; but that necessity, at least in all
of Kripke's cases, needs to be licensed by the discovery of
semantic constraints.  So: it might even turn out that "the
mass of the electron = X" is necessary, but only because we
wouldn't call something with different mass an electron.
This is a far cry from turning all physical necessity into
metaphysical necessity.  e.g. the statement "the thing that
orbits around the nucleus has mass X" would remain entirely
contingent.

For all nomic necessity to turn out to be metaphysical necessity
would be very bizarre, as I said.  It certainly couldn't be
established solely by Kripke-style semantic considerations,
and it's not clear what other considerations could establish it.
It's more plausible that it might turn out that various
scientific laws turn out to be necessary for the development
of life, or of intelligence (if the thing that orbits around
the nucleus had been a little bit heavier, then complex organic
molecules would have been unstable, or some such) -- see various
discussion of the "Anthropic Principle" -- but this falls a
long way short of metaphysical necessity.

>Of course we don't (yet?) know this is
>the case, but it seems that contingency is a function of advances in
>physics, which are a function of time.  So contingency is really
>contingency(t).

Well, a more natural way to interpret this would be that necessity
and contingency is fixed (modulo actual changes in the meaning
of various terms), but that over time we can make discoveries
about what's necessary and what's contingent.  So "water is H20"
was necessary back in 200 A.D., people just didn't know it.

-- 
Dave Chalmers                            (dave@cogsci.indiana.edu)      
Center for Research on Concepts and Cognition, Indiana University.
"It is not the least charm of a theory that it is refutable."


