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Article 5142 of comp.ai.philosophy:
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>From: orourke@sophia.smith.edu (Joseph O'Rourke)
Subject: Re: A rock implements every FSA
Message-ID: <1992Apr18.000226.19369@sophia.smith.edu>
Organization: Smith College, Northampton, MA, US
References: <1992Apr17.202258.20091@bronze.ucs.indiana.edu> <1992Apr17.211851.18106@sophia.smith.edu> <1992Apr17.222658.1055@bronze.ucs.indiana.edu>
Date: Sat, 18 Apr 1992 00:02:26 GMT
Lines: 50

>In article <1992Apr17.211851.18106@sophia.smith.edu> I asked:

>>[Where does Kripke discuss contingent vs. metaphysical necessity
>>in "Naming and Necessity"?]

In article <1992Apr17.222658.1055@bronze.ucs.indiana.edu> 
	chalmers@bronze.ucs.indiana.edu (David Chalmers) replied:

>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.

Thanks. I will reread Lecture III.  Does anyone know if he followed up 
on this in "future work" in the intervening two decades?

>[...]
>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...

But can you only conceive of such a world because you do not
understand physics fully?  (You and everyone else, that is.)
Your view is only coherent (perhaps) because you don't follow
out the details of the physics.  It is conceivable (to me) that 
the existence of matter necessarily implies gravity, that matter 
without gravity is self-contradictory, in the same sense that a 
program that can solve the halting problem is self-contradictory.
	Can you coherently conceive of a world in which particles can 
travel faster than light? In which like charges attract?  In which 
gravity is repulsive?  In which time can flow backwards?  

>[...]
>So "water is H20"
>was necessary back in 200 A.D., people just didn't know it.

[Hydrogen-twenty, eh? :-)]
If you hold this, then it seems you cannot say that any claim about
gravity is "blatantly false," as we surely do not understand gravity
today.  It may well be that gravity is necessary in 1992, but we
just don't know it.  In 10,000 years this may be as evident as
is the necessity of H2O today.  What you mean is that, according to
our present abysmal understanding of the physics of gravity today,
a situation that can only clarify in the future, it is blatantly 
false that gravity is contingent. This hedges the claim so severely
that use of the word "blatant" seems inappropriate.
						--Joe O'Rourke


