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RE: [jboske] Opacity and belief



John:
> And Rosta scripsit:
> 
> > For Clark Kent and Superman, I think it is clear that
> > they are not synonymous. 
> 
> [snip]
> 
> > Similarly, I think that "water" and "H2O" are not intensionally
> > equivalent but "wolfram" and "tungsten" are. 
> 
> I think you are confusing *a priori*-city with necessity. It's true
> that we discover that Clark Kent is Superman, or that H2O is water,
> only by *a posteriori* investigation, but that doesn't mean that there
> are possible worlds in which Superman is not Clark Kent. There might be
> someone very *like* Superman who was not Clark, but that person would
> not *be* Superman. (Of course Superman might have been adopted by a
> different family and therefore bear a different mundane name, but that
> wouldn't affect his identity.) In short, identity holds necessarily if
> it holds at all 

I'm not sure whether you are saying more than that 'Superman' and
'Clark Kent' are two names for the same individual. If that's all
you're saying, then it doesn't really conflict with my way of
looking at things, which is that Mr Superman and Mr Clark are
two different subkinds of Mr Clark Superman, the one being in
Superman guise and the other being in Clark Kent guise. If they
are are merely two names for the same individual, then the example
does not differ from the Jorge/xorces, tungsten/wolfram case.

> This is IMHO easier to see in the case of water. If water were not
> H2O, it simply would not have the properties that we ascribe to water: a
> highly polar substance, with a very large specific heat, liquid through a
> specific range of temperature. Hilary Putnam's Twin Earth, where water is
> not H2O but something with a very different ("highly complex") chemical
> formula, just isn't physically possible. 
> 
> As for the wolfram/tungsten case, this too was discovered *a posteriori*:
> a German and a Swedish miner compared notes, or groups thereof, and
> found they were talking about the same stuff 

I would say that the words have changed in meaning, then, to become mere
synonyms.

At any rate, it seems clear to me that we have two different kinds
of situation. In one, two different wordshapes both point to the 
same sense. In the other, two wordshapes point to senses that may
or may not be believed to be equivalent. 

I don't want to distinguish aprioricity and necessity. I want to
distinguish synonymy and necessity. For example, "4" and "the square
of 2" are not synonymous but are (a priori) necessarily equivalent.
That is a traditional argument against truth-conditional models
of meaning.

I would contend, then, that "4" and "the square of 2" aren't
exchangeable in intentionsal contexts, because they are nonsynonymous,
but "12" and "a dozen" are exchangeable, and if we wanted to capture
the idea that Ralph would assent to "12 da broda" but not to 
"a dozen da brdoa" then either we would have to talk about Ralph
assenting to sedu'u or we would have to talk about Ralph believing
that mo'e la'e zoi zoi 12 zoi da broda.

--And.