Monday, November 06, 2006

In Defense of Priest

I'm going to step up to the plate and defend Priest against the objections of last class, I'll do them in descending order, from toughest to easiest. (Proff Tillman I know I asked you about this already, but I'd like to present it here)

No Friggin Way:
A rough sketch of this objection goes like so:
- Objects are functions from worlds to identities
- "Russel Jones" is "Old Dirty Bastard"
- Under Priest's semantics we achieve RJ = ODB
- Under Priest's semantics we are forced to have RJ(W) and ODB(W) to output different identities for some world W
- Therefore the functions RJ and ODB are not equal
- Therefore, even at the actual world, RJ is not ODB, even though RJ = ODB is true at the actual world
- Therefore, No Friggin Way Priest!!!

Now, I'd like to make a concession on Priest's behalf. An object is not a function. I'm an object, and I take food, oxygen, beer etc. as input and output things like philosophical jargon, and other unmentionables. I do not take in worlds and output abstract concepts, and I doubt Priest is trying to say I do. This is just a convenient way of developing the semantics. So, ODB is not a function, he is whatever he is, and at this world he is Russel Jones. So what of this function from worlds to identities? The completion of this response I'll give in the context of the next response.

What the Deuce? (I dedicate this response to Stewie Griffin)

The objection goes as follows:
- What the deuce are identities?

First of all, I'd like to note than the concept of identity isn't quite as intuitive when dealing with other worlds. Supposedly there is a world in which Russel Jones is a jazz musician, and not a rapper. However, you can't say that these two RJs are identical in the ordinary sense, I mean c'mon, Leibnitz's law blatantly fails with respect to these two entities. However, we don't want to say something like "Russel Jones couldn't have been a Jazz musician because by Leibnitz's law he wouldn't be Russel Jones anymore". However, given possible worlds, arguably RJ's alternate selves can be arbitrarily different. Still, there's some intuitive notion that even though Russel Jones can be radically different in different worlds, we're still talking about Russel Jones. So, to indicate we're talking about the same things modified at different worlds, and not just different entities, we have the function RJ(x) (where x is a world) that points to the same thing (in most worlds) in order to indicate we're still talking about the same thing. But, we still need to relate this function to the actual object somehow. We can simply say that every object has a coresponding identity function, at the actual world Russel Jones's identity function is RJ.
Still No Friggin Way

- even if this is the case, why does RJ(W) and ODB(W) point to a different identity at some world?

This isn't such a problem anymore. Consider common world-varient speach. If we say "Russel Jones could have been a jazz musician" we would want to refer to the RJ we know and love, and merely talk about a world in which he doesn't rap. But if we say something like "it could have been the case that ODB is not RJ", then we are no longer identifying the two, and RJ would have his same old identity while ODB must assume a new one (at that world). This makes sense, because the statement paraphrased is "It could have been the case that ODB and RJ did not have the same identity". Note that at the actual world the two are still identical since the two functions point to the same identity (and strictly speaking, RJ is not a function). Plainly speaking, the world-to-identity functions are derived from who we mean to describe when discussing a world, and the identities assure that we're describing who we mean to be.

C'mon

no comment, I thought this was a pretty good objection

Rationality

This is a response I'm not too sure about. The move from de-dicto to de-re requires that "bugsy" be a rigid designator. But Elmer doesn't know that "bugsy" is a rigid designator. He doesn't think its denotation remains the same at all worlds, in fact, he thinks its denotation varies in the actual world! Therefore, he can't be expected, even as a perfect logician, to make the leap from de-dicto to de-re claims.


Priest... I've done my best, may your theory survive the onslaught!

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