Something struck me as strange in the Kim rehash of Putnam and Burge’s thought experiments. In describing the earth-born astronaut Jones’ use of ‘water’ Kim says that “[i]f Jones stays on twin earth long enough, we will eventually interpret her word ‘water’ to mean twater [that is XYZ], not water, and attribute to her twater-thoughts rather than water thoughts, although of course it is difficult to say exactly when this change will come about.”
This brings to the fore all kinds of questions about how reference attaches to word meaning and use. As far as I remember, the historical-causal story of how reference fixing works is something like the following: the reference of any name ‘blah’ is fixed by an original user in a “baptism ceremony” which consist of the original user either ostensively or descriptively picking out the object blah and saying ‘blah’. The meaning (including reference) of ‘blah’ is then transmitted to new users of ‘blah’ when they intend to use ‘blah’ as the original user did. In this way, a long historical-causal chain of ‘blah’-use explains the transmission of the meaning along with the reference of the word.
So far so good.
Now let us turn our attention to poor tharthritis having Fred. Presumably, Fred intends to use ‘arthritis’ in the same way that his original community does. Yet, he also presumably knows that people outside of his community also use ‘arthritis’ (since otherwise he would not use ‘arthritis’ when complaining to the doctor); and no doubt also intends to use ‘arthritis’ in the way that the doctor does when he talks to the doctor. But now he intends to use ‘arthritis’ as both his community and the doctor do. On the historical-causal view it is unclear what the word ‘arthritis’ means. Is the extension of his use of ‘arthritis’, arthritis? Is it tharthritis? Is it both!?
One way to disambiguate would be to claim that the meaning of a word W in the mouth of a user X is always the meaning that W first had in X’s mouth unless X consciously corrects his meaning of the word. But if this holds, then it looks like Jones’ use of ‘water’ does not eventually come to mean ‘twater’ as Kim claims.
Another way to disambiguate would be to hold that the meaning of a word W in the mouth of a user X at time t is the meaning that X intends W to have at t (spelled out in an appropriate historical-causal way). But then it appears that Fred’s use of ‘arthritis’ might end up referring to both arthritis and thartritis. If this is true it would certainly be a startling discovery (at least for me). Most semantic theories that I know of only allow words in literal sentences to have single referents.
Of course there might be other ways to disambiguate the meaning of W. Perhaps the meaning of a word W in the mouth of a user X at time t is the meaning that the community C adorns W with. Where C is the community that X spends most of his time in. However, this account has the exact same problem as the second one whenever X has spent *equal* amounts of time in several communities. In any case, it has been interesting reviewing the thought experiments of Putman and Burge.