> When Oscar uses the word “water” he is talking about water, whereas when Twin Oscar uses the word “water” he is talking about twin water. As a result, what you mean depends in part, but crucially, on the world around you.

(edit: i'm sure the "Criticism" section of the wikipedia article abt Twin Earth does a better job explaining this, but anyway...)

i never understood this perspective. let's assume the Oscars don't know anything about water's chemical composition, and H2O and XYZ have the same properties (which i think the experiment does). then magically swap the Oscars; neither of them would realize it, nor would anyone around them. and there's no magical oracle who would be able to say that e.g. Twin Oscar's thoughts about "water" are now all nonsensical because he's thinking about Twin Water and not the Normal Water he's actually experiencing -- actually, i'd say they'd make as much sense as they did before the swap. because "meanings" are in the head, they're not magically bound to the real world, at best correlated.

though if i'm misreading Putnam, please let me know! i'd be happy to stop being vaguely annoyed every time i see his stuff mentioned :)