Opiniatrety

"any other F [besides Y]' entails or presupposes that Y is in fact F"

That seems to be correct, but that doesn't seem to be the form of the sentence beginning with 'McX'. You don't have a 'besides Y' in your sentence. It's just an implication: if X is an indexical, it will behave in thus and such ways; X is not behaving in thus-and-such a way, therefore, it can't be an indexical.

(Quoth DeRose: 'Nuh-uh!')

Still, it's infelicitous, I think. As written it seems to imply that if 'knows' behaved like any one indexical (because indexicals all behave different?), the contextualist would be in the clear, and depending on what McX means, that doesn't seem to be strong enough. The problem is that 'knows' doesn't behave like a member of the class of indexicals, not that it doesn't behave like any specific indexical.

Maybe 'it doesn't behave like other indexicals.'

I agree that it's infelicitous, but I don't think the problem is with "any" (as Cala seems to be suggesting). It seems to me that "besides Y" is implied by "other" as a matter of lexical semantics, so "other" the problem here. Would "any known indexical" (or something like that, maybe "established") work?

I thought of this post when I came across the following sentence in Hutchinson's introduction to the Alcibiades:

"The clearest argument against Plato's authorship is probably that Plato never wrote a work whose interpretation was as simple and straightforward as that of Alcibiades."

Teofilo is getting at what I'm thinking. The 'besides Y' isn't supposed to be in the sentence; it's just that for 'other' to make sense it has to be contrasted with something; in this case Y. Adding 'besides Y' does seem to bias the sentence, though, since it brings in the semantics of 'besides' as well as those (that?) of 'any other'. So I shouldn't have done that.

I think the 'any one indexical' interpretation is the one that's meant. McX, in these papers, usually says, "Let's take the types of indexical one by one [there are usually two or three]. 'Know' doesn't behave like this kind, or that kind, or that kind. So it's not an indexical." If 'know' did behave like one other indexical, the contextualist would be OK.

The sentence currently reads "McX argues that ‘know’ does not behave like a context-sensitive term." Gotta save words! And I decided the general audience might not immediately know what 'indexical' meant, which may be stupid. (I'm new at this book-reviewing game.)

Mike J, that's funny. Offhand it seems like it's not incoherent but merely question-begging; the premise of the argument presupposes that Plato did not write the Alcibiades.

Neat example. It reminded me of "I am the youngest of my siblings." I haven't read it but there's a paper by Chris Barker arguing this is a case of "temporary accommodation."

Here's the abstract:

This paper seeks to explain a previously unnoticed semantic phenomenon illustrated by the contrast between (1) I am the oldest of my enemies, which presupposes that the speaker is one of his or her own enemies, versus (2) I am the oldest of my siblings, which for most speakers does not presuppose that the speaker is his or her own sibling. I argue that the behavior of (2) is the result of temporarily enlarging the extension of the predicate (sibling) in order to meet an otherwise unsatisfiable presupposition. I propose that this temporary accommodation occurs only with lexical and complex predicates whose denotations are of a certain mathematical class that I call quasi-equivalence relations. I also briefly discuss a number of closely related construction types, and draw out the functional motivation for this unusual type of grammaticized accommodation.