I take it the minimal commitment of contextualism starts with something like this: statements of the form 'S knows that p' can express different propositions in different conversational contexts. And to this, presumably, we add that the context-sensitivity of these sentences derives from the 'knows' -- it's not enough that various singular terms (the 'S's') or statements of propositions (the 'p's') are sometimes context-sensitive. But this leaves open some choices for what to do with 'knows'.
One choice is to treat 'knows' as an indexical, which refers to different relations in different conversational contexts. Call this "indexicalism." The other choice is not to treat 'knows' as an indexical, suggesting that something about it generates context-sensitivity in some other way. (It is unfortunate that 'non-indexical contextualism' has been used as a name for a different view, which is not a contextualist one by the standard of the previous paragraph.) Jonathan Schaffer has argued for a version of contextualism of this latter type. Schaffer's view, 'contrastivism,' is that 'knows' univocally picks out a three-place relation, relating a subject, a proposition, and a contrast class. The contrast class is often left implicit in sentences of the form 'S knows that p', and so it is filled in tacitly; since different contexts will suggest different ways of filling it in, 'S knows that p' ends up expressing different propositions in different contexts. (Schaffer uses his terms differently, too; he calls my indexicalism 'contextualism'.)
Schaffer's isn't the only way of being a contextualist who doesn't treat 'knows' as an indexical. Contrastivism is only one example of a view of this kind -- this kind of view needs a name! I really want to use 'non-indexical contextualist'... do y'all think I could reclaim that label? I think the view I'm describing is extremely well deserving of that name... Anyway, whatever you want to call it, there are lots of things besides contrast classes that might be arguments for 'knows'. I rather suspect that a view of this sort is correct, and one of my projects at the moment is to articulate such a view and explain why it might be preferable to any other form of contextualism.
So we have at least three different forms of contextualism on the table:
- Indexicalism. 'Knows' is an indexical; which epistemic relation it expresses depends on the conversational context. As far as I can tell, no one has actually seriously defended this view, even though it's often taken to be the standard claim of contextualism.
- Contrastivism. Jonathan Schaffer's view. 'Knows' univocally expresses a ternary relation Kspq, relating a speaker, a proposition, and a contrast class. This last is often filled in by the conversational context.
- Non-contrastivist extra-argument-place views. (I guess we need a name for this one too.) 'Knows' univocally expresses a ternary relation Kspx, where x is something other than a contrast class, and is often filled in by the conversational context. Until we get more specific, we might think of x as standing generically for an 'epistemic standard'.
I'm curious as to whether these exhaust the options for the contextualist. They do if the only ways that 'S knows p' can be relevantly context-sensitive are for 'knows' to be an indexical, or to take an extra argument place supplied by context. Anybody see any more choices here?