Full Idea
One might have a 'hidden-indexical' theory of knowledge sentences: they contain constituents that are not the semantic values of any terms; ...or 'to know' itself might be indexical, as in 'I know[easy] I have hands' or 'I know[tough] I have hands'.
Gist of Idea
The indexical aspect of contextual knowledge might be hidden, or it might be in what 'know' means
Source
Stephen Schiffer (Contextualist Solutions to Scepticism [1996], p.326-7), quoted by Keith DeRose - The Case for Contextualism 1.5
Book Reference
DeRose,Keith: 'The Case for Contextualism' [OUP 2009], p.10
A Reaction
[very compressed] Given the choice, I would have thought it was in 'know', since to say 'either you know p or you don't' sounds silly to me.
Related Idea
Idea 19508 Contextualism needs a semantics for knowledge sentences that are partly indexical [Schiffer,S]