Full Idea
Kaplan distinguished two different semantic features of indexical expressions: a 'character' that captures the standing meaning of the expression, and a 'content' that consists of their truth-conditional contribution in particular contexts.
Gist of Idea
Indexicals have a 'character' (the standing meaning), and a 'content' (truth-conditions for one context)
Source
report of David Kaplan (Demonstratives [1989]) by Macià/Garcia-Carpentiro - Introduction to 'Two-Dimensional Semantics' 1
Book Reference
'Two-Dimensional Semantics', ed/tr. Garcia-Carpentero/Macia [OUP 2006], p.2
A Reaction
This seems so clearly right that there isn't much to dispute. You can't understand the word 'I' or 'now' if you don't understand both its general purpose, and what it is doing in a particular utterance. But will this generalise to other semantics?