We have used natural language examples in this article,
although natural language is not our main concern. Nevertheless,
I hope that formalizing context in the ways we propose may be
useful in studying the semantics of natural language. Natural
language exhibits the striking phenomenon that context may
vary on a very small scale; several contexts may occur in a
single sentence.
Consider the context of an operation in which the
surgeon says, ``Scalpel''. In context, this may be equivalent
to the sentence, ``Please give me the number 3 scalpel''.