Kris de Jaegher (Utrecht School of Economics, Utrecht University)
Strategic Vagueness and Appropriate Contexts (j/w with R. van Rooij)
This paper brings together several approaches to
vagueness, and ends by suggesting a new approach. The common thread in these
approaches is the crucial role played by context. In Section 2, we treat
game-theoretic rationales for vagueness, and for the related concepts of
ambiguity and generality. Common about these rationales is that they are based
on the assumption of a conflict of interest between speaker and listener. We review
this literature using a single example. We argue that the most plausible
application to vagueness in natural language of these models is one where the
listener only imperfectly observes the context in which the speaker makes her
utterances. Yet, it is clear that not all vagueness can be accounted for by
conflicts of interest. This is why the rest of the paper looks at the case of
common interest. Section 3 argues that being vague by saying that someone is
bald makes sense in a context where precision is of less importance; in a
context where precision is of more importance, one can then refer to someone as
completely bald. This make sense because the longer and therefore more costly
to utter expression `completely bald' is then used less often. Vagueness is
thus seen as an application of Horn's pragmatic rule that (un)marked states get
an (un)marked expression. Section 4 tackles the Sorites paradox, which
apparently leads to the violation of standard axioms of rational behaviour, and
shows that this paradox arises from the use of vague predicates in an
inappropriate context. If, as suggested by the Sorites paradox, fine-grainedness
is important, then a vague language should not be used. Once vague language is
used in an appropriate context, standard axioms of rational behaviour are no
longer violated. Section 5 finally takes a different approach from the previous
sections, and following prospect theory assumes that context directly enter
agents' utility functions in the form of reference points, with respect to
which agents think in gains and losses. The rationale for vagueness here is
that vague predicates allow players to express their valuations, without necessarily
uttering the context, so that the advantage of vague predicates is that they
can be expressed across contexts.