What Is A Negative Polarity Item?

Traditional approaches to polarity phenomena presuppose that the linguistic environment of a negative polarity item licenses the item, and that the environment typically contains some negative expression or implication. Such theories aim at achieving licensing conditions by generalizing empirically from data, which is a method undermined by too many counterexamples. This article proposes a different approach based on game-theoretic semantics and game rules for polarity items. The NPI0thesis is formulated, which says that the grammaticality condition of polarity sentences containing negative polarity items and sentences with suitably defined contrast terms. Consequently, it becomes possible to account descriptively for a wide range of polarity phenomena and to define precise licensing conditions for polarity items. This theory has significant repercussions for linguistic methodology as grammaticality becomes semantically constrained.