The mountains are impure: the semantics of lexical plurality

This paper is concerned with the semantics of so-called plurals of extension, a class of lexical plurals such as mountains, cliffs, skies, Hebrides, and Pyrenees. While similar on the surface to regular plural nouns, they behave differently in certain regards, including their compatibility with determiners, interpretation in half of the N partitives and possibility to occur as weak definites. We will argue that plurals of extension denote predicates over impure atoms, predicting that theybehave as singulars from a semantic point of view and as plurals from a morphological point of view. The analysis will be extended to temporal plurals of extension and plural mass nouns.