Ergative Adjectives a Proposition-Selecting Predicates

Cinque (1990) first discussed a class of ergative adjectives, mapping their subject internally. The existence of such adjectives is somewhat surprising, given that the subject of all other adjectives, including adjectival passives, is mapped externally. Establishing what sets apart ergative and unergative adjectives is thus crucial for understanding argument structure in the adjectival domain. However, previous morphological or thematic attempts to define ergative adjectives are inadequate. In the current paper, I suggest that, cross-linguistically, the class of ergative adjectives can be defined semantically as adjectives denoting properties of propositions, rather than of individuals or events. To establish this claim, I present the results of a grammaticality judgment survey in Hebrew, showing that propositional adjectives behave ergatively with respect to a number of syntactic diagnostics, whereas non-propositional adjectives behave unergatively in these contexts. I then propose that while, in general, one thematic role of an adjective is marked to undergo λ-abstraction, resulting in "externalization" of this role, the same cannot occur with thematic roles assigned to propositions, since the λ-operator involved in adjective formation can abstract only over variables of the type of individuals or events, not of propositions.