Abstract

The conjunction of singular nominal subjects normally triggers plural agreement in verbal or adjectival predicates ("Karl and Marc are tall/have arrived"). This is however not the case with sentential subjects ("that IP and that IP is strange/puzzles me"), and other types of (mostly, nonnominal) subjects. A common approach to the problem is based on the idea that plurality can emerge from the conjunction of elements endowed with a Number feature. Sentential subjects would not have any f -feature (Number, Gender, Person), so they could not trigger plurality. The article defends this idea against some putative counterexamples that have appeared in the recent literature, but also argues that a purely syntactic view of the phenomenon is incompatible with the fact that sentential conjunctions can easily be the subjects of plural predicate nominals ("That IP and that IP are odd facts/- observations/possibilities/. . . "). These cases can however be accounted for if we assume that predicate nominals can determine the semantic type of their argument, triggering the application of type-shifting operators. Depending on the point of application of these operators, singular or plural readings will be generated. Number optionality with sentential subjects is then contrasted with the behavior of DP-internal coordinations of abstract nouns, which displays a similar pattern.