Actuality Entailments

In 1999, Rajesh Bhatt observed a curious interaction between modality and grammatical aspect: Under imperfective marking, ability modals describe “pure,” potentially unrealized abilities, but their perfectively marked counterparts instead describe actual events. These apparently nonmodal interpretations are known as actuality entailments. The effect has resisted straightforward explanation on standard semantic approaches to both aspect and modality: Perfective aspect is typically taken to introduce a bounded or episodic temporal perspective, and there is no obvious reason that this should erase the core contribution (i.e., hypotheticality) of a modal predicate. This article discusses the scope and distribution of actuality entailments, including their extension to nonabilitative and necessity modals. I survey a number of proposed accounts of the phenomenon, focusing in turn on the structural (compositional) interaction between modality and aspect and on the individual semantic contributions of the implicated elements. I conclude by noting some aspects of the phenomenon that—despite a wealth of literature—have yet to be thoroughly explored and may thus help to adjudicate between existing analyses.