On 'certainly'

Abstract

This paper challenges the received view that epistemic adverbs in English such as certainly, probably, and possibly are subjective modal operators while their adjectival counterparts express objective epistemic modality (cf. Lassiter, 2016; Yatsushiro et al., 2022; Krifka, 2023). When we consider contexts in which hedging is pragmatically obligatory, the behavior of certainly diverges from the behavior of subjective epistemic modals and self-ascriptions of certainty. Embedding patterns reveal epistemic adverbs to be illocutionary operators which modify the nature of commitment associated with assertion. Rather than construing the modality associated with expressions of certainty as indicative of high likelihood, I offer an alternative interpretation that certain and certainly mark content as evidentially closed. I propose that certainly expresses the speaker’s commitment that available evidence fully and affirmatively settles the question of the truth of the content of her assertion.