A source-based ambiguity for 'believe'

Abstract

I propose that the English propositional attitude verb believe shows an ambiguity that is based on whether or not its meaning implicitly involves the presupposition of a source for the belief. The posited ambiguity is inspired by recent accounts (Roberts, 2021; Djärv, 2023) that propose a semantics for the optional overt source argument that can co-occur with believe. Roberts (2021) proposes that the lexical entry for believe includes an argument slot for a source, but the argument slot may be covertly existenitally closed. Djärv (2023) argues that the source is introduced by an optional covert functional head. I propose a synthesis of the two accounts. Specifically, I propose that sources are introduced by an optional functional head as in Djärv (2023), but that when present the optional head can be covertly saturated, like in Roberts (2021). This means that even when there is no overt source, there can still be a source-based ambiguity in believe. Evidence is presented from the interaction of believe with propositional anaphors, neg-raising and negative polarity items.