Scope and the development of epistemic modality: evidence fromought to

Discussions of modality (e.g. Bybee, Perkins & Pagliuca, 1994; Coates, 1983; Lyons, 1977; Palmer, 1986; Traugott, 1989) typically center around two issues: deonticity vs. epistemicity, and degree of subjectivity. Using diachronic evidence from the quasi-modal ought to , this paper argues for the need to recognize a third, crosscutting these two: narrow vs. wide scope. We argue that the epistemic use of ought to developed out of a wide-scope deontic construction, in which the modal was used with deontic meaning, but with propositional scope ( contra Bybee, 1988). Rather than attributing an obligation to the subject (i.e. having narrow scope), the modal in this construction makes an assertion about the proposition as a whole, like an epistemic. However, such ought to constructions are found some four hundred years before the first epistemic examples, and thus can be shown to be distinct from epistemic uses ( contra Gamon, 1994).