A Layered Semantics for Utterance Modifiers *

Bach (1999) classifies these adverbials as utterance modifiers, a term that gets right to the heart of their contribution. One also finds ‘second-order speech act’ (Bach 1999), ‘pragmatic adverb’ (Bellert 1977), and ‘illocutionary adverbial’ (Bach and Harnish 1979). The labels all recognize, in various ways, that these linguistic items permit speakers to qualify, restrict, and modify their relationships to the sentences they utter. This paper takes up the task of making good on the intuitions reflected in such labels while at the same time keeping these expressions in the grammar. They might be metalinguistic, but this does not mean that we can allow their descriptions to stand as metagrammatical. Useful tools and techniques for meeting this requirement are found in recent work on layered logics and layered structures (Gabbay 1999; Blackburn et al. 1993; Blackburn and Meyer-Viol 1997). In the layered setting defined below, we can talk about discourses and the objects they contain; we can also move down a level, to talk about the meanings of individual sentences. The semantics for utterance modifiers is located mainly in the upper layer of the logic and model theory. It should be said that the layering idea is not really new in linguistic semantics. Montagovian intensional models contain a lower layer of first-order structures and an upper layer of worlds (atomic