Knowledge-how: Interrogatives and Free Relatives

It has been widely accepted since Stanley and Williamson (2001) that the only linguistically acceptable semantic treatments for sentences of the form ‘S knows how to V’ involve treating the wh-complement ‘how to V’ as an interrogative phrase, denoting a set of propositions. Recently a number of authors have suggested that the ‘how to V’ phrase denotes not a proposition, but an object. This view points toward a prima facie plausible non-propositional semantics for knowledge-how, which treats ‘how to V’ as a free relative noun phrase. In this paper I argue that the free relative semantics is implausible. I show that linguistic phenomena which seem to support a free relative semantics can be explained by the supporter of an interrogative semantics, and demonstrate that standard linguistic tests strongly suggest that ‘how to V’ has an interrogative reading, and no free relative reading.