Definedness conditions on admission-of-ignorance moves.

Given a set of alternatives, a speaker can explicitly admit ignorance about which of them hold true. The (in)felicity of such admission-of-ignorance moves immediately following disjunctions and conjunctions follows from the semantics of or and and. However, semantics alone turns out to be insufficient in cases when the disjunction/conjunction and the admission-of-ignorance move are separated by additional conversational moves of acceptance, objection, or removal of an existing assertion. I argue that these patterns follow if admission-of-ignorance are associated to a speech act operator admit whose input is restricted to propositions that the current speaker is publicly committed to at the current conversational stage. [ABSTRACT FROM AUTHOR]