In this talk I argue that there is a presumptive (albeit defeasible) entitlement for participants in a conversation to assume that a hearer’s silence in the face of an observed assertion indicates acceptance. I argue for this on the basis of considerations pertaining to our actual practices with assertion, together with considerations pertaining to the normative dimensions of that practice (deriving from Stalnaker’s account of the "essential effect" of assertion). One result of my thesis is that in contexts in which a hearer is known or observed to have observed an assertion, she is under prima facie normative pressure, if she rejects the assertion, to signal having done so. After defending these claims, I address the variety of contexts in which the entitlement itself is defeated (including but not limited to conditions of "silencing").