The present paper argues Plastic Door Film that there is a knowledge norm for conversational implicature: one may conversationally implicate p only if one knows p.Linguistic data about the cancellation behavior of implicatures and the ways they are challenged and criticized by speakers is presented to support the thesis.The knowledge norm for implicature is then used to present a new consideration in favor of the KK thesis.
It is argued that if implicature and assertion have knowledge norms, then assertion requires not only knowledge but iterated knowledge: knowing that you know that you know that.you know.Such a condition Massage Oil on permissible assertion is argued to be plausible only if the KK thesis is true.