 Finally, in standard contexts, it is perfectly appropriate to challenge an assertion with questions like  (28),  but  (28)  presupposes that the speaker knows that what she says is true.  (KNA)  is well positioned to explain why this presupposition is appropriate: if speakers are only entitled to assert what they know, then it is within the hearer’s conversational rights to assume (and presuppose) that the speaker knows that what they say is true. Further conversational patterns supporting  (KNA)  have been proposed, e.g., by Benton (2011).