AbstractIn this paper I compare Timothy Williamson's knowledge rule of assertion with Ishani Maitra and Brian Weatherson's action rule. The paper is in two parts. In the first part I present and respond to Maitra and Weatherson's master argument against the knowledge rule. I argue that while its second premise, to the effect that an action X can be the thing to do though one is in no position to know that it is, is true, its first premise is not: the data do not support the claim that whenever X is the thing for one to do, one is in a position to assert that it is. In the second part I consider Maitra and Weatherson's alternative hypotheses, arguing that they do not provide a better explanation of the linguistic data. I conclude, in particular, that the knowledge rule is preferable to the action rule.