  I cannot slow the expansion of the universe or convince you of the truth of a claim by saying that I am doing so. However, these two cases differ in that the latter, but not the former, is a characteristic aim of a speech act. One characteristic aim of assertion is the production of belief in an addressee, whereas there is no speech act one of whose characteristic aims is the slowing of the universe’s expansion. A type of speech act can have a characteristic aim without each speech act of that type being issued with that aim: Speakers sometimes make assertions without aiming to produce belief in anyone, even themselves. Instead, the view that a speech act-type has a characteristic aim is akin to the view that a biological trait has a function. The characteristic role of wings is to aid in flight even though some flightless creatures are winged.