Full Idea
Stalnaker starts with the general thesis that the role of a successful assertion of s is to update the context by adding to it the content of s.
Gist of Idea
An assertion aims to add to the content of a context
Source
report of Robert C. Stalnaker (Assertion [1978]) by Ofra Magidor - Category Mistakes 5.3.2
Book Reference
Magidor,Ofra: 'Category Mistakes' [OUP 2013], p.126
A Reaction
This is to be compared with criteria of meaningfulness, such as verificationism, and with Grice's rules of conversational implicature. Presumably if you assert what the context presupposes, you fail to assert, without being meaningless.
Related Idea
Idea 18053 The semantics of a sentence is its potential for changing a context [Magidor]