A. Rieger quotes Grice in abstract for his "Analysis" paper

"I propose an account of the indicative conditional according to which the truth conditions are material, and the assertability conditions are that one may assert "if A then C" only if one knows the material conditional without knowing the truth value of either A or C. The account is defended against Frank Jackson's criticisms of Paul Grice's (related) account. Connections are made with Timothy Williamson's views on knowledge and assertion, and with the Gettier problem."