 David Lewis’s first book was Convention (1969a; note that all citations are to works by David Lewis, unless explicitly stated otherwise). It was based on his Harvard Ph. D. thesis, and published in 1969. The book was an extended argument that language could be entirely grounded in convention. There is a simple argument that this could not be so. Conventions are formed by agreement, agreements are made in language, so language must precede convention, not be grounded in convention. (In the foreward Quine contributes to Convention, Quine appears to express some sympathy for this argument.) Lewis’s response is to deny that conventions require anything like an agreement. Rather, on his view, conventions are regularities in action that solve co-ordination problems. We can stumble into such a regularity without ever agreeing to do so. And such a regularity can persist simply because it is in everyone’s best interest that it persist.