David Lewis on Convention

In this paper I show that the definition of convention offered by david lewis in his book "convention: a philosophical study" fails to shed much light on "our common, Established concept of convention." first I set out lewis' definition of convention. I then show, Via counterexample, That satisfaction of lewis' definition is not a necessary condition for something to be a convention. I also show via counterexample that it is doubtful that satisfaction of lewis' definition is a sufficient condition for something to be a convention. I conclude that lewis has invented a new concept of convention that is seriously at odds with the established concept of convention