Abstract
At the start of Convention (1969) Lewis says that it is "a platitude that language is ruled by convention" and that he proposes to give us "an analysis of convention in its full generality, including tacit convention not created by agreement." Almost no clause, however, of Lewis's analysis has withstood the barrage of counter examples over the years,1 and a glance at the big dictionary suggests why, for there are a dozen different senses listed there. Left unfettered, convention wanders freely from conventional wisdom through conventional medicine, conventions of art and "conventions of morality" to conventions of bidding in bridge.2 Surely it is unwise to try to fell these all with a single stone. Lewis's original goal, however, pursued further in (Lewis 1975), was to describe the conventionality of language, and this may be a more reasonable target