This little book brings together some of Marmor's recent thinking on conventions and offers a new application of his theory. In clear, straightforward prose, Marmor introduces an analysis of what conventions are and makes some theoretical distinctions (chapters 1–3), which he then applies to language (chapters 4–5) and law and morality (chapter 6–7).
Marmor's theory is best regarded as a response to David Lewis's (1969) seminal Convention. According to Marmor, a social rule R is a convention if and only if:
There is a population P that normally follows R in circumstances C.
There is a reason A for members of P to follow R in C.
There is at least one other potential rule, S, that if members of P had actually followed in C, then A would have been sufficient reason for members of P to follow S instead of R...