What is a mistake?

This article seeks to examine the question of what the essential nature and definition of a mistake is. It examines whether it can be properly distinguished from ignorance. The article then seeks to examine the requirement of provability, first in the context of mistakes of fact and then in that of mistakes of law. A Dworkinian approach is taken, arguing that it is possible to be mistaken as to the law. The article then shows why an opinion or misprediction cannot be seen as a mistake, before turning to the topical issue of the manner of the recent removal of the mistake of law bar. Using Dworkin's analysis it will be suggested that where a case is overruled it can be said to have been u mistake to rely on it. The article also argues that Birks’ analysis of the question is flawed, in that he fails to see the real distinction between a mistake and a misprediction.