 Hart started by arguing that Bentham and Austin had explained the meaning and use of normative language in a way that failed to account for its role in ordinary discourse. He pointed out that their account of the meaning of the word ‘duty’ left them unable to draw a distinction that people ordinarily draw in their use of language, between the command of a gunman (which no one would say imposes a ‘duty’ or an ‘obligation’), and a legal prescription: