Abstract
The author argues that philosophers' attempts to use philosophy of language to solve problems of jurisprudence have often failed- the most dramatic failure being that of Jeremy Bentham. H.L.A.Hart made some related mistakes in his creative use of philosophy of language, yet his focus on language still yields some very significant insights for jurisprudence: the context principle (that the correct application of linguistic expressions typically depends on context in ways that are important for jurisprudence), the diversity principle (that grounds of correct application of legal language may be diverse), and the importance of vagueness.