Llewellyn and the legal realists put significantly more emphasis on the facts of a specific case than on general legal rules. Law, the realists contended, is not a deductive science. He is famous for his statement that (referring to judges, sheriffs, clerks, jailers and lawyers), ‘[w]hat these officials do about disputes is, to my mind, the law itself.’ (Bramble Bush, p. 3). While this predictive approach to defining law of the law was criticised as incomplete by H.L.A. Hart in his book The Concept of Law, it has had a significant impact on jurisprudence generally. Indeed, it has been contended that Hart's legal positivism is closer to the legal realist position than first appears. Hart's response to the problem of legal rules being both binding on judges and simultaneously changeable is that rules are formed relative to context and are vulnerable to being unsettled. He must then argue that rules can guide conduct because they function in the context of taken for granted assumptions, a position not far from that which he claims to eschew.