What is law, and how do we know what law is? When a philosopher of law asks these questions, it pays to be cautious. When asked philosophically, the question what is law? is clearly not a question about the content of particular laws, although that question is not devoid of philosophical interest: As Nigel Simmonds has said, when disagreements about the law’s content occur, these are generally not disagreements about what the rules are, nor do they revolve around theses of ambiguity in the semantic structure of specific rules. Rather, they seem to depend upon varying conceptions of the framework of principles upon which the law is based.See Nigel Simmonds, The Decline Of Juridical Reason 17–19 (1984).