Jurisprudence is most usefully conceived as a theory about law, not as a theory of law. The distinction is perhaps best understood in economic theory in which the differences are often striking between the perspectives of academic economists and the working assumptions of businessmen and regulators of business. In the history of theories about law it is obvious that some conceptions of jurisprudence have only slowly achieved influence upon the everyday work of the legal process. Other conceptions have, however, exercised a demonstrable effect from the time they were first formulated. The fact is that jurisprudential ideas are unavoidable in the daily lives of judges, advocates, administrators and legislators. Consider, for example, the exp...