The Essay contrasts three accounts of judicial fidelity to law, labeled ‘legalism’, ‘idealism’ and ‘pluralism’. It then explores the more persuasive model of adjudication—pluralism—in greater depth, examining five fundamental principles of the law both in general theory and in the exemplary context of stare decisis. This framework is deployed to outline a typology of judicial activism comprising three varieties. A final section focuses briefly on the special case of judicial review of legislation.