Jurisprudence is the philosophy and theory of law. The term is derived from the Latin juris prudentia, which means the study, science or knowledge of law. Jurisprudence involves developing an understanding of the customs, laws and rights of individuals in a society in order to apply due administration of justice.
Legal realism is the position that the law is a mechanism for resolving particular problems, and that flexibility and discretion is required on the part of the judge to ensure the best possible outcome. United States Supreme Court Justice Oliver Wendell Holmes has expressed this position by stating that "the life of the law has not been logic, it has been experience." [1]
The formalist school of thought is that legal decisions are based on deterministic formal rules of law, expressed by the Declaratory Theory of Law. The role of the judge in legal decisions in formalist thought is to identify the relevant rules that apply to a case, and logically deduce an outcome that is appropriate to existing rules and precedent.
Further Reading
Jerome Frank, Law and the Modern Mind (New York: Brentano's, 1931; New York: Coward-McCann, 1949).
H.L.A. Hart, The Concept of Law (Oxford: Oxford University Press, 1961).
Jeffrie G. Murphy and Jules L. Coleman, The Philosophy of Law: An Introduction to Jurisprudence (Boulder, CO: Westview Press, 1989).