Solum, Lawrence B. "Legal Theory Lexicon: The Nature of Law." LEGAL THEORY BLOG February 22, 2009.

What is the nature of law? This question has occupired center stage jurisprudence and philosophy of law in the modern era, and has been the central occupation of contemporary analytic jurispurdence. This entry in the Legal Theory Lexicon aims to give an overview of the "What is Law?" debate. Historically, the answer to the question, "What is law?," is thought to have two competing answers. The classical answer is provided by natural law theory, which is frequently characterized as asserting that there is an essential relationship between law and morality or justice. The modern answer is provided by legal positivisim, which, as developed by John Austin, asserted that law is the command of the sovereign backed by the threat of punishment. Contemporary debates over the nature of law focus on a revised set of positions. Legal positivism is represented by analytic legal positivists, like H. L. A. Hart, Joseph Raz, and Jules Coleman. The natural law tradition is defended by John Finnis. And a new positition, interpretivism is represented by Ronald Dworkin. In some ways, the title of this Lexicon entry is misleading, because of our focus on the "What is law?" question as it has been approached by contemporary legal philosophers. There are other important perspectives on the nature of law that focus on law's functions rather than the the meaning of the concept or the criteria of legal validity. For example, the sociological tradition includes important work on the nature of law by Max Weber and Niklas Luhmann. These issues are discussed by Brian Tamanaha in the article cited in the Links section at the end of this entry. This Lexicon entry maps the territory of the "What is Law?" controversy, and provides introductory sketches of the major positions. As always, the Lexicon is written for law students, especially first-year law students, with an interest in legal theory. . . . Read the rest here: http://lsolum.typepad.com/legaltheory/2009/02/legal-theory-lexicon-the-nature-of-law.html.