What is law?

The question that has received the most substantial attention from philosophers of law is What is law? Several schools of thought have provided rival answers to this question, the most influential of which are:
Natural law theory asserts that there are laws that are immanent in nature, to which enacted laws should correspond as closely as possible. This view is frequently summarized by the maxim: an unjust law is not a true law, in which ‘unjust’ is defined as contrary to natural law.
Legal positivism is the view that the law is defined by the social rules or practices that identify certain norms as laws. One of the early positivists was Jeremy Bentham, whose views were popularized by his student, John Austin. Both held that that law is the command of the sovereign backed by the threat of punishment. Contemporary legal positivism has long abandoned this view. In the twentieth century, two positivists had a profound influence on the philosophy of law. On the continent, Hans Kelsen was the most influential, where his notion of a Grundnorm or a “presupposed” ultimate and basic legal norm, still retains some influence. In the Anglophone world, the pivotal writer was H.L.A. Hart, who argued that the law should be understood as a system of social rules. Hart rejected Kelsen’s views that sanctions were essential to law and that a normative social phenomenon, like law, can not be grounded in non-normative social facts. According to Hart, law is essentially a system of primary social rules that guide the conduct of law’s subjects, and secondary rules that regulate how the primary rules may be changed, how disputes about them are to be adjudicated and, especially, how the primary rules are to be identified. Hart argues that this last function is performed by a “rule of recognition”, a customary practice of the officials (especially judges) that identifies certain acts and decisions as sources of law. Hart’s theory, although widely admired, has also been criticized by a variety of late twentieth century philosophers of law, including Ronald Dworkin, John Finnis, and Joseph Raz.
Legal realism was a view popular with some Scandinavian and American writers. Sceptical in tone, it held that the law should be understood determined by the actual practices of courts, law offices, and police stations, rather than as the rules and doctrines set forth in statutes or learned treatises. It had some affinities with the sociology of law.
Legal interpretivism is the view, espoused mainly by Ronald Dworkin, that law is not entirely based on social facts, but includes the morally best justification for the institutional facts and practices that we intuitively regard as legal. It follows on Dworkin’s view that one cannot know whether a society has a legal system in force, or what any of its laws are, until one knows some moral truths about the justifications for the practices in that society. It is consistent with Dworkin’s view—in contrast with the views of legal positivists or legal realists—that *no one* in a society may know what its laws are (because no one may know the best justification its practices.)
In recent years, debates about the nature of law have become increasingly fine-grained. One important debate is within legal positivism. One school is sometimes called exclusive legal positivism, and it is associated with the view that the legal validity of a norm can never depend on its moral correctness. A second school is labeled inclusive legal positivism, and it is associated with the view that moral considerations may determine the legal validity of a norm, but that it is not necessary that this is the case. Some philosophers used to contend that positivism was the theory that there is “no necessary connection” between law and morality; but influential contemporary positivists, including Joseph Raz, John Gardner, and Leslie Green, reject that view. As Raz points out, it is a necessary truth that there are vices that a legal system cannot possibly have (for example, it cannot commit rape or murder). In fact, it is even unclear whether Hart himself held this view in its broad form, for he insisted both that to be a legal system rules must have a certain minimum content, which content overlaps with moral concerns, and that it must attain at least some degree of justice in the administration of laws.
A second important debate in recent years concerns interpretivism, a view that is associated mainly with Ronald Dworkin. An interpretivist theory of law holds that legal rights and duties are determined by the best interpretation of the political practices of a particular community. Interpretation, according to Dworkin’s law as integrity theory, has two dimensions. To count as an interpretation, the reading of a text must meet the criterion of fit. But of those interpretations that fit, Dworkin maintains that the correct interpretation is the one that puts the political practices of the community in their best light, or makes of them the best that they can be. But many writers have doubted whether there is a single best justification for the complex practices of any given community, and others have doubted whether, even if there are, they should be counted as part of the law of that community.

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