“But what, after all, is a law? [...] When I say that the object of laws is always general, I mean that law considers subjects en masse and actions in the abstract, and never a particular person or action. [...] On this view, we at once see that it can no longer be asked whose business it is to make laws, since they are acts of the general will; nor whether the prince is above the law, since he is a member of the State; nor whether the law can be unjust, since no one is unjust to himself; nor how we can be both free and subject to the laws, since they are but registers of our wills.”
The philosophy of law is commonly known as jurisprudence. Normative jurisprudence is essentially political philosophy, and asks “what should law be?”, while analytic jurisprudence asks “what is law?”. John Austin‘s utilitarian answer was that law is “commands, backed by threat of sanctions, from a sovereign, to whom people have a habit of obedience”. Natural lawyers on the other side, such as Jean-Jacques Rousseau, argue that law reflects essentially moral and unchangeable laws of nature. The concept of “natural law” emerged in ancient Greek philosophy concurrently and in entanglement with the notion of justice, and re-entered the mainstream of Western culture through the writings of Thomas Aquinas.
Hugo Grotius, the founder of a purely rationalistic system of natural law, argued that law arises from both a social impulse—as Aristotle had indicated—and reason. Immanuel Kant believed a moral imperative requires laws “be chosen as though they should hold as universal laws of nature”. Jeremy Bentham and his student Austin, following David Hume, believed that this conflated the “is” and what “ought to be” problem. Bentham and Austin argued for law’s positivism; that real law is entirely separate from “morality”. Kant was also criticised by Friedrich Nietzsche, who rejected the principle of equality, and believed that law emanates from the will to power, and cannot be labelled as “moral” or “immoral”.
In 1934, the Austrian philosopher Hans Kelsen continued the positivist tradition in his book the Pure Theory of Law. Kelsen believed that although law is separate from morality, it is endowed with “normativity”; meaning we ought to obey it. While laws are positive “is” statements (e.g. the fine for reversing on a highway is €500); law tells us what we “should” do. Thus, each legal system can be hypothesised to have a basic norm (Grundnorm) instructing us to obey. Kelsen’s major opponent, Carl Schmitt, rejected both positivism and the idea of the rule of law because he did not accept the primacy of abstract normative principles over concrete political positions and decisions. Therefore, Schmitt advocated a jurisprudence of the exception (state of emergency), which denied that legal norms could encompass of all political experience.
Later in the 20th century, H. L. A. Hart attacked Austin for his simplifications and Kelsen for his fictions in The Concept of Law. Hart argued law is a system of rules, divided into primary (rules of conduct) and secondary ones (rules addressed to officials to administer primary rules). Secondary rules are further divided into rules of adjudication (to resolve legal disputes), rules of change (allowing laws to be varied) and the rule of recognition (allowing laws to be identified as valid). Two of Hart’s students continued the debate: In his book Law’s Empire, Ronald Dworkin attacked Hart and the positivists for their refusal to treat law as a moral issue. Dworkin argues that law is an “interpretive concept”, that requires judges to find the best fitting and most just solution to a legal dispute, given their constitutional traditions. Joseph Raz, on the other hand, defended the positivist outlook and criticised Hart’s “soft social thesis” approach in The Authority of Law. Raz argues that law is authority, identifiable purely through social sources and without reference to moral reasoning. In his view, any categorisation of rules beyond their role as authoritative instruments in mediation are best left to sociology, rather than jurisprudence.