Legal positivism is a school of thought of analytical jurisprudence largely developed by legal thinkers in the 18th and 19th centuries, such as Jeremy Bentham and John Austin. While Bentham and Austin developed legal positivist theory, empiricism set the theoretical foundations for such developments to occur. The most prominent legal positivist writer in English has been H. L. A. Hart, who, in 1958, found common usages of "positivism" as applied to law to include the contentions that:
Historically, legal positivism sits in opposition to natural law's theories of jurisprudence, with particular disagreement surrounding the natural lawyer's claim that there is a necessary connection between law and morality.
In the positivist view, the "source" of a law is the establishment of that law by some socially recognised legal authority. The "merits" of a law are a separate issue: it may be a "bad law" by some standard, but if it was added to the system by a legitimate authority, it is still a law.
The Stanford Encyclopedia of Philosophy summarises the distinction between merit and source like so: "The fact that a policy would be just, wise, efficient, or prudent is never sufficient reason for thinking that it is actually the law, and the fact that it is unjust, unwise, inefficient or imprudent is never sufficient reason for doubting it. According to positivism, law is a matter of what has been posited (ordered, decided, practiced, tolerated, etc.); as we might say in a more modern idiom, positivism is the view that law is a social construction."
Legal positivism does not claim that the laws so identified should be followed or obeyed or that there is value in having clear, identifiable rules (although some positivists may also make these claims). Indeed, the laws of a legal system may be quite unjust, and the state may be quite illegitimate. As a result, there may be no obligation to obey them. Moreover, the fact that a law has been identified by a court as valid provides no guidance as to whether the court should apply it in a particular case. As John Gardner has said, legal positivism is "normatively inert"; it is a theory of law, not a theory of legal practice, adjudication, or political obligation. Legal positivists believe that intellectual clarity is best achieved by leaving these questions to a separate investigation.
Legal positivism is distinct from legal realism. The differences are both analytically and normatively important. Both systems consider that law is a human construct. Unlike the American legal realists, positivists believe that in many instances, the law provides reasonably determinate guidance to its subjects and to judges, at least in trial courts.
Niklas Luhmann asserts "We can reduce ... positive law to a formula, that law is not only posited (that is, selected) through decision, but also is valid by the power of decision (thus contingent and changeable)." However, positivists do not assert that law is made valid by anyone's decision. In Hart's opinion, the validity of law is a matter of the customary and collective practices of the courts. As for the moral validity of law, both positivists and realists maintain that this is a matter of moral principles. "The power of decision" has no essential role in either, since individual decision rarely suffices to create a social practice of recognition, and it would be implausible to suppose that moral principles are made so by anyone's decision.
The main antecedent of legal positivism is Empiricism, whose thinkers range back as far as Sextus Empiricus, Thomas Hobbes, John Locke, George Berkeley, David Hume, and Auguste Comte. Central to the empiricism is the claim that all knowledge of fact must be validated by sense experience or be inferred from propositions derived unambiguously from sense data. Further, empiricism stands in opposition to metaphysics; for instance, Hume rejected metaphysics as mere speculation beyond what can be learnt from sense experience. The teachings of the empiricists acted as a harbinger for a systematic version of a positivist approach to problems of comprehension and analysis, which was later mirrored in legal positivism.
Logical positivists, such as Rudolf Carnap and Alfred Jules Ayer paved the way for another important tenet of legal positivism, namely, that propositions and the use of words must be examined in order to understand reality. A sentence has literal significance if, and only if, it expresses something which is either tautologous or empirically verifiable.
With the empiricist and logical positivist theoretical influences borne in mind, the essence of legal positivism as a descriptive investigation of particular legal orders is revealed, which, as Peter Curzon wrote, "utilises in its investigations the inductive method (i.e., proceeding from observation of particular facts to generalisations concerning all such facts)". During these investigations, matters of ethics, social policies and morality are eschewed; as Julius Stone wrote, it is concerned primarily with "an analysis of legal terms, and an enquiry into the logical interrelations of legal propositions". Further, law and its authority is seen as source-based; i.e., the validity of a legal norm depends not on the moral value attached thereto, but from the sources determined by a social community's rules and conventions. The source-based conception of law is reminiscent of the logical positivist, Carnap, who starkly rejected metaphysics on the basis that it attempts to interpret the nature of reality beyond the physical and experiential.
Thomas Hobbes, in his seminal work Leviathan, postulated the first clear notion of law based on the notion of sovereign power. As Hampton writes, "law is understood [by Hobbes] to depend on the sovereign's will. No matter what a law's content, no matter how unjust it seems, if it has been commanded by the sovereign, then and only then is it law." There is, however, debate surrounding Hobbes's status as a legal positivist.
The English jurist and philosopher Jeremy Bentham is arguably the greatest historical figure in the British legal positivist movement. In An Introduction to the Principles of Morals and Legislation, Bentham laid the groundwork for a theory of law as the expressed will of a sovereign. Bentham made a sharp distinction between the following types of people:
The philosophy of law, considered strictly, was to explain the real laws of the expositors, rather than the criticisms of the censors.
Bentham was also noted for calling natural law "nonsense upon stilts".
John Austin followed in the theoretical footsteps of Bentham by writing The Province of jurisprudence Determined. However, Austin departed from Bentham on a number of points, for example, by supporting the common law.
Differences aside, Austin embraced Hobbes's and Bentham's conception of law as a sovereign command, whose authority is recognised by most members of a society; the authority of which is enforced by the use of sanctions, but which is not bound by any human superior. The criterion for validity of a legal rule in such a society is that it has the warrant of the sovereign and will be enforced by the sovereign power and its agents.
The three main tenets of Austin's command theory are:
Austin considered law to be commands from a sovereign that are enforced by a threat of sanction. In determining 'a sovereign', Austin recognised it is one whom society obeys habitually. This sovereign can be a single person or a collective sovereign such as Parliament, with a number of individuals, with each having various authoritative powers. Austin's theory is also somewhat brief in his explanations of Constitutions, International Law, non-sanctioned rules, or law that gives rights. Insofar as non-sanctioned rules and laws that allow persons to do things, such as contract law, Austin said that failure to obey the rules does result in sanctions; however, such sanctions are in the form of "the sanction of nullity."
The British legal positivism hitherto mentioned was founded on empiricism; by contrast, Germanic legal positivism was founded on the transcendental idealism of the German philosopher Immanuel Kant. Whereas British legal positivists regard law as distinct from morals, their Germanic counterparts regard law as both separate from both fact and morals. The most famous proponent of Germanic legal positivism is Hans Kelsen, whose central thesis on legal positivism is unpacked by Suri Ratnapala, who writes:
The key elements of Kelsen's theory are these. Facts consist of things and events in the physical world. Facts are about what there is. When we wish to know what caused a fact we look for another fact. A stone thrown in the air comes down because of the force of Earth's gravity. There are seasons because the Earth's axis is tilted at 23.5 degrees. A norm, unlike a fact, is not about what there is but is about what ought to be done or not done. Whereas facts exist in the physical world, norms exist in the world of ideas. Facts are caused by other facts. Norms are imputed by other norms. The requirement that a person who commits theft ought to be punished is a norm. It does not cease being a norm because the thief is not punished. (He may not get caught.) The norm that the thief ought to be punished exists because another norm says so. Not all norms are laws. There are also moral norms. Legal norms are coercive; moral norms are not.
From this framework, Kelsen opined that the regression of validated norms cannot go on infinitely and must arrive at a first cause, which he called a Grundnorm (basic norm). The legal system is therefore a system of legal norms connected to each other by their common origin, like the branches and leaves of a tree.
For Kelsen, "sovereignty" was a loaded concept: "We can derive from the concept of sovereignty nothing else other than what we have purposely put into its definition."
Kelsen attracted disciples among scholars of public law worldwide. These disciples developed "schools" of thought to extend his theories, such as the Vienna School in Austria and the Brno School in Czechoslovakia. In English-speaking countries, H. L. A. Hart and Joseph Raz are perhaps the most well-known authors who were influenced by Kelsen, though both schools differed from Kelsen's theories in several respects.
Hart liked Austin's theory of a sovereign, but claimed that Austin's command theory failed in several important respects. Among the ideas developed in Hart's book The Concept of Law (1961) are:
A pupil of Hart's, Joseph Raz has been important in continuing Hart's arguments of legal positivism since Hart's death. This has included editing in 1994 a second edition of Hart's The Concept of Law, with an additional section including Hart's responses to other philosophers' criticisms of his work.
Raz has also argued, contrary to Hart, that the validity of a law can never depend on its morality. However, Raz has come to accept that law may depend upon morality in certain circumstances.