Introduction
The question ‘what is law?’ is a central and enduring question in legal philosophy, or jurisprudence. There is no simple answer, and centuries of debate have produced a variety of competing theories. The question is not just about defining a word; it is about understanding the nature of authority, the basis of obligation, and the relationship between rules and morality. Similarly, exploring the origin of law forces us to consider whether it is a product of human command, a reflection of divine or natural order, or simply the practices of a community. This essay will explore these fundamental questions by examining two of the most significant schools of thought: natural law and legal positivism. It will also briefly consider legal realism as an alternative perspective. The essay will demonstrate that while these theories provide very different answers, they each illuminate important aspects of what law is and where it comes from, showing that the nature of law is a complex and multi-faceted concept.
The Natural Law Tradition
The oldest theory of law is natural law. Its central idea is that there is a connection between law and morality. According to natural law theorists, true law is derived from a higher source than human creation, such as God, nature, or reason. This higher law provides a moral standard against which man-made (or ‘positive’) law can be judged. A key maxim associated with this tradition is lex injusta non est lex – an unjust law is not a true law. This means that for a rule to be considered a valid law, it must conform to certain moral principles.
The origins of natural law thinking can be traced back to ancient philosophers like Aristotle, who distinguished between natural justice, which is universal, and legal justice, which varies from place to place. The theory was developed significantly by the theologian St Thomas Aquinas in the 13th century. Aquinas argued that law is "an ordinance of reason for the common good, made by him who has care of the community, and promulgated" (as cited in Bix, 2012, p. 71). He proposed a hierarchy of law: eternal law (God's plan for the universe), divine law (revealed in scripture), natural law (the part of eternal law discoverable by human reason), and human law (the specific laws we create for our societies). For Aquinas, human law is only valid if it is consistent with natural law. Its origin, therefore, is ultimately in God's reason, which humans can partly access through their own rational faculties.
A more modern version of natural law theory was put forward by Lon Fuller. Rather than focusing on a substantive moral code from God or nature, Fuller proposed a ‘procedural’ natural law. In his book The Morality of Law, Fuller (1964) argued that for a system of rules to be properly called a legal system, it must meet eight principles of what he termed the ‘inner morality of law’. These principles include that laws must be public, clear, non-contradictory, and applied prospectively. A system that grossly fails to meet these procedural requirements, such as the Nazi regime, would not, in Fuller’s view, be a legal system at all. For Fuller, the origin of law is tied to the very process of creating and maintaining a system of rules that can guide human conduct effectively and justly. While natural law provides a moral compass for evaluating law, its main weakness is the lack of agreement on what constitutes the ‘higher’ moral principles from which law is said to derive.
Legal Positivism
In direct contrast to natural law, legal positivism insists on a strict separation between law and morality. For positivists, the question of 'what is law?' is a matter of social fact, not moral judgment. A law’s validity depends not on its moral content, but on its source. If a law has been created through the recognised procedures of a legal system, it is a valid law, regardless of whether it is just or unjust.
An early and influential positivist was John Austin, who in The Province of Jurisprudence Determined (1832) defined law as a command issued by a sovereign, backed by the threat of a sanction. The ‘sovereign’ is the person or body that is habitually obeyed by the bulk of society and does not itself obey any other authority. In this view, the origin of law is simply the will of the ruler. While this command theory is clear, it has been criticised as being too simplistic to describe a modern legal system. For example, it does not easily account for laws that grant powers rather than impose duties (like the power to make a will), or for constitutional laws that limit the power of the legislature itself.
A more sophisticated and influential version of positivism was developed by H.L.A. Hart in The Concept of Law (1961). Hart rejected Austin’s idea of law as a mere command and instead described law as a system of rules. He identified two types of rules: primary rules and secondary rules. Primary rules are those that impose duties or grant rights to individuals, such as the criminal law or the law of tort. Secondary rules are rules about the primary rules. They confer the power to create, change, and adjudicate the primary rules. Hart identified three key secondary rules:
- The Rule of Recognition: This is the master rule of the system. It specifies the criteria that must be met for a rule to be considered a valid law (e.g., it must be passed by Parliament and receive Royal Assent). The existence of the rule of recognition is a social fact, demonstrated by the way judges and officials identify and apply the law.
- Rules of Change: These rules govern how laws can be amended or repealed.
- Rules of Adjudication: These rules give power to officials (judges) to decide when a primary rule has been broken and to impose a penalty.
For Hart, the origin of law is the combination of these primary and secondary rules. A legal system exists where the population generally obeys the primary rules and the officials of the system accept the secondary rules, particularly the rule of recognition, as a common standard for their official behaviour (Hart, 2012). This approach successfully separates the validity of law from its moral content, allowing for moral criticism of the law while still recognising it as law.
Legal Realism: A Practical Alternative
A third perspective, which challenges both natural law and positivism, is legal realism. Realists are less interested in the abstract nature of law and more focused on how it works in practice. For them, law is not just the rules written in statutes and cases, but what officials, particularly judges, actually do. Oliver Wendell Holmes Jr., a key figure in American legal realism, famously wrote that "The prophecies of what the courts will do in fact, and nothing more pretentious, are what I mean by the law" (Holmes, 1897, p. 461).
According to this view, the formal rules often fail to explain why a case was decided in a particular way. Realists argue that judges are influenced by many other factors, including their personal beliefs, political views, and prejudices. The origin of 'law' in any given case is therefore found not just in legal texts, but in the complex mix of factors that influence a judge's decision. While positivism looks at the formal sources of law, realism looks at the practical reality of its application. This provides a useful, though perhaps cynical, perspective on the legal process, reminding us that law is a human activity, not just an abstract system of rules.
Conclusion
This essay has explored the question of what law is and its origin by examining three major jurisprudential theories. The natural law tradition argues that law is fundamentally connected to morality, and that its origin lies in a higher source of reason or divine will, providing a standard against which human laws can be measured. In contrast, legal positivism, particularly in the sophisticated form offered by H.L.A. Hart, defines law as a human-made system of social rules, whose validity is determined by its source rather than its moral worth. Finally, legal realism offers a pragmatic view, suggesting that law is best understood as the practice of officials and the prediction of what courts will actually do.
Ultimately, there is no single, universally accepted answer to what law is. Each theory highlights a different dimension of a complex social institution. Positivism helps us identify the rules that are formally in force in a society. Natural law provides a framework for morally evaluating those rules and questioning our obligation to obey them. Realism forces us to look behind the formal rules to see how law operates in the real world. A full understanding of law requires an appreciation of the insights offered by all these different perspectives.
References
Austin, J. (1832) The Province of Jurisprudence Determined. John Murray.
Bix, B. H. (2012) Jurisprudence: Theory and Context. 6th edn. Sweet & Maxwell.
Fuller, L. L. (1964) The Morality of Law. Yale University Press.
Hart, H. L. A. (2012) The Concept of Law. 3rd edn. Oxford University Press.
Holmes, O. W. Jr. (1897) 'The Path of the Law', Harvard Law Review, 10(8), pp. 457–478.
Wacks, R. (2020) Understanding Jurisprudence: An Introduction to Legal Theory. 6th edn. Oxford University Press.
