Law is a system of rules created and enforced by a society or government to regulate behavior. Its precise definition is a matter of longstanding debate. Law includes not only the written statutes and regulations, but also the unwritten customs and policies of a society. Law encompasses the whole of human activity, from family life to the management of international affairs. Law spreads into virtually every area of human endeavour, which is why it is usually divided into three broad subjects: constitutional law; criminal law; and civil law.
The main functions of any legal system are to protect individuals, preserve the social order and promote justice. Some legal systems do this better than others. For example, an authoritarian regime may keep the peace and maintain the status quo, but it may oppress minorities and prevent social change. In contrast, a constitutional democracy may be more democratic, but it must ensure that the laws are applied fairly and without discrimination.
Consequently, the main purpose of legal science is to study and improve the law. This is achieved through research and analysis, education and training, and the drafting of legislation. The law is also subject to review and revision. Some changes are based on new research, while others are motivated by political and economic considerations. In the case of the latter, the aim is to make the law more responsive to social needs and changing circumstances.
In addition to constitutional law, other branches of the law include labour law; contract law; tort law; and administrative law. Labour law focuses on the tripartite industrial relationship between worker, employer and trade union; it involves both collective bargaining regulation and individual employment rights, such as job security or the right to strike. Tort law includes the rules for civil liability and damages, and provides a framework for deciding when someone is to blame for an injury. Administrative law, meanwhile, covers rules governing the operation of public services and utilities such as water, energy and transport.
Other areas of the law cover specialised fields such as aviation law, bankruptcy law, carriage of goods and medical jurisprudence. There is also a body of rules called ‘precedent’ that govern the decisions made by judges in cases with similar facts and law. This principle, known as stare decisis, means that a decision of one court must be followed by subsequent courts unless overturned on appeal.
Other legal terms that are important to understand include discovery – the examination, before trial, of material in possession of the opponents to help their lawyers prepare for the case; and en banc – when a court decides to hear a case with its full bench, rather than in a small group of judges. The articles on the legal profession and on the legal system provide further background on the law. For an overview of the relationship between law and other institutions, see legal philosophy; state; civil society; and governmental structure. For the relationship between law and politics, see political system; party; and ideology.