A law is a set of rules made by authorities which must be obeyed. This can refer to any sort of government-imposed rules, including traffic laws or a law against murder, as well as the rules that govern how courts operate and what materials are admissible in cases.
Laws are sometimes thought of as being a set of social restrictions that help to create order and keep people safe from each other and from dangerous things, such as disease and war. However, laws can also be thought of in more abstract ways, and the precise nature of law is a subject of intense debate. The word is most often used to describe the rules that a nation or group of nations sets up to govern itself and its citizens, although it can also be applied more broadly to all societal restrictions.
Often, laws are created by a group legislature, resulting in statutes; by the executive through decrees and regulations; or by judges through case law, which relies on detailed records of previous decisions to evaluate the situation at hand. Sometimes a judge’s decision can become a precedent for new legislation in the future, known as stare decisis.
The field of law is vast, and it covers all aspects of human activity that can be regulated by society. For example, banking and finance law regulates how much capital banks must hold and how to invest it, while the law of contract defines how a business deal is to be conducted and the rights and responsibilities of its parties.
Family law deals with marriage and divorce proceedings, as well as the rights of children and the property that may be acquired by one party upon death. Environmental law examines how to protect the planet from pollutants, and a large part of this involves setting and monitoring governmental standards for safety and clean air.
There are also specialised laws such as those that govern the air transport of goods, and the law of torts describes how to compensate someone when their property is damaged, such as in an automobile accident or for defamation. International law is the study of the rules that a country, group of countries or organization such as the United Nations applies to its members.
The role of law in modern societies is complex, and it is important to examine the underlying issues of democracy and power. For example, a key question is whether laws that might appear oppressive or unjust are justified by the fact that they are intended to promote democracy, while other questions include the extent to which people should have rights over their private lives and the limits of the judicial system. See also censorship; crime and punishment; and police.