Law is a system of rules made by a government that citizens must obey, or face punishment. Law shapes politics, economics and history in many ways, and it also serves as a mediator of relations between people. It is complex from a methodological viewpoint, being a normative social science (say, as opposed to empirical sciences such as the law of gravity or even social sciences such as sociology) that is framed by an explicit adherence to authority (be it the constitution, legal precedent or scholarly opinion).
While law shapes politics and history, it also functions on a much more ordinary level. Contract law regulates agreements to exchange goods or services, including everything from buying a bus ticket to trading options on a derivatives market. Property law defines people’s rights and duties toward tangible property, whether land or personal possessions. In addition, civil and criminal procedure govern the way courts handle trials or appeals. And, the legal profession itself is governed by the law of professional responsibility.
Many different areas of law exist, and each has its own special features. For example, environmental law aims to penalise polluters within domestic legal systems, while aviation law is framed by national civil aviation acts that are mostly aligned with the recommendations or mandatory standards of the International Civil Aviation Organisation or ICAO.
Other areas of law include labour law, which studies a tripartite industrial relationship between worker, employer and trade union, and intellectual property law which regulates ownership of patents and copyrights. The law of torts outlines the rules that courts must follow in a case of negligence or defamation, and evidence law defines which materials are admissible for use in court cases.
Most societies rely on some form of enforceable laws to govern them and ensure that individuals do what is expected of them. These can be laws imposed by a sovereign, or laws created and enforced through social institutions such as the police force or judiciary. Governmental laws can be written by a legislative body, resulting in statutes or regulations, or they may be created and enforced through executive decrees or by judges acting alone, with the creation of legal precedent (in common law jurisdictions).
There are also religious laws which are explicitly based on a religion’s precepts, such as Jewish Halakha, Islamic Sharia or Christian canon. Such laws often rely on further human elaboration and interpretation through jurisprudence, Qiyas, Ijma and precedent, and they may survive in religious communities despite the collapse of governments or the rise of secularism.