Law is a set of rules that govern human conduct and maintain societal order. Laws may be a result of custom and policy, or they may be written and enforced by a government or judicial authority. The discipline of law studies this body of rules, as well as the principles that guide its development and application.
A central question is the extent to which law reflects morality. For example, utilitarian philosopher Jeremy Bentham argued that laws are commands backed by threat of sanctions from a sovereign, to which people have a habit of obedience; others, such as Jean-Jacques Rousseau and Thomas Aquinas, argued that law reflects a divinely appointed order of nature or an innate sense of fairness.
The principal functions of law are establishing standards, maintaining order, resolving disputes and protecting liberties and rights. It is difficult to define these functions precisely, but they generally involve enforcing the rights of citizens and ensuring that all persons are treated fairly. The legal system also must ensure that the transition of power is stable, and that laws are transparent and understandable.
Many different types of law exist, covering a wide range of topics. The most common are criminal, civil and administrative law. Criminal law includes a broad spectrum of offences against the state, from traffic violations to murder and terrorism. Civil law deals with issues affecting individual citizens, such as property law (including the rights to privacy), torts and contract law.
The legal system must ensure that laws are publicly promulgated and enforced, and that the courts are impartial and independent. It must also ensure that all citizens are held equal before the law and have a voice in the making of laws, and that laws respect international human rights standards. The legal system also must be stable and consistent, with checks on its power to prevent abuses.
A large and diverse body of law exists in every nation, covering a wide range of social and economic issues. Banking and financial law, for example, include regulations that set minimum capital requirements or guidelines for best practice for investment; environmental law addresses matters such as pollution; and labour law covers industrial relations issues such as collective bargaining and worker rights. Other areas of law include maritime law, maritime safety and security, medical jurisprudence and forensic science.