Law is a field of human activity that consists of the rules people have agreed to follow. Its purposes are establishing standards, maintaining order, resolving disputes and protecting liberties and rights. It also has a moral dimension: it tells people how they ought to behave or not. It is a source of a wide range of scholarly inquiry, including history, philosophy, economic analysis, and sociology.

Despite the complex nature of the study of law, some generalisations can be made. The first is that, unlike normative statements in empirical sciences (such as the law of gravity) or social science (as the law of supply and demand in economics), there is no possibility of proof that any particular set of legal precepts is correct. This makes the law unique among human activities in this regard.

The second generalisation is that law entails the exercise of power to enforce and punish certain behaviour, so it carries a degree of moral weight that other human activities do not. Moreover, it deals with the distribution of goods and burdens in society.

For example, criminal law enables the state to punish those who commit crimes such as murder or fraud by depriving them of their liberty. Civil law aims to settle differences between individuals and to protect their property rights, such as the right to own and sell land. The practice of law has its own specific disciplines, such as tort law (which covers compensation for harmed people and their property), contract law (regulating commercial transactions), tax law, banking law and corporate regulation.

Finally, a well-functioning legal system requires an independent judiciary and transparent public business to ensure that the law is upheld and the transfer of power is subject to checks. It also needs mechanisms for preventing abuse of public power and resolving disputes between citizens.

The legal system also encompasses institutions such as courts, prosecutors and defence lawyers. It involves processes such as trial by jury and pro se – representing oneself without the assistance of a lawyer. It also includes public defenders, who represent people who can’t afford to hire their own lawyer in criminal cases. It also incorporates the drafting and operation of government constitutions, the administration of justice by governmental agencies and the political foundations for laws. For more specific articles see: agency; air law; bankruptcy; business law; family law; maritime law; medical jurisprudence; property law; procedure; tax law and tort law. For an examination of the relationships between law and politics, see constitution; legal profession; political system; legal philosophy; and legal education. For articles focusing on the impact of law on everyday life, see civil society; criminal justice; land reform; and the rule of law. For more on the development of law, see law, philosophy of; and legal history. For an exploration of the relationship between law and religion, see Islam; Judaism; Talmud; and midrash. For an article that explores the nature of different legal systems, see comparative law.