A system of rules that imposes order on a community by controlling the activities of its members and of those who try to interfere with them. It may consist of a body of written laws, of customs recognized and enforced by legal decisions, or of regulations prescribed by governmental authority. Law may also be defined as the department of knowledge concerned with these rules. Its practitioners are called lawyers or barristers, and its scholars are known as jurists.
The principal functions of law are to keep the peace, maintain the status quo, preserve rights and property, provide for peaceful social change, and encourage cooperation between people. The nature of these functions varies from nation to nation. Governments that can command military and political power can make and enforce laws, but they are not necessarily capable of serving the other essential purposes of law.
In “common law” legal systems, which are found on most continents and account for about 40% of the world’s population, statutes are interpreted by judges to provide a basis for judicial decision making. Judges and barristers base their decisions on a legal principle known as stare decisis, by which earlier court decisions are binding on future courts.
In contrast, “civil law” systems (which are found on about 60% of the world’s population) base their rules mainly on Roman law and canon law, supplemented by local culture, custom, and tradition. These systems tend to have more detailed codes of legislation, and judicial decisions are less likely to bind future courts under the rule of precedent.