Law is the system of rules that governs a society. These rules can be enforceable through mechanisms such as punishment and sanction. Some people also use the term to refer to the discipline and profession of those who advise others about laws, represent them in court, or make legal decisions.
The precise definition of law has long been a matter of debate, with many different theories being advanced. One theory, called legal positivism, focuses on the fact that law is a set of rules that are enforceable by a sovereign power. Another view is that law consists of a set of moral principles. This theory argues that any principle that is widely accepted and followed by a large enough group of people can be considered to be law. For example, the prohibition against insider trading might be considered to be a moral principle because it promotes fairness. The principle of due process in judicial proceedings is also a moral principle.
There are many types of law, including administrative law, family law, criminal law, and civil rights. Some types of law have to do with specific kinds of property, such as real estate or intellectual property. Others are broader in scope, such as family or immigration laws. Many types of laws regulate government activities, such as taxation or military activity. Some laws are purely regulatory, while others impose sanctions and/or penalties for violations.
Laws can be created by a legislative body, resulting in statutes; by the executive, through decrees or regulations; or by judges, resulting in judicial decisions. In common law systems, judicial decisions have broad legal weight and can be cited in future cases, a principle known as precedent or stare decisis. In some areas, like aviation or railroads, the federal government has developed a comprehensive scheme of laws that preempts all state law. In other areas, such as insurance or antitrust, federal and state law coexist.
In addition to regulating government activities, some laws are based on religious beliefs or social customs. For example, Islamic law is based on the Koran and Sunni and Shia practices, while Hindu law is rooted in ancient texts like the Rig Veda. Other laws may be based on ethical considerations, such as the prohibition against murder or sexual harassment.
In most countries, a mixture of both legal positivism and morality is reflected in the law. For example, the laws of the United States prohibit murder and sexual harassment but do not prohibit religious freedom or the right to free expression. Those who practice law are often called attorneys or jurists, and they usually have at least an associate’s degree in the subject. They must be licensed to practice. Other professionals in the field of law include paralegals, prosecutors, and police officers.