A law is a set of rules enforced by a controlling authority to regulate conduct or protect property and people. Such a body of rules can be written by a legislature, as in the case of statutes; derived from custom and policies, as in the case of common law; or established through judicial decisions, as in the case of case law or stare decisis. The discipline and profession that deals with systems of laws and their enforcement is called jurisprudence.
The concept of what constitutes law has been widely debated over the years. Some definitions, like those of legal positivism, define law as commands, backed by the threat of sanctions, from a sovereign, to which people have a habit of obedience. Others, such as Jeremy Bentham’s utilitarian theory of law, describe it as an instrument of social control that promotes the general welfare. Yet others, such as Jean-Jacques Rousseau, argue that law reflects essentially moral and unchanging laws of nature.
Law is enforced by the state through penalties, which can be money, prison time or other deterrents. It may also be created by private individuals and organizations through contracts, such as arbitration agreements, that adopt alternative ways of resolving disputes to standard court litigation. A broader definition of law includes the norms that are deemed acceptable by society, such as a prohibition on insider trading or due process in government actions.
A law can be either positive or negative, depending on its purpose and the means by which it is enacted. A positive law is a legislative act, whether a statute or other type of document, that is enacted to regulate conduct. A negative law is a prohibition, such as a ban on gambling, that prohibits an activity that is deemed undesirable.
Different nations have different legal systems. For example, the United States has a federal system of law that consists of a collection of statutes and regulations that are enforced through a judicial system. Other countries, such as Japan, have a civil law system that relies on codes of conduct rather than judicial decisions.
The main purposes of a law are to keep the peace, maintain the status quo, preserve individual rights and liberties, provide for social change and provide a means of resolving conflicts between people. Many legal theorists have emphasized that laws serve these purposes best when they are fair and reasonable and when people respect them. In contrast, an authoritarian regime can keep the peace and maintain order, but may oppress minorities and suppress political opponents. It might also promote social justice, but at the expense of human rights and civil liberties. These types of regimes are often described as cruel and inhumane. They can also be difficult to abolish because of the deep-rooted beliefs that they are necessary for maintaining stability and progress in a nation. On the other hand, a democratic government can keep the peace and promote social justice with the help of international law and treaties.