Law is a system of rules that are enforced through social or governmental institutions to regulate behavior. It can be created or codified by a legislature (resulting in statutes) or by the executive branch of government through decrees and regulations or established as precedent by judges in common law jurisdictions. Law is a complex subject that encompasses an enormous range of subjects. These subjects include criminal, civil, constitutional and administrative law, but the subject also includes specific areas of law such as labour law, tax law, family law, space law, business law, international law, environmental law, and property law.
There are many laws that govern our daily lives, from the traffic laws we must abide by to the privacy laws that protect our personal information. Laws are a central part of the society we live in and help to keep order, promote prosperity and ensure the safety of all citizens. Laws are enforceable by the government through courts and may result in fines, imprisonment or loss of a license.
The precise nature of a law varies according to the country and even within a country, depending on its cultural, historical and social background. However, most legal systems tend to fall into groups or patterns with similarities based on historically accepted justice ideals.
A basic function of a law is to create and maintain peace, preserve the status quo, protect minorities against majorities, promote social change and allow for orderly evolution of society. Laws vary in effectiveness at meeting these goals, with some laws being more effective than others. For example, a nation ruled by an authoritarian regime may keep the peace but oppress minorities and political opponents.
The source of a law can also vary from one country to another, with the main sources being legislation and custom. Legislation can be passed by a legislature, as in a statute, or created through an executive branch decree or regulation, but most countries in the world today use the system of civil law that originates from ancient Babylonian codifications and early Roman practices. The civil law system is a mixture of legislative and case-law-based practice, which originated from the fact that the judges in civil cases did not receive pay for their decisions, but were referred to as iudex – lay magistrates.
Other laws are based on religious precepts, such as the Jewish Halakha and Islamic Sharia. These are often considered a form of moral law. Other sources of law are Qiyas (reasoning by analogy), Ijma (consensus) and jurisprudence (case law). All of these forms of law must be taken into account when deciding a case. In addition, law can be influenced by a constitution, either written or tacit, that dictates the rights and duties of the people that it affects. This can be a political document or it can be the rules of natural law. The field of law also contains a large body of literature on how to decide a case, which is called the Law of Evidence.