Law is the system of rules that regulates conduct and that can be enforced by a controlling authority. It encompasses a variety of forms: rules established by statute, decree, or regulation; custom and practice that have been endorsed by judicial decisions; and the discipline, study, and profession of law. Law can be applied to any of a range of issues, including criminal and civil justice, economics, property, and social relations.
In the modern world, laws may be created by a legislative body, often consisting of a parliamentary body or a cabinet; by executive decree or regulation; or through case law developed in a court of law. These laws are then enforced by courts or other judicial bodies, such as administrative tribunals. Laws may also be imposed by religious authorities, as is the case with Sharia law in Islam.
A wide variety of theories occupy the field of law. Early utilitarian thinkers, like Jeremy Bentham, held that the laws of the land were simply commandments, backed by threat of sanctions, from a sovereign, to whom people had a habit of obedience; but more recently thinkers such as Jean-Jacques Rousseau have advocated the concept of natural law, whereby moral principles, not the will of sovereigns, dictate the law.
Different countries have different legal systems. The United States employs a common law system, whereby the law is derived from the decisions of judges in individual cases; this body of decision is known as case law. Other countries, such as Japan, have a civil law system, whereby the law is codified in statutes.
There are other, less commonly used sources of law as well. For example, some religions have their own codes of law, such as the Jewish halakha and Islamic sharia; these are typically unalterable, because they are based on religious precepts and therefore considered to be God’s word. Despite this, most religions do not have very detailed legal systems; instead they rely on further human elaboration through interpretation, Qiyas (reasoning by analogy), Ijma (consensus), and precedent to create more detailed law.
The development and implementation of law is a complex process. There are many factors that must be taken into consideration, such as: the need for a fair trial; whether there is sufficient evidence to prove a defendant’s guilt or innocence; and the appropriate method of punishment or correction for an offence. Other important aspects of the law include the extent to which it is enforced, whether or not there are checks and balances on government power (such as a free and independent press), and the degree to which transitions of power are subject to the rule of law. A system of law is also a major determinant of the level of democracy in a country, as it provides an essential measure of equality of opportunity.