A system of rules enforced by social or governmental institutions to regulate behavior, law aims to ensure a safe and harmonious society. It is a vast subject with many different fields, but it is generally categorized into public and private law. Public law is concerned with the government, its officials and agencies, such as the police or courts. The legal system also tries to prevent conflicts between people, such as in cases of property ownership or personal disputes. The word law can also be used to refer to a specific area of the law, such as criminal or commercial law.
Legal systems vary widely around the world, but most have similar features. They have a legislative component that establishes rights, duties and liabilities, backed up by a judiciary that interprets and develops the law through case and precedent. The system should be transparent, clear and accessible to citizens. It should also leave room for interpretation and jurisprudence to adjust the law to changing social situations and new needs.
Law can be based on religious precepts, such as the Jewish Halakha or Islamic Sharia, although this would normally not be considered legal law and would instead be regarded as religious doctrine. However, religions do provide the basis for a large number of laws worldwide. Other sources of law include philosophies such as Aristotle’s, which are based on natural reason and the principles of justice. Then there are the inherited traditions of a society, for example the laws outlined in the Bible or in the ancient Greek legal maxims compiled by Cicero. In most societies, laws are based on a combination of these different types of law.
It is a common view that the purpose of law is to protect citizens from the dangers that arise when individuals try to take advantage of each other or impose their own wills on others. This purpose is achieved by a combination of tools, including punishments such as fines or imprisonment, and the power of a state to enforce the law through its military and bureaucratic apparatus.
In a democracy, the law is made by elected representatives, resulting in statutes, decrees or regulations. A law may also be established by the executive, for example through decrees or orders, or enacted through judicial rulings, known as caselaw. In a constitutional monarchy, the law is embodied in a constitution, written or tacit, which may be supplemented by royal ordinances.
The study of law is a vast subject, covering every aspect of modern life. The core subjects are civil and criminal law, but there are numerous other fields. For instance, immigration law deals with the rules that govern the movement of people into and out of a country, intellectual property law concerns ownership of ideas, trademarks, copyrights and patents and evidence law involves which materials are admissible in court proceedings. Other areas include labour law, which is the regulation of a tripartite industrial relationship between employer, employee and trade union, and maritime law, which covers sea and river transport, shipping and the safety of ships and crews.