Law is a system of rules that are enforced by social or governmental institutions to regulate behaviour. It has a number of different functions, including establishing standards, maintaining order, resolving disputes and protecting liberties and rights. Law is a complex concept with many contested views, but it generally includes the idea of a set of principles that govern human relationships and the distribution of resources. It is also the name given to the professions that deal with advising people about the law, representing them in court or enforcing laws.
The main types of law are civil and criminal. Civil law systems, which are found on all continents except Antarctica, are based on Roman and Germanic law concepts, categories, and rules, supplemented by local custom and culture. They tend to emphasise cooperation between individuals, and are usually secular.
Criminal law, on the other hand, deals with violations of public order and state authority. It is often based on a hierarchy of offences, from misdemeanours to capital crimes. There are a number of other legal fields, including company law; contract law; environmental law; family law; labour law; maritime law; medical jurisprudence; property law; and tax law.
Some laws are codified in books called statutes, which contain individual pieces of legislation arranged by subject matter. Compilations of statutes, known as the United States Code, are published at the end of each session of Congress and contain all of the laws passed during that time, with any later amendments incorporated. Other legislation may be published as slip laws, which are single sheets or pamphlets that contain the text of a law.
There are also uncodified laws, in which case judges decide cases according to their own interpretations of the law and can make up their own decisions. These are often referred to as common law, although there is a wide range of debate over whether or not such laws are really legal at all.
The definition of law is a constantly evolving, and the precise nature of what it comprises has been a source of longstanding controversy. It is widely accepted that it has certain essential characteristics:
First, it must be capable of being enacted and enforced by a human agency. This can be seen in the way that different cultures define what is a crime. It is also impossible to verify the content of law by empirical methods, because there are no means of measuring the consequences of precepts that are not enforceable as such. However, the fact that there are such arguments is testament to the power of law to shape human life. It is important to understand this power, in order to criticise it effectively. This is why it is so important to study the history and philosophy of law. See also legal education; and legal system.