Law is a system of rules created and enforced through social or governmental institutions to regulate behavior. Laws may be enacted by legislatures and implemented through the executive or judicial branches of government, or they can be found in a constitution or written code. In the latter case, laws must be interpreted and applied by a legal profession trained in the interpretive skills needed to understand and apply complex legislative and constitutional principles. The practice of law also requires a strong understanding of the history and context of the laws being interpreted.
The purpose of law is to serve a variety of purposes in a society, including maintaining peace, providing a safety net for the vulnerable and needy, protecting property rights, preserving minorities against majorities, fostering social justice and facilitating orderly social change. The effectiveness of law in these areas varies from country to country, and from the perspective of individual citizens, depending on how well the law is designed and implemented.
Historically, the philosophy of law has involved a wide range of theories about what law is and what it does. Some of the more prominent views include utilitarian theory, natural law theory and legal positivism. Early utilitarian theorists like Bentham and John Austin held that the normative aspect of law consists in the fact that it imposes sanctions on people, thus requiring their obedience. This view has been criticized, however, by legal positivists like H.L.A. Hart, who has argued that this approach obscures the fact that rules have a reason-giving function and that deviations from the law can be viewed as a cause for prediction of hostile reactions by others.
A major challenge to the philosophy of law is determining whether or not there are universal laws that can be understood and applied by everyone in the same way. The law is a human construct and, as such, will always be subject to the vagaries of human thinking and human interpretation. Some philosophers are concerned with examining these challenges, while others are frustrated with these traditional debates and are seeking to move the field of law philosophy forward in new directions.
There are a number of specific types of law, such as labor law (tripartite industrial relations between workers, employers and trade unions), tort law (claims for damages caused by accidents such as automobile accidents or defamation) and criminal law (offenses against the state, such as murder). The legal systems of various nations differ, and some have adopted parts of the common law tradition established in England. Other nations, such as Japan, have developed a civil law tradition that draws on codes formulated by legal professionals to guide judges in the course of trials and appeals. Other specialties of law include medical jurisprudence, the intersection of law and the biosciences and transactional law. In addition, some scholars have sought to distinguish between law as a concept and the study of actual laws in their many different forms.