Law is a set of rules and customs that govern behavior in society. It includes practices and guidelines that are geared to control human behavior and keep societal order, and it addresses issues of rationality, morality, reason and honesty from both the judicial and societal viewpoints. The study of law reveals how social needs and political philosophy are balanced against each other in the making of laws and their enforcement, while legal history presents insights into the adjustments and justifications of the laws over time.
The major purposes of law are to establish standards, maintain order, resolve disputes and protect liberties and rights. Laws serve these functions in a variety of ways, and the way they work is as complex and diversified as the societies that make them.
For example, the law that enables people to sue over car accidents is called tort law; laws protecting businesses from being unfairly defamed are known as trademark law. Governments create laws on a range of topics, and in some areas like aviation and railroads, the law is at the federal level and preempts state law. Other areas, including family and labor law, are governed by state and local law. The practice of law also includes many specialized fields such as immigration and nationality law, transactional law and biolaw.
The understanding of law varies widely among scholars and individuals. For example, Hans Kelsen created a “pure theory of law” which states that “law is not something that must occur; it is the product of the will of an individual.” Others, such as Roscoe Pound, took a different approach to the law definition, arguing that it is a tool of social control and that law is coercive by nature.