Law is a set of rules enforced by a controlling authority. It may also refer to the body of rules that govern a specific situation or industry, like banking, aviation, railroads, pharmaceuticals, copyrights, patents, and trade secrets. Laws may be imposed by government, corporations, or individuals. They are typically enforceable by the threat of sanction or punishment. A legal system is often established to keep the peace, maintain the status quo, protect individual rights, and enable orderly social change. Some laws are more effective than others at meeting these goals.
Many definitions of law emphasize that it is coercive—that is, that it has the power to force people to obey. This view of law was popularized by John Austin’s utilitarian definition, which argued that “law is the aggregate of commands backed by threats of sanctions from a sovereign to men as his subjects.”
But some people argue that the concept of law is much more broad than this. They point out that not all law is a set of written rules handed down from a sovereign, that some laws may be based on customary practices rather than being the result of a specific legislative act by a political body, and that many laws reflect a moral stance. For example, the prohibition against insider trading or the principle of due process could be viewed as reflecting a moral position against cruelty.
Another way to think of law is as a body of facts about the ways in which natural and human forces work. For instance, it is a fact that the Earth revolves around the Sun, and that it takes 24 hours for the Earth to make one revolution on its axis. Such laws are called explanatory, because they explain what happens in the world and why, but do not dictate what should happen or how things ought to be organized.
Other types of laws include those governing marriage, divorce, and property. Family law is an area of law that deals with issues such as custody and access to children. Immigration law and nationality law are areas of law that deal with the right of individuals to live and work in a nation-state other than their own. Laws on international commerce and foreign relations, tariffs, intellectual property, and mail are also areas of law.
Lawyers are people who practice law—that is, they help people and businesses interpret the law and get what they are entitled to under it. Normally, people who practice law are attorneys, but the word is sometimes used to refer to someone who has made a career of studying and understanding the laws. In the United States, the term is sometimes abbreviated as “L.L.B.” or “J.D.” A person who has a doctorate in law is known as a professor of law. The word law is derived from the Old Norse word lag, which means “order,” or perhaps more accurately, “a fixed tune.” In addition to explaining how things work, the science of law tries to predict what will happen in various scenarios.