Law is a system of rules that a society or government develops in order to deal with criminal activity, business agreements and social relationships. These rules are binding upon those who follow them and they can be enforced by a controlling authority through penalties. People who study and practice the law are known as lawyers or judges.
Legal systems vary considerably across the world. Some are highly centralized, while others are decentralized. There are also variations in the extent to which laws impose standards and in the nature of their enforcement. Some laws are written, while others are unwritten and implicit. The purpose of law is to establish standards, maintain order, resolve disputes and protect liberties and rights. Some countries use authoritarian means to accomplish these goals, while others do so with a more democratic balance between different interests.
A fundamental point of controversy in legal theory concerns the definition of a law. Many people assume that a law is any kind of standard, while others think that a law must be something that is enforceable by coercion. For example, Hans Kelsen held that the monopolization of violence by a state is the essential characteristic of a law. Other 20th century legal positivists, such as H.L.A Hart and Joseph Raz, have argued that a law is any kind of norm that makes a difference to the behavior of those who know it.
The definition of a law is important because it determines the extent to which legal theories can be considered to be evaluative. It also determines whether or not it is possible to reduce a body of laws to some basic set of facts without making any moral or all-things-considered judgment about those laws.
It is also important to define a law because the concept of a law serves as a foundation for legal reasoning and decision-making. A basic law is a standard that sets the stage for other laws to be drafted and enforced, so that there are predictable ways in which a legal system can achieve its goals.
Many different types of law exist, depending on the needs and problems of a particular society or culture. International law, for instance, focuses on issues such as international treaties and the status of foreign nationals. Commercial law relates to legal transactions and the rights of property owners. There is also family law, which deals with marriage and divorce, and civil rights. Laws can also be framed around specific fields such as the environment, medicine and biosciences. A rich academic doctrine informs all of these areas of law and helps to shape the way in which laws are interpreted and applied. This is a key part of the legal process in most countries and regions. It allows legal scholars and lawyers to apply their knowledge of the field to new cases and solve old ones. This makes law an essential part of human life.