Law is the system of rules that a group or society creates to regulate behavior. It can be created by government institutions, such as a legislature or executive council, creating statutes and regulations; or it can develop through customary practices, as in common law jurisdictions. Law can also be established by private individuals, who may draft legally binding contracts or arbitration agreements. Law has many purposes, including establishing standards, maintaining order, resolving disputes and protecting liberties and rights.

There are several theories about what law is and how it should function. One theory is that the primary purpose of law is to establish standards, which can include moral and ethical considerations. This view is known as legal positivism. Another theory is that law is a social construct. This view is called natural law theory and it holds that the fundamental governing principles of society are embodied in the social contract, a document that has been interpreted and developed over time to reflect the social realities of the times in which it was written.

A third theory is that the law should be a rule of reason, which posits that the legal system and the people who use it are governed by a set of principles of reason. This theory is called the rule of law. Its core principles are supremacy of the law, equal and independent enforcement of the law, participation in the rule of law through transparent and accessible processes and adherence to international human rights norms and standards. It requires measures to ensure a clear and publicized law, that is stable and predictable, that enables all persons, regardless of wealth or social class to gain access to justice and that is consistently applied.

Lastly, there are religious theories of the law. These are based on the teachings of a particular religion and are often expressed as a body of rules known as Sharia or Fiqh. These are often subject to further elaboration through interpretation, Qiyas and Ijma.

In addition to these various theories about what law is, there are many debates about how to interpret the word. A big question is whether it only refers to the specific words written down on paper, or whether a judge’s sense of what is right and wrong should count as well. For example, some judges argue that the prohibition against insider trading (using nonpublic information to make a profit) encompasses the idea of fairness, which is a moral consideration. Others disagree.