Law is a system of rules made by governments that citizens must follow in order to live safely. For example, murder is against the law in most places and if someone breaks the laws they can be punished. The word law can also be used to describe the field of study that deals with systems of laws, or it can refer to a career such as a lawyer or judge.
Laws are rules or principles that describe direct links between the causes and effects of phenomena. Laws are established through empirical observations and experiments. They can be proven or hypothetical, sanctioned or unsanctioned, true or false, harmonious or antagonistic, or anything else that can be discerned by human senses or rational deliberation.
Legal systems vary widely around the world. Some examples include common law, civil law, and Islamic law. In common law legal systems, decisions by courts are explicitly acknowledged as law on equal footing with statutes adopted through the legislative process and regulations issued by executive branches. This is known as the “doctrine of precedent” or stare decisis, and it ensures that similar cases will reach similar results. In civil law systems, judicial decisions are generally shorter and less detailed, but they still bind lower courts, thus making them an important source of case law.
There are four basic purposes for law: establishing standards, maintaining order, resolving disputes, and protecting liberties and rights. Different legal systems may serve these functions more effectively than others. For example, an authoritarian government may keep the peace and maintain the status quo, but it could also oppress minorities or political opponents.