Law is the set of rules that govern a society. It is enforced by a controlling authority and is typically a system of penalties for breaking the rules. The law is often codified and can be understood by the general population.
The Law is distinct from the sciences and social science because it contains normative statements of what people ought to do or not do as opposed to descriptive statements such as those found in empirical science (like the laws of gravity) or even social science such as a law of supply and demand (in economics). It also has a prescriptive nature, in that it tells people what they can and cannot do or what they have to or must not have. This makes it an unscientific and therefore not subject to the same type of verification as other scientific disciplines.
Because of these characteristics, law is a complex topic from a methodological perspective. In fact, it is the most difficult of all subjects to describe in terms of its nature and purpose. Despite this, it is still possible to make generalisations. The Law serves four principal purposes in any nation: establishing standards, maintaining order, resolving disputes, and protecting liberties and rights. Different legal systems serve these purposes in different ways. For example, an authoritarian government may keep the peace and maintain the status quo but oppress minorities or political opponents. In contrast, a constitutional democracy will usually promote social change while ensuring the liberty of individuals.