In its broadest sense, justice is the idea that individuals should be treated fairly. According to the Stanford Encyclopedia of Philosophy, the most plausible candidate for a core definition comes from the Institutes of Justinian, a 6th-century codification of Roman law, where justice is defined as "the constant and perpetual will to render to each his due".

A society where justice has been achieved would be one in which individuals receive what they "deserve". The interpretation of what "deserve" means draws on a variety of fields and philosophical branches including ethics, rationality, law, religion, and fairness. The state may pursue justice by operating courts and enforcing their rulings.

History

Early Western theories of justice were developed in part by Ancient Greek philosophers such as Plato in his work The Republic, and Aristotle, in his Nicomachean Ethics and Politics. Modern-day Western notions of justice also have their roots in Christian theology, which largely follows the divine command theory, according to which God dictates morality and determines whether or not an action is seen as morally "good". This, in turn, determines justice.

Western thinkers later advanced different theories about where the foundations of justice lie. In the 17th century, philosophers such as John Locke said justice derives from natural law.