Justice is the concept of moral rightness based on ethics, rationality, law, natural law, fairness and equity."

Justice concerns the proper ordering of things and persons within a society. As a concept it has been subject to philosophical, legal, and theological reflection and debate throughout history. A number of important questions surrounding justice have been fiercely debated over the course of western history: What is justice? What does it demand of individuals and societies? What is the proper distribution of wealth and resources in society: equal, meritocratic, according to status, or some other arrangement? There is a myriad of possible answers to these questions from divergent perspectives on the political and philosophical spectrum. According to most theories of justice, it is overwhelmingly important: John Rawls, for instance, claims that "Justice is the first virtue of social institutions, as truth is of systems of thought.": Justice can be thought of as distinct from and more fundamental than benevolence, charity, mercy, generosity or compassion. Studies at UCLA in 2008 have indicated that reactions to fairness are "wired" into the brain and that, "Fairness is activating the same part of the brain that responds to food in rats... This is consistent with the notion that being treated fairly satisfies a basic need". Research conducted in 2003 at Emory University, Georgia, involving Capuchin Monkeys demonstrated that other cooperative animals also possess such a sense and that "inequality aversion may not be uniquely human." indicating that ideas of fairness and justice may be instinctual in nature.