Law's scope can be divided into two domains. Public law concerns government and society, including constitutional law, administrative law, and criminal law. Private law deals with legal disputes between individuals and/or organisations in areas such as contracts, property, torts/delicts and commercial law. This distinction is stronger in civil law countries, particularly those with a separate system of administrative courts by contrast, the public-private law divide is less pronounced in common law jurisdictions. Law provides a source of scholarly inquiry into legal history, philosophy, economic analysis and sociology. Law also raises important and complex issues concerning equality, fairness, and justice. The philosophy of law is commonly known as jurisprudence. Normative jurisprudence asks "what should law be?", while analytic jurisprudence asks "what is law?" John Austin's utilitarian answer was that law is "commands, backed by threat of sanctions, from a sovereign, to whom people have a habit of obedience". Natural lawyers on the other side, such as Jean-Jacques Rousseau, argue that law reflects essentially moral and unchangeable laws of nature. The concept of "natural law" emerged in ancient Greek philosophy concurrently and in connection with the notion of justice, and re-entered the mainstream of Western culture through the writings of Thomas Aquinas, notably his Treatise on Law