John Austin is considered the father of analytical positivism. In his work Province of Jurisprudence Determined, he analyzed the English legal system and divided law into two parts - laws set by God and human laws set by men. According to Austin, law is the command of the sovereign, and there is no necessary connection between law and morality. Austin's theory views the legal system as a closed logical system defined by a sovereign, whose commands are backed by sanctions for disobedience. While influential, his theory overlooks customs and ignores precedent, and his notion of sovereignty has been challenged by modern legal systems.