There are a number of theoretical approaches to the discipline of syntax. One school of thought, founded in the works of Derek Bickerton, sees syntax as a branch of biology, since it conceives of syntax as the study of linguistic knowledge as embodied in the human mind. Other linguists (e.g., Gerald Gazdar) take a more Platonistic view, since they regard syntax to be the study of an abstract formal system. Yet others (e.g., Joseph Greenberg) consider syntax a taxonomical device to reach broad generalizations across languages.