Jürgen Habermas (born June 18, 1929) is a German philosopher and sociologist, or someone who studies different societies. He uses a type of theory called critical theory, where he studies how people use power. He also uses the theory of American pragmatism, which studies if something is true or not by the effects of actions. He is known for his work on the theory of the public sphere. He studies power in democracy, and politics. He also studies how people develop a society through language and communication, and tries to understand how that society and the government work together.