Logical Positivism (or Logical Empiricism) was a philosophical movement that originated in Vienna in the 1920s and 1930s. Its key figures, who came to be known as the Vienna Circle, included Schlick, Waismann, Neurath, and Carnap; A. J. Ayer was a British proponent who popularized their views in his classic primer, Language, Truth and Logic. 1 Because of the rise of Nazism in Germany and Austria, many of these intellectuals emigrated to England and the United States. Thus, their views were disseminated to the English-speaking academy first hand and they became influential, even the dominant orthodoxy, in English-speaking philosophy from the thirties through the early sixties.