Karl Marx rejected Comte's positivism but nevertheless aimed to establish a "science of society" based on historical materialism, becoming recognized as a founding figure of sociology posthumously as the term gained broader meaning. Around the start of the 20th century, the first wave of German sociologists, including Max Weber and Georg Simmel, developed sociological antipositivism. The field may be broadly recognized as an amalgam of three modes of social thought in particular: Durkheimian positivism and structural functionalism; Marxist historical materialism and conflict theory; and Weberian antipositivism and verstehen analysis. American sociology broadly arose on a separate trajectory, with little Marxist influence, an emphasis on rigorous experimental methodology, and a closer association with pragmatism and social psychology. In the 1920s, the Chicago school developed symbolic interactionism. Meanwhile, in the 1930s, the Frankfurt School pioneered the idea of critical theory, an interdisciplinary form of Marxist sociology drawing upon thinkers as diverse as Sigmund Freud and Friedrich Nietzsche. Critical theory would take on something of a life of its own after World War II, influencing literary criticism and the Birmingham School establishment of cultural studies.