Introduction: Karl Popper and Philosophy in the Twentieth Century *

Without doubt Karl Popper is one of the most important thinkers of the twentieth century. Popper’s ideas have influenced all the development of the philosophy of science and of social philosophy, but also the development of many sciences and the public discussion of political problems. Popper has tried to show how metaphysical propositions can be rationally discussed and he himself has made contributions to the kind of discussion. The relationship of Popper to the Vienna Circle is often represented as if he had exaggerated the differences between his views and the views of members of the Circle. For Popper had originally accepted the search for causal laws and causal explanation as part of the aim of the social sciences. Karl Popper embedded the construction of his model of the open society into a historical, sociological, and anthropological framework which has inspired many critical examinations.