Ludwik Fleck situated himself epistemologically in opposition to the two most prominant schools of the philosophy of science of his time: the Logical Positivism of Carnap, Schlick and others of the Vienna Circle, and the Historicism of Durkheim, Levy-Bruhl, Jerusalem and the sociologists of knowledge (46-51)¹. A brief statement of where he stood with respect to each is helpful.