The paper gives an analysis of the role of constructivism in post-positivist epistemo-logy and in the philosophy of science. The role of constructivism is thus analyzed in the sphere of the sociology of cognition. The author gives a detailed interpretation of Berger’s and Luckman’s social constructivisms. Attention is paid also to the relationship between constructivism and co called “standpoint epistemology” and reflexivity. The author sheds light especially on the various characteristics of social determinacy of scientific knowledge.