This article examines the epistemological views of key quantum physicists of the Copenhagen circle (Niels Bohr, Werner Heisenberg and Léon Rosenfeld). The discussion begins with a presentation of their conception of measurement, indeterminacy and complementarity, and goes on to focus on their views regarding the nature of being and knowledge. The author identifies the basic areas of consensus in the Copenhagen circle as well as the disagreements and disputes that arose between its members. Three main points are argued: (1) The fundamental epistemological consensus in the group was that subject and object are inseparable; that the subject participates in the formation of images of reality, which are multiple and depend on how the subject is concretely constituted historically; the disagreements within the group did not arise with logical inevitability from the principles of quantum mechanics but largely stemmed from ideological clash in the Cold War context. (2) Being linked to specific configurations of the subjects, knowledge is always relative; but it does not follow that knowledge is illusory or inadequate; on the contrary, it is the pretension of attaining the ultimate nature of things “in themselves” that leads to devaluation of any concrete knowledge. (3) The world is something external, generally independent of our desires and will, but at the same time is constructed as concrete objects through the specific configuration of each concrete subject.

Contemporary Philosophy