SummaryThe present paper attemps to demonstrate an analogy between the metascientific, i. e. epistemological, concepts of Niels Bohr and Jean Piaget. To make such a comparison possible a general model of an open circular process of acquiring knowledge is proposed including the following stages: generalization of a successful theory, origin of implicit assumptions, counter‐examples, disclosure of implicit and tacit assumptions ; attempts to eliminate counter‐examples, cul‐de‐sac, emergence of competing theories, explication of fundamental notions, distinction between narrower and broader theories. Parallelly, (...) historical exemplifications on each stage are given. Finally, the argument is advanced that scientific epistemology is only possible at the expense of re‐defining ≫science≪ in such a way that it would cease to be science in its strict classical sense on which the claim to this name has been based so far. (shrink)