The article opens with an indication that the conception of cultural systems of Florian Znaniecki is the counterpart of the notion of World 3 of Karl Popper, although the first was formulated much earlier and in more general categories. Both conceptions assume the existence of objective systems of human knowledge which are human creations gradually reaching autonomy, being possessed of inner order and a defined logic of development. The author attempts at interpreting that idea on the grounds of a conception of human knowledge which implies that any knowledge is nothing more than convictions of one or many individuals. The systems of objective knowledge are interpreted as a sphere of intermediate, stable communication understood in...