The specifics of how scientific knowledge on international relations is formed have long been the subject of a discussion which is still ongoing. The author highlights the features of the relationship between the fundamental and applied levels of knowledge of international relations, analyzes the division of actual scientific knowledge and reflection upon practical international politics (which, in its most general form, is referred to as ‘big ideas’). The relationship between science and international practice is considered in the aspect that scientific knowledge and ‘big ideas’ intersect, having a different nature and, in fact, being incomparable. The author comes to the conclusion that the development of international relations – as an objective science that meets the criteria of science – is associated with difficulties, which also complicates the formation of the applied level of research. As the science of international relations finds solutions to its epistemological problems and accumulates knowledge, prerequisites are created for the formation of its theoretical and applied levels in the fullest sense of the word. However, this process is not instantaneous, but requires constant attention from researchers.