The work considers interdisciplinarity as a characteristic of modern scientific knowledge. The reasons for the emergence of this phenomenon, its formation within the framework of classical science, the peculiarities of formation in non-classical and post-non-classical are identified. The concept of "level of interdisciplinarity" is proposed. Several levels of interdisciplinarity are indicated: disciplinary, interdisciplinary, transdisciplinary, objective. The theoretical and methodological content of each level together with its heuristic potential is shown. The thesis is based: interdisciplinarity is not only the integration of sciences, but also has other forms of appearance. Each indicated level has its own "centre" of integration: on the disciplinary level there is an association of sciences; on the transdisciplinary level, there is the expansion of universal models of knowledge; on the problematic level, there is a combination of sciences to solve some problem; on the object level, science is attracted to examine a specific topic (property, power, family, etc.). It is assumed that in addition to the vertical levels of interdisciplinarity, other horizontal levels connecting them can be distinguished in the future.