The division is based largely on classification of reality on certain philosophical grounds. That is to say, each discipline whether it is physics, chemistry, economics or sociology, assumed that it had for its study a separate 'subject-matter'.

However, as knowledge advanced in depth and stock, it was observed that the scope of a discipline could not be demarcated on the basis of the 'subject-matter' which may have been shared by many disciplines in that group

For example, study of individual is the subject matter for disciplines of Social Sciences group (like Economics, Political Science, Sociology etc.).

The individual which is the subject matter cannot be fragmented among the disciplines. They are merely different because they adopt different conceptual approaches to, and study different facets of the same subject matter i.e., the individual.

That is where there lies hope for integration of knowledge for comprehensive understanding of the subject matter (individual in social sciences) through genuine inter-disciplinary researches.