According to Merton, sociological theory refers to logically interconnected sets of propositions from which empirical uniformities can be derived. The function of a theory is to help ordering empirical findings

There are two tendencies in sociological inquiry which Merton finds unacceptable. One is radical or narrow empiricism[1] which stresses solely on the collection of data without any attention to a theory. The other is the abstract theorizing[2] of scholars who are engaged in the attempt to construct a total theoretical system covering all aspects of social life. Merton proposes sociological theories of the middle range as a solution to the two extreme positions. According to Merton,

Firstly, middle range theory starts its theorizing with limited aspects of social phenomena rather than with a broad, abstract entity such as society. Middle range theories have to be constructed for phenomena that are observable or comprehendable.

Secondly, Middle range theories may seem to be similar to general, total theories in the sense that they also involve abstractions. However, unlike those in the general theories, the abstractions in theories of the middle range are firmly backed up by observed data.

The examples of middle range theories are a theory of reference groups, of social mobility, of role-conflict, of the formation of social norms, etc. Merton’s objective in proposing the notion of middle range theory can be summarized by his statement that:

‘Our major task today is to develop special theories applicable to limited conceptual ranges — theories, for example, of deviant behavior, the unanticipated consequences of purposive action, social perception, reference groups, social control, the interdependence of social institutions — rather than to seek the total conceptual structure that is adequate to derive these and other theories of the middle range’ .

Finally, Merton suggests ‘Sociological theory, if it is to advance significantly, must proceed on these interconnected planes:

•         by developing special theories from which to derive hypotheses that can be empirically investigated and (middle range theories)
•          by evolving a progressively more general conceptual scheme that is adequate to consolidate groups of special theories’ . ( middle range consolidating into grand theories)