A scientifically unimportant discovery is one which, however true and however interesting for other reasons, has no consequences for a system of theory with which scientists in that field are concerned.

If observed facts of undoubted accuracy will not fit any of the alternatives it leaves open, the system itself is in need of reconstruction.

It is that of increasing knowledge of empirical fact, intimately combined with changing interpretations of this body of fact - hence changing general statements about it - and, not least, a changing a structure of the theoretical system.

Sociology should... be thought of as a science of action-of the ultimate common value element in its relations to the other elements of action.

But the scientific importance of a change in knowledge of fact consists precisely in j its having consequences for a system of theory.

A theoretical system does not merely state facts which have been observed and that logically deducible relations to other facts which have also been observed.

The importance of certain problems concerning the facts will be inherent in the structure of the system.