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.

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.

The part an actor played on stage was once written on a separate roll of paper.

It is probably safe to say that all the changes of factual knowledge which have led to the relativity theory, resulting in a very great theoretical development, are completely trivial from any point of view except their relevance to the structure of a theoretical system.

The functions of the family in a highly differentiated society are not to be interpreted as functions directly on behalf of the society, but on behalf of personality.

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.

If there are four equations and only three variables, and no one of the equations is derivable from the others by algebraic manipulation then there is another variable missing.