Now obviously the propositions of the system have reference to matters of empirical fact; if they did not, they could have no claim to be called scientific.
The system becomes logically closed when each of the logical implications which can be derived from any one proposition within the system finds its statement in another proposition in the same system.
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.
The conception that, instead of this, contemporary society is at or near a turning point is very prominent in the views of a school of social scientists who, though they are still comparatively few, are getting more and more of a hearing.
Theory not only formulates what we know but also tells us what we want to know, that is, the questions to which an answer is needed.
The importance of certain problems concerning the facts will be inherent in the structure of the 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.
The part an actor played on stage was once written on a separate roll of paper.