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.
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.
But the fact a person denies that he is theorising is no reason for taking him at his word and failing to investigate what implicit theory is involved in his statements.
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.
Empirical interest will be in the facts so far as they are relevant to the solution of these problems.
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.
Special emphasis should be laid on this intimate interrelation of general statements about empirical fact with the logical elements and structure of theoretical systems.
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.
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.
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 implications of these considerations justify the statement that all empirically verifiable knowledge even the commonsense knowledge of everyday life - involves implicitly, if not explicitly, systematic theory in this sense.
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 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.
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.