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.

Empirical interest will be in the facts so far as they are relevant to the solution of these problems.

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.

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.

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.