Special emphasis should be laid on this intimate interrelation of general statements about empirical fact with the logical elements and structure of theoretical systems.
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.
But the scientific importance of a change in knowledge of fact consists precisely in j its having consequences for a system of theory.
The importance of certain problems concerning the facts will be inherent in the structure of the system.
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.
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.
If observed facts of undoubted accuracy will not fit any of the alternatives it leaves open, the system itself is in need of reconstruction.