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

In so far as such a theory is empirically correct it will also tell us what empirical facts it should be possible to observe in a given set of circumstances.

The importance of certain problems concerning the facts will be inherent in the structure of the system.

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.

That is, a system starts with a group of interrelated propositions which involve reference to empirical observations within the logical framework of the propositions in question.

If observed facts of undoubted accuracy will not fit any of the alternatives it leaves open, the system itself is in need of reconstruction.