I propose to study here some of the problems which have been raised about the character of the disclosures of sense experience as these are made in the knowledge process. No situation is entirely open and this is especially true of problems which are restricted in scope because they carry with them a range of possible solutions. In difficult cases — those which are found in epistemology for instance — it is important for the investigator to know just what he is dealing with, for once it has been well stated his task is nearly at an end.