We have now-to borrow Kant’s expression,— explored and surveyed the land of pure understanding or of truth,1 and I do not at present propose to embark with him upon the stormy sea of illusion. Nevertheless as we look, on, his sug­ gestion,2 at the map of the area we have left, we cannot but be conscious that the character of certain regions is still regrettably vague, or at any rate that we have concentrated more upon the physical features than upon the spiritual life of the country. More simply, we have dealt in some detail with the objects of outer sense, but the study of inner sense and its objects has been comparatively slight. Kant himself was obviously con­ scious of this weakness, for in the second edition he attempts to deal more fully, although not fully enough, with the problem of inner sense and with the cognate problem of the relation between inner and outer sense.