It would seem, then, that not only philosophical, but absolutely every higher species of knowledge is an internal science of experience. For the formal science of mathematics is not a positive science for the cognition of a real object, so much as an organon and aid for other sciences, which, however, as such, is both excellent in itself, and admits of many useful applications. We may, therefore, on this hypothesis consider each of these four faculties of man, which I have called the principal poles or leading branches of human consciousness, as a peculiar sense for a particular domain of truth. For all experience and all science thereof rests on some cognitive sense as the organ of its immediate perceptions. Now, the reason, which, in its form of conscience, announces itself as an internal sense of right and wrong, is, as the faculty for the development and communication of thought, usually named the common sense. It constitutes the bond of connection between men and their thoughts, which is dependent on and conditioned by language and its organ, and may be called the sense for all that is distinctively human. In this respect it forms the foundation and first grade of all other senses for, and immediate organs of, a higher knowledge. Fancy, again, being itself but a reflection of life and of the living powers of the natural world, is the inward sense for nature, which, as will hereafter be more fully shown, first lends and assures to natural science its due import and true living significance. And, inasmuch as the perfect intellection of a single object results from the totality alone--the significance and spirit of the whole--therefore the understanding is the sense for that mind [_geist_] which manifests itself in the sensible world, whether this be a human or natural, or the supreme Divine intelligence.