We have then first to enquire whether there is any real unity corresponding to the several terms, desire, intelligence, will, on the part of spiritual principles to which these terms are appropriate. Do they merely indicate each certain resemblances between certain sets of inner phenomena, a single point of view from which these several sets of phenomena may be regarded, and thus a unity not in the phenomena themselves but on the part of the person contemplating them? Or is there, on the other hand, a single principle which manifests itself under endless diversity of circumstance and relation in all the particular desires of a man, and is thus in virtue of its own nature designated by a single name? And, in like manner, are our acts of intelligence and will severally the expression of a single principle, which renders each group of acts possible and is entitled in its own right to the single name it bears? We shall find reason to adopt this latter view. The meaning we attach to it, however, is not that in one man there are three separate or separable principles or agents severally underlying his acts of desire, understanding, and will. We adopt it in the sense that there is one subject or spirit, which desires in all a man's experiences of desire, understands in all operations of his intelligence, wills in all his acts of willing; and that the essential character of his desires depends on their all being desires of one and the same subject which also understands, the essential character of his intelligence on its being an activity of one and the same subject which also desires, the essential character of his acts of will on their proceeding from one and the same subject which also desires and understands. (§ 117 ¶ 1)