Evidently, then, it is in Art that the unity of human natures finds its most complete and most natural representation. For Art is in direct relation with the three orders of phenomena by which human nature is characterized; Feelings, Thoughts, and Actions. It originates in Feeling; the proof of this is even more obvious than in the case of Philosophy and Polity. It has its basis in Thought, and its end is Action. Hence its power of exerting an influence for good alike on every phase of our existence, whether personal or social. Hence too its peculiar attribute of giving equal pleasure to all ranks and ages. Art invites the thinker to leave his abstractions for the study of real life; it elevates the practical man into a region of thought where self-love has no place. By its intermediate position it promotes the mutual reaction of Affection and Reason. It stimulates feeling in those who are too much engrossed with intellectual questions: it strengthens the contemplative faculty in natures where sympathy predominates. It has been said of Art that its province is to hold a mirror to nature. The saying is usually applied to social life where its truth is most apparent. But it is no less true of every aspect of our existence; for under every aspect it may be a source of Art, and may be represented and modified by it. Turning to Biology for the cause of this sociological relation, we find it in the relation of the muscular and nervous systems. Our motions, involuntary at first, and then voluntary, indicate internal impressions, moral impressions more especially; and as they proceed from them, so they react upon them. Here we find the first germ of a true theory of Art. Throughout the animal kingdom language is simply gesticulation of a more or less expressive kind. And with man esthetic development begins in the same spontaneous way. [Three stages in the esthetic process: Imitation, Idealization, Expression]