I. On the origin of æsthetic feeling, and consequently on the character peculiar to it among all other emotions, writers belonging to all schools of philosophy are in agreement to an extent rarely found elsewhere. It has its source in a superfluity of life—a luxury of activity; in fact it is a form of play. Schiller is supposed to have been the first to state its formula: “Supreme art is that in which play reaches its highest point, when we play, so to speak, from the depths of our being. Such is poetry, and especially dramatic poetry.... As the gods of Olympus, free from all wants, knowing nothing of work or of duty, which are limitations of being, occupied themselves in taking mortal forms in order to play at human passions, so, in the drama, we play with the achievements, crimes, virtues, vices, which are not our own.”[203] Kant referred the beautiful to the free play of the intellect and the imagination, and his immediate disciples follow him on this point. Schopenhauer says the same thing in other words, “Art is a momentary liberation.” Finally, Herbert Spencer develops this thesis, from the experimental point of view, by connecting it with biological conditions. ----- Footnote 203: This theory of play, however, appears, from recent researches, to be of English origin, and due to Home (1696-1782), so that, when taken up again by Herbert Spencer (_Principles of Psychology_, vol. ii., last chapter), it would seem only to have returned to its original home. ----- The primary activity of our physical and mental faculties relates to proximate ends: the conservation of the individual, and his adaptation to his environment. The secondary activity is its own end, and is of somewhat late appearance in the animal kingdom. The lower animals are shut up in a narrow circle: they feed, defend themselves, sleep, and propagate their species. On a higher level appears “a useless activity of unused organs” (Spencer, _op. cit._, ii. p. 630); as in the rat with incisors growing continuously in adaptation to the excessive wear they undergo; the cat, exercising her claws on the bark of a tree or the covering of a chair, etc. Higher still appears the true play-impulse; dogs pretending to hunt or fight, cats running after a ball which they catch, push away, catch again, and pursue, bounding as if after their prey. In children, we know the pre-eminent function of play, and how it differs according to sex, disposition, and age: it has its individual characteristics, and is often a creation.