The supreme life, of which every created thing partakes,--the stone, the flower, the animal, and man,--is beauty, because it is the supreme harmony wherein everything has its place in relation to every other thing. This central unity has its existence in expression. The round earth, broken off from the stellar system and whirling along its little orbit through space, is yet ever in communication with the great system; the tree, with its roots in the earth, puts forth branches, the branches expand into twigs, the twigs burst into leaves whose veins reach out into the air; out of the twigs spring buds swelling into blossoms, the blossoms ripen into fruit, the fruit drops seed into the earth which gave it and springs up into new trees. The tree by its growth, which is the putting forth of itself or expression, develops needs, these needs are satisfied, and the satisfying of the needs is the condition of its continued expansion. Man, too, has his existence in expression. By growth through expression, which is the creation of a new need, he is enabled to take up more into himself; he brings more into the unity of his personality, and thus he expands into the universal harmony. The unity which underlies the cosmos--to define once more the conception which is the basis of the preceding chapters--is of the spirit. The material world which we see and touch is but the symbol and bodying forth of spiritual relations. The tranquillizing, satisfying power of art is due to the revelation which art accomplishes of a spiritual harmony which transcends the seeming chaos of instant experience. So it comes about that harmony, or beauty, which is of the spirit, is apprehended by the spirit. That faculty in the artist by which he is able to perceive beauty is called _temperament._ By temperament is to be understood the receptive faculty, the power to feel, the capacity for sensations, emotions, and "such intellectual apprehensions as, in strength and directness and their immediately realized values at the bar of an actual experience, are most like sensations." The function of temperament is to receive and to transmit, to interpret, to create in the sense that it reveals. In the result it is felt to be present only as the medium through which the forces behind it come to expression. Art, the human spirit, temperament,--these terms are general and abstract. Now the abstract to be realized must be made concrete. Just as art, in order to be manifest, must be embodied in the particular work, as the statue, the picture, the building, the drama, the symphony, so the human spirit becomes operative in the person of the individual, and temperament may be best studied in the character of the individual artist.