Great art is more than a transient refreshment. It is something which adds to the permanent richness of the soul's self-attainment. It justifies itself both by its immediate enjoyment, and also by its discipline of the inmost being. Its discipline is not distinct from enjoyment but by reason of it. It transforms the soul into the permanent realization of values extending beyond its former self.
Whitehead's American Essays in Social Philosophy (ed. Greenwood Publishing Group, 1975) - ISBN: 9780837177168