In his "Letters of Aestheical Education",Siller points out:Aesthetics i rooted in the depth of human nature,it is the object of game impulse which is the combination of perceptual impulse and rational impulse resulted from interraction of human character and human nature.
席勒在《审美教育书简》中明确地提出:美根植于人性深处,美是游戏冲动的对象,游戏冲动是结合感性冲动和理性冲动的冲动,它们根源于人性的抽象结果(人格、状态及其相互作用)。