《史记·八书·乐书》
凡音都是由于人心产生的，天与人是有某种关联的，两者就象镜中的影子与物形那样相像，响与应声那样相应和。
凡音由于人心，天之与人有以相通，如景之象形，响之应声。
All sounds are produced by human hearts, and there is a certain connection between heaven and man, just like the shadow in the mirror and the shape of the object, and the sound and the response.