《毛詩•大序》可謂為中國傳統詩論之宗，歷代詩論多以〈大序〉所論而發也。其言情性感於物而動，故形於聲、發為詩，以至於可以正得失、動天地、感鬼神，所論亦與傳統樂論之祖《樂記》相互輝映，而兩者皆對後代之詩歌美學論有莫大的影響。二者雖相傳與子夏、公孫尼子有關，但由於文獻之不足徵，而無法確切的追溯其思想淵源。然而最近幾年於湖北荊門郭店等地出土了不少早已失傳的先秦儒家逸書，對於中國早期的詩論、樂論之發展，可給我們提供一些新的線索。本文擬以〈性自命出〉一篇為主，探討此其思想淵源，而接著將其中所蘊含的美學意義，加以進一步的發揮，以便給中國之傳統詩歌音樂美學做一初步的溯源。

　　　　　The “Great Preface” to the Shi Jing stands as ancestor to traditional Chinese theories of poetics, being an important basis for all subsequent discourses on the subject throughout the ages. In speaking of how human nature and its affections are motivated by contact with external things to take expression in music and poetry, which, in turn, might ultimately come to serve as ethical or even cosmic motivators in themselves, the “Great Preface” shares much in common with the Yue Ji, the principal text of traditional Chinese musical discourse. Together, both works would exert a tremendous influence upon the later development of Chinese theories of aesthetics. Until now, scholars have been unable to firmly ascribe either work to any particular thinker, or to ascertain their common philosophical sources with any certainty. Fortunately, however, the recently excavated texts of Guodian contain a number of lost Confucian texts that yield new clues for a reconstruction of the emergence of the musical and poetic theories those works reflect. Concentrating on the text entitled “Xing zi ming chu,” this article explores its philosophical sources and elaborates upon the aesthetic ideas implicit within it, in order to help us better trace the origins of China’s musical and poetic aesthetic traditions.