本文的主旨在探討李翱「復性書」的思想淵源。這個問題學界討論已多，但和過去的研究不同，本文并不特別關心「復性書」的思想與特定文獻或個人的聯繫。本文的基本目的，是在找出這部作品與過往思想史的內在關係。更具體地說，本文試圖展現，「復性書」探索的主題以及提出的答案，和漢魏以下的重要思潮或觀念有怎樣的關聯。希望藉由這個取徑，能夠發掘出若干曾對中晚唐儒家心性思想的重建發生重要作用的歷史力量。 本文首先分析「復性書」的內容，發現這部作品的主幹是由三組觀念所構成的。首先，是透過精神修養以成聖人的問題意識。其次，「復性書」以為人的本性是善的，現實上之所以少有聖人，是因為邪妄的「惰」障蔽了「性」。人要成聖，就必須滅情復性。再者，「復性書」主張，人的本然善性是寂靜的。就修養方法而言，滅情復性是把動蕩的「情」安定下來，達到絕對寂靜的狀態，這就是本性的呈現。本文的主要工作在追溯以下三組觀念的歷史 源流：（一）修養成聖，（二）性善情惡、滅情復性，（三）)性本寂靜、由靜復性。希望 經由這些討論，「復性書」與漢唐之間思想潮流的關係得以顯豁。 本文在完成自身的分析後，將對以往學者的重要論點有所檢討。這兩方面比照、配合， 應能為李翱心性思想的淵源提供比較完整的認識。

　　　　　This paper examines the intellectual origins of Li Ao's (7747-836) Fu-hsing shu, universally recognized as the most creative late-T'ang Confucian writing on spiritual cultivation. The sources of Li's outlooks expressed in the Fu-hsing shu have long interested scholars. Unlike most previous research on this topic, the present work does not concern itself with the connections between the Fu-hsing shu and specific texts or individuals. Rather, it tries to identify the intellectual currents in prece ding times that are attributable to the formation of the thought of the Fu-hsing shu. It is hoped that this approach can help us not only to gain further insights into an old issue, but also to detect the crucial historical forces behind the late-T'ang endeavors in constructing a Confucian philosophy of interior life. The article begins with a close analysis of the text of the Fu-hsing shu, and argues that three sets of ideas are at the core of this work. The first is the problematik of reaching sage-hood through spiritual cultivation, which is the central theme of the Fu-hsing shu. Second, the Fu-hsing shu holds that one's "nature" (hsing) is good and "emotions" (hsing) evil. In order to become a sage, one has to extinguish his emotions and return to his true nature. Third, the Fu- hsing shu also takes the view that one's "nature" is absolutely tranquil. Therefore, extinguishing emotions and returning to the true nature actually means the "quieting down" of one's emotions. The paper traces the origins and development of these three sets of ideas separately. It finds that the ideal of questing for sage-hood mainly comes from the Buddhist tradition. The idea of extinguishing emotions and returning to the true nature has its distant roots in Han Confucianism and classical Taoist thought. In the Tang context, it resembles most closely a religious Taoist approach to immortality. Furthermore, the notion of one's nature being tranquil was current in classical and medieval Taoist thought, whereas quietude as a method of individual cultivation prevailed in religious Taoism and, to a lesser extent, Buddhism. A general point this paper makes is that the theme of the Fu-hsing shu was formed very much under Buddhist influence, but the substantial ideas Li used to construct his philosophy of spirituality drew mostly from the Taoist tradition. The paper also gives a review of existing theories on the intellectual origins of the Fu-hsing shu.