多年來，我們對中國古典哲學的研究，對於其哲學議題的提出，以及概念與命題的出現，尋找 樣幾個線索：第一、哲學概念之形成，往往由一般觀念而後演變成一哲學概念或範疇；第二、複合詞的出現晚於單詞；第三、由概念發展為命題；第四、哲學議題常是由未顯題化到顯題化的發展。本文主要即透過這幾條線索，嘗試對中國哲學「理」範疇的發展過程作「第二序」的詮釋。 本文在考察先秦至兩宋關於「理」的重要詮釋後，歸結出其中的發展脈絡為：(一)在莊子的哲學體系中，「理」首次具有宇宙論的哲學意涵。(二)其後〈說卦〉提出「窮理盡性」一命題，在主客關係架構中，進一步發揮了莊子關於理與性之間的論點。(三)至魏晉時期，在王弼、郭象的詮釋下，理範疇有了更豐富的意涵。王弼重理一，而郭象重分殊，他們思想是程朱理一分殊思想的先導。(四)到了唐代成玄英，在關於「理」的詮釋上，他首次將「理」提升為與道同等階位的最高本體範疇。而將理與性提昇至本體論層次上，則試圖將傳統心性論議題引辭體論中；另外，透過「窮理盡性」之論，則展開物我合一、境智相泯之境。凡此皆為程朱開闢了一嶄新的方向；(五)至程朱理學，「理」成為哲學體系的核心。程朱繼承了老莊在道氣問題上的論點，並援引者莊道──德模式，同時直接繼承成玄英在氣先的理氣關係論，以及「窮理盡性」的理路，試圖由本體之理來證成原始儒家道德學說的普遍有效性。然而程朱因此將人的道德善性予以實然化，而在道時實踐上便著重在如實地體認以及體現人性中的理。這讓程朱以虛明之本心為基礎，展開格物窮理的認識進程，以識得本體之理及人性之理來實現道德行為。 綜觀先秦至兩宋「理」範疇理論模式的發展，主要是以老莊的道論、道與萬物的關係，及其心性論為理論主軸，透過分析「理」內涵的發展，再一次呈現出以道論及道與物的關係為核心理論的道家思想在中國哲學理論體系的建構及發展歷程中具有重要地位。

　　　　　In our research on the classical Chinese philosophy in which we have focused on its presentation of philosophical concepts, issues as well as propositions, we have discovered some clues to tackle these subjects more effectively. These are as follows: First, the formation of any philosophical idea often goes under the transformation from the general ideas into philosophical ideas or categories. Second, a term of single character comes earlier than a compound term. Third, an idea can be transformed into a proposition in its development. And four, a philosophical issue which has been implicit, manifests itself outwardly in its process of development. Bearing these in mind, this article attempts to reflect our interpretative methods by means of elucidating the process of the development of the philosophical category of li (principle). The article investigates the development of important interpretations from the pre-Qin period to song dynasty concerning the concept of li. This research has shown that the development of the term can be divided into the following five stages. First, the term li was adopted first as a philosophical idea in the philosophical system of Zhuang Zi (Zhuang Zhou). Second, it was the “Shuogua,” a commentary to The Book of Changes, that has proposed a theme of “exhausting the principle and exterting the human nature to the utmost.” (qiong li jin xing) This theme was instrumental for it could explain the content of Zhuang Zhou’s conception of li and xing (nature) under the argumentative framework of the subject-object relationship. Third, during the Wei-Jin period, the interpretative efforts by Guo Xiang and Wang Bi enriched the meaning of li. Wang Bi, on the one hand, focused every closely on the hand, focused very closely on the unity in the concept of li, while guo Xiang, on the other hand, on its various manifestations. Their interpretative efforts can seen as a source of the theme “one principle and may manifestations” (li yi fen shu) that is later proposed by Cheng brothers and Zhu Xi. Four, down to the Tang dynasty, Cheng Xuanying was the first commentator who invested the term with the significance as the highest ontological category. Before Cheng’s interpretation, only the term Dao contained such significance. Cheng’s efforts consequently upgraded the importance of the terms xing and li on the ontological level, by which Cheng tried to import the traditional argument about human nature and mind onto ontological dimension. Moreover, by adopting the them of “exhausting the principle and exerting the human nature to the utmost,” Cheng revealed the “realm of the unity of things and the self,” as well as of the “disappearance of the cognitive barrier which divides the self and this.” Indeed, all these interpretative effort by Cheng Xuanying has opened the door for the new philosophical attempt by Cheng brothers and Zhu Xi. And five, in the stage of the Learning of li“ by Cheng brothers and Zhu Xi, the idea of Li has come to the core in their philosophical system. Cheng brothers and Zhu Xi, the idea of li has come to the core in their philosophical system. Cheng brothers and Zhu Xi has accepted the views about the way and vital breath in the Lao-Zhuang Daosim, as well as importing the framework of the Way and Virtue also in the Lao-Zhuang Daoism in order to support their arguments. At the same time, they have also learned from Cheng Xuanying’s interpretation the reasoning method which had been attained by the theme “exhausting the principle and exerting the human nature to the utmost,” and the argument about the relationship between the principle and vital breathe in which vital breath comes earlier. In doing so, Cheng brothers and Zhu Xi adopted the idea of ontological li in order to validate the universal effect of the ethical theory of the classical Confusianism. On the basis, Cheng brothers and Zhu Xi presupposed that the inborn ethical good nature of men should be embodied and that the principle in inborn human nature should be also deeply recognized and manifested through the practice of morality. This presupposition enabled Cheng brothers and Zhu Xi to lay their theoretical basis on the true mind which has no substance but is illuminating, and to propose cognitive process of “mastery of the principle of things.” (g wu qiong li) In doing so, men can attain a deep comprehension on the ontological and inborn human principle which leads human beings to the attainment of moral behaviors. In our investigation into the important development of the interpretative implications on the tern of li from the pre-Qin period to Song dynasty, we have found the fact the main theoretical elements in its conceptual development have been involved in the argument on the Way, the relationship between the Way and things, and the theory on nature and mind, all of which came from Lao-Zhuang Daoist philosophy. Thus, in its Neo-Confucian appearance, “the Learning of li” by Cheng brothers and Zhu Xi has been constructed on the basis of the Daoist philosophy. Indeed, it is through our research on the development of the concept of li that again reveals the utmost importance of Daoism for the construction and development of t he Chinese philosophy.