道教重玄學與佛教中觀學間的對比與交談：以成玄英與吉藏之方法論為例

Contrast and Communication between Daoist Chongxuanxue and Buddhist Madhyamaka: Cheng Xuanying and Jizang's Methodologies as a Case Study

學界公認重玄學之思維方法，不僅承襲了老莊之道家傳統，更深刻地受到佛教中觀學所發展的四句論法之影響；至於影響來源，或以為為印度之龍樹，或以為為中國之吉藏。本文旨在以重玄學之大家──成玄英──之重玄方法為例，借助沈清松之對比哲學，考察成玄英如何融攝佛教中觀學之語言乃至思維模式，與對方進行交談與溝通，以檢視此交談能否豐富道教義學上的內涵。本文首先對比吉藏與龍樹《中論》的四句論法，以明其於佛教中觀學內部的發展；其次以成玄英著作中的重玄方法為主，對比其與《老子》、《莊子》、向郭注中涉及雙遣雙非之處，以期辨明重玄方法對於道家傳統之繼承或創新。最後根據以上二節所得，對比吉藏的四句論法與成玄英的重玄方法，並以重玄學為主，考察其與佛學之間的交談。

Chongxuanxue, The Study of Twofold Mystery, is a philosophical current within religious Daoism which ingeniously integrates the reasoning methodologies of the Daoist and Buddhist traditions, or more specifically for the latter, Buddhist Madhyamika catuṣkoṭi(ka). Inspired by the philosophy of contrast devised by Vincent Shen, this paper aims at investigating how Cheng Xuanying, the most representative Chongxuan thinker, communicates with Jizang, a Chinese Buddhist scholar who further developed catuṣkoṭi(ka), on the subject of reasoning methodology. In this paper, I first determine the way in which Jizang appropriated and developed Nāgārjuna's catuṣkoṭi(ka). Second, I trace the influence in Cheng Xuanying's work by comparing his Chongxuan methodology with the methodology of negation found in the Zhuangzi and its Xiang-Guo commentary. Finally, having established the positions of Jizang and Cheng Xuanying within their own respective traditions, I put into contrast their reasoning methodologies, with a particular emphasis on how Cheng responds to Jizang's critique of Daoism.