This is a study of the concept of the ＂six causes＂ developed from the Indian Buddhist tradition of Logic and later elaborated by the Chinese Buddhist scholar monks in the Tang dynasty. This study focuses in particular on Kuiji's elaboration of the ＂six causes＂ found in his Great Commentary (因明大疏), a commentary to Xuanzang's translation of Sankarasvamin's Nyayapravesa (因明入正理論). In addition to introducing these understudied ＂six causes＂, this study attempts to call for a reconsideration of the view that epistemology was overlooked in Chinese Buddhist scholarly works in general and in the Medieval Chinese Buddhist logical studies in particular. In this study, I hope to show that Kuiji's elaboration of the ＂six causes＂ exhibits a sophisticated etymology that illustrates how linguistic and spiritual knowledge are complimentary for spiritual cultivation and intellectual learning.
一般而言，陳那在印度發展的佛教因明學的正式傳入中國，可說是起始於玄奘對商羯羅主所著《因明入正理論》 Nyāyapraveśa與陳那所著《因明正理門論》 Nyāyamukha 的漢譯。佛教因明學者注 意 到 玄 奘 並 未 翻 譯 陳 那 另 一 部 更 大 部 的 巨 著 《 集 量 論 》Pramāṇasamuccaya，雖然玄奘提到此論。這個遺漏讓有些西方學者對漢傳佛教的佛教因明學的容受得出以下的結論：認為漢傳佛教對佛教因明的認識局限在邏輯形式與宗教意涵，而沒法發展出認識論。筆者認為這個結論頗有值得商榷之處。透過對玄奘弟子神泰、文軌，特別是窺基所闡述的「六因」理論的研究，筆者認為「六因」理論具有多層次而獨特的認識論意涵。同時透過這個研究，筆者也想指出漢地本土所發展的佛教因明仍待更多的研究。
關鍵詞：
佛教因明、窺基、集量論、因明正理門論、認識論