《太玄》與《易》的「殊塗同歸」關係

The Relationship between Yang Xiong’s Taixuan and the Book of Changes

揚雄（前53-18年）的《太玄》與《易》和西漢《易》說，有著極其密切的關係，乃是學界的一項常識。然而，《太玄》與《易》呈現哪一種形態的學術關係，卻是兩漢思想研究中，極不容易清晰說明的課題。再者，《太玄》與《易》的具體關聯及證據如何，於今仍是眾說紛紜，莫衷一是。本文先從學界流行的「贊易」、「擬易」和「準易」諸說，申明以往學者對《太玄》與《易》學關係描述的異同，以見出不同說法的限制所在。復別開新路，從孔子對《易》學的範式轉移，開啟「義理」《易》學之路，對比不同的《易》學子系統，以見漢代《易》在理想與現實中的範式衝突，以及《太玄》試圖以何種形式，介入卜筮《易》說與義理《易》說的爭議，並透過與《帛書．易》〈要〉篇孔子與先前《易》學「同塗殊歸」之說，對照揚雄如何及為何，發展一套與《易》相反相成的「殊塗同歸」的《太玄》系統。由是觀之，揚雄之作《太玄》，乃深受《易》學內部範式衝突的困擾，透過別闢蹊徑的方式，試圖以新的《太玄》系統，與現存殊塗的《易》學系統，以功能相似，運作相異的方式，同歸向仁義的目標。

One of Yang Xiong’s most important books is the Taixuan, which is generally thought to be related to the Book of Changes and the studies on it in the Han Dynasty, but with different evidences, scholars have various opinions on the way the two books are connected. This paper first differentiates the theories about the relationship between them and then develops a new theory based on Confucius’s interpretation of the Book of Changes. Taking reality into account, Yang Xiong approves Confucius’s focusing on renyi (仁義, benevolence and righteousness) rather than follows the common interpretations that strongly associate the Book of Changes with divination. He writes the Taixuan to resolve the contradictions between these two kinds of interpretations and integrate them into one system centering on renyi.