以「通」為道——杜光庭《道德真經廣聖義》之老學詮釋

Tao as ''openness（Tong）'': the interpretation on Laozi of Du Guangting’s ''Daode zhenjing guangshengyi''

唐代重玄思潮下之老子學，受到佛教性空義理論辯，質難道之「有體（實體性）」或「無體（非實體性）」的問題，使得注釋家重新檢視何謂「道」。唐初成玄英、李榮注《老》乃以「理」為道，偏向道之虛理義、客觀面，中唐玄宗注疏以「導」為道，偏重道之世俗義、主觀面，轉至晚唐杜光庭《道德真經廣聖義》，則以「通」釋道，發展出一種前（超）於主客二分之道，謂為「無體之體」，道體既是體又不是體，準確來說，是一種無有定體的體，云「道者，通也」，即是企欲「通」乎有體與無體之間，遂開展出幾個面向的道之「通」義：（一）根源之通（二）一氣之通（三）中道之通，（四）道路之通（五）應感之通。總上通義，皆可收攝於消極面的「『無滯』之通」與積極面的「『通生』之通」下，由此發展出其特殊型態的存有論之道。

The debate during the Tang Dynasty on the issue of of the Dao’s ''entity （substance）'' and ''non-entity（non-substance）'' was profoundly influenced by Buddhist theories regarding emptiness, and forced annotators of the text “Laozi” to re-examine the concept of the Dao. Cheng Xuanying （成玄英） and Li Rong （李榮） mainly equated the concept of principle （Li 理） with that of the Dao, with a tendency towards articulating the Dao’s relationship to Li as well as its objective dimensions. During the middle Tang, Tang Xuanzong’s （唐玄宗） commentary on the Laozi highlighted the notion of the Dao as a guide, emphasizing its secular meaning as well as its subjective dimensions. In the late Tang, Du Guangting’s（杜光庭）’s Daode zhenjing guangshengyi （道德真經廣聖義）'' interpreted the Dao as ''openness （Tong 通）'', creating an understanding of the Dao that was not constrained within the objective-subjective binary presented by the previous two commentaries. This new interpretation took the Dao to be an entity without substance （無體之體）, which means an entity that does not have a fixed form. The Daode zhenjing guangshengyi thus argued that “Dao is Tong.” That is to indicate an “openness（Tong 通）” between entity and non-entity, involving several meanings regarding the Dao: A） the root of Tong；B） oneness of Qi （氣） of the Tong；C） the middle way of the Tong；D） the road/way of Tong；E） induction of Tong. Above all, the meaning of Tong could be summed up in its negative sense as an ''unobstructed Tong'' and in a positive sense as an ''openness in becoming of Tong.” In this way, a particularly notable ontology of the Dao was developed.