Taoism treats language as a tool somewhat deficient in unfolding ultimate reality to the full extent, as epitomized by the adage in the Lao-tzu: “Those who know do not speak; those who speak do not know” (Chapter 56). Also the Hsi-tz’u ch’uan (“Commentary on the Appended Judgements” of the I Ching), which is a text of Wang Pi’s commentary, quotes Confucius as stating: “Writing does not do full justice to words, which in turn do not do full justice to ideas” (11-12). The ineptness of words can be seen in the ineffable nature of li. Kuo Hsiang echoes this point: “The ultimate li is not something to be spoken of … li is not that which can be verbalized.”

Tao-sheng is in agreement with the Taoists on the limits of language. Various adjectival modifiers descriptive of li, such as deep, profound, wide, mysterious, far-off, and dark, all clearly identifiable in the Taoist literature, express the unspeakable nature of li. At best the role of language is to circumscribe li through approximation. He pointedly declares: “li is transcendent of words.”

Implicit in the limitation of words, on the other hand, is their intermediary value. Language belongs to the category of exigency (ch’ūan) or expediency (fang-pien, upāya). Tao-sheng declares: “li by nature is unspeakable, and yet we speak of it by resort to words in their temporary and false role, which we call expedient means.” Words as a medium or “ferry” are indispensable, especially to those who have not “witnessed” li in the course of their self-realization. In this respect, language can be best described as a catalyst in the realization of li. In Buddhist terms, it can be counted among the supporting causes (pratyaya), whereas the primary cause (hetu) making realization possible lies in the original capacity innate in human nature. …

Nevertheless, language, especially in connection with the Sage, is sometimes credited with more than a catalytic role. Here, Tao-sheng also finds common ground with the neo-Taoists. The words of the Sage, who has had an experiential encounter with li, are an authentic testimonial, a right source of mystical knowledge. Language here does not remain merely descriptive but becomes prescriptive. Therefore, in the adulation of the sūtra, repeatedly urged by the sūtra itself, there may not be anything unacceptable to Tao-sheng, whose approach in the commentary otherwise reflects a rationalist frame of mind.