Does Tao-sheng provide adequate metaphysical and epistemological grounds for sudden enlightenment? The key to this question lies in the concept of li: a term of extreme significance in the Chinese philosophical tradition, and one that is ubiquitous in Tao-sheng’s writings. li has a wide spectrum of implications embracing both the particular and the universal, yet it may be safe to relate li to the essential substance underlying all things, including the Buddha’s teachings. However, Tao-sheng seems to take particulars as representations of the universal, and therefore, in his view, there is no serious conflict between the two levels. It may be possible to see li as a metaphysical term for the ultimate reality. li is identified with what is immutable (ch’ang): nirvāṇa, Dharmatā, and Dharma-kāya. By losing it one enters into the bondage of birth-and-death (saṃsāra); and by attaining it one reaches nirvāṇa. Whatever it is, li represents that by which one is to be enlightened; that is, it is the content of enlightenment.

Then, why sudden enlightenment? Because li is indivisible and nonanalytic, and the ontological nature of li dictates its epistemological mode. Tao-sheng makes this point in his [Commentary on the Nirvāṇa Sūtra]: “The true li (or Truth) is self-so (tzu-jan): enlightenment also is [the process of] mysteriously identifying oneself with [Truth]. What is true being not gradational (nondifferentiated), then can enlightenment allow any [stages of] changing?” The interrelation of ontology and epistemology seen here receives a clearer exposition by Tao-sheng in the following quotation: “What is the meaning of sudden? It means that li is indivisible; while the word enlightenment means illuminating the ultimate [that li is]. Hence, nondual enlightenment matches with indivisible li. [The distinction between] li and knowledge being done away with, we call it sudden enlightenment.” Thus, the indivisible nature of li requires an equally indivisible means to grasp it.

As a corollary, one also can consider the expression one. li is often described as “one,” especially in the [Commentary on the Lotus Sutra]. One is found along with such words as ultimate (or “final”) (chi), mysterious (miao), everlasting (ch’ang), as well as vehicle (yāna), referring to One Vehicle as the point of synthesis in the dialectical process involving the three vehicles. Hsieh’s argument in the [Pien-tsung lun] begins with the premise that “li is united with the One ultimate (or one and final).” As a logical consequence in his view, “one enlightenment” therefore is in order: “with one enlightenment all the fetters of existence are dispensed with simultaneously.”

Tao-sheng does not specifically reject the established doctrine of stages (bhūmi), which apparently typifies gradual enlightenment, but he locates the ultimate li beyond the confines of the ten stages. The ten stages and four grades of sagehood are merely the means that the Buddha devised to bring li within reach of all sentient beings.

Faith (hsin) is relegated by Tao-sheng as something short of enlightenment. “Understanding through faith” (hsin-chieh) in his view is not genuine enlightenment: when enlightenment sets in, faith gives way. In the [Pien-tsung lun] we find this view reiterated by Hsieh Ling-yūn; “Understanding is not to be gradually reached, whereas faith arises [gradually] from instruction. What do I mean by this? The fact that faith arises from instruction [shows that] there is such a thing as the work of daily advancement. But since [final] understanding is not gradual, there can be no such thing as partial entry into illumination.” In this way, Buddhahood does not allow gradual access, but rather an all-or-nothing, once-and-for-all situation.