大乘義章 1.55

1.55

問曰：何故㝹角之無，無而不可生；佛性之無，無而可生？釋言：㝹角於四無中是畢竟無，故不可生。望性淨果，法佛之性但是了因，非是生因。云何得知非是生因？如《涅槃》說「涅槃因者，所謂佛性。」佛性之性不生涅槃，故非生因。是義云何？性淨因果體一無別，隨時分異，在染為因、出纏為果。據因以望，因外更無果體可生；據果以望，果外更無因體能生。故非生因，但是了因。是義云何？諸佛之性是真識心體有，從本已來有可顯了成果之義，故名了因。如瓶中燈，有可了義，破瓶則見。以有如是可了義故，《涅槃》說云「佛性雖有，不同虛空。虛空雖以無量方便，不可得見；佛性可見。」可見猶是可了義矣。以可了故，名為了因。

Question: Why is the non-existence of a rabbit's horn non-existent and incapable of being generated, whereas the non-existence of Buddha-nature is non-existent yet capable of being generated? Explanation: Among the four kinds of non-existence, a rabbit's horn is absolute non-existence, and therefore cannot be generated. Looking toward the inherently pure fruition, the nature of the Dharma-Buddha is only a revealing cause, not a generating cause. How is it known that it is not a generating cause? As the Nirvāṇa [Sūtra] says: 'The cause of nirvāṇa is so-called Buddha-nature.' The nature of Buddha-nature does not generate nirvāṇa; hence it is not a generating cause. What is the meaning of this? Cause and fruition of inherent purity are of one identical essence without distinction; they are distinguished only according to time: in defilement it is the cause, and freed from entanglements it is the fruition. Viewed from the perspective of the cause, outside the cause there is no other essence of fruition that can be generated; viewed from the perspective of fruition, outside the fruition there is no other essence of cause that can generate it. Hence it is not a generating cause, but only a revealing cause. What is the meaning of this? The nature of the Buddhas is the existent essence of the true consciousness-mind; from the beginningless past, it possesses the capacity to be revealed to accomplish fruition; hence it is called a revealing cause. Just like a lamp inside a jar, which has the capacity to be revealed, and upon breaking the jar it is seen. Because it possesses such a capacity to be revealed, the Nirvāṇa [Sūtra] says: 'Although Buddha-nature is existent, it is not like empty space. Although empty space, even through countless skillful means, cannot be seen, Buddha-nature can be seen.' Being visible is precisely the meaning of being revealable. Because it can be revealed, it is called a revealing cause.