無量壽經優婆提舍願生偈註 2.93

2.93

問曰：心是覺知相，云何可得同地水火風無分別耶？答曰：心雖知相，入實相則無知也。譬如蛇性雖曲，入竹筒則直。又如人身若鍼刺、若蜂螫（式亦反）則有覺知，若石蛭（之一反）噉、若甘刀割則無覺知。如是等有知無知在于因緣，若在因緣則非知非無知也。

Question: Mind has the characteristic of conscious awareness; how can it be said to be without discrimination, like earth, water, fire, and wind? Answer: Although the mind has the characteristic of knowing, when it enters the real mark it is without knowing. For example, though the nature of a snake is crooked, when it enters a bamboo tube it becomes straight. Furthermore, if a human body is pricked by a needle or stung by a bee, it has conscious awareness; but if it is sucked by a stone-leech or cut with a sharp surgical blade, it has no conscious awareness. Such states of knowing and not knowing depend on causes and conditions; if they depend on causes and conditions, then [mind] is neither knowing nor non-knowing.