大般涅槃經集解 54.167

54.167

案道生曰：智解十二因緣，是因佛性也。今分為二：以理由解得，從理故成佛果，理為佛因也。解既得理，解為理因，是謂因之因也。僧亮曰：觀智於涅槃為因因也，以菩提智是涅槃觀智，是菩提故。所以不於菩提為因因者，欲周歷四法故耳。

Daosheng comments: The wisdom that understands the twelve links of dependent origination is the causal buddhadhātu. Now it is divided into two: because the principle is obtained through understanding, and in following the principle the Buddha effect is achieved, the principle is the cause of the Buddha. Since understanding has obtained the principle, understanding is the cause of the principle; this is called the cause of the cause. Sengliang comments: Contemplative wisdom is the cause of causes for nirvāṇa, because bodhi wisdom is nirvāṇa's [cause], and contemplative wisdom is bodhi's [cause]. The reason it is not the cause of causes with respect to bodhi is simply to traverse the four phenomena completely.