瑜伽師地論略纂 13.4

13.4

「有之因緣」者，此有第八之所以也。雖言說有，未知有之所以，既知所以有，故第八存之，其與現數受等俱轉。　「廣分別義」，即為第三問。

Regarding "the causes and conditions of its existence": this is the reason why this eighth exists. Although it is stated to exist, one does not yet know the reason for its existence; once the reason for its existence is known, the eighth is established, and it functions concurrently with the mental factors of the present moment such as sensation (vedanā). "The extensive discrimination of its meaning" constitutes the third question.