大乘百法明門論開宗義決 1.256

1.256

"Phenomena external to one's own mind are either existent or non-existent, and so forth": The conditioned maula-ālambana is called an external phenomenon; the mental reflection is called an internal phenomenon. When grasping a self identical with the aggregates, the substance of the aggregates exists; because there is a maula-ālambana, it is spoken of as "either existent." When grasping a self separate from the aggregates, the substance of the self is completely non-existent; because there is no maula-ālambana, it is spoken of as "or non-existent." As for the internal phenomena of the mind—all marks of a self that are the reflected nimitta-bhāga—whenever the mind arises, they necessarily exist. Therefore, internal phenomena of the mind all exist without exception.