唯識二十論述記 2.250

2.250

述曰：此正為難，諸識既緣不離識境，無心外法，理即便無善、惡二友，亦無他說正、邪二法。此能聽者，或正或邪二識決定，云何得成？或無外境，云何得有能教、所教二識決定？

Commentary: This is the formal objection: Since all consciousnesses take as objects what is not apart from consciousness and there are no phenomena outside the mind, in principle there would be neither good nor bad friends, nor would there be the true or false teachings expounded by others. How could it be established that this listener is determined in either of the two consciousnesses, right or wrong? Or, if there are no external objects, how could the determination of the two consciousnesses of the teacher and the taught be established?