成唯識論述記 6.120

6.120

述曰：釋業義，顯非遍行。然於愚昧心中無者，非一切愚皆無，以邪見者癡增上故。今但愚而亦昧，心即無也；愚不昧者，或可有故。第八識昧而不愚，亦無惠也。

The Commentary states: This explains the meaning of its operation, showing that it is not omnipresent. However, as for its absence in a foolish and darkened mind, it is not absent in all fools, because those with wrong views have a predominance of delusion. Here it is only when one is foolish and also darkened that it is absent in the mind; in those who are foolish but not darkened, it may perhaps exist. The eighth consciousness is darkened but not foolish, and it also lacks wisdom.