成唯識論述記 8.225

8.225

述曰：今依因位，現行望自親所熏種，能為二緣，即因、增上，唯除第八及六識中極劣無記。非能熏故，與非親種不辨體故，除自種外，但一增上。

The Commentary states: Now based on the causal stage: manifest activity toward the seed directly perfumed by itself can serve as two conditions, namely the cause condition (hetu-pratyaya) and the predominant condition (adhipati-pratyaya). Excepted are only the eighth [consciousness] and the extremely weak indeterminate [states] among the six consciousnesses, because they cannot perfume. Toward seeds that are not direct [seeds], because their substances are not differentiated, apart from its own seeds it serves only as the single predominant [condition].