成唯識論述記 3.313

3.313

述曰：須七識等受用於境，從第八生，非不緣故即不令起，如無漏心亦從起故。若有實體，第八即緣，無為有體，應第八緣。

The Commentary states: The seven consciousnesses and so forth are required to experience and utilize objects, and they arise from the eighth; it is not that because it does not cognize them, it does not cause them to arise, just as the anāsrava mind also arises from it. If having a substantial entity meant the eighth would cognize it, then unconditioned dharmas have substantial entities, so the eighth should cognize them.