俱舍論記 6.166

6.166

「唯說能生故至故不成難」者，經部答。謂經說諸因諸緣能生識者，此諸因緣皆是無常，不說一切為識所緣境者皆無常，故不成難。由此無為，可得與識作所緣緣。又解：不說一切為識四緣者皆是無常。

Regarding 'It speaks only of that which can generate […] therefore this is not a valid objection': the Sautrāntikas reply. The sūtra states that the causes and conditions that can generate consciousness are all impermanent; it does not say that everything that is an intentional object for consciousness is impermanent; therefore this is not a valid objection. Thereby, the unconditioned can act as an ālambana-pratyaya for consciousness. Another explanation: It does not say that everything that serves as the four conditions for consciousness is impermanent.