成唯識論述記 4.240

4.240

述曰：此既別破大眾六識俱轉，故知初破但破經部。縱成俱轉，難非受熏，由前破經部同時六識受熏故。彼大眾部六識無持種義，此不立假類受熏故言唯六識，無前熏後故言唯俱轉。

The Commentary states: Since this separately refutes the Mahāsāṃghika [view that] the six consciousnesses arise together, we know that the first refutation only refuted the Sautrāntikas. Even granting that they arise together, it is challenged that they cannot receive perfuming, because it was refuted earlier that the six consciousnesses simultaneously receive perfuming according to the Sautrāntikas. In that Mahāsāṃghika school, the six consciousnesses lack the meaning of upholding seeds; because here they do not posit an unreal category receiving perfuming, it says 'only the six consciousnesses'; because there is no earlier perfuming the later, it says 'only arise together.'