成唯識論述記 4.397

4.397

述曰：上座部師說：有根本計，有末所計，根本計麁細二意許得並生，末計不然，必別時起。今此本計，別有細意識，生死位中，一類微細行相、所緣俱不可了。非如薩婆多等故，我無咎者。不然。

The Commentary states: The masters of the Sthavira school state: there is a root doctrine and a derivative doctrine. The root doctrine admits that coarse and subtle mental consciousnesses can arise simultaneously; the derivative doctrine says otherwise, that they must arise at different times. Now this root doctrine holds that there is a separate subtle mental consciousness; at birth and death, it is of a single subtle type whose active mode and cognitive object are both uncognizable. [They argue:] Since it is not like the Sarvāstivādins and the like, we are without fault. This is not correct.