成唯識論述記 7.76

7.76

The Commentary states: Below is the second gate: association among themselves. The two dharmas of investigation and examination are definitely never concurrent with each other; their substances are both volition and discernment, and their categories are both deliberation. It is impossible for dharmas of identical substance and identical function that are mutually contrary in grossness and subtlety to arise side by side, because gross and subtle are distinct, just as with higher and lower sensations (vedanā) and the like. Question: If investigation and examination cannot arise concurrently, how does the Mahāyāna speak of three stages: "with investigation and with examination," etc.? For when examination arises, the simultaneous mind and mental factors would mean that the desire realm has a stage "with examination and without investigation"; if only investigation arises, the simultaneous mind and so forth should be called "with investigation and without examination"; if neither arises, the simultaneous mind and so forth should be called the stage "without investigation and without examination"—thus your three stages would all fail to be established. Because the two do not arise together, there could be no such stages. To answer this question, the treatise next states: