成唯識論述記 5.810

5.810

述曰：此釋難也。雖必俱起與前師同，與五同性，即不決定。由此理故，前所設難，能引意識通三性者，於此唐捐。問：如《解深密》等，說意與五同緣，故定同性；《集量論》說五俱意識必現量故，何故得知不同性也？為答此問也。

The Commentary states: This resolves the objection. Although the five consciousnesses necessarily arise together [with the mental consciousness], which is the same as the previous master's view, their having the same nature as the five is not determinate. Due to this reasoning, the objection raised earlier—that [if] the mental consciousness which induces [them] pervades the three natures, then [the rule that consciousnesses arising together must be of the same nature] is in vain in this case—[holds]. Question: Given that texts such as the Saṃdhinirmocana-sūtra state that the mental consciousness takes the same cognitive object as the five, and therefore must be of the same nature; and the Pramāṇasamuccaya states that the mental consciousness concurrent with the five is necessarily a direct perception (pratyakṣa), how is it known that they are not of the same nature? This is to answer this question.