成唯識論述記 2.195

2.195

述曰：此難作用，其因有別，謂非異色、心及心所等，現比二量作用可得故，宗、喻同前。真如與心等，非一向異，亦無過失。

The Commentary states: This challenges their functioning; its reason is distinct: because, not being distinct from form, mind, and mental factors, functioning cannot be apprehended through the two valid cognitions of perception and inference. The thesis and example are the same as before. Tathatā and mind and so forth are not categorically different, so there is also no fallacy.