八識規矩補註 1.34

1.34

This means that this sixth consciousness constantly transforms and changes among the three natures, the three realms, and the five feelings, because its cognitive form easily shifts. Only regarding the feelings are there five kinds, and the treatises do not agree: it is said that the seventh and eighth consciousnesses have only equanimity feeling, the first five evolving consciousnesses have painful and pleasant feelings, while regarding the sixth manovijñāna, two masters differ in their accounts. The master who maintains that there is pain in the mental plane says that the sixth completely possesses the five feelings; the master who maintains that there is no pain in the mental plane says that the sixth has only the three feelings of grief, joy, and equanimity. Yet when considering extreme pain and extreme pleasure, how could their contact with pain and pleasure not penetrate the mind? With the pain of Avīci or the pleasure of the third dhyāna, who could forget their distressing or agreeable objects? What oppresses or gladdens the body is called painful or pleasant feeling; what oppresses or gladdens the mind is called grief or joy feeling; and what neither oppresses nor gladdens is called equanimity feeling. Speaking according to principle, the master who maintains that there is pain in the mental plane exhausts the meaning.