成唯識論了義燈 5.38

5.38

問：苦、樂貫身、心，二受即分兩，捨受身心遍，何故不分多？答：苦、樂通尤微，是以各分兩。捨受唯一類，所以不分多。又解捨受相無別，身、心並名捨。逼、悅相有殊，苦、樂各分二。

Question: Pain and pleasure pervade both body and mind, so these two feelings are divided into two pairs. Equanimity feeling pervades both body and mind; why is it not divided into multiple ones? Answer: Pain and pleasure extend through the intense and the subtle; therefore, each is divided into two. Equanimity feeling is of only a single kind; therefore, it is not divided into multiple ones. Another explanation: The character of equanimity feeling has no distinction; both bodily and mental are called equanimity. The characteristics of affliction and delight differ; thus, pain and pleasure are each divided into two.