4. 后 and 先 (up. 3rd tone) are verbs. 弟=悌. Choo He here quotes from the commentator. Ch＇in (陈=氏): "Filial piety and fraternal duty are the natural outgoings of the nature, of which men have an intuitive knowledge, and for which they have an intuitive ability (良知良能). Yaou and Shun showed the perfection of the human relations, but they simply acted in accordance with this nature. How could they add a hair＇s point to it?" He also quotes another (陽氏),who says: "The way of Yaou and Shun was great,