又曰：「知是心之本体，心自然会知。见父，自然知孝；见兄，自然知弟；见孺子入井，自然知恻隐。此便是『良知』，不假外求。若『良知』之发，更无私意障碍；即所谓『充其恻隐之心，而仁不可胜用矣』。然在常人，不能无私意障碍；所以须用『致知』、『格物』之功。胜私复理，即心之『良知』更无障碍，得以充塞[1]流行；便是致其知。知致，则意诚。」
又说：「知是心的本体，心自然会知。见到父亲，自然知道孝；见到兄长，自然知道悌；看见小孩要掉进井里，自然知道恻隐。这便是『良知』，不须向外面求取。若良知的发用更无私意障碍，就是所谓『扩充其恻隐之心，而仁便用之不尽了』。然而在常人，不能没有私意的障碍，所以必须用『致知』『格物』的功夫。战胜私欲、恢复天理，心的良知便再无障碍，得以充塞流行，便是致其知。知致了，意便诚。」
He also said: "Knowledge is the original substance of the mind; the mind naturally knows. Seeing a father, it naturally knows filial piety; seeing an elder brother, brotherly respect; seeing a child about to fall into a well, it naturally knows the pang of compassion. This is 'innate knowledge' (liangzhi), not to be sought outside. Were its expression unhindered by private opinion, it would be as is said: 'fully expanding the compassionate heart, one's humaneness becomes inexhaustible.' But in ordinary people there is no lack of such hindrance, hence the work of 'extending knowledge' and 'investigating things'. Overcoming selfishness and restoring principle, the mind's innate knowledge flows unimpeded and fills all — this is extending one's knowledge. Knowledge extended, the intention becomes sincere."
- 塞字本张载「天地之塞，吾其体」（《西铭》）。