论述诚与明的关系。人能够明白事理，就可以确定自己内心所向的目标，以至去指导自己的行为。由于人天生性善，也可反躬自省，自己的行为是否合于心中向善的本性，即真诚。如此看来，真诚与明白事理，互为促进，相辅相成。“自诚明”是说由真诚而明理。“自明诚”是说由明理而真诚。不论是出于天性或是教育的结果，一个人处世立身的原则都应是为仁行善，自觉自愿，不为外在力量所促使，做到这样，人就能达到至真至纯，至善至美的境界。
中庸·二十一
自诚明，谓之性。自明诚，谓之教。诚则明矣；明则诚矣。
XXI
The intelligence which comes from the direct apprehension of truth is intuition. The apprehension of truth which comes from the exercise of intelligence is the result of education. Where there is truth, there is intelligence; where there is intelligence, there is truth.
