First appeared in Mencius, the term zhiyan (知言) means to be able to tell whether various statements are truthful, right and good, in order to gain true knowledge. Yangqi (养气) refers to nurturing one’s mind and righteousness. Mencius (372?-289BC) emphasized that he's good at cuiltivating the noble spirit in himsef, which is then displayed in outward verbal articulation,and others can also understand this person's inner world from his writing. Based on a philosophical proposition, this literary concept highlights the influence of a writer’s self-cultivation on expressions used in writings and stresses that one’s righteousness can enhance his learning, moral character, outlook and temperament, which will ultimately manifest themselves as the vigorous style or appeal of their writings. The style of language is determined by the author's inner spiritual cultivation and his noble character. The Chinese literary theory of "resonance and empathy" in the later time is deeply affected by this view.

[Gongsun Chou said,] “May I ask in which area do you excel?” Mencius replied, “I can perceive the true meaning of various statements, and I am good at self-cultivating righteousness.” (Mencius)

The author of the writing is moved by emotions and expresses them through words. The readers understand the author's emotions and aspirations by reading the words. Tracing back to the source along the external turbulence, and the deepest emotions and aspirations will be revealed. (Liu Xie: The Literary Mind and the Carving of Dragons)

The reason why Du Fu’s poems and Han Yu’s essays have been read for many generations is that Du Fu and Han Yu understood the true meaning of statements and could foster righteousness. Because they knew the true meaning of statements, their writings are insightful, and they also understood the importance of major political development of the day. As they fostered righteousness, there is not a sense of feebleness or weakness in their poems and writings. (Diaries of Zeng Guofan)