The term means likening certain characteristics of things in nature, including plants and animals, to human virtues. When extended to the domain of literary appreciation, it generally involves likening desirable objects to a noble personality. To perceive a natural phenomenon as a reflection or symbol of human characteristics is typical of the Confucian School, which takes aesthetic quality as a moral standard for people as well as literature and arts. Likening humans to nature implies that appreciation of nature is actually appreciation of humanity itself, particularly its moral character. It later became a technique employed in rhetoric and poetry.
- 昔者君子比德于玉焉，温润而泽，仁也。 （《礼记·聘义》） （从前，君子的道德人格可以和美玉相比，温润而有光泽，体现出的就是仁。）
In the past, the moral integrity of a man of virtue was likened to fine jade, which is smooth, mellow, and lustrous, an exact embodiment of benevolence. (The Book of Rites)
- 及三闾《橘颂》，情采芬芳，比类寓意，乃覃及细物矣。 （刘勰《文心雕龙·颂赞》） （到了屈原创作《橘颂》，情感和文采都很出色，用橘来类比并寄托某些寓意，于是延伸到对细小事物的描绘了。）
By the time Qu Yuan wrote “Ode to the Orange”, both his sentiment and literary style had become highly refined. He used orange to draw analogy and convey a certain message before preceding to describe details. (Liu Xie: The Literary Mind and the Carving of Dragons)