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.
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)
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)