Yet Confucians disagree on the nature of human beings
The Chinese idiom, 江山易改，本性难移 (jiangshan yi gai, benxing nan yi), tells us: while nature as in rivers and mountains (jiangshan) changes, though very slowly, human nature (benxing) is difficult to change. It’s more difficulty to change human nature than nature to change the course of a river or move mountains. Yet there is another closely related interpretation.
Jiangshan can be read as the territory representing what Chinese dynasties of the past have accomplished. So, the enlargement or shrinkage of territory reflects the changing fortune of dynasties, for example, the Song dynasty, which lost its northern half and the capital Kaifeng to the Jurchen Jin invasion.
Thus, in this pithy statement, Jiangshan yi gai, benxing nan yi, we can draw out the dominant theme in Chinese philosophy — that which is change. Rivers can change course, mountains crumble, and dynasties rise and fall, but human nature remains the same. Yet within the large repertory of Confucianism, the dominant moral and political philosophy of China, there is the idea that although human nature is good, as they mature, people can divert from this disposition.
One central idea of Confucianism is that ren (仁), often translated as benevolence or humaneness, is intrinsic to human nature. From the “Three Character Classic”: People are born good, but through habits they divert (人之初，性本善。性相近，习相远). By habits, this could mean education and social practices or ritual (li) of deference and maintenance of harmonious relations, particularly with one’s family and relatives.
While it seems that the idiom contradicts what classical Confucians believe in human nature, they don’t necessary disagree that human nature is difficult to change. Is the task of educating young men and women to be the ideal moral person, junzi, to be more difficult than changing the course of the Huang He (the Yellow River)? It might be so because it is worth more than any river, mountain, or dynasty.