恒常的法则。古人认为，天地万物的运行、人伦生活的运转都遵循着某些恒常不变的法则。人们将这样的法则称为“常”，有时也称“常道”或“常理”。“常”与“变”相对，但又密切相关。“常”作为事物遵循的法则是恒常不变的，但这种恒常的法则又是在事物纷繁的变化中呈现出来的。人们正是在事物的不断变化中，去探寻、把握恒常的法则。

It refers to the constant nature or regular pattern of natural laws. The ancient Chinese believed that phenomena in the universe and life in human society are governed by constant laws in their movement. People characterize these laws as being "constant" and sometimes call them "constant ways" or "constant principles." "Constant" is in contrast to "change," but it is also closely connected with "change." Given that these are the natural laws or patterns that phenomena follow, they are stable and unchangeable. But these constant natural laws are manifested through myriad changing things. It is by learning about continuous changes that people seek to identify and comprehend underlying constant laws or principles.

引例 Citations：

◎天行有常，不为尧存，不为桀亡。（《荀子·天论》）

天的运行有其常道，不因为尧在位而存在，不因为桀在位而消失。

Nature's ways are constant. They did not exist because Yao was on the throne or disappear because Jie was the ruler. (Xunzi)

◎夫物芸芸，各复归其根。归根曰静，是谓复命。复命曰常，知常曰明。（《老子·十六章》）

万物纷纭，各自回归其根本。回归根本称为静，达到静就是回复到生命的本原状态。回复本原状态称为常，知晓这一恒常的法则称为明。

Things in nature are numerous and diverse and will eventually return to their roots. Returning to one's root is reaching tranquility. To reach tranquility is to go back to the original state of life. Going back to the original state of life is returning to the constant. Knowing what is constant is called wisdom. (Laozi)

推荐：教育部 国家语委

供稿：北京外国语大学 外语教学与研究出版社

责任编辑：钱耐安