The term means to observe and maintain the natural state of things. This notion first appeared in the book Laozi. The original meaning of su (素) is undyed silk; pu (朴) is unworked wood or timber. Laozi used these terms as analogies for people and objects in their natural untouched state. He believed that those in power should not try to influence people or things with ideas or demands that run counter to their natural conditions. Instead they should guide the populace back to its simple, natural origin. The term later came to mean “be unaffected by external factors and retain its earliest, pure nature.”

Cast aside saintliness and wisdom, and the people will benefit greatly; cast aside benevolence and righteousness, and the people will revert to their natural dutiful feelings; cast aside smartness and gain and thieves will disappear. Saintliness and wisdom, benevolence and righteousness, and smartness and gain are all unnecessary embellishments and are inadequate for governance. People must return to their natural state and restrain their desire. (Laozi)