This maxim was first seen in Wang Zhi by Xunzi, a philosopher in the Warring States Period: "Shu Ren is in charge, and then the gentleman is in charge. Chuan said:' the monarch, the boat is also; Shu Ren, water also; The knife cuts bread and fingers. During the reign of Emperor Taizong, Wei Zhi, a famous minister, also quoted a similar view in Zhenguan Politicians: "I have also heard an old saying:' The monarch is also a boat; People (avoiding the taboo of Emperor Taizong and Li Shimin, replacing "people" with "people"), water also. The knife cuts bread and fingers. ”"

Water is buoyant, so it can carry a boat. At the same time, the water will rise because of the wind and waves, and it can also capsize when the waves are big. In fact, this is a dialectical thought in the understanding of water. As far as water itself is concerned, it is not difficult to obtain such an understanding, but the value of the ancients lies in popularizing this dialectical thought into social life and making it a ruling means to maintain social stability. In the ancient class society of China, the monarch and the people were ruled and ruled, and their class interests were fundamentally different, but this does not mean that they were sharply opposed at any time. "Water can carry a boat, but it can also overturn it" is a means to reconcile class contradictions within the ruling class. Through proper redistribution of interests, class reconciliation can be achieved to a certain extent, thus promoting the development of social productive forces. It is precisely because Li Shimin, Emperor Taizong, listened to Wei Zhi's advice that "water can carry a boat, but it can also overturn it" that he finally realized the famous "Zhenguan Rule" in China history.