What do you mean, the public is born bright, and the students are born dark?

It means: justice is a discerning person, and favoritism is fatuous and stupid.

Source: Xunzi. There is no third "

The original sentence: "The public is bright, partial, and ultimately embarrassed, cheating; Honesty gives birth to God, boasting gives birth to chaos ".

Interpretation: it will produce intelligence, and selfishness will produce ignorance; Correct and cautious will lead to access, fraud and hypocrisy will lead to occlusion; Sincerity and honesty will produce gods, and boasting will produce chaos.

Extended data:

An example of public light and partial darkness-

Pang Xiangshou, the secretariat of Zhou Pu in Tang Dynasty, was dismissed for corruption. He told himself that he had been a guest of Qin Gong. The emperor yearned for the old love and wanted him to be reinstated.

Wei Zhi remonstrated and said, "In the past, there were many people around the king of Qin, both inside and outside the palace. I'm afraid everyone wants to break the law by having sex with you, which is enough to make those who are good at persuasion shudder. " The emperor readily accepted this opinion and said to Xiang Shou, "I used to be the king of Qin and the head of a house. Now I am the emperor, and I am the king of the four seas. I can't be selfish with my old friends. Ministers insist on this view, how dare I violate it! " So he gave Xiang Shou some silk goods and sent him away. Sang Shou left in tears.

References:

Baidu Encyclopedia-Dai Zhou broke the law