The similarities and differences between Li Shimin's voice and Ji Kang's theory of no sorrow and music are as follows:

Ji Kang was a famous writer and musician in the late Wei Dynasty, with a sense of justice and resistance in politics. He opposed the feudal ethics of Sima, the ruler of the Jin Dynasty, and put forward "not Tang Wu but thin Zhou Kong". Because of his uncooperative attitude with Sima, the ruler, he was killed.

The Theory of Sound Without Sorrow is a musical aesthetic work written by him. Its basic point is that music cannot express people's emotions of emotions.

Ji Kang thinks that music is an objective entity, and sadness and joy are the expression of emotions. There is no direct connection between them, thus denying that music can express people's sadness and joy, and denying that music has certain ideological content. He said that music can move people, and music can arouse people's feelings of sadness and joy, but it is not the music itself that shows any sadness and joy.

He thinks that music is just a kind of "harmony", and the reason why it can arouse people's sorrow and joy is only because the sorrow and joy "starts from the heart and then appears because of harmony". Ji Kang admits that different musical instruments will produce various sounds with different timbres and sizes, and they also have different sounds. However, whether fierce or quiet, its end must be attributed to "harmony", that is, "beauty." He believes that it is this "beauty" that can move people and inspire people's emotions.

Ji Kang sometimes uses the words "good" and "evil" to describe the quality of music, but he separates "good" and "evil" from emotion. He said: "When the voice is dominated by good and evil, there is nothing about sorrow and joy; Sorrow and joy should be based on emotion (mainly), then there is nothing about sound. " Thus completely negating the music can express people's feelings of sadness and joy.

Due to social and historical reasons, Ji Kang's musical thoughts are very contradictory in many places. For example, on other occasions (for example, in Qin Fu), he affirmed that music creation is emotional. "Laborers sing about their work, and musicians dance about their work".

At the same time, we must affirm that "Zheng Sheng" (a general term for folk music) is wonderful, and we must listen to the affection of "Zheng Sheng" on him. In the history of China's ancient music aesthetics, most music aesthetics documents think that music can express people's thoughts and feelings or express certain contents, and Ji Kang's On Sound without Sorrow and Music is unique with its unique expression.