The theory of positive change refers to the positive change of elegance, also called change of style and elegance. Originally from "Preface to Poems (Preface to Mao's Poems)".
The content of the theory of positive change: The division between "rightness" and "change" is not based on time, but on the basis of "political and religious gains and losses." It is believed that "Zhengfeng" and "Zhengya" are works from the prosperous period of the Western Zhou Dynasty, while "Bianfeng" and "Bianya" are works from the decline period of the Western Zhou Dynasty.
According to the traditional view, Feng and Ya refer to the genre of the Book of Songs, while Zheng and Bian refer to the content of the poems. However, scholars from various schools and schools in the past dynasties have different opinions on the origin of Fengya Zhengbian theory, the historical background of its emergence and the possibility of its existence.
Extended information:
Traditional Fengya is the local music of the Zhou Dynasty and its jurisdiction and different regions. The "Zhengfeng Zhengya" under the ritual and music system was not directly used at first. What restrains people's behavioral ethics is the "tools to entertain the gods" that strictly follow the requirements and norms of etiquette and music under specific banquet procedures and consciousness.
In the slavery society of the Zhou Dynasty, everyone from the emperor to the common people adhered to their respective hierarchical statuses and maintained the majesty of the "god" of the higher ruler.
But under the tyrannical rule of the King of Zhou, the Book of Songs was no longer a harmonious and beautiful song enshrined in the ancestral temple to entertain the gods. The turmoil in the country caused the traditional elegance to sing enthusiastically about reality. The ideal state has been broken. What is reflected in the "Book of Songs" is the transformation from "upright style and upright elegance" to "changing style and elegance".
Baidu Encyclopedia - Changing style and becoming elegant