What theory did the Tang literati put forward to oppose the retro movement?

Those who consciously opposed the retro movement on a large scale were "Tang and Song School", "Public Security School" and "Jingling School". The representative figures in Tang and Song Dynasties are Wang, Mao Kun and Gui Youguang. Although their main energy is prose, their thoughts of "speaking for themselves" and "expressing their thoughts directly" are also applicable to poetry. Three brothers, Yuan Zongdao, Yuan Hongdao and Yuan, represented by the Gong 'an School, as well as Li Zhi and Tang Xianzu before them, made great contributions to the liquidation of retro literature. Li Zhi advocated "the theory of childlike innocence", Tang Xianzu advocated that "those who have feelings will be unreasonable, and those who have reasons will be ruthless" ("Da Xin"), and Yuan Hongdao even put forward "the theory of human nature". These propositions will inevitably urge them to break the old cliche pattern and express their true feelings, and also urge their creation to "mostly express their own spirit, not stick to any pattern, and refuse to write unless it comes from their own minds." (Yuan Hongdao's Poems) The Jingling School is represented by the hammers Xing and Tan. They also advocate the spirit of nature, but pay more attention to "attracting the spirit of the ancients to satisfy the hearts of future generations" and bring poetry creation back to the deep and lonely narrow path. Generally speaking, although the creative achievements of these schools were not very high, they broke through the stale atmosphere of retro-ism that enveloped the poetry circle at that time.