What is the background of Liu Yuxi's creation of Tianlun?

In the middle Tang Dynasty when Liu Yuxi lived, a central issue in the struggle between materialism and idealism, atheism and theism on the philosophical front was the relationship between man and nature. Han Yu believes that heaven has a will and can reward and punish. Liu Zongyuan wrote Tian Shuo and criticized Han Yu. However, Tian Shuo was written simply, and Liu Yuxi thought that the relationship between heaven and man was not fully explained. For the sake of "Liu Zi's debate" and "the time between man and nature", he wrote "The Theory of Heaven", which supplemented and developed it. Tian Lun is included in Liu Bin Ji, also known as Liu Meng Kidd, which has four parts in Qing Dynasty. Shanghai Ancient Books Publishing House published Liu Yuxi's Notes 1989. The Collection of Liu Yuxi was published by Zhonghua Book Company 1990.