The evolution of the concept of filial piety (xiao) in the Laozi, the Zhuangzi, and the Guodian bamboo text Yucong

As is well known, the term “xiao” (filial piety) appears only twice in the current version of the Laozi. First, in Chapter 18, the Laozi states:

When the Great Dao declines, there are benevolence and rightness. When knowledge and wisdom emerge, there are great achievements. When the six family relationships are not in harmony, there are filial piety [xiao] and compassion. When a country is in disorder, there are loyal ministers. ¹