Tian Yingzhang’s calligraphy collection. The saying "ignorance is often complacent, knowledge is not frivolous" means: people without knowledge tend to be more complacent and look down on others, while people with knowledge and insight are not frivolous and will be more humble. This sentence comes from a collection of Tian Yingzhang's calligraphy. It is a famous saying used by Mr. Tian Yingzhang to warn himself to be modest and cautious, and to guard against arrogance and impetuosity.