Stilwell believes that children are born with certain qualities and natural development tendency, so in order to achieve good results in education and teaching, they must "adapt to natural teaching". He said: in education, generally speaking, everything should be done according to human nature, and individually, everything should be done according to people's age characteristics. His so-called "teaching with nature" means that teachers should educate in strict accordance with human nature and its development law, and adapt to children's age characteristics and individual differences. He understood natural nature as the quality of wisdom and ability. The process of children's intellectual development is divided into three stages, namely, the feeling stage, the memory stage and the rational stage. Children show different psychological characteristics at different stages. Teachers should study and understand children's psychological characteristics as the basis of education and teaching. He said that if a teacher can deeply understand children's natural nature through his own life observation and research, then his inner feelings will guide him how to teach properly and promote the normal development of children's nature when interacting directly with students. Otherwise, it will "destroy the noble nature of mankind" and have extremely harmful effects.