Xu was one of the earliest student of the philosopher Wang Yangming. He was considered as a royal, important member and the second generation of the Yangming School of Mind (陽明心學/阳明心学).
Wang Yangming proposed his thought of conscience and intuitive knowledge, but most people and Confucians during his time didn't accept it. Xu mainly contributed to the further expatiation and the consummation of Wang's philosophy in this domain, and also further developed Wang's school of philosophy.
Xu recorded most of Wang's words (from both his daily living and teaching) and works, collected and recensing them, also printed and published these philosophical monographies. So Xu also played an important role in publicizing the philosophy in a popular style.
