Whenever Zhu Xi's students are discussed, they are usually believed to hold on stereotypically to their teacher's views; in fact this may not be true because sometimes they keep their individual perspectives, not faithfully conforming to Zhu Xi's thoughts. Chen Xun, though Zhu Xi's brother, is also his student. Chen Xun likes very much the Su Brothers' philosophy but holds a critical attitude toward the Chen Brothers'; Zhu Xi, however, respects very much the Chen Brothers' thoughts but criticizes those of the Su Brothers. It is worth noting that Chen Xun's academic viewpoints have twists and turns. According to Chen Ton's ”The Biography of Chen Ke-An”, Chen Xu agrees in early days with both the Chen Brothers' and the Su Brothers' thoughts; later in his life, he subsumes thoughts of Confucius, Mencius, Zhou Dunyi and the Chen Brothers. Nevertheless, when investigating the corresponding letters between Zhu Xi and Chen Xun, scholars find that the latter goes through the stages of supporting the Su Brothers' views to negating the Chen Brothers'. To be sure, it still needs effort to make sure whether Chen Xun really gives up the Su Brothers' philosophy.