In the book Records of Gui by Zhong Sicheng, the author remarks in his preface that "the life of humans is of this world; we only know that the dead become gui, and not that the living can also be gui."
有一個叫鐘嗣成的人寫了一本《錄鬼簿》，他在序裡說「人之生斯世也，但知已死者為鬼，而未知未死者亦鬼也。」