《论衡·卷三·骨相篇》
人们只知道命有明显的骨相，不知道性也有骨法，这是命被认为有表象，性不被认为有征象。
唯知命有明相，莫知性有骨法，此见命之表证，不见性之符验也。
People only know that life has obvious bone and physique but don't realize that nature also has bones and physique, which is that life is considered to have image while nature is considered to have no signs.