《旧唐书·列传·卷二十九》
有的在天文历法方面有了成果，有的在生理卫生方面有了心得，日月星辰在天上运行，温热凉寒在地上交替，这才是阴阳理论的正道，片刻不能忘掉。至于丧葬的吉凶祸福，那是附会阴阳学说弄虚作假。
或成于昼夜之道，感于男女之化，三光运于上，四气通于下，斯乃阴阳之大经，不可失之于斯须也。至于丧葬之吉凶，乃附此为妖妄。
Some have made achievements in astronomy and calendar, some have experience in physiology and health, the sun, moon and stars run in the sky, and heat, cold and cold alternate on the ground, this is the right way of yin and yang theory, and cannot be forgotten for a moment. As for the good and bad luck of funerals, it is the falsification of the theory of yin and yang.