《资治通鉴·汉纪·汉纪四十四》
而且，律历、卦候、九宫、风角所作的预测，曾不断应验，世人不肯学习，却争相称赞谶纬之书，正犹如画工厌恶画狗画马，却喜好画鬼怪，确实是因为实在的事物很难画好，而虚无飘渺的东西可以信笔乱画。
且律历、卦候、九宫、风角，数有征效，世莫肯学，而竞称不占之书，譬犹画工恶图犬马而好作鬼魅，诚以实事难形而虚伪不穷也！
Moreover, the predictions made by the calendar, the divination by hexagrams, the nine palaces, and the wind direction have been proven to be effective time and time again. People are reluctant to study, but they are eager to praise the books of prophecy. It is just like a painter who hates painting dogs and horses but likes to paint ghosts and monsters. It is indeed because real things are difficult to paint well, while unreal things can be drawn freely.