《吕氏春秋·论·似顺论》
金木功用各异，水火用途有别，阴阳性质不同，但它们作为对人们有用之物则是相同的。
金木异任，水火殊事，阴阳不同，其为民利一也。
Metal and wood have different functions, water and fire have different uses, and yin and yang have different characteristics; however, they are all the same in that they serve as useful objects for human beings.