I am of course quoting from a famous essay by Leonard Read, the economist in the 1950s, called "I, Pencil" in which he wrote about how a pencil came to be made, and how nobody knows even how to make a pencil, because the people who assemble it don't know how to mine graphite, and they don't know how to fell trees and that kind of thing.
的确我要引用1950年代的经济学家， 伦纳德·里德Leonard Read的著名作品里的话， “我，铅笔”。 他写道铅笔是怎样被制做的， 竟然没人知道铅笔怎样被制成的， 缘于人们生产铅笔，却不知道怎样开采石墨。 人们也不知道怎样砍伐树木等等类似的事情。