Confucius said to a disciple,"Shall I teach you what is understanding? To know what it is that you know, and to know what it is that you do not know,——that is understanding."

中文：子曰：“由！誨汝知之乎？知之為知之，不知為不知，是知也?！?br>

注釋：孔子對(duì)一個(gè)學(xué)生說(shuō)：“讓我告訴你什么是聰明吧？要知道什么東西是你所知道的，也要知道什么東西是你所不知道的——這就是聰明?！?/p>