Thomas· Jefferson tells us in his own experience, we should acquire knowledge through hands-on investigation from the source, not only obtained through reading. He said, we can not only obtain valuable knowledge from experts of high social status, but also can be obtained from those humble ordinary people there. Jefferson thinks, we must seriously consider themselves, rather than simply echoed the views of others. To avoid different opinions or contradictions are wrong. In a word, he left a rich heritage and examples to America people