The original text of Zhuangzi's Chapter III Master of Health Preservation is: "My life is limited, but my knowledge is also limited. With restrictions, there is no restriction, and it is almost there! People who already know are almost enough! " Translated into modern Chinese, our life is limited and our knowledge is infinite. If we pursue infinite knowledge with limited life, we will be exhausted. In that case, people who pursue knowledge can only be tired.