法律体系是根据其自身的有效性标准而有效的规则体系。

The use of a program to prove the 4-color theorem will not change mathematics - it merely demonstrates that the theorem, a challenge for a century, is probably not important to mathematics.

If your goal does not have a schedule， it is a dream.

我希望我的书能帮助孩子们以不同的方式看待世界，注意到那些微小的细节和隐藏的意义。

成功者与不成功者的唯一区别就是是否愿意努力工作。