理解变化的唯一方法是投入其中,随之而动,并加入舞蹈。
【大意】一个国家如果没有正义,即使再强大也定会灭亡。一个人如果没有良善的志趣,即使勇猛也必会遭遇挫伤。
The method of psychology must be as exact as the methods of the natural sciences.
In mathematics, the art of proposing a question must be held of higher value than solving it.