But it is the same with man as with the tree. The more he seeks to rise into the height and light, the more vigorously do his roots struggle earthword, downword, into the dark, the deep - into evil.

Let him who would move the world first move himself.

逻辑学的研究是对正确推理原则的研究。

思想开阔，才能包容天下的千山万壑；思想谦虚，才能接受天下的真知大德；思想平明，才能纵论天下的善恶得失；思想深沉，才能讨论天下的学说哲理；思想稳定，才能应付天下的风云变幻。