Three things are necessary for the salvation of man: to know what he ought to believe； to know what he ought to desire； and to know what he ought to do.

每个问题都有两面性。

The utility of an idea determines its place in mental life.

故事不是用来阅读的信，而是一扇等待被打开的门。

"To read is to travel without moving, to explore without leaving home."

数学家是将咖啡转化为定理的装置。