数学的美只向更有耐心的追随者展示。

We work with the earth, not against it.

The greatest obstacle to being heroic is the doubt whether one may not be going to prove one's self a fool; the truest heroism is to resist the doubt, and the profoundest wisdom to know when it ought to be resisted, and when it be obeyed.

"The difference between correlation and causation is fundamental in empirical work."