相关性和因果关系之间的区别在实证工作中是根本性的。
"The difference between correlation and causation is fundamental in empirical work."
The causal approach is about understanding the mechanisms that generate the data.
The only limit to our realization of tomorrow is our doubts of today.
"We are all in the gutter, but some of us are looking at the stars."
Remember, hope is a good thing, maybe the best of things. And no good thing ever dies.
元素周期表是现实构建模块的地图。
勇气是所有美德中最重要的，因为没有勇气，你就无法始终如一地实践其他美德。