"Randomized experiments are the gold standard for causal inference, but they are not always feasible."

I'm not afraid to speak my mind and stand up for what I believe in.

Innovation often happens at the boundaries of different fields.

所以，国家的钱财不足以来应付饥荒，救济孤儿寡妇，这样，国家就贫困，百姓就难于治理。 

I think that plays are there to disturb, not to reassure.

Strive for excellence, not mediocrity.

The truth will set you free. But not until it is finished with you.

没有根本的气节，就好像醉汉喝醉酒打人，酒醉时很勇敢，酒醒后勇气全消，没有一点气力。没有以学问为根本的见识，就好像厨师在炉灶前面，面前光亮而背后黑暗。