译文：怀疑就不要任用，任用了就不要怀疑。

The fountain of content must spring up in the mind, and they who have so little knowledge of human nature as to seek happiness by changing anything but their own dispositions will waste their lives in fruitless efforts.

自然界的所有效应只是少数不变定律的数学结果。

幸福不是好运或外部事件的结果，而是我们解释这些事件的方式。