The mathematician does not study pure mathematics because it is useful; he studies it because he delights in it and he delights in it because it is beautiful.

We are what we repeatedly do. Excellence, then, is not an act, but a habit.

心理学必须基于可观察的事实，而非推测。

"Silence can be just as powerful as words in a story."

解释：影子的弯曲与正直是随身体而变化的，根源不在影子自身；自己的屈曲与伸直是随外物而变化的，而不在于个人的主观意志。这就是保持谦退才能使自己处世为先的道理。

Facts are stubborn things; and whatever may be our wishes, our inclinations, or the dictates of our passion, they cannot alter the state of facts and evidence.