Theorems are the permanent literature of mathematics.

如果你不顽强，你就会过早放弃试验。如果你不灵活，你就会以头撞墙，而不会找到解决问题的不同办法。

The philosopher in the bedroom is as ludicrous a figure as the philosopher in the nightclub.

The best revenge is success and happiness.

Collaboration across borders is essential—fish don't recognize national boundaries, and neither should our efforts to protect them.

Of all the things which wisdom provides to make us entirely happy, much the greatest is the possession of friendship.

团结使我们强大，分裂使我们弱小。

选自汉·桓宽《盐铁论·相刺》。橘柚生长于江南，各地的人吃起来都有甜的感觉，这是因为大家的味觉是相同的；郑国卫国的音乐，大家都觉得好听，那是因为大家对声音效果的感受是相同的。这句话以吃橘柚的感觉与听音乐的感受为喻，说明是非好坏的标准是客观存在的，人类社会的价值认同大体是相同的。