Nature tends to produce constancy in all her works, but she does not always succeed.
大自然倾向于在她所有的作品中产生恒常性，但并不总是成功。
逻辑学研究不仅仅是关于规则，更是关于理解思维的结构。
The poet’s job is to put into words those feelings we all have that are so deep, so important, and yet so difficult to name.
最深刻的发现往往来自最简单的观察。
The unity of mathematics is not imposed but discovered.