States are rational actors, and they will always act in their own self-interest.

至今一切社会的历史都是阶级斗争的历史，即剥削阶级和被剥削阶级之间、统治阶级和被压迫阶级之间斗争的历史。

相机让每个人成为他人现实中的游客，最终也成为自己现实中的游客。

一个人独处要超脱，与别人共处要和蔼；没有事时享受闲适；有了事情要果断；得意时要显出淡泊，失意时要安然处之。

教育学中的实验方法不仅是研究的工具，更是理解教育过程的基本原则。

The universe is not only stranger than we imagine, it is stranger than we can imagine.

"We inherit not only our parents’ features but also their silences."

Consciousness exists for the sake of action.