The stranger is an element of the group itself, not unlike the poor and sundry 'inner enemies'—an element whose membership within the group involves both being outside it and confronting it.

Every discovery in physics opens the door to a new mystery.

我只是努力保持一致性，每天坚持训练。

数学家研究纯数学不是因为它有用；他研究它是因为他喜欢它，他喜欢它是因为它美丽。