作战虽然讲究排兵布阵，但士兵的勇敢是其中的根本;丧葬虽然讲究礼节，但对亲人的哀思是其中的根本;一个人虽然很有学识，但思想道德、行为举止是其中的根本。

The first duty of the sovereign， that of protecting the society from the violence and invasion of other independent societies， can be performed only by means of a military force.

The magic number 150 suggests that the size of our social networks is limited by the size of our brains.

无径之林，常有情趣

牙痛的人认为牙齿健康的人都快乐。穷人对富人也犯同样的错误。