现代国家的挑战是在提供服务和维护秩序的同时保持其合法性。
The challenge for modern states is to maintain their legitimacy while also being effective in providing services and maintaining order.
The propensity to truck， barter， and exchange one thing for another is common to all men， and to be found in no other race of animals.
Profit without purpose is empty; purpose without profit is unsustainable.
The method of psychology must be as exact as the methods of the natural sciences.
Don't feel stupid if you don't like what everyone else pretends to love.