一个人的价值或价值，就像所有其他事物一样，是他的价格；也就是说，为了使用他的力量而愿意付出的代价。
The value or worth of a man is, as of all other things, his price; that is to say, so much as would be given for the use of his power.
Coal miners don't just dig in the dirt, they dig for progress.
A great truth is a truth whose opposite is also a great truth.
Psychology is the science of mental life in its adaptive relations.