苦难是智慧的学校。

我从不试图预测市场；我只是试图为它所做的任何事情做好准备。

代数是人类创造的一种智力工具，用于清晰地表达世界的数量关系。

One can choose to go back toward safety or forward toward growth. Growth must be chosen again and again; fear must be overcome again and again.

We shall never prevent the abuse of power if we are not prepared to limit power in a way which occasionally may prevent its use for desirable purposes.