To be free is not to have no master, but to choose your own.

The great philosophers are those who have made a difference in the way we think about the world and our place in it.

我有一个非常简单的想法，如何变富。第一，花得比赚得少；第二，明智地投资差额。

The only limit to our realization of tomorrow will be our doubts of today.

人们不禁会感到这些数学公式拥有独立的存在和自己的智慧，它们比我们更聪明，甚至比它们的发现者更聪明。