我凡事先做好最坏的打算。

在数学中，提出问题的艺术必须比解决问题更有价值。

唯有通过形式，才能征服混沌。

The best way to predict the future is to invent it.

你对自己了解得越多，对你在别人身上看到的东西就越有耐心。

Every improvement in the circumstances of the society tends either directly or indirectly to raise the real rent of land, to increase the real wealth of the landlord, his power of purchasing the labour, or the produce of the labour of other people.