恐惧是迷信的主要根源，也是残酷的主要根源之一。战胜恐惧是智慧的开端。

人类能够达到的最高活动是为了理解而学习，因为理解就是自由。

We must accept finite disappointment， but never lose infinite hope.

I am only resolved to act in that manner, which will, in my own opinion, constitute my happiness, without reference to you, or to any person so wholly unconnected with me.

道路越艰难，发现就越有价值。