The only real failure in life is not to be true to the best one knows.
生活中唯一真正的失败是不忠于自己所知道的最好。
真相总是不便的。
The goal of mathematics is not to solve problems, but to understand them.
A proof of a proposition is a process the nature of which is such as to produce in us a belief in that proposition.
"Imagination is more important than knowledge."