真理是一面从上帝手中掉下来摔成碎片的镜子。每个人都拿了一块，看着它，以为他们拥有了真理。
The truth is not always the best basis for happiness.
Nothing will work unless you do.
We teach a subject not to produce little living libraries on that subject, but rather to get a student to think mathematically for himself.