数学是理性的音乐。
It is better by noble boldness to run the risk of being subject to half of the evils we anticipate than to remain in cowardly listlessness for fear of what might happen.
地理学是关于地方的科学，而不是关于人的科学。
Mathematics is not just about numbers, equations, computations, or algorithms: it is about understanding.
思考就是将自己限制在一个单一的思想中，有一天它会像世界天空中的一颗星星一样静止不动。