Happiness is as a butterfly which, when pursued, is always beyond our grasp, but which if you will sit down quietly, may alight upon you.

The stream of thought, of consciousness, is always flowing.

Every mental state corresponds to a specific brain state.

数学的快乐来自创造的行为，而不仅仅是结果。

深刻沉着、忠厚笃信，是第一等的禀赋；直率开朗、豪迈雄健，是第二等的禀赋；明智聪慧、能言善辩，是第三等的禀赋。