A good mathematician is someone who can see analogies between theorems. A great mathematician is someone who can see analogies between analogies.

The world is so unpredictable. Things happen suddenly, unexpectedly. We want to feel we are in control of our own existence. In some ways we are, in some ways we're not. We are ruled by the forces of chance and coincidence.

Never stop learning; the world is always changing.

过去是一个异国；他们在那里做事的方式不同。