The unity of mathematics is not imposed but discovered.

For me they normally happen, these career crises, often, actually, on a Sunday evening, just as the sun is starting to set, and the gap between my hopes for myself and the reality of my life starts to diverge so painfully that I normally end up weeping into a pillow.

The companies that thrive will be those that turn environmental challenges into business opportunities.

Everything is hard before it is easy. The day before something is a breakthrough， it’s a stupid idea.