Cities tolerate crazy people. Companies don't.

We form cities in order to enhance interaction, to facilitate growth, wealth creation, ideas, innovation, but in so doing, we create from - from a physicist's viewpoint, entropy, meaning all of those bad things that we feel are engulfing us.

One of the remarkable things about slums is that they do develop their own social organization and economy and even culture that is, on some level, functional and in some cases, remarkably resilient. This is kind of amazing.

When people come together, they become much more productive.

Cities tolerate crazy people. Companies don't.

Cities are the crucible of civilization.

The paradigm of physics - with its interplay of data, theory and prediction - is the most powerful in science.