I remember very vividly, as a child growing up in England, living through the Cuban Missile Crisis. For a few days, the entire biosphere seemed to be on the verge of destruction. And the same weapons are still here, and they're still armed. If we avoid that trap, others are waiting for us.

Learning to domesticate the horse was a sort of energy revolution.

Unfortunately, historians have become so absorbed in detailed research that they have tended to neglect the job of building larger-scale maps of the past.

Every kid goes to school full of questions about meaning. You know, 'What's my place in the universe? What does it mean to be a human being? What are human beings?' Existing courses cannot help you answer those questions. They can't even help you ask them.