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.

I believe human beings mark a threshold in the development of the planet, of course, but it is only part of the picture. What Big History can do is show us the nature of our complexity and fragility and the dangers that face us, but it can also show us our power, with collective learning.

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

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.