In literature classes, you don't learn about genes; in physics classes you don't learn about human evolution. So you get a fragmented view of the world. That makes it hard to find meaning in education.

Humans are remarkable: the first species in almost four billion years of life on earth that dominates the biosphere. This gives us the power, in principle, to build societies in which everyone flourishes. But it also creates great dangers because it is not clear that we really understand how to use our potentially devastating powers.

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.

Big History's not going to replace existing educational courses. It's not an attack on specialisation. It is simply the argument that specialisation needs to be complemented with an overview, which I think is scientific commonsense.

Modern scientific knowledge appeared piecemeal. Historians wrote about human history; physicists tackled the material world; and biologists studied the world of living organisms. But there were few links between these disciplines, as researchers focused on getting the details right.