I meet so many people who are intimidated by arithmetic.

History is but the record of the public and official acts of human beings. It is our object, therefore, to humanize our history and deal with people past and present; people who ate and possibly drank; people who were born, flourished and died; not grave tragedians, posing perpetually for their photographs.

The more you find out about the world, the more opportunities there are to laugh at it.

The most serious problem facing humankind is climate change. All of these people breathing and burning our atmosphere has led to an extraordinarily dangerous situation. I hope next generation will emerge and produce technology, regulations, and a worldview that enable as many of us as possible to live happy healthy lives.

We are special in the sense that we can know our place in the cosmos. We can know our place in space. We are at least one of the cosmos's ways of knowing itself. That fills me with reverence and joy. Another insight I really want people to consider is this: everyone has gotten this far. Everyone you meet has made it this far. Nobody is superior to anyone else from an evolutionary standpoint.

The thing about a theory in science is it allows you make predictions. Evolutionary theory allows us to predict what apples will taste good next harvest.

It is my mission to change the world. I'm not kidding: Make no small plans, dream mighty things. I feel if we get enough people engaged in climate change, we will get enough people to change the world. We will revolutionize the way we produce electricity and provide clean water to people.