We should educate more women and girls. Because that is the surest route to controllably, manageably reducing the human population. Educated women have fewer kids. And the kids they do have are better cared for and are more successful. As I like to say, it's not one thing that we need to focus on. It's everything all at once.

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.

A two-and-a-half-year-old is pretty experienced at making a mess, anyway.

I try to speak plainly and be sympathetic to the idea of religions where people gather in community. They get a sense of people looking out for each other. My claim is that we have a tendency to look out for each other whether or not there is a religion involved.

I like to regard myself as someone who's capable of critical thought, that is to say, who can evaluate claims.

Not wasting any water bottles is good. Not leaving the lights on is good. Turning the thermostat down in the winter, up in the summer, is good. But the best thing any of us in the developed world, especially in the United States, can be doing is talking about it.

Everyone, red state, blue state, everyone supports space exploration.