The two major challenges for the 21st century are to improve the economic situation of the majority and save as much of the planet as we can.

Every kid has a bug period, I like to say, and I just got so fascinated and I had that experience, that wonderful life of being able to go out on my own without really any supervision at all. I just lucked out that way. I was trusted as a kid.

The closer the genetic relationship of the family members, as for example father-to-son, as opposed to uncle-to-nephew, the higher the degree of cooperation.

The variety of genes on the planet in viruses exceeds, or is likely to exceed, that in all of the rest of life combined.

In 2010, my two Harvard mathematician colleagues and I dismantled kin-selection theory, which was the reigning theory of the origin of altruism at the time.

And pigs may fly. And we may be able to terraform and send surface populations to Mars. And Jesus may come next week anyway, so it doesn't matter one way or the other. All these crazy things run through people's minds.

The genius of human society is in fact the ease with which alliances are formed, broken, and reconstituted, always with strong emotional appeals to rules believed to be absolute.