People need a sacred narrative. They must have a sense of larger purpose, in one form or another, however intellectualized. They will find a way to keep ancestral spirits alive.

If insemination were the sole biological function of sex, it could be achieved far more economically in a few seconds of mounting and insertion. Indeed, the least social of mammals mate with scarcely more ceremony. The species that have evolved long-term bonds are also, by and large, the ones that rely on elaborate courtship rituals. . . . Love and sex do indeed go together.

In science, obsessiveness under psychological control can be a virtue.

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.

Most people believe they know how they themselves think, how others think too, and even how institutions evolve. But they are wrong. Their understanding is based on folk psychology, the grasp of human nature by common sense ¾ defined (by Einstein) as everything learned to the age of 18 ¾ shot through with misconceptions, and only slightly advanced over ideas employed by the Greek philosophers

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 historical circumstance of interest is that the tropical rain forests have persisted over broad parts of the continents since their origins as stronghold of the flowering plants 150 million years ago.