All my life I have placed great store in civility and good manners, practices I find scarce among the often hard-edged, badly socialized scientists with whom I associate. Tone of voice means a great deal to me in the course of debate. I despise the arrogance and doting self-regard so frequently found among the very bright.

Most people are surprised when they hear my somber figures: we know of 2 million species of plants, animals and microorganisms, and we can give them each a scientific name and a diagnostic description. We know, perhaps generously, more than just a little bit of the anatomy in no more than 10 percent. We have done thorough studies in fewer than one-tenth of 1 percent. And the total number of species on Earth is unknown to the nearest order of magnitude.

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

When you have seen one ant, one bird, one tree, you have not seen them all.

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 the process of natural selection, then, any device that can insert a higher proportion of certain genes into subsequent generations will come to characterize the species.

The most dangerous of devotions, in my opinion, is the one endemic to Christianity: I was not born to be of this world. With a second life waiting, suffering can be endured - especially in other people. The natural environment can be used up. Enemies of the faith can be savaged and suicidal martyrdom praised.