It is my belief, based partly on personal experience but partly also arrived at by looking around at others, that childhood lasts considerably longer in the males of our species than in the females.

We are a spectacular, splendid manifestation of life. We have language. . . . We have affection. We have genes for usefulness, and usefulness is about as close to a 'common goal' of nature as I can guess at.

It is a distortion, with something profoundly disloyal about it, to picture the human being as a teetering, fallible contraption, always needing, watching and patching, always on the verge of flapping to pieces.

In the fields I know best, among the life sciences, it is required that the most expert and sophisticated minds be capable of changing course - often with a great lurch - every few years.

We still think of human disease as the work of an organized, modernized kind of demonology, in which the bacteria are the most visible and centrally placed of our adversaries. We assume that they must somehow relish what they do.

The drive to be useful is encoded in our genes. But when we gather in very large numbers, as in the modern nation-state, we seem capable of levels of folly and self-destruction to be found nowhere else in all of nature. But if we keep at it and keep alive, we are in for one surprise after another. We can build structures for human society never seen before, thoughts never heard before, music never heard before.

Our behavior toward each other is the strangest, most unpredictable, and most unaccountable of all the phenomena with which we are obliged to live. In all of nature, there is nothing so threatening to humanity as humanity itself.