Survival, in the cool economics of biology, means simply the persistence of one's own genes in the generations to follow.

It is almost always a greater pleasure to come across a semicolon than a period. The period tells you that that is that; if you didn't get all the meaning you wanted or expected, anyway you got all the writer intended to parcel out and now you have to move along. But with a semicolon there you get a pleasant little feeling of expectancy; there is more to come; read on; it will get clearer.

Viewed from the distance of the moon, the astonishing thing about the earth, catching the breath, is that it is alive. The photographs show the dry, pounded surface of the moon in the foreground, dry as an old bone. Aloft, floating free beneath the moist, gleaming, membrane of bright blue sky, is the rising earth, the only exuberant thing in this part of the cosmos.

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.

As a species, taking all in all, we are still too young, too juvenile, to be trusted. We have spread across the face of the earth in just a few thousand years, no time at all as evolution clocks time, covering all livable parts of the planet, endangering other forms of life, and now threatening ourselves.

We pass the word around; we ponder how the case is put by different people, we read the poetry; we meditate over the literature; we play the music; we change our minds; we reach an understanding. Society evolves this way, not by shouting each other down, but by the unique capacity of unique, individual human beings to comprehend each other.

Chemical waste products are the droppings of science.