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 only solid piece of scientific truth about which I feel totally confident is that we are profoundly ignorant about nature... It is this sudden confrontation with the depth and scope of ignorance that represents the most significant contribution of twentieth-century science to the human intellect.

The earliest sensation at the onset of illness, often preceding the recognition of identifiable symptoms, is apprehension. Something has gone wrong, and a glimpse of mortality shifts somewhere deep in the mind. It is the most ancient of our fears.

I do not agree with this century's fashion of running down the human species as a failed try, a doomed sport. At our worst, we may be going through the early stages of adolescence, and everyone remembers what that is like.

It is in our genes to understand the universe if we can, to keep trying even if we cannot, and to be enchanted by the act of learning all the way.

I agree that you might clone some people who would look amazingly like their parental cell donors, but the odds are that they'd be almost as different as you or me, and certainly more different than any of today's identical twins.

We have dominated and overruled nature, and from now on the earth is ours, a kitchen garden until we learn to make our own chlorophyll and float it out in the sun inside plastic mebranes. We will build Scarsdale on Mount Everest.