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

We are, perhaps, uniquely among the earth's creatures, the worrying animal. We worry away our lives, fearing the future, discontent with the present, unable to take in the idea of dying, unable to sit still.

We are told that the trouble with modern man is that he has been trying to detach himself from nature... In this scenario, Man comes on as a stupendous lethal force, and the Earth is pictured as something delicate, like rising bubbles at the surface of a country pond, or flights of fragile birds.

The dilemma of modern medicine, and the underlying central flaw in medical education and, most of all, in the training of interns, is the irresistible drive to do something, anything. It is expected by patients and too often agreed to by their doctors, in the face of ignorance.

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.

The human brain is the most public organ on the face of the earth, open to everything, sending out messages to everything. To be sure, it is hidden away in bone and conducts internal affairs in secrecy, but virtually all the business is the direct result of thinking that has already occurred in other minds.

We are not made up, as we had always supposed, of successively enriched packets of our own parts. We are shared, rented, occupied. At the interior of our cells, driving them, providing the oxidative energy that sends us out for the improvement of each shining day, are the mitochondria, and in a strict sense they are not ours.