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.

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.

I suggest that the introductory courses in science, at all levels from grade school through college, be radically revised. Leave the fundamentals, the so-called basics, aside for a while, and concentrate the attention of all students on the things that are not known.

There's really no such thing as the agony of dying. I'm quite sure that pain is shut off at the moment of death. You see, something happens when the body knows it's about to go. Peptide hormones are released by cells in the hypothalamus and pituitary gland. Endorphins. They attach themselves to the cells responsible for feeling pain.

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.

All of today's DNA, strung through all the cells of the earth, is simply an extension and elaboration of [the] first molecule.

Cats are a standing rebuke to behavioral scientists wanting to know how the minds of animals work. The mind of a cat is an unscrutable mystery.