Individual versus group selection results in a mix of altruism and selfishness, of virtue and sin, among the members of a society.

Individual versus group selection results in a mix of altruism and selfishness, of virtue and sin, among the members of a society.

The genes hold culture on a leash. The leash is very long, but inevitably values will be constrained in accordance with their effects on the human gene pool. The brain is a product of evolution. Human behavior-like the deepest capacities for emotional respone which drive and guide it-is the circuitous technique by which human genetic material has been and will be kept intact.

No species ... possesses a purpose beyond the imperatives created by genetic history ... The human mind is a device for survival and reproduction, and reason is just one of its various techniques.

Each of these [bacterial] species are masterpieces of evolution. Each has persisted for thousands to millions of years. Each is exquisitely adapted to the environment in which it lives, interlocked with other species to form ecosystems upon which our own lives depend in ways we have not begun even to imagine.

I grew up as a Southern Baptist with strict adherence to the Bible, which I read as a youngster.

Most people are surprised when they hear my somber figures: we know of 2 million species of plants, animals and microorganisms, and we can give them each a scientific name and a diagnostic description. We know, perhaps generously, more than just a little bit of the anatomy in no more than 10 percent. We have done thorough studies in fewer than one-tenth of 1 percent. And the total number of species on Earth is unknown to the nearest order of magnitude.