Climbing Mount Improbable
By Richard Dawkins
(W.W. Norton & Co.; 288 pages; $25)
Other theorists, notably David Sloan Wilson of the State University of New York at Binghamton, have proposed that natural selection may sometimes favor "altruistic" individuals, who sacrifice their own selfish interests for those of their herd, or their species, or even the entire ecosystem in which they are embedded. The most extreme version of this concept, called "group selection," is Gaia, which suggests that all of life cooperates so as to ensure its continued survival.
Dawkins has rebutted these notions convincingly, showing that the phenomena they attempt to explain can all be accounted for with conventional Darwinian theory. But his defenses of natural selection sometimes lend it more power than it really has. In one passage, for example, he likens it to a force or "pressure" that "drives evolution up the slopes of Mount Improbable." This image offers a grossly distorted view of evolution. For roughly 85 percent of life's 3.5 billion-year history, it was entirely made up of single-celled organisms, such as bacteria and algae. Then, for some reason--we will probably never know precisely why--the era of trilobites, triceratops, and other multicellular creatures commenced. Viewed this way, the ascent from the foothills of Mount Improbable to its multicellular aeries hardly seems inevitable.
Dawkins' own honesty and thoroughness undermine his case in other ways as well--for example, when he brings up the origin of life. "My guess is that life probably isn't all that rare and the origin of life probably wasn't all that improbable," Dawkins remarks. "But there are arguments to the contrary." There certainly are. Dawkins himself notes that after decades of searching, scientists have found no conclusive evidence that life exists elsewhere in the universe. (The discovery of organic matter in a meteorite, reported in early August, represents at best an extremely circumstantial piece of evidence for life on Mars.)
Moreover, as far as we know, life emerged here on earth only once. In spite of the immensely powerful tools of modern biotechnology, scientists still cannot make matter animate in the laboratory. They really have no idea how exactly life began, or whether its emergence was in some sense inevitable or simply a prodigious bit of good fortune.
Theorists also disagree over why, once life began, it was able to persist for so long and to proliferate into such an astonishing variety of species. Dawkins enjoys pointing out that among all the possible variants of a given species, the vast majority never reproduce; they are failures, dead ends. There are many more ways to be a loser in the game of life, he asserts, than to be a success. Surely that holds true for all of life, not just for its constituent parts. The essence of the selfish-gene model is that each individual pursues its short-term interests regardless of the long-term consequences for life as a whole, or even for other members of the species. Given that premise, why couldn't one species--a bacterium or virus, perhaps--run amok and destroy all other life on earth before finally succumbing itself? But life has managed, nonetheless, not only to endure but also to produce spiders, newts, and congressmen.
I know Dawkins knows how utterly improbable we are, because I have discussed the matter with him. Yet he seems to think that if he allows us weak-minded mortals to perceive that naked truth too directly, we will succumb to creationism or mysticism or theories such as Gaia, which is wishful thinking dressed up as science. Of course, most of us will succumb. But Dawkins should at least give us the chance to savor one of the great paradoxes of our era before we slip into darkness: The more that science explains our existence, the more implausible we seem.