Why Darwin Matters: The Case Against Intelligent Design - Hardcover

Michael Shermer is one of the best-known public intellectuals defending evolutionary theory today. The author of eight previous books, he is a columnist for Scientific American, the publisher of Skeptic magazine, and the founder of the international Skeptics Society. He lives in Southern California.

Prologue

Why Evolution Matters
 
Hence both in space and time, we seem to be brought somewhat near to that great fact--that mystery of mysteries--the first appearance of new beings on this earth.
 
--Charles Darwin, Journal of Researches, 1845
 
In June 2004, the science historian Frank Sulloway and I began a month-long expedition to retrace Charles Darwin's footsteps in the Galápagos Islands. It turned out to be one of the most physically grueling experiences of my life, and as I have raced a bicycle across America five times, that is saying something special about what the young British naturalist was able to accomplish in 1835. Charles Darwin was not only one sagacious scientist; he was also one tenacious explorer.1
 
I fully appreciated Darwin's doggedness when we hit the stark and barren lava fields on the island of San Cristóbal, the first place Darwin explored in the archipelago. With a sweltering equatorial sun and almost no fresh water, it is not long before water-loaded seventy-pound packs begin to buckle your knees and strain your back. Add hours of daily bushwhacking through dense, scratchy vegetation, and the romance of fieldwork quickly fades. At the end of one three-day excursion my water supply was so dangerously low that Frank and I collected the dew that had accumulated on the tents the night before. One day I sliced my left shin on a chunk of a'a lava. Another day I was stung by a wasp and one side of my face nearly doubled in size. At the end of one particularly grueling climb through a moonscapelike area Darwin called the "craterized district," we collapsed in utter exhaustion, muscles quivering and sweat pouring off our hands and faces, after which we read from Darwin's diary, in which the naturalist described a similar excursion as "a long walk."
 
Death permeates these islands. Animal carcasses are scattered everywhere. The vegetation is coarse and scrappy. Dried and shriveled cactus trunks dot the bleak landscape. The lava terrain is so broken with razor-sharp edges that progress across it is glacially slow. Many people have died there, from stranded sailors of centuries past to wanderlust-driven tourists in recent years. Within days I had a deep sense of isolation and fragility. Without the protective blanket of civilization none of us are far from death. With precious little water and even less edible foliage, organisms eke out a precarious living, their adaptations to this harsh environment selected over millions of years. A lifelong observer of and participant in the evolution-creation controversy, I was struck by how clear it is in these islands: Creation by intelligent design is absurd. So how then did Darwin depart the Galápagos a creationist?
 
This is the question that Frank Sulloway went there to answer. Sulloway has spent a lifetime reconstructing how Darwin pieced together the theory of evolution. The iconic myth is that Darwin became an evolutionist in the Galápagos, discovering natural selection as he itemized finch beaks and tortoise carapaces, as he observed how each species had uniquely adapted to the available food and the island ecology. The legend endures, Sulloway notes, because it fits elegantly into a Joseph Campbell-like tripartite myth of the hero who (1) leaves home on a great adventure, (2) endures immeasurable hardship in the quest for noble truths, and (3) returns to deliver a deep message--in Darwin's case, evolution. The myth is ubiquitous, appearing in everything from biology textbooks to travel brochures, the latter of which inveigle potential customers to see what Darwin saw.
 
The Darwin Galápagos legend is emblematic of a broader myth that science proceeds by select eureka discoveries followed by sudden revolutionary revelations, as old theories fall before new facts. Not quite. Theories power perceptions. Nine months after departing the Galápagos, Darwin made the following entry in his ornithological catalogue about his mockingbird collection: "When I see these Islands in sight of each other, & possessed of but a scanty stock of animals, tenanted by these birds, but slightly differing in structure & filling the same place in Nature, I must suspect they are only varieties." He was seeing similar varieties of fixed kinds, not an evolution of separate species. Darwin did not even bother to record the island locations of the few finches he collected (and in some cases mislabeled), and these now-famous birds were never specifically mentioned in the Origin of Species. Darwin was still a creationist.2
 
Through careful analysis of Darwin's notes and journals, Sulloway dates Darwin's acceptance of evolution to the second week of March, 1837, after a meeting Darwin had with the eminent ornithologist John Gould, who had been studying Darwin's Galápagos bird specimens. With access to museum ornithological collections from areas of South America that Darwin had not visited, Gould corrected a number of taxonomic errors Darwin had made (such as labeling two finch species a "Wren" and an "Icterus"), and pointed out to him that although the land birds in the Galápagos were endemic to the islands, they were notably South American in character.
 
Darwin left the meeting with Gould, Sulloway concludes, convinced "beyond a doubt that transmutation must be responsible for the presence of similar but distinct species on the different islands of the Galápagos group." In Darwin's mind, the allegedly immutable "species barrier" had been shattered. That July, 1837, Darwin began his first notebook on Transmutation of Species. By 1844 he was confident enough to write in a letter to his botanist friend and colleague Joseph Hooker, "I was so struck with distribution of Galapagos organisms &c &c, & with the character of the American fossil mammifers &c &c, that I determined to collect blindly every sort of fact which cd bear any way on what are species." Five years at sea and nine years at home poring through "heaps" of books led Darwin to admit that, for him, "at last gleams of light have come, & I am almost convinced, (quite contrary to opinion I started with) that species are not (it is like confessing a murder) immutable."3
 
 
Like confessing a murder. Dramatic words for something as seemingly innocuous as a technical problem in biology: the immutability of species. But it doesn't take a rocket scientist--or an English naturalist--to understand why the theory of the origin of species by means of natural selection would be so controversial: If new species are created naturally, what place, then, for God? No wonder Darwin waited twenty years before publishing his theory.4
 
From the time of Plato and Aristotle in ancient Greece to the time of Darwin and his fellow naturalist Alfred Russel Wallace in the nineteenth century, nearly everyone believed that a species retained a fixed and immutable "essence." A species, in fact, was defined by its very essence--the characteristics that made it like no other species. The theory of evolution by means of natural selection, then, is the theory of how kinds can become other kinds, and that upset not only the scientific cart, but the cultural horse pulling it. The great Harvard evolutionary biologist Ernst Mayr stressed just how radical was Darwin's theory: "The fixed, essentialistic species was the fortress to be stormed and destroyed; once this had been accomplished, evolutionary thinking rushed through the breach like a flood through a break in a dike."5
 
The dike, however, was slow to crumble. Darwin's close friend, the geologist Charles Lyell, withheld his support for a full nine years, and even then hinted at a providential design behind the whole scheme. The astronomer John Herschel called natural selection the "law of higgledy-piggledy." And Adam Sedgwick, a...