Why Darwin Matters: Excerpt
Prologue — Why Evolution Matters:
What is at Stake in the Evolution-Creation Controversy
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.
In June of 2004, Frank Sulloway and I began a month-long expedition to retrace Charles Darwin’s footsteps in the Galapagos Islands. It turned out to be one of the most physically grueling experiences of my life, and having raced a bicycle across America five times that is saying something special about what the young British naturalist was able to accomplish there 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 isn’t long before 70-pound water-loaded packs begin to buckle knees and strain backs. Add hours of daily bushwacking 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 from the tents that had accumulated the night before. One day I sliced my left shin on a chunk of a’a lava, whose edges are like broken glass. Another day I was stung by a wasp that caused my face to nearly double in size. At the end of one particularly grueling climb through a moonscape-like 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 hither and yon. The vegetation is coarse and scrappy. Dried and shriveled cacti trunks dot the bleak lava landscape that is so broken with razor sharp edges that moving across it is glacially slow. Many people have died there, from stranded sailors of centuries past to wanderlust tourists of 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 eatable foliage, organisms eek 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. Why, then, did Darwin depart the Galápagos a creationist?
This is the question that Sulloway went there to answer. A historian of science and Darwin scholar, Frank 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 when he discovered natural selection operating on finch beaks and tortoise carapaces, each species uniquely adapted by food type or island ecology. The legend endures, Sulloway notes, because of its elegant fit into a Joseph Campbell-like tripartite myth of the hero who
- leaves home on a great adventure (Darwin’s five-year voyage on the Beagle),
- endures immeasurable hardship in the quest for noble truths (Darwin suffered seasickness and other maladies), and
- returns to deliver a deep message (evolution).
The myth is ubiquitous, appearing in everything from biology textbooks to travel brochures, the latter of which inveigle potential customers to come walk in the footsteps of Darwin.
The Darwin Galápagos legend is emblematic of a broader myth that science proceeds by select eureka discoveries followed by sudden revolutionary revelations, where old theories fall before new facts. Not quite. Paradigms power percepts. Nine months after departing the Galápagos, Sulloway discovered, 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.” Similar varieties of fixed kinds, not evolution of separate species. Darwin was still a creationist! This explains why Darwin did not even bother to record the island locations of the few finches he collected (and in some cases mislabeled), and why these now-famous birds were never specifically mentioned in the Origin of Species.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 his 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 “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. The supposedly immutable ‘species barrier’ had finally been broken, at least in Darwin’s own mind.” That July, 1837, Darwin opened his first notebook on Transmutation of Species. By 1844 he was confident enough 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 pouring through “heaps” of books led Darwin to admit: “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 on the origin of species by means of natural selection would be so controversial: if new species are created naturally — not supernaturally — 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 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 geologist and Anglican cleric, proclaimed that natural selection was a moral outrage, and penned this ripping harangue to Darwin:
There is a moral or metaphysical part of nature as well as a physical. A man who denies this is deep in the mire of folly. You have ignored this link; and, if I do not mistake your meaning, you have done your best in one or two cases to break it. Were it possible (which thank God it is not) to break it, humanity, in my mind, would suffer a damage that might brutalize it, and sink the human race into a lower grade of degradation than any into which it has fallen since its written records tell us of its history.
In a review in Macmillan’s Magazine, Henry Fawcett wrote of the great divide surrounding On the Origin of Species: “No scientific work that has been published within this century has excited so much general curiosity as the treatise of Mr. Darwin. It has for a time divided the scientific world with two great contending sections. A Darwinite and an anti-Darwinite are now the badges of opposed scientific parties.”6
Darwinites and anti-Darwinites. Although the scientific community is now united in agreement that evolution happened (most scientists, however, eschew such labels as Darwinian or neo-Darwinian), a century and a half later the cultural world is still so divided. According to a 2005 poll by the Pew Research Center: 42 percent of Americans hold strict creationist views that “living things have existed in their present form since the beginning of time” while 48 percent believe that humans “evolved over time.” More to the point of why evolution has been in the news of late, the survey also found that 64 percent said they were open to the idea of teaching creationism in addition to evolution in public schools, while 38 percent said they think evolution should be replaced by creationism in biology classrooms.7
The evolution-creationism controversy is a cultural tempest in a scientific teapot — much ado about nothing as far as scientists are concerned, but much ado about everything as far as everyone else knows. Consider the geographic and political differences in attitudes about evolution, starting with the fact that evolution is controversial only in America (there are a few small creationist pockets in Australia, New Zealand, and the U.K., but they are politically impotent). And within the states, geography matters: 51 percent of southerners accept the strict creationist view that humans were created as we are now and only 19 percent believe that we evolved through natural selection, while 59 percent of northerners accept evolution through natural selection, and only 32 percent are creationists.
Given these demographics of belief, it came as no surprise to both conservatives and liberals when President George W. Bush endorsed the teaching of Intelligent Design in public school science classes. Or did he? When this story broke the first week of August, 2005, there was considerable media hype and I did a number of interviews, including a live debate on CNN with lead Intelligent Design (ID) theorist William Dembski. As the story unfolded over the next two weeks, however, I discovered that the creationists, along with many in the media and pundits on both the right and the left, greatly exaggerated Bush’s remarks. Here is what actually happened.
On Monday, August 1, Bush gave an interview at the White House to a group of Texas newspaper reporters in which he said that when he was governor of Texas “I felt like both sides ought to be properly taught.” When a reporter asked for his position today, Bush equivocated: “I think that part of education is to expose people to different schools of thought. You’re asking me whether or not people ought to be exposed to different ideas, and the answer is yes.” Well of course, but that’s a different question.
So, the boast by conservative Christians, along with complaints by liberals that President Bush endorses Intelligent Design, is exaggerated. In fact, Bush’s science adviser, John H. Marburger 3rd, said in a telephone interview with the New York Times the next day that “evolution is the cornerstone of modern biology” and “intelligent design is not a scientific concept.” He added that the president’s comments should be interpreted to mean that ID be discussed not as science but as part of the “social context” in science classes, and that it would be “over-interpreting” Bush’s remarks to conclude that the president believes that Intelligent Design and evolution should be given equal treatment in public school science curriculum.8
These political machinations are interesting from a sociological perspective, and such polling data reveal a lot about the psychology of belief, but truth in science is not determined vox populi. It does not matter whether 99 percent or only 1 percent of the public (or politicians) accepts a scientific theory — the theory stands or falls on evidence, and there are few theories in science that are more robust than the theory of evolution. It took me a long time to realize this fact, for I began my career as a creationist. Saying this today almost feels like confessing a murder.
Like Confessing a murder. Like Darwin, that is precisely how I felt when I realized that my creationist beliefs were wrong and that evolution actually happened. I was a creationist from the time I became a born-again Christian in high school in 1971, through graduate school in 1977.9 The evangelical movement was just gathering momentum in the 1970s, and one of the central dogmas I took from it was that the biblical story of creation was to be taken literally; ergo, the theory of evolution had to be wrong.
Knowing next to nothing about evolution other than what I gleaned from reading creationist literature, I absorbed the arguments against the theory and practiced them on my undergraduate science and philosophy teachers. At Glendale College, where I attended for the first two years for General Education requirements, my debating skills were honed as my creationist arguments were met with firm evolutionist counterarguments. At Pepperdine University, a Church of Christ institution where I finished my undergraduate degree, evolution was a nonentity as I witnessed for Christ and studied the theological underpinnings of the Christian faith. When I arrived at Pepperdine, in fact, I considered theology as a profession, but when I discovered that a doctorate required proficiency in Hebrew, Greek, Latin, and Aramaic, and knowing that foreign languages were not my strong suit (I struggled through two years of high school Spanish), I switched to psychology and mastered one of the languages of science: statistics. By the time I matriculated at the California State University at Fullerton for graduate training in experimental psychology, I was ensconced in the ways of science.
In science, there are ways to get at solutions to problems for which we can establish parameters to determine whether a hypothesis is probably right (such as rejecting the null hypothesis at the 0.01 level of significance) or definitely wrong (not statistically significant). Instead of the rhetoric and disputation of theology, there was the logic and probabilities of science. What a difference this difference in thinking makes. In graduate school, I took a bevy of courses in research methods and statistics, and for recreation I signed up for a Tuesday evening course in evolution, just to see what creationists were up in arms about. The course was taught by an eccentrically charismatic biologist named Bayard Brattstrom, who from 7–10 pm regaled us with breathtaking discoveries from the science of evolutionary biology, and who from 10pm to closing time at the 301 Club just down the street, held forth on science and religion, Darwin and Genesis, and all manner of related topics, accompanied by appropriate libations.
The scales fell from my eyes! It turns out that the creationist literature I was reading presented a Darwinian cardboard cutout that a child could knock down. What I discovered was that the preponderance of evidence from numerous converging lines of scientific inquiry — geology, paleontology, zoology, botany, comparative anatomy, molecular biology, population genetics, biogeography, embryology, and others — all independently converge to the same conclusion: evolution happened. Why Darwin Matters is about how we know evolution happened, in the context of challenges to the theory mounted by creationists and Intelligent Design theorists.
Why does evolution matter? The influence of the theory of evolution on the general culture is so pervasive it can be summed up in a single observation: we live in the age of Darwin. Arguably the most culturally jarring theory in the history of science, the Darwinian revolution changed both science and culture in ways immeasurable:
- The static creationist model of species as fixed types, replaced with a fluid evolutionary model of species as ever-changing entities.
- The theory of top-down intelligent design through a supernatural force, replaced with the theory of bottom-up natural design through natural forces.
- The anthropocentric view of humans as special creations above all others, replaced with the view of humans as just another animal species.
- The view of life and the cosmos as having design, direction, and purpose from above, replaced with the view of the world as the product of bottom-up design through necessitating laws of nature and contingent events of history.
- The view that human nature is infinitely malleable and primarily good, replaced with the view of a constraining human nature in which we are good and evil.10
In the memorable observation by Theodosius Dobzhansky: Nothing in biology makes sense except in the light of evolution.11
Darwin matters, not only because his theory changed the world and reconfigured our position in the cosmos, but because he was such a brilliant, creative, and thoughtful man. As Shakespeare wrote of another giant from another era (in Julius Caesar):
The elements So mix’d in him,
that Nature might stand up
And say to all the world,
“this was a man!”
- We were accompanied on this expedition by botanist Phil Pack, snail specialist Robert Smith, explorer Daniel Bennett, and medical engineer Chuck Lemme.
- Sulloway’s historical reconstruction of the development of Darwin’s evolutionary thinking can be found in a number of papers: “Darwin and His Finches: The Evolution of a Legend.” Journal of the History of Biology, 15 (1982):1–53. “Darwin’s Conversion: The Beagle Voyage and Its Aftermath.” Journal of the History of Biology, 15 (1982):325–96. “The Legend of Darwin’s Finches.” Nature, 303 (1983):372. “Darwin and the Galapagos.” Biological Journal of the Linnean Society, 21 (1984):29–59.
- Letter to Joseph Hooker dated January 14, 1844, quoted in Browne, Janet. 1995. Voyaging: Charles Darwin. A Biography. New York: Knopf, p. 452.
- Darwin would have waited even longer had he not rushed into print for priority sake because the naturalist Alfred Russel Wallace had sent Darwin his own theory of evolution the year before. For a detailed account of the “priority dispute” between Darwin and Wallace, see: Shermer, Michael. 2002. In Darwin’s Shadow: The Life and Science of Alfred Russel Wallace. New York: Oxford University Press.
- Mayr, Ernst. 1982. Growth of Biological Thought. Cambridge: Harvard University Press, p. 495.
- All quotes on the reaction to Darwin’s theory in: Korey, K. 1984. The Essential Darwin: Selections and Commentary. Boston: Little, Brown.
- Interestingly, a sizable 41 percent believe that parents, rather than scientists (28 percent) or school boards (21 percent) should be responsible for teaching children about the origin and evolution of life. Pew survey data: http://people-press.org/reports/display.php3?ReportID=254
- Bumiller, Elisabeth. 2005. “Bush Remarks Roil Debate on Teaching of Evolution.” New York Times, August 3. Available at: www.nytimes.com/2005/08/03/politics/03bush.html?ex=1128484800&en=ed4097f35b6c999c&ei=5070
- I have written about this at length in: Shermer, Michael. 1999. How We Believe: Science, Skepticism, and the Search for God. New York: Henry Holt/Times Books
- Adopted and paraphrased from: Mayr, Ernst. 1982. The Growth of Biological Thought. Cambridge: Harvard University Press, p. 501.
- Dobzhansky, Theodosius. 1973. “Nothing in Biology Makes Sense Except in the Light of Evolution.” American Biology Teacher, 35: 125–129.