Book Review

The Greatest Show on Earth: The Evidence for Evolution

by Richard Dawkins

Free Press 2009

About midway through this page-turner by Richard Dawkins, the author tells the story of a scientist who is chatted up by a fellow as they travel together in one of humankind's most amazing inventions, the airplane. These passengers don't know each other from Adam. They sit next to one another because of some chance seating assignment by an unknown agent. The non-scientist asks the scientist what he does and soon the non-scientist is visibly engrossed and excited by the work the scientist is doing on tadpoles in ponds. The conversation ends abruptly and the non-scientist turns away in disgust and sinks into a frozen silence when the scientist, in response to a question, tells the non-scientist that he is working on a way to demonstrate Darwin's theory of natural selection. Any theory but that theory and the conversation may have continued in lively fashion until the plane landed. For some people, evolution is a conversation stopper, a deal breaker, a non-starter. To me, this is the saddest fact to emerge from the proselytizing of the young Earth creationists.

This is the book many high-school biology teachers (and their students!) in the U.S. need to supplement the bowdlerized and stripped-down versions approved by local school boards in their effort to keep our children safe from the truth about evolution. This is a book of evidence and patient explanation. It is book of sophisticated ideas written in a simple, elegant style for the general reader.* It is not a book of proselytizing, though the author is compelled to address creationists from time to time because of the 40% of Americans (and a growing number in the U.K. and Australia), not to mention the majority of Muslims in Islamic countries and others around the world, who think the Earth is less than 10,000 years old and a Creator made all the species one by one.

facts and theories

Before getting to the evidence for evolution, Dawkins paves the way with several preliminary chapters, the first of which concerns the concepts of facts and theories and their relationship to each other. The title of the chapter, "Only a Theory," is taken from a common refrain from creationists who oppose evolution. Evolution, they say, is only a theory. The implication, sometimes stated, sometimes not, is that evolution is not a fact. Dawkins tries to explain what it means to say that evolution is a theory and what it means to say that evolution is also a fact. Others have tried this. Stephen Jay Gould, for example, pointed out that in the biological sciences evolution is considered a fact that can be denied only by those perversely averse to evidence, while theories like natural selection are explanations of the facts. Dawkins takes a similar tack.

Because of the ambiguity of the word 'theory,' Dawkins proposes a new word ('theorum') to be used to refer to theory in the sense of 'an explanation that has been confirmed or established by observations or experiment, and is propounded or accepted as accounting for the known facts." He tries to distinguish 'theorum' from the other meaning of theory, a hypothesis proposed as an explanation; a speculation or conjecture. He tries to keep 'theorum' in line with the first definition of 'theory given in the OED, but even that definition is misleading because it is easy to confuse 'observation' with 'direct observation.' This confusion leads to the mistaken belief that direct observation, or eyewitness testimony, is superior to inference from the observed facts. Dawkins doesn't go into the details but there is an abundance of evidence demonstrating that while eyewitness testimony is the most convincing to the average person, it is much less reliable than solid inferential reasoning. Dawkins uses the compelling example of the superiority of DNA evidence to eyewitnesses of crimes to hammer home the point that inference, if done properly, can lead to conclusions that are certain beyond any reasonable doubt. (See the Innocence Project for many examples of the superiority of inference to direct observation.) So, to the creationist who gloats in the fact that they don't see humans coming out of monkeys, and think this counts as evidence against evolution, Dawkins has two replies. One, no evolutionist ever thought a human came out of a monkey (the species share a common ancestor), and, as a matter of fact, evolution does occur before our very eyes. Chapter five is devoted to providing the evidence for that claim.

As noted above, Dawkins doesn't go directly to the evidence for evolution. Before getting to the heart of the evidence, he first explains artificial selection with examples from the breeding of dogs and flowers. The hardest thing for creationists to understand, apparently, is that while we divide all living things into species, we're all related. Looking at us from the outside, you wouldn't think there is much similarity between a human and a snail or a redwood, but there is. If we look carefully at the internal structure of organisms there is a great revelation awaiting us. Looked at internally, at the molecular level, especially at the level of genes, there is a profound similarity among humans, chimpanzees, monkeys, horses, koalas, lizards, potatoes, primroses, bacteria, fungi, and coral reefs. The glorious variety of diverse species is a manifold that has emerged over millions of years of evolution from a common ancestor. Whether you believe God created that common ancestor or believe that some natural process led up to it, you must be senseless not to be overwhelmed by the grandeur of it all.

on closer inspection

The theme of how different things look when inspected  more closely is one that runs throughout Dawkins's book. The different view one gets about evolution from looking at creatures internally versus externally is just one example. The fossils offer a different view from comparative anatomy, which in turn offers a different view from molecular biology. He describes how things look to an insect (science has ways to "see" things in the ultraviolet range that normal vision can't see) and why this is important for natural selection. He reminds us how messy is the patchwork of our internal organs. We may seem elegantly designed to the careless eye that examines only the superficial aspects of our bodies, but we appear to be a botch job to anyone who examines us closely with a design engineer's sensitivity. The eye used to be a favorite model for those defending intelligent design. Now that we know more about the eye, it looks more like the design of "a complete idiot" (p. 354). The eye is good at seeing not because it is elegantly designed, but "because natural selection, working as a sweeper-up of countless little details, came along after the big original error of installing the retina backwards, and restored it to a high-quality precision instrument." Other examples of things that look intelligently designed until one examines them carefully are well-known but are described by Dawkins in fresh ways: the human birth canal, our spines not quite made for upright existence, the recurrent laryngeal nerve (the poor design is more evident in giraffes, of course, than in humans), the vas deferens, the sinus passage, and the pouch of the koala (which opens on the bottom because they are descended from a wombat-like creature that was a digger, not a climber).

the evidence for evolution

If you think you know the evidence for evolution but think evolution is false, you should read this book. Otherwise, you are like the priests who wouldn't look through Galileo's telescope because they already knew that heavenly objects were perfect. We don't need to look, they said, any imperfections you think you see must be due to imperfections in your lens or to clouds or other objects between here and there. The evidence for evolution is massive and will provide you with an opportunity to defend your belief in a young Earth and direct creation of species by a Creator. Think of the challenge. You could write a book called the Evidence for Creation that would be based on a response to the actual evidence rather than to the straw men that so many creationists are fond of attacking.

On the other hand, if you think you know the evidence for evolution and accept that evolution is a fact and that natural selection is the best explanation for the facts, do yourself a favor and read this book. It is an elegant reminder of how grand and terrible the planet is that you live on.

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* Well, there are a couple of exceptions. My favorite is on p. 227: "In neurulation, as in gastrulation, invagination is much in evidence."

See also The Creationist Delusion (in Newsletter v 8 no. 10)

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Read an excerpt from chapter one. Here Dawkins compares the anti-evolution creationists (whom he calls history deniers) to an imaginary group that denies the existence of the ancient Roman empire. Imagine the waste of time facing a teacher of Roman history in such a circumstance. That's what biology teachers in the U.S. face today.