The other day I sallied forth to the local Barnes and Noble to pick up my copy of Richard Dawkins’s new book The Greatest Show on Earth: The Evidence for Evolution. As I walked into the store I noticed a person stacking books on the main kiosk. She asked me if I was looking for something in particular.
Now, ordinarily I would have said something like, “No thanks, I’m good.” I spend so much time hanging out at Barnes and Noble, you see, that I’m pretty certain I know the layout of the store better than most of the people who work there. Besides, half the fun of browsing is all the must-have books you notice while searching for the one you are specifically looking for.
But since I am living in one of the most conservative counties in Virginia I wanted it to be heard far and wide that I was excited by the prospect of a new Dawkins book. So I replied, “Yes. I am looking for the new book by Richard Dawkins. It is supposed to come out today.”
She furrowed her brow and said something like, “I just saw it a moment ago, but now I can’t remember where. What is the title?” I replied, “The Greatest Show on Earth.” While we were talking I had scanned the main kiosk. Dan Brown’s new book was hard to miss, but there was no sign of Dawkins. I began to grow worried. My employee friend still could not quite seem to remember where she had seen the book. I began to fear it might be buried deep within the science ghetto. (The “Christian Inspiration” section is about three times larger. Groan.)
That was when she moved to the side and I noticed, almost directly behind her, a huge display given over entirely to Dawkins’s book. I smiled and said, “I think I know where you saw it.”
I was planning simply to read the book and then post a review of it. But then it dawned on me that, while the official purpose of this blog is to discuss issues related to evolution and creationism, I had never given any systematic consideration to the evidence for evolution. So how about a chapter by chapter consideration of the case for evolution as presented by Richard Dawkins? Here we go.
My intorduction to Dawkins’s writing came when I was in graduate school. I had just started to get interested in evolutionary biology, and Stepehn Jay Gould was the only contemporary evolutionary biologist with whom I was familiar. I had read his first three essay collections, and though I loved all three of them I decided it was about time to get someone else’s view of the subject. I browsed through the evolution section of the local public library and noticed a book called, The Blind Watchmaker: How the Evidence for Evolution Reveals a World Without Design. Intriguing! I checked out the book and read it. My first time through I was disappointed, since the book did not really present any evidence for evolution. To me it seemed the point of the book was to clear up certain common misconceptions about evolution, as opposed to making a case from the ground up.
So I was gratified to see, in the preface of the present book, a forthright statement that I had successfully ascertained his intent.
The relatively short Chapter One is really just an introduction. Dawkins notes that the term “theory” means different things in different contexts. In everyday language it tends to mean something pretty close to “hypothesis,” that is, a proposed explanation that is only slightly above an outright guess. But in scientific language it tends to refer to an explanatory scheme that successfully accounts for a wide array of observed facts. The germ theory of disease, for example, is surely something far more worthy of general agreement than a mere hypothesis.
As others have noted, this dichotomy can cause confusion when people discuss “the theory of evolution.” People tend to think the everyday usage is intended when it is really the scientific sense that is meant. Dawkins explains that to avoid the confusion he likes to use the mathematician’s word “theorem” to describe evolution. Just to make it clear, though, that he is not really talking about a mathematical theorem, he alters the word to, “theorum”
At first I balked at this. First he coopts our word, then he misspells it! Outrageous! But I started to soften my view when Dawkins suggested it should be pronounced to rhyme with “decorum.” That is kind of a cool sounding word. And the fact is that mathematicians do sometimes talk about “evolution equations” (roughly, they describe systems that unfold in time). If we can use his word, I suppose I can not begrudge him the use of one of our words.
There is also the fact that the real difference between “theory” and “ theorem” is that the latter carries with it the notion of proof. Theorems are proved, theories not so much. Dawkins wishes to convey that evolution ought to be granted a level of certainty that is not well-captured by the word “theory.” Okay, fair enough.
I do think, though, that Dawkins sometimes overdoes the level of certainty we ought to accord to evolution. It is very well-established indeed, and I would agree we can repose rather a lot of confidence in it. But is it really as certain as the idea that Paris is in the Northern Hemisphere? That seems a bit much.
Dawkins also includes an important discussion on the nature of inferential evidence. It is sometimes thought that eye-witness testimony is somehow the gold standard of evidence, while the circumstantial version is more suspect. Since evolution is based entirely on circumstantial evidence, some people use this as a reason to doubt it. I have had more than one creationist suggest to me that since I didn’t actually see our ape-like ancestors evolve into modern humans, I really have no basis for being confident of the idea. Dawkins quite rightly squashes that bit of silliness. He uses the familiar analogy of a detective trying to solve a crime without the benefit of an eye-witness. No one thinks the detective’s efforts will inevitably be in vain.
Finally, I can’t let this one go by:
Pythagoras’ Theorem is necessarily true, provided only that we assume Euclidean axioms, such as the axiom that parallel straight lines never meet. You are wasting your time measuring thousands of right-angled triangles, trying to find one that falsifies Pythagoras’ Theorem. The Pyhtagoreans proved it, anybody can work through the proof, it’s just true and that’s that. (p. 11)
Attributing the proof of the Pythagorean theorem to the Pythagoreans is rather like attributing the authorship of the Torah to Moses. Traditional, but historically dubious. There is the evidence that the Babylonians were familiar with it a full thousand years before the Pythagoreans arrived, and contemporaneous Chinese mathematicians were also aware of the theorem. There is also the issue of “parallel lines never meet” being one of Euclid’s axioms. That is a bit of a simplification, to put it kindly.
Of course, were I now to follow the example of some of The God Delusion‘s more hyperbolic reviewers, I would at this point dismiss the book out of hand, declare that Dawkins is comepletely out of his depth, and protest that he has no business discussing the history of mathematics without first reading a few dozen texts on the subject.
I will resist the temptation, however, and move gamely on to Chapter Two.