Å·±¦ÓéÀÖ

Having thoroughly enjoyed Dawkins� outstanding The Selfish Gene, my initial impression of The Blind Watchmaker was a bit of a letdown. Dawkins wrote the book to counter creationist thinking, but for a firm believer in Darwinian evolution, his lengthy arguments were unnecessary. However, if Dawkins converted any creationists, I would consider the book a great success. With that said, there were a number of things I did like. Below are some items that caught my attention.

Darwin’s concept of gradual evolution overturned the ideas of the catastrophists, who believed the earth and its creatures were formed by sudden drastic changes. Gradual evolution was then challenged by saltationists who believed large genetic changes or macro-mutations could explain much of evolution. A more refined view is that of Stephen Jay Gould who posited punctuated equilibrium. This view recognized varying rates of change, periods of relative stasis with intervals of rapid modification. Keep in mind rapid was on a geologic time scale where 50,000 years is a short time. Thus Gould’s rapid change could still have evolved step-by-step in line with Darwin. The effect of gradualism that struck me was the notion that speciation is contingent on the demise of intermediate individuals. Otherwise one could not tell where one species began and another ended.

An upshot of Dawkins� idea concerns our own connection with our ancestors. The view of chimpanzees as property is made more acceptable because there are no living intermediaries that show our close relationship. This made me wonder how Neanderthals would be treated if some were found alive. Would they be treated like chimpanzees as a different species? Since they are beings who can successfully interbreed with Homo sapiens, would they be given the same rights? Would Christians consider them as individuals with souls that should be saved?

I enjoyed Dawkins explanation of the development of the eye in support of gradualism. The book’s title comes from a pre-Darwin argument that if one found a watch, one would have to assume someone made it. The watch is too intricate to have formed naturally. Post-Darwin, like the watch, some held that the eye was so complex as to defy gradual evolution. Dawkins counters. He takes us from a cell with a light sensitive spot to a creature with several such cells that is helped by this sense of light or dark. Then if the light sensitive cells are recessed, the creature can tell the direction of the shadow. If the recess takes on a cuplike shape, this sense of the light’s direction is enhanced. Next if the walls of the cup build up and protrude partially over the cup, a pinhole camera is formed casting an image on the cup. Then, protecting the cup by extending a membrane over the pinhole forms a lens. And so on�

I enjoyed the section on bats and echolocation. Dawkins also offers a reasonable explanation of how this seemingly amazing ability could develop. Dolphins, whales and some birds have independently developed this use of sound showing such development not to be quite as extraordinary as one might think. Dawkins pondering of how bats experience this sense I found fascinating. Do the nerve impulses get mapped by the brain to a model similar to the one we experience as vision? And then there is the fish that senses its environment from disruption to an electrical field � elctrolocation. How is this sense perceived?

Another intriguing topic was how sexual selection augments natural selection. Unlike environmental factors which wax and wane in intensity, sexual selection forms a positive feedback loop. A female bird’s preference for long tails in her mate not only promotes the gene for long tails but the gene for the desire for long tails. As both genes proliferate tails will grow longer until a practical limit is reached. The bird still has to be an able flyer to survive. One’s mind quickly turns to how this idea works in humans.

This book will mean different things to different readers. Every creationist should read it although I suspect few will. For the rest of us, the book is still worthwhile just to get Dawkins� unique views on odd and end topics, a few of which I covered. If you get bored reading why creationism is wrong, keep in mind the book is written to be easily read, so you can get through those sections quickly.