The Origin of Species

I recently finished reading one of the most famous scientific works of the modern age, Charles Darwin's The Origin of Species. I'm not sure what I was expecting, but I'll have to say it is a pretty impressive piece of scholarship. His prose is generally quite readable, though some parts are rather slow going, especially towards the beginning where he goes into fairly exhaustive detail about his and others research with pigeons and various plants. Still, the general reader (assuming a modicum of intelligence and education) will have no problem following the majority of it. His arguments are very well laid out, and I was particularly impressed by his effort to anticipate all the possible objections to his theory, and do so in a very modest way ("a crowd of difficulties will have occurred to the reader..."; "objections which might be justly urged against the views maintained in this volume..."). He discusses his theory from almost every possible angle, and even given that we know far more now than we do then (he didn't know about genetics or DNA, for example), his arguments are still very much valid -- if anything, many have since been strengthened by later research.

Perhaps a brief recapitulation of Darwin's theory is in order. Briefly put, variations are common among individuals of all species, and all of these individuals engage in a struggle for existence, both with members of their own species and with other species. If some variations among individuals prove advantageous in the struggle for existence, they will tend to be preserved among later generations, and by a slow, gradual process will accumulate to the point that new species arise. Darwin called this "Natural Selection", in something of analogy with artificial selection used by humans in breeding dogs, horse, pigeons and other animals and plants (the term "survival of the fittest" did not originate with Darwin, though he did add an approving reference to it into later editions of The Origin of Species).

Darwin explains how, given sufficient time, natural selection (or evolution, as we would say now -- Darwin didn't use this word either, though the very last word in his book is the verb form of it, "evolve") can cause varieties to develop within a particular species, and how these varieties can eventually differentiate into separate species (he points out that in his day there were many cases where naturalists, i.e., biologists, couldn't agree whether a particular form was a variety or a species -- a situation that still arises often today -- illustrating that species are simply more clearly defined varieties). He shows that natural selection can even create such specialized organs as wings or eyes, though he acknowledges that this is counter-intuitive, saying "to suppose that the eye, with all its inimitable contrivances..., could have been formed by natural selection, seems, I freely confess, absurd in the highest possible degree." But, as he explains, what seems impossible at a glance can be shown to be very much possible.

Darwin then goes on to discuss the geological record, which as he points out is very incomplete and therefore cannot be expected to show every step in the evolutionary process. What it does show, however, tends to support his theory. He also spends two chapters discussing geographic distribution, including issues such as how two widely separated areas can end up with the same species living in them, how various plants could have been transported to islands (he did a number of experiments with seeds showing that many of them can survive for long periods in salt water), and so forth.

Finally he talks about how groupings of different species and morphology provide evidence for evolution. For example, the reason different kinds of felines (lions, tigers, and other cats) are similar in many ways, having particular features in common, is because they are in fact related to each other. He makes the point that a given modern species will not be descended from any other related modern species, but the two will have a common ancestor, one which will be in a certain sense intermediate between the two, but not exactly intermediate, just as a grandparent of two cousins will have certain features that both cousins have inherited, some that were inherited by only one, and others that neither has. This is why people who think that evolution means humans "descended from apes" have clearly failed to grasp the concept. People are not descended from any of the modern apes; rather, we all have a common ancestor, one which in some ways resembled apes, in other ways resembled humans, but in yet others neither (it is worth noting, however, that in The Origin of Species Darwin does not talk about humans, simply leaving readers to draw their own conclusions about what his theory means for human origins -- though he did address the subject in a later book).

As mentioned above, Darwin does a good job of anticipating objections to his theory and explaining why they are not fatal to it, as well as showing that his theory is the best explanation for many of the things we observe in nature. He spends little time attacking the traditional view, except for a pointed passage in the final chapter, which he concludes by saying "although naturalists very properly demand a full explanation of every difficulty from those who believe in the mutability of species, on their own side they ignore the whole subject of the first appearance of species in what they consider reverent silence." As he says, this refusal to even discuss the details of their own ideas is not scientific: "it is so easy to hide our ignorance under such expressions as the "plan of creation," "unity of design," etc., and to think that we give an explanation when we only restate a fact." As The Origin of Species clearly shows, natural selection is the only theory that provides a real explanation for why life on Earth exists in the forms that it does, a fact that is if anything even more true today than it was in Darwin's time.

One minor quibble I had with the book had nothing to do with the content, and may not even have been Darwin's fault, namely the excessive use of commas. There are many commas that obviously don't belong, particularly before restrictive clauses. I don't know if Darwin himself put them there (perhaps people tended to use more commas in his day?) or if it is a problem with the particular edition that I read. However, this takes nothing from the value of the work as a whole.

While I wouldn't necessary recommend The Origin of Species to anyone who is looking for an entertaining read, I would certainly recommend it to anyone who wants a fuller understanding of the theory of evolution, or to anyone who is interested reading a master work in the history of science. By all accounts, this is probably the most accessible of all the great, revolutionary science books, certainly more so than books like Isaac Newton's Prinicipia Mathematica, which is said to be almost unintelligible to all but a few. Certainly anyone who presumes to attack Darwin and his theory should at least make the effort to understand what he actually said, though as he himself stated, people with preconceived notions about such things are not likely to be swayed by any arguments, no matter how rational or how clearly in accordance with the facts they are.