Books discussed in this essay

Richard Dawkins, "The Blind Watchmaker: Why the Evidence of Evolution Reveals a Universe Without Design" (Norton, 349 pp.; $10.95, paper, 1987 [first published 1986]).

Richard Dawkins, "River Out of Eden: A Darwinian View of Life" (Basic, 172 pp.; $20, 1995).

Phillip E. Johnson, "Darwin on Trial," 2d. ed. (InterVarsity, 195 pp.; $10.95, paper, 1993).

Phillip E. Johnson, "Reason in the Balance: The Case Against Naturalism in Science," Law and Education (InterVarsity, 245 pp.; $19.99, 1995).

Richard Dawkins is absolutely confident that science will finally accomplish what philosophy has been unable to do in more than 2,000 years--make theism intellectually indefensible.

Dawkins, a fellow of New College at Oxford University and the author of several best-selling expositions of Darwinism, acknowledges that prior to Darwin, philosophers who rejected belief in a divine creator had no good explanation for the order and complexity of living organisms. An atheist like David Hume could only say to a theist: "I have no explanation for complex biological design. All I know is that God isn't a good explanation, so we must wait and hope that somebody comes up with a better one." According to Dawkins, Darwin supplied that better explanation and "made it possible to be an intellectually fulfilled atheist."

Dawkins is quite explicit that Darwinism is more than simply a scientific theory. In the preface to his most recent book, "River Out of Eden: A Darwinian View of Life" (the title is taken from Genesis 2:10), Dawkins writes,

Not only does the Darwinian theory command superabundant power to explain. Its economy in doing so has a sinewy elegance, a poetic beauty that outclasses even the most haunting of the world's origin myths. One of my purposes in writing this book has been to accord due recognition to the inspirational quality of our modern understanding of Darwinian life. There is more poetry in Mitochondrial Eve than in her mythological namesake.

Indeed, Dawkins is a forceful and persuasive advocate of Darwinism precisely because he does not belittle the order and complexity of the natural world that theists point to as evidence of a creator. In "The Blind Watchmaker: Why the Evidence of Evolution Reveals a Universe Without Design," Dawkins attempts to better William Paley's description of the marvelous complexity of the human eye by describing the incredible engineering wonders that make it possible for bats to "see" with their ears. Dawkins insists, however, that the "good design" seemingly apparent in human eyes and bat ears is, in fact, the product of cumulative selection working on random errors in the genetic code.

The notion of cumulative selection is at the heart of Dawkins's argument. He agrees with many theists who argue that the odds against atoms bouncing around in the void and by chance arranging themselves into a human eye or a bat's ear are too astronomical to be taken seriously. Of course, pre-Darwinian atheists like Hume argued that in an infinite amount of time anything is possible. But while this argument might satisfy a philosopher, Dawkins does not think such a response will ever satisfy one who has spent much time examining the amazing complexities of nature.

To explain such wonders it is necessary, he says, that we understand the power of cumulative selection. Cumulative selection is simply the ability of living organisms to transmit to their progeny useful errors in the genetic code while weeding out those that are harmful to the organism. While the errors in the genetic code are wholly random, the selection of small but useful changes is not random. This is the all-important difference between Humean and Darwinian explanations of biological complexity. To illustrate this difference, Dawkins considers a single line from Shakespeare's Hamlet: "Methinks it is like a weasel." The odds against a monkey producing this sentence by randomly hitting keys on a typewriter, Dawkins calculates, are "about 1 in 10,000 million million million million million million. To put it mildly, the phrase we seek would be a long time coming, to say nothing of the complete works of Shakespeare." Since a single cell is vastly more complex than this line from Shakespeare, Dawkins says that it is simply not reasonable to believe that organic cells evolved by chance in a single step.

But suppose a computer starts with a random sequence of 28 letters (the number of letters in the sentence from Hamlet, counting each space between words as a "letter") and duplicates the sequence repeatedly, but with a certain chance of random error (or "mutation") in the copying. The computer examines the mutant nonsense phrases, the progeny of the original phrase, and chooses the one that, however slightly, most resembles the target phrase ("Methinks it is like a weasel"). Or, to use a familiar game analogy, consider the difference in the odds between rolling five dice in three tries so they all are sixes and rolling a Yahtzee--five sixes in three tries but now allowing the player to select and keep any of the dice that serve his purpose and rethrowing the others. When Dawkins wrote a program to play computer Yahtzee with "Methinks it is like a weasel" as its goal, his computer came up with the winning combination in only 43 tries.

Now there is an obvious objection to this analogy that Dawkins anticipates. While the processes inside the computer may have been random, the target phrase was supplied by Dawkins himself, not random chance. Therefore, following the analogy, if evolution is to work, it must have a target or goal supplied by an intelligent being--not a happy conclusion from Dawkins's point of view, since he says that evolution has no long-term goal and no controlling intelligence.

To circumvent this objection, Dawkins wrote a computer program in which extremely simple stick figures randomly evolve into complex figures. Using the principle of cumulative selection, within a period of only 30 to 40 generations, amazingly lifelike pictures evolve of everything from jumping spiders to a man wearing a hat. And in this case, there never was a preselected target. This illustrates in Dawkins's mind how evolution can proceed without any goal other than the survival of the individual organism.

But this leads to a second objection. To speak of an organism's survival presupposes the existence of creatures able to reproduce. "The theory of the blind watchmaker is extremely powerful," says Dawkins, "given that we are allowed to assume replication and hence cumulative selection" (emphasis added). Dawkins realizes that this is a big assumption because he has already told us that the complexity necessary for even a single cell to replicate itself is much greater than the odds against the chance creation of a single hemoglobin molecule or "1 with 190 noughts after it!" To which he adds, "And a hemoglobin molecule has only a minute fraction of the complexity of a living body." In other words, cumulative selection can only provide a naturalistic explanation of the complexity if replicators exist. But cumulative selection cannot, without arguing in a circle, explain the existence of primitive replicators, which are themselves astronomically complex.

At this stage, Dawkins admits that "we cannot escape the need to postulate a single-step chance event in the origin of the cumulative selection itself." While Dawkins believes the number of planets in the universe is large enough to make this single-step chance event sufficiently probable so as to have happened on at least one planet (ours), he does not hide the speculative nature of his argument at this point. "This chapter has had," he writes, "the modest aim of explaining only the kind of way in which it [the origin of life] must have happened." In other words, when it comes to the origin of life1, even Dawkins relies on philosophical arguments: Well, I don't know how life originated, but I know God isn't a good explanation.

If Dawkins represents Darwinian orthodoxy, Phillip Johnson is the Darwin establishment's most prominent critic. Johnson, a professor of law at the University of California, Berkeley, entered the evolution debate with the bestseller "Darwin on Trial." He resembles Dawkins in his ability to present his views clearly and persuasively to a large audience.

Johnson says that he approaches "the creation-evolution dispute not as a scientist but as a professor of law, which means among other things that I know something about the ways that words are used in arguments." Now one of the first things lawyers learn is that the burden of proof falls on the prosecution, not the defense. Though the title "Darwin on Trial" is ambiguous, Johnson assumes the role of a defense attorney: he does not attempt to prove theism to be true; he only attempts to show that Darwin's case against theism is unproven. He objects that the National Academy of Science's "rule against negative argument automatically eliminates the possibility that science has not discovered how complex organisms could have developed. However wrong the current answer may be, it stands until a better answer arrives. It is as if a criminal defendant were not allowed to present an alibi unless he could also show who did commit the crime."

Further, the Academy of Science rules out a priori supernatural explanations as antithetical to the scientific method. Its position is "heads I win, tails you lose." If theists provide a supernatural explanation for biological complexity, naturalistic scientists rule such an explanation out of court. On the other hand, if creationists limit themselves to pointing out weaknesses in the evolutionists' arguments, evolutionists complain that creationists have no positive account to explain the evidence.

Johnson's frustration with the academy is understandable given his reliance on Karl Popper's philosophy of science. The last chapter of Darwin on Trial, "Science and Pseudoscience," begins by asserting that "Karl Popper provides the indispensable starting point for understanding the difference between science and pseudoscience." According to Popper, the mark of real science is that it makes risky predictions that open its theories to the possibility of falsification. Pseudoscientific theories, such as those of Marxists and Freudians, are formulated in such a way that no matter what occurs, they win. As Johnson wittily summarizes, "If wages fell this was because the capitalists were exploiting the workers, as Marx predicted they would, and if wages rose this was because the capitalists were trying to save a rotten system with bribery, which was also what Marxism predicted. A psychoanalyst could explain why a man would commit murder--or, with equal facility, why the same man would sacrifice his own life to save another." Such "heads I win, tails you lose" arguments clearly deserve the label "pseudoscience."

So is the Academy of Science's defense of evolution itself a species of pseudoscience? The issues raised here go to the very heart of much-debated questions in the philosophy of science. One event in the history of science illustrates the problem.

By the late nineteenth century, Newtonian physics reigned without rivals. So much was this the case, that when slight irregularities (from the Newtonian point of view) in the orbit of Uranus were observed by astronomers, they refused to believe that Newton's theory was false, or even in need of correction. Instead, they calculated where and how big a heretofore unobserved planet would have to be in order to account for the irregularities of Uranus's orbit. Shortly thereafter, astronomers pointed their telescopes to the predicted location and were rewarded with the discovery of Neptune.

A short time later, similar irregularities in the orbit of Mercury were observed. Following the same procedures, theoretical astronomers calculated where the missing planet would have to be according to Newton. Given the previous successes of Newtonian physics, it did not seem to be an act of hubris when the missing planet was given a name, Vulcan, before it was ever observed.2

But this time, there was a difference. Observations never revealed another missing planet. However, this "negative evidence" was not considered either a reason to stop looking for Vulcan or proof that Newton's theories were imperfect until Einstein came up with an alternative naturalistic explanation for Mercury's irregularities.

It is events such as this in the history of science that have led to the negative-evidence rule and the requirement that naturalistic alternatives be provided. Philosophically speaking, it is not obvious that the Academy of Science has stacked the deck in its favor. After all, as physicist Owen Gingerich observes, "science's great success has been in the production of a remarkably coherent view of nature rather than in an intricately dovetailed set of proofs."3 Though followers of Popper had hoped to discover a clean demarcation between the sciences and philosophy, cases like this have led most scientists and philosophers to conclude that the division between cutting-edge science and difficult philosophical questions--such as whether the universe is the result of chance or design--is pretty fuzzy.

Copyright (c) 1995 Christianity Today, Inc./BOOKS AND CULTURE Review

(continued in Part 2)

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