Unit Four: Richard Dawkins
Mechanisms of Evolution

Interview: Richard Dawkins

Oxford professor Richard Dawkins has helped explain Darwin and natural selection to the public through a series of award-winning books, beginning with The Selfish Gene in 1976. He followed that international best-seller with The Blind Watchmaker, The Extended Phenotype, River Out of Eden, and Climbing Mount Improbable. While making the beauty and power of natural selection accessible to nonscientists, Dawkins's books have also stirred controversy among evolutionary biologists. Particularly provocative has been Dawkins's argument that genes, not whole organisms, are the units of natural selection. In this view of Darwinism, organisms are "survival machines" for the "replicators," selfish molecules known as genes. Many biologists disagree, countering that a strictly gene-centered concept of natural selection is too simplistic. Richard Dawkins is among the very few scientists who can stimulate thoughtful debate and research in a scientific field at the same time as he engages and challenges nonscientists.

One of your books, The Blind Watchmaker, argues the case for the cumulative power of natural selection in the adaptation of organisms. Tell us about the metaphorical title of that book.

The "watchmaker" comes from William Paley, the eighteenth- and early nineteenth-century theologian who was one of the most famous exponents of the argument of design. Paley famously said that if you are wandering along and stumble upon a watch and you pick it up and open it, you realize that the internal mechanism—the way in which it's all meshed together—is detailed perfection. Add this to the fact that the watch mechanism has a purpose—namely, telling the time—then this compels you to conclude that the watch had to have a designer. Paley then went on throughout his book giving example after example of detailed structure of living organisms—eyes, heart, bowels, joints, and everything about animals—showing how beautifully designed they apparently are, how well they work, how intricately the parts mesh together, just like the cog wheels of a watch. And if the watch had to have a watchmaker, then of course these biological structures also had to have a designer.

My reason for beginning The Blind Watchmaker was Paley. He really saw the magnitude of the problem of adaptation when most people just didn't see how elegant, how beautiful, apparent design in life is. Paley saw that, and Darwin saw that. And Darwin was introduced to it at least partly by Paley. All undergraduates at Cambridge had to read William Paley. He at least put the question right. So the only thing Paley got wrong, which is quite a big thing, was the answer to the question. And nobody got the right answer until Charles Darwin in the nineteenth century.

Is it that answer that puts the "blind" in your book title?

The "blind" watchmaker is natural selection. Natural selection is totally blind to the future. It's always just picking the best of available alternatives in the present. It can never say, "Well, if we tolerate a bit of unpleasantness for the next 2 million years, then that will set us up wonderfully to improve in 2 million years' time." Natural selection can't do that. It's always optimizing in the short term, though it's blind to the future.

In Climbing Mount Improbable, you built on the theme of how natural selection can lead to elegant structure by optimizing for the short term. Tell us how that book title relates to the problem of adaptation.

"Mount Improbable" is a metaphor for adaptation occurring gradually, in increments. The metaphor is that of a mountain which has an absolutely sheer cliff face. If we relate this cliff to adaptation, to the most complicated piece of biological machinery you can think of, which for many people is an eye, then you say to yourself that it's impossible to leap from the bottom of this mountain to the top, which indeed it is. Leaping from the bottom of the cliff to the top would correspond to having the sheer luck to get that eye coming into place in one fell swoop. Many people wrongly think that Darwinism is a theory of chance, that it means that eyes and other complex organs come about by sheer luck. So no wonder these people don't believe natural selection. Of course an eye couldn't possibly come about like that. But on the other side of the mountain, you've got a slow, gradual slope, and it is very easy to get to the top of the mountain if you go around the other side and just walk up the slope. Relating this to adaptation, you have gradual, incremental improvement. You begin with hardly any eye at all and then each step of the way up the mountain is a gradual improvement. It may not be much, but it's enough to be better than your predecessors, who didn't have even that improvement. Climbing Mount Improbable emphasizes that evolution of complex adaptations has got to be gradual.

In another of your books, The Selfish Gene, you argue that genes are the units upon which natural selection acts and that organisms are "survival machines" for genes. To what extent are humans exceptions to this mechanistic view of life?

Humans are fundamentally not exceptional because we came from the same evolutionary source as every other species. It is natural selection of selfish genes that has given us our bodies and our brains. However, the brains that natural selection gave us are exceptionally big brains, so big that they have done a rather unusual thing. Using language and culture, humans have formed societies in which there is something like Darwinian evolution going on, though it is not really Darwinian. We live in a highly domestic environment, largely governed by technology, largely divorced from the environment in which our genes were originally naturally selected. So what is different about us is that it is no longer possible to look at a human the way one might look at a wildebeest or a kangaroo and ask, "Why is that? What's that kangaroo doing that increases its gene survival?" If you see a wild animal doing something in the wild, then it's sensible to ask the question, "What is it about that behavior, or what is it about that morphological structure, which improves its survival, or more particularly the survival of its genes?"

And you can't do that for humans?

No, you can't look at humans playing the violin, or trying to run a company, or writing a book or writing a symphony, and ask, "In what way does writing this symphony benefit survival and replication of that human's genes?" because it doesn't. You have to be more sophisticated and ask, "In what way does the behavior of a brain which was originally built by natural selection for surviving in Africa in the Pleistocene and Pliocene translate into the behavior of this brain, now that it finds itself in this very different, artificial environment?" For example, we still enjoy sex, even though today we often use contraceptives, which separate the enjoyment of sex from the reproductive function. Before contraceptives, enjoying sex translated into Darwinian reproductive success. Back then, as Steven Pinker has argued, if there had been a tree with berries that were the equivalents of today's contraceptive pills, we would probably have treated those trees with the same terror as we would a poisonous snake or poisonous spider. Now that's obviously not the case. All the questions that you might wish to ask about humans have to be rewritten in a more sophisticated way.

This example of modern humans choosing to limit their reproduction seems like the most counter-Darwinian of all human behaviors. Is it possible that there will be long-term, global limiting of population growth by choice rather than by famine and disease?

If we were relying purely on Darwinian mechanisms, there would be no hope. There is nothing in Darwinism that explains limiting reproduction for the good of future populations. But where natural selection has no foresight, human brains do have foresight. The human brain is an adaptive mechanism which, having been put together for quite different reasons, now finds itself capable of gazing into the distant future and working out the long-term consequences of our actions. So it is possible for us now to do what has never been possible before. We can look into the long-term future; we can see it would be a very bad idea to do all sorts of things, such as over-reproducing, overfishing, depleting our natural resources. But being able to do that by no means gets us out of the woods. It's one thing for individuals to sit down and say, "Well, I can see that it's a bad thing to over-reproduce and overfish," but it's quite another matter to persuade humanity at large to see that. I don't mean that humanity at large is stupid. Anybody can see that it would benefit everybody if we all limited our greed, but as long as others are not limiting their greed, people quite understandably say, "Why on Earth should I? Why should I be the first to limit my own appetite, limit my own greed, limit my own desire for selfish advancement?" But having recognized this behavior is at least a first step. We do have institutions like government, we do pay our taxes, we have police forces. We pass laws to limit selfish overexploitation. Most of us accept paying taxes and obeying laws if we are assured that everybody else is paying their taxes and obeying the same laws. So in many countries it does seem to work. We're kind of teetering on the edge when you look at things like overexploiting whales or fish on an international level. There are international conferences and conventions that are aimed at avoiding overexploitation. To a limited extent they seem to work. I mean they are constantly on the brink of not working, with people constantly walking out and refusing to abide by the rules. But there is something like a social machinery coming into place for limiting greed. And I see hope in that because this tendency to restrain individual advantage for the sake of group advantage is something no other species has ever even come close to.

Earlier, you mentioned that in human culture, there may be something like Darwinian evolution. Tell us more about that.

There's no doubt, of course, that cultural evolution happened, and it has some analogy to evolution, perhaps even Darwinian evolution. In The Selfish Gene I constantly emphasized the importance of genes as the central units of natural selection. Genes are the only things that pass down through generations. But what's special about genes is that they are replicated, they function as what I called "replicators" in The Selfish Gene So, it's replicators that matter, not specifically genes. Anything that is self-replicating anywhere in the universe is fair game for natural selection. There probably is life on other planets, and if there is, then I absolutely bet my shirt that it's based upon natural selection. That would require a replicator. It doesn't have to be DNA, but it would have the fundamental property of self-replication. In making this point in The Selfish Gene that replicators are the units of selection, I also gave the example of what I called the "meme," the unit of cultural evolution. You can look at human culture and ask yourself, "Is there something which is passing from brain to brain and perhaps from generation to generation by nongenetic means?" I think there is. For example, when we were at school, I think we all had the experience of some craze that spreads through a school like a measles epidemic—a new kind of toy or a new style of wearing a hat. It literally does spread from person to person and then it may die away, or it may perhaps leap to another school. Well, that's a trivial example, but it's enough to show that there is some replicator which is analogous to a virus but does not consist of DNA.

The phenotypes of most memes are behavioral, such as religious traditions. So there we have memes that pass longitudinally down the generations. The school craze is a meme that passes horizontally across one generation. And we live in an environment that is saturated by both kinds of memes. You then have to ask, "Do some memes survive better than others because they have what it takes to survive?" If they do, that is all that you need to establish that there is a Darwinian-like component to cultural evolution.

What if you could travel in time and visit with Darwin? What would you ask him?

First, I'd be so overawed that I wouldn't know quite what to say. But I think maybe if I were really forced to ask him one question it would be, "Why did you wait so long after you had this brilliantly simple yet powerful idea? Didn't it seem to you so fantastically simple yet so fantastically powerful that if you didn't write it down quickly, somebody else would?" I'm genuinely baffled about that because it's as though Darwin thought he had all the time in the world, and pretty nearly he did. I mean Wallace did get there, but still Darwin had about 20 years before that. What I find remarkable is that Aristotle didn't get it and Plato didn't get it, nor did Pythagorus, Archimedes, Newton, even though you don't need any technical know-how to get the idea. Natural selection is a bewilderingly simple idea. And yet what it explains is the whole of life, the diversity of life, the complexity of life, the apparent design of life. It all flows from this one remarkably simple idea.

©2005 Pearson Education, Inc., publishing as Benjamin Cummings