Consider what it has to say. First, we must accept that the world is continually changing. Life on earth has to adapt to those changes in order to survive. Adaptation occurs because each generation of life inherits slight random variations in its genetic makeup from the previous generation, and these variations produce slight differences between individuals. This means that some individuals and not others are better equipped to deal with the pressures of the environment where there is competition to breed. The selection occurs because these individuals are more likely to survive and pass on to their offspring the genes that gave them the advantage. Over time – a lot of time – this gradual process of selection by nature accumulates to produce significant change and diversity.
That’s Darwin’s theory of evolution in a nutshell. It is a simple, elegant, powerful theory that explains so much about diversity on our planet. But, as Richard Dawkins himself once lamented, it’s almost as if the human brain is designed to misunderstand evolution.22 I think he is right. Evolution is so damned counterintuitive. For example, we can easily see patterns in the diversity of life at any moment in time. However, the same processes that lead us to group animals together also lead us to treat them as separate. As individuals with relatively short life spans, we don’t have experience of immense passages of time, and so we cannot observe evolution at work. As laypeople, we don’t have the luxury of the historical record to show us how life has changed. All we have as nonscientists are our intuitions about life. And evolution runs counter to those intuitions. How can all living things, from the complexity of humans to the simplicity of bacteria, come from the same original source? How can the complexity of design emerge without a designer? It’s precisely because it doesn’t fit with our mind design that we find evolution a really hard process to understand.
Also, when people say they are not creationists, are they fully aware of how natural selection works, or are they just rejecting the religious account? Does the rest of the world really understand natural selection any better than the Americans? I am not so sure. In Europe we may readily supply the answer ‘evolution’ to the question, ‘Where did the diversity of life on earth come from?’ but, as with many other phenomena, we often say we understand explanations when in fact we don’t. This weakness in our ability to be accurate in judging how much we know is called the illusion of explanatory depth.23 We all typically overestimate how much we understand, and this is especially true of Darwin’s theory of natural selection. For example, most people think evolution works by ‘survival of the fittest’, a term coined not by Darwin but by his contemporary Herbert Spencer.24 This concept has been misinterpreted to mean that nature selects for those with the most physical strength. This misconception was at the core of Nazi eugenics to kill off individuals who they deemed would weaken the genetic pool. However, this is a gross misunderstanding of the original theory, in which ‘fittest’ meant how well the individual was matched to his or her environment. It’s not always the largest or the strongest individuals who are best matched, because environments are constantly changing, a point Dawkins elegantly explains in his first book, The Selfish Gene. If we all evolved into seven-foot-tall, muscular athletes, we would not be very successful in an environment with a limited food supply to feed our massive bodies. This is one consoling fact for those of us lower down the food chain. Eventually those at the top are going to evolve themselves out of existence.
Probably the most difficult aspect of the theory, and the one that smashes headlong into the face of common sense, is the shared ancestry of all life forms. Ever since the Scopes monkey trial, most people have been familiar with the furor over the Darwinists’ claim that humans are related to monkeys. But that’s nothing compared to the truth about ourselves as revealed by modern genetics. All living things – humans, animals, insects, trees, plants, flowers, fruit, amoebas, and even simple moulds – are genetically related. We know this because science has been able to unravel the building blocks of life and show that all living things share varying degrees of similarity in their DNA structures, the stuff of life. And Darwin’s theory of evolution is the only meaningful explanation for this fact. All living things must have evolved from a common ancestor way back in the infancy of life on earth. But, like the argument about whether there are eleven or twelve dimensions to our universe, the science of genetics does not make intuitive sense. From an early age, children treat all manner of living things as fundamentally different in kind. As we shall see, they understand that people are different from pets. Dogs are different from cats. Animals are different from plants. Children are not taught these distinctions. It’s a natural way to carve up the living world into all its different forms. Not only that, but children think that all living forms have always existed the way they are today.25 They are naturally inclined to the creationist’s viewpoint.
Like many adults, children cannot conceive of an animal, let alone humans, as a product of constant change. They simply don’t have any experience of this, and so they consider it impossible. Of course, we can learn these facts through science education, but they still do not make intuitive sense. That’s why we are so fascinated by natural metamorphosis, such as is demonstrated by tadpoles and butterflies. They seem magical because an individual can dramatically change in a lifetime. Actually, metamorphosis in the animal kingdom is not that uncommon. Many species can even change sex, with fish topping the gender-bender list.26 That might be acceptable for animals, but a transgender human who decides to have a sex change operation is abhorrent to most people – because transgender individuals violate our natural view of humans as being either male or female, a property fixed from birth. In truth, many of our intuitive biological boundaries, such as gender, are more apparent than real. There is much more shared similarity and common origins than we appreciate. And if you don’t believe me, ask yourself this: why do men have nipples?27
As humans, we do not naturally see ourselves as a product of continual change. Most of us think we are direct descendants in a lineage of ancestors who were also human. That’s why we feel a connection with the prehistoric artists of the Niaux caves. However, thirteen thousand years is just a blink of the eye in evolutionary terms. If we go back far enough, we find that life was literally much simpler. I can know this on an intellectual level, but I cannot easily accept that all living organisms have evolved from the same origin. I simply cannot see how I am related to the furry green mould growing on the cheese in my fridge. The full implications of evolution are rarely considered because we cannot conceive what it really means. Our physical resemblance to chimpanzees may make it easier for us to understand that we share around 98 per cent of our genetic makeup. Much harder to accept is that we also share 50 per cent of our genetic makeup with a banana.28 I may feel that some of my fellow humans have the intelligence of a banana, but to fully accept that all life is related by the same basic genetic building blocks is beyond belief. No matter how simple or complicated an organism can be, all life forms share about one thousand genes. As I write this, I am contemplating the bananas in the fruit bowl in front of me, which for some strange reason suddenly seem less appetizing.