2009 will be the year of Charles Darwin. 12 February is the 200th anniversary of his birth, and his great book On the Origin of Species was published 150 years ago on 24th November. Festivals and symposia are already planned, and we may look forward to endless comment in the press.
We can see Darwin as the great liberator – freeing us from the superstitious burden of being created by God, and transporting us into the sunny uplands of scientific nirvana. In recent times, his theory of natural selection has become a proxy for a general view that the flora and fauna of the world have come about through biological causes, relegating the existence of God to a gratuitous hypothesis.
On the other side of the divide is the theory of intelligent design in which God is the necessary agent intervening to a greater or less degree in the creation of the species. My purpose is to explain why this difference is born of a false dichotomy, and that neither approach conflicts, so long as our thinking is clear and we understand the limitations of each.
Evolution is an immensely complicated subject (and appears more complicated every day) but the principle is simple. In the process of reproduction many mutations occur. The great majority are harmful and so disappear. But a tiny number prove useful and give the species a small additional chance of survival in the existing environment. Those with this advantage are likely to breed more than those without, and so the advantage tends to accumulate. Over many thousands of generations, genetic mutations can result in substantial changes.
The story of the peppered moth is illustrative. Before the Industrial Revolution the light-coloured moths were camouflaged against the light-coloured trees, while the dark-coloured were an easy prey for birds. But as the tree trunks blackened through industrial pollution, the advantage switched to the dark-coloured version. And, with successive generations, the proportion of black moths increased greatly, at the expense of their lighter cousins. The survival of the fittest for the prevailing environment could be observed in action.
But this relatively minor alteration within a species is a long way from the development of the variety of complex species from the original basic life forms. And so we are right to call evolution a theory since there is no practical way in which all the missing links can be discovered. Nevertheless it is a very strong theory, supported by various different forms of complementary evidence – and recently much strengthened by deepening knowledge of DNA. Indeed this new knowledge is prompting science to explore supplementary ways through evolution may occur. There cannot be a proof, but the degree of plausibility is so high that those who discount the theory appear to be generally motivated by principle rather than by rigorous examination of the science.
Intelligent design always needs definition. The meaning can range from the literal 6-day account of Genesis to various levels of divine intervention in the evolutionary process in order to correct its course towards God’s ultimate ends. At the very least it cannot be disproved, and since satisfactory empirical evidence is not obtainable it is not a scientific issue.
Evolution in itself is a mindless process; it has no internal purpose. It works though filtered chance in which the random mutations of reproduction have to pass the test of enhancing, or at least not diminishing, the survival value of their host. One might compare it with a fisherman who uses a large meshed net. The fish that swim in are of random size but only those who pass the test of the mesh are caught.
This makes evolution, as you would expect, untidy. So the bower bird builds a nest to attract a mate, but the nest is never used. The peacock has an unnecessarily large tail to prove his suitability as a father. We are prone to bad backs because we were not originally bipedal. The spermatic cord travels in a vulnerable circuitous loop because an ancestor had its gonads near its liver. All rather unintelligent, but because these systems work well enough they survive.
Naturally our interest is focussed on the human line. Although homo sapiens is genetically closer to the chimpanzee than the chimpanzee is to the gorilla, it did not spring into existence overnight. In fact our lines of descent diverged about 5 million years ago, and we have no evidence of any significant changes in the hominid line for the next 3 million years. Our own species is very new in evolutionary terms, appearing in Africa about 200,000 years ago. The small population (perhaps 10,000 to 50,000 individuals) began its emigration about 60,000 years ago. Neanderthals, our evolutionary cousins, spread somewhat earlier. Current evidence suggests that they sometimes lived alongside homo sapiens, and may have interbred to some degree. They declined for a variety of reasons. Fossil records suggest that they were skilled, innovative and may have had limited powers of speech.
Despite our genetic similarity to the chimpanzee (which is by no means the whole story for genes can express themselves differently and in different combinations) we are struck by the obvious differences. Our capacity for self consciousness, abstract thinking, freedom of the will, and our sense of moral obligation stand out. These faculties are not explicable through biology, although they necessarily work through the brain. For example, freewill cannot by definition be caused by the biological, and without freewill moral responsibility has no meaning.
If I describe such faculties, as I do, as being infused by God I have no account to give about how this happened beyond the fact that the human brain must have evolved biologically into an instrument through which the faculties could work. I do not know whether Neanderthals, or other species earlier in the human line, had souls, but the evidence of intelligent activities suggests that we cannot rule this out.
If homo sapiens were purely the result of biological evolution the anthropologists would hold that descent from a single couple was extremely unlikely. But this would be irrelevant in the case of a soul infused by an act of God, who could have chosen monogenism or polygenism according to his purposes. What we do know is that we inherit a nature which is a blend of the biological and the spiritual, and that it is our inability to integrate our selfish, biological, elements with our aspirational, spiritual elements in which disorder lies.
So I do believe in intelligent design in the sense that God used evolution as his biological methodology. Whatever his reasons may have been, in human terms I recognise that the fisherman who uses a combination of the random tempered by the filter of the mesh has chosen a more economical method than picking out his fish by hand. But I need to remember that nothing, in the end, is random to God, who knows from all eternity the movement, and mutation of creation, right down to the most basic sub-nuclear particle. The outcome of evolution was known and intended in every detail from the beginning.
I also know that my spiritual faculties were created and given to me directly by God. I could not meaningfully claim truth for any proposition I have made if I were obliged to make it only through the biology of my brain. Biology could not give me a mind to judge the workings of my brain or my emotions. And I could not see how far I fall short of the life of love if biology were my only means of knowing that I should follow the good and avoid the evil. Moreover such faculties are not susceptible to evolution. For instance one either has free will or one has not: there is no halfway house.
So, as believers in a creator God, natural selection through evolution is not an obstacle but a fruitful way of exploring the wonderful way through which he most probably worked. Our celebration of Darwin’s anniversary year should be all the richer since we are able to see the methodology in its proper context.
I am aware that my account is simplistic. There is much more to say about the complexities of evolution, including some real difficulties raised by its critics. Or the part that a Catholic priest played in discovering the mechanism of inheritance. The integral intellectual connection of Darwinism to eugenics needs to be examined. The claim that the source of altruism is evolutionary advantage requires assessment. I would like to have written more about the myopic vision of the secular scientist. I would like to have looked more closely at our first ancestors and discussed the part that Original Sin played in our inheritance from them. I shall try to deal with some of this in my fortnightly Science and Faith column during the year. But I would be greatly helped by your comments and suggestions.