When I told the taxi driver that I was a priest, there was a pause. Then he said ‘Oh. I believe in evolution.’ ‘So do I’, I replied. That was too much for him. ‘I can’t take that.’
The study of evolution, like many academic disciplines, produces real insights and there is no good reason for Christians to reject it. However the case for it is undermined when its enthusiasts claim more for it than they should.
I have already discussed the issues with selfish genes and evolution as a moral guide. Here I respond to the determinist argument: that everything we are, or do, must have an evolutionary cause – that we have to be the way we are for evolutionary reasons.
Everything must be a nail because evolutionists have a hammer. It often happens. To psychologists all human behaviour has a psychological explanation, to sociologists all human behaviour has a sociological explanation, and so on. When we get excited about our discoveries, we exaggerate how much they can do.
Evolution means gradual change over time. It does not cause anything at all; it only describes long-term changes. The causes of the changes are a myriad different things.
What evolutionary theory does claim is that some of our characteristics exist because, if our ancestors had not had them, the population would have died out. Most obviously the sexual libido, and the desire to give birth to children and nurture them, has to be strong enough to ensure that every generation produces enough fertile offspring. Otherwise the species goes extinct.
Unfortunately Charles Darwin was over-influenced by Malthus’ population theories and exaggerated the role of competition. He thought of life as a constant struggle to produce fertile offspring. So the rich should have more children than the poor, which they don’t. Actually, we are not constantly competing against each other to have more children. If you have more children than I have, that’s fine by me. Some of us even use contraception.
What evolutionary theory shows is more limited: that the sexual libido and the desire to produce and nurture children have to be strong enough in every generation.
The point can be easily understood by comparing the present human population with our ancestors of, say, a hundred thousand years ago. Like us, they had diverse characteristics. Through natural selection we are descended from some of those people. Others had no children, and others again had children whose descendants died out some time between then and now.
Thus evolution by natural selection presupposes that, at any given time in the past, some individuals produced lines of fertile offspring which still survive, and others did not. Some were gay or celibate, but every species alive today exists because its ancestors produced enough offspring.
If this is true of our ancestors a hundred thousand years ago, it is equally true of us today. There is no evidence that natural selection is reducing the proportion of gays and celibates, either in humans or in any other species.
So at the most we might say that ‘evolution makes sure we have enough children’, but even this would be too positive a way of putting it. Evolution doesn’t make sure of anything. It doesn’t make anything happen. It is just a way of saying that if our ancestors hadn’t had enough children, our species would have died out.