By RICHARD DAWKINS
Added: Mon, 15 May 2006 23:00:00 UTC

In my previous column, I raised the question of the Darwinian survival value of religion. Why, given that natural selection abhors waste and extravagance, is religious behaviour a human universal? I discussed various suggestions of direct advantages to religion, all more or less unconvincing, and promised to return to something more plausible. Darwinians who seek the survival value of religion are asking the wrong question. Instead, we should focus on something in our evolving ancestors which we would not then have recognized as religion, but which is primed to become recognizable as religion in the changed context of civilised society.

I cited the pecking order in hens, and the point is so central to my thesis that I hope you will forgive another animal example to ram it home. Moths fly into the candle flame, and it doesn't look like an accident. They go out of their way to make a burnt offering of themselves. We could label it 'self-immolation behaviour' and wonder how Darwinian natural selection could possibly favour it. My point, again, is that we need to rewrite the question before we can even attempt an intelligent answer. It isn't suicide. Apparent suicide emerges as an inadvertent side-effect.

Artificial light is a recent arrival on the night scene. Until recently, the only night lights were the moon and the stars. Being at optical infinity, their rays are parallel, which makes them ideal compasses. Insects are known to use celestial objects to steer accurately in a straight line. The insect nervous system is adept at setting up a temporary rule of thumb such as "Steer a course such that the light rays hit your eye at an angle of 30 degrees." Since insects have compound eyes, this will amount to favouring a particular ommatidium ? individual optical tube radiating out from the centre of the compound eye.
But the light compass relies critically on the celestial object being at optical infinity. If it isn't, the rays are not parallel but diverge like the spokes of a wheel. A nervous system using a 30 degree rule of thumb to a candle, as though it were the moon, will steer its moth, in a neat logarithmic spiral, into the flame.

It is still, on average, a good rule of thumb. We don't notice the hundreds of moths who are silently and effectively steering by the moon or a bright star, or even the lights of a distant city. We see only moths hurling themselves at our lights, and we ask the wrong question. Why are all these moths committing suicide? Instead, we should ask why they have nervous systems that steer by maintaining an automatic fixed angle to light rays, a tactic which we only notice on the occasions when it goes wrong. When the question is rephrased, the mystery evaporates. It never was right to call it suicide.

Once again, apply the lesson to religious behaviour in humans. We observe large numbers of people ? in many local areas it amounts to 100 percent ? who hold beliefs that flatly contradict demonstrable scientific facts, as well as rival religions. They not only hold these beliefs but devote time and resources to costly activities that flow from holding them. They die for them, or kill for them. We marvel at all this, just as we marvelled at the 'self-immolation behaviour' of the moths. Baffled, we ask Why. Yet again, the point I am making is that we may be asking the wrong question. The religious behaviour may be a misfiring, an unfortunate manifestation of an underlying psychological propensity which in other circumstances was once useful.

What might that psychological propensity have been? What is the equivalent of the parallel rays from the moon as a useful compass? I shall offer a suggestion, but I must stress that it is only an example of the kind of thing I am talking about. I am much more wedded to the general idea that the question should be properly rephrased than I am to any particular answer.

My specific hypothesis is about children. More than any other species, we survive by the accumulated experience of previous generations. Theoretically, children might learn from experience not to swim in crocodile-infested waters. But, to say the least, there will be a selective advantage to child brains with a rule of thumb: Believe whatever your grown-ups tell you. Obey your parents, obey the tribal elders, especially when they adopt a solemn, minatory tone. Obey without question.

I have never forgotten a horrifying sermon, preached in my school chapel when I was little. Horrifying in retrospect: at the time, my child brain accepted it as intended by the preacher. He told the story of a squad of soldiers, drilling beside a railway line. At a critical moment the drill sergeant's attention was distracted, and he failed to give the order to halt. The soldiers were so well schooled to obey orders without question, they carried on marching, right into the path of an oncoming train. Now, of course, I don't believe the story, but I did when I was nine. The point is that the preacher wished us children to regard as a virtue the soldiers' slavish and unquestioning obedience to an order, however preposterous. And, speaking for myself, I think we did regard it as a virtue. I wondered whether I would have had the courage to do my duty by marching into the train.

Like ideally drilled soldiers, computers do what they are told. They slavishly obey whatever instructions are properly delivered in their own programming language. This is how they do useful things like word processing and spreadsheet calculations. But, as an inevitable byproduct, they are equally automatic in obeying bad instructions. They have no way of telling whether an instruction will have a good effect or a bad. They simply obey, as soldiers are supposed to.

It is their unquestioning obedience that makes computers vulnerable to infection by viruses and worms. A maliciously designed program that says, "Copy me to every name in any address list that you find on this hard disk" will simply be obeyed, and then obeyed again by the other computers to which it is sent, in exponential expansion. It is impossible to design a computer which is usefully obedient and at the same time immune to infection.

If I have done my softening up work well, you will already have completed the argument about child brains and religion. Natural selection builds child brains with a tendency to believe whatever their parents and tribal elders tell them. And this very quality automatically makes them vulnerable to infection by mind viruses. For excellent survival reasons, child brains need to trust parents, and trust elders whom their parents tell them to trust. An automatic consequence is that the truster has no way of distinguishing good advice from bad. The child cannot tell that "If you swim in the river you'll be eaten by crocodiles" is good advice but "If you don't sacrifice a goat at the time of the full moon, the crops will fail" is bad advice. They both sound the same. They are both advice from a trusted source, both delivered with a solemn earnestness that commands respect and demands obedience.

The same goes for propositions about the world, about the cosmos, about morality, and about human nature. And, of course, when the child grows up and has children of her own, she will naturally pass the whole lot on to her own children, using the same impressive gravitas of manner.

On this model, we should expect that, in different geographical regions, different arbitrary beliefs having no factual basis will be handed down, to be believed with the same conviction as useful pieces of traditional wisdom such as the belief that manure is good for the crops. We should also expect that these non-factual beliefs will evolve over generations, either by random drift or following some sort of analogue of Darwinian selection, eventually showing a pattern of significant divergence from common ancestry. Languages drift apart from a common parent given sufficient time in geographical separation. The same is true of traditional beliefs and injunctions, handed down the generations, initially because of the programmability of the child brain.

Darwinian selection sets up childhood brains with a tendency to believe their elders. It sets up brains with a tendency to imitate, hence indirectly to spread rumours, spread urban legends, and believe religions. But given that genetic selection has set up brains of this kind, they then provide the equivalent of a new kind of nongenetic heredity, which might form the basis for a new kind of epidemiology, and perhaps even a new kind of nongenetic Darwinian selection. I believe that religion is one of a group of phenomena explained by this kind of nongenetic epidemiology, with the possible admixture of nongenetic Darwinian selection. If I am right, religion has no survival value for individual human beings, nor for the benefit of their genes. The benefit, if there is any, is to religion itself.

TAGGED: RELIGION, RICHARD DAWKINS