Science in the Soul

by Richard Dawkins

  Though the details differ across cultures, no culture is known that does not practise some version of the time-consuming, wealth-consuming, hostility-provoking, fecundity-forfeiting rituals of religion. All this presents a major puzzle to anyone who thinks in a Darwinian way. Isn’t religion a challenge, an a priori affront to Darwinism, demanding similar explanation? Why do we pray and indulge in costly practices which, in many cases, more or less totally consume our lives?

  Could religion be a recent phenomenon, sprung up since our genes underwent most of their natural selection? Its ubiquity argues against any simple version of this idea. Nevertheless there is a version of it that it will be my main purpose to advocate today. The propensity that was naturally selected in our ancestors was not religion per se. It had some other benefit, and it only incidentally manifests itself as religious behaviour. We’ll understand religious behaviour only after we have renamed it. Once again, it is natural for an ethologist to use an example from non-human animals.

  The ‘dominance hierarchy’ was first discovered as the ‘pecking order’ in hens. Each hen learns which individuals she can beat in a fight, and which beat her. In a well-established dominance hierarchy, little overt fighting is seen. Stable groupings of hens, who have time to sort themselves into a pecking order, lay more eggs than hens in coops whose membership is continually changed. This might suggest an ‘advantage’ to the phenomenon of the dominance hierarchy. But that’s not good Darwinism, because the dominance hierarchy is a group-level phenomenon. Farmers may care about group productivity, but natural selection doesn’t.

  For a Darwinian, the question, ‘What is the survival value of the dominance hierarchy?’ is an illegitimate question. The proper question is: ‘What is the individual survival value of deferring to stronger hens and punishing lack of deference from weaker ones?’ Darwinian questions have to direct attention towards the level at which genetic variations might exist. Tendencies to aggression or deference in individual hens are a proper target because they either do or easily might vary genetically. Group phenomena like dominance hierarchies don’t in themselves vary genetically, because groups don’t have genes. Or at least, you’ll have your work cut out arguing some peculiar sense in which a group phenomenon could be subject to genetic variation. You might contrive it via some version of what I have called the ‘extended phenotype’, but I am too sceptical to accompany you on that theoretical journey.

  My point, of course, is that the phenomenon of religion may be like the dominance hierarchy. ‘What is the survival value of religion?’ may be the wrong question. The right question may have the form, ‘What is the survival value of some as yet unspecified individual behaviour, or psychological characteristic, which manifests itself, under appropriate circumstances, as religion?’ We have to rewrite the question before we can sensibly answer it.

  I must first acknowledge that other Darwinians have gone straight for the un-rewritten question, and proposed direct Darwinian advantages of religion itself – as opposed to psychological predispositions that accidentally manifest themselves as religion. There is a little evidence that religious belief protects people from stress-related diseases. The evidence is not good, but it would not be surprising. A non-negligible part of what a doctor can provide for a patient is consolation and reassurance. My doctor doesn’t literally practise the laying on of hands. But many’s the time I have been instantly cured of some minor ailment by a reassuringly calm voice from an intelligent face surmounting a stethoscope. The placebo effect is well documented. Dummy pills, with no pharmacological activity at all, demonstrably improve health. That is why drug trials have to use placebos as controls. It’s why homoeopathic remedies appear to work, even though they’re so dilute that they have the same amount of the active ingredients as the placebo control – zero molecules.

  Is religion a medical placebo, which prolongs life by reducing stress? Perhaps, although the theory is going to have to run the gauntlet of sceptics who point out the many circumstances in which religion increases stress rather than decreases it. In any case, I find the placebo theory too meagre to account for the massive and all-pervasive worldwide phenomenon of religion. I do not think we have religion because our ancestors reduced their stress levels and hence survived a little longer. I don’t think that’s a big enough theory for the job.

  Other theories miss the point of Darwinian explanations altogether. I mean suggestions such as: ‘Religion satisfies our curiosity about the universe and our place in it.’ Or: ‘Religion is consoling. People fear death and are drawn to religion because of the promise of surviving it.’ There may be some psychological truth here, but it’s not in itself a Darwinian explanation. A Darwinian version of the fear-of-death theory would have to be of the form, ‘Belief in survival after death tends to postpone the moment when it is put to the test.’ This could be true or it could be false – maybe it’s another version of the stress and placebo theory – but I shall not pursue the matter. My only point is that this is the kind of way in which a Darwinian must rewrite the question. Psychological statements – that people find some belief agreeable or disagreeable – are proximate, not ultimate, explanations.

  Darwinians make much of the distinction between proximate and ultimate. Proximate questions lead us into physiology and neuroanatomy. There is nothing wrong with proximate explanations. They are important, and they are scientific. But my preoccupation today is with Darwinian ultimate explanations. If neuroscientists, such as the Canadian Michael Persinger, find a ‘god centre’ in the brain, Darwinian scientists like me want to know why the god centre evolved. Why did those of our ancestors who had a genetic tendency to grow a god centre survive better than rivals who did not?

  Some alleged ultimate explanations turn out to be – or in some cases avowedly are – group selection theories. Group selection is the controversial idea that Darwinian selection chooses among groups of individuals, in the same kind of way as it chooses among individuals within groups.

  Here’s a made-up example, to show what a group-selection theory of religion might look like. A tribe with a stirringly belligerent ‘god of battles’ wins wars against a tribe whose god urges peace and harmony, or a tribe with no god at all. Warriors who believe that a martyr’s death will send them straight to paradise fight bravely and willingly give up their lives. So tribes with certain kinds of religion are more likely to survive in intertribal selection, steal the conquered tribe’s cattle and seize their women as concubines. Such successful tribes spawn daughter tribes who go off and propagate more daughter tribes, all worshipping the same tribal god. Notice that this is different from saying that the idea of the warlike religion survives. Of course it will, but in this case the point is that the group of people who hold the idea survive.

  There are formidable objections to group selection theories. A partisan in the controversy, I must beware of riding off on a hobby horse far from today’s subject. There is also much confusion in the literature between true group selection, as in my hypothetical example of the god of battles, and something else that is called group selection but turns out to be either kin selection or reciprocal altruism. Or there may be a confusion of ‘selection between groups’ and ‘selection between individuals in the particular circumstances furnished by group living’.

  Those of us who object to group selection have always admitted that in principle it can happen. The problem is that, when it is pitted against individual-level selection – as when group selection is advanced as an explanation for individual self-sacrifice – individual-level selection is likely to be stronger. In our hypothetical tribe of martyrs, a single self-interested warrior, who leaves martyrdom to his colleagues, will end up on the winning side because of their gallantry. Unlike them, however, he ends up alive, outnumbered by women, and in a conspicuously better position to pass on his genes than his fallen comrades.

  Group selection theories of individual self-sacrifice are always vulnerable to subversion from within. If it comes to a tus
sle between the two levels of selection, individual selection will tend to win because it has a faster turnover. Mathematical models arguably come up with special conditions under which group selection might work. Arguably, religions in human tribes set up just such special conditions. This is an interesting line of theory to pursue, but I shall not do so here.

  Instead, I shall return to the idea of rewriting the question. I previously 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. Because they are 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.*3 They can use the same compass, with reversed sign, for returning home after a foray. 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°.’ Since insects have compound eyes, this will amount to favouring a particular ommatidium.*4

  But the compass relies critically on the celestial object being at optical infinity. If it is not at infinity, the light rays are not parallel but diverge like the spokes of a wheel. A nervous system using a 30° 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 that we notice only 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 per cent – 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 that 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 put 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.

  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 equally trustworthy. 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 both classes of advice on to her own children – nonsense as well as sense – using the same solemn 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.

  I must again stress that the hypothesis of the programmability of the child brain is only one example of the kind of thing I mean. The message of the moths and the candle flame is more general. As a Darwinian, I am proposing a family of hypotheses, all of which have in common that they do not ask what is the survival value of religion. Instead they ask, ‘What was the survival value, in the wild past, of having the kind of brain which, in the cultural present, manifests itself as religion?’*5 And I should add that child brains are not the only ones that are vulnerable to infection of this kind. Adult brains are too, especially if primed in childhood. Charismatic preachers can spread the word far and wide, as if they were diseased persons spreading an epidemic.

  So far, the hypothesis suggests only that brains (especially child brains) are vulnerable to infection. It says nothing about which viruses will infect. In one sense it doesn’t matter. Anything the child believes with sufficient conviction will get passed on to its children, and hence to future generations. This is a non-genetic analogue of heredity. Some people will say it is memes rather than genes. I don’t want to sell memetic terminology to you today, but it is important to stress that we are not talking about genetic inheritance. What is genetically inherited, according to the theory, is the tendency of the child brain to believe what it is told. This is what makes the child brain a suitable vehicle for non-genetic heredity.

  If there is non-genetic heredity, could there also be non-genetic Darwinism? Is it arbitrary which mind viruses end up exploiting the vulnerability of child brains? Or do some viruses survive better than others? This is where those theories that I earlier dismissed as proximate, not ultimate, come in. If fear of death is common, the idea of immortality might survive as a mind virus better than the competing idea that death snuffs us out like a light. Conversely, the idea of posthumous punishment for sins might survive, not because children like the idea but because adults find it a useful way to control them. The important point is that survival value does not have its normal Darwinian meaning of genetic survival value. This is not the normal Darwinian conversation about why a gene survives in preference to its alleles in the gene pool. This is about why one idea survives in the pool of ideas in preference to rival ideas. It is this notion of rival ideas surviving, or failing to survive, in a pool of ideas that the word ‘meme’ was intended to capture.

  Let’s go back to first principles and re
mind ourselves of exactly what is going on in natural selection. The necessary condition is that accurately self-replicating information exists in alternative, competing versions. Following George C. Williams in his Natural Selection, I shall call them ‘codices’ (singular: ‘codex’). The archetypal codex is a gene: not the physical molecule of DNA but the information it carries.

  Biological codices, or genes, are carried around inside bodies whose qualities – phenotypes – they helped to influence. The death of the body entails the destruction of any codices that it contains, unless they have previously been passed on to another body, in reproduction. Automatically, therefore, those genes that positively affect the survival and reproduction of bodies in which they sit will come to predominate in the world, at the expense of rival genes.

  A familiar example of a non-genetic codex is the so-called chain letter, although ‘chain’ is not a good word. It is too linear, doesn’t capture the idea of explosive, exponential spread. Equally ill-named, and for the same reason, is the so-called chain reaction in an atomic bomb. Let’s change ‘chain letter’ to ‘postal virus’ and look at the phenomenon through Darwinian eyes.

  Suppose you received through the mail a letter which simply said: ‘Make six copies of this letter and send them to six friends.’ If you slavishly obeyed the instruction, and if your friends and their friends did too, the letter would spread exponentially and we’d soon be wading knee deep in letters. Of course most people would not obey such a bald, unadorned instruction. But now, suppose the letter said: ‘If you do not copy this letter to six friends, you will be jinxed, a voodoo will be placed on you, and you will die young in agony.’ Most people still wouldn’t send it on, but a significant number probably would. Even quite a low percentage would be enough for it to take off.

  The promise of reward may be more effective than the threat of punishment. We have probably all received examples of the slightly more sophisticated style of letter, which invites you to send a small sum of money to people already on the list, with the promise that you will eventually receive millions of dollars when the exponential explosion has advanced further. Whatever our personal guesses as to who might fall for these things, the fact is that many do. It is an empirical fact that chain letters circulate. No genes are involved, yet postal viruses display an entirely authentic epidemiology, including the successive waves of infection rolling around the world and including the evolution of new mutant strains of the original virus.