i G I () N 163
THE DARWINIAN IMPERATIVE
Everybody has their own pet theory of where religion comes from and why all human cultures have it.
THE DARWINIAN IMPERATIVE
Everybody has their own pet theory of where religion comes from and why all human cultures have it.
Richard-Dawkins-God-Delusion
It is, of course, precisely the oppo- site of simple.
Swinburne pulls off the trick to his own satisfaction by a breathtaking piece of intellectual chutzpah.
He asserts, with- out justification, that God is only a single substance.
What brilliant economy of explanatory causes, compared with all those gigazillions of independent electrons all just happening to be the
i same!
Theism claims that every other object which exists is caused to exist and kept in existence by just one sub- stance, God. And it claims that every property which every substance has is due to God causing or permitting it to exist. It is a hallmark of a simple explanation to postulate few causes. There could in this respect be no
WHY THKRK ALVI OS I CERTAINLY IS NO (,()]) 149
simpler explanation than one which postulated only one cause. Theism is simpler than polytheism. And theism postulates for its one cause, a person [with] infinite power (God can do anything logically possible), infinite knowledge (God knows everything logically possible to know), and infinite freedom.
Swinburne generously concedes that God cannot accomplish feats that are logically impossible, and one feels grateful for this forbearance. Having said that, there is no limit to the explanatory purposes to which God's infinite power is put. Is science having a little difficulty explaining X? No problem. Don't give X another glance. God's infinite power is effortlessly wheeled in to explain X (along with everything else), and it is always a supremely simple explanation because, after all, there is only one God. What could be simpler than that?
Well, actually, almost everything. A God capable of con- tinuously monitoring and controlling the individual status of every particle in the universe cannot be simple. His existence is going to need a mammoth explanation in its own right. Worse (from the point of view of simplicity), other corners of God's giant consciousness are simultaneously preoccupied with the doings and emotions and prayers of every single human being - and whatever intelligent aliens there might be on other planets in this and 100 billion other galaxies. He even, according to Swinburne, has to decide continuously not to intervene miraculously to save us when we get cancer. That would never do, for, 'If God answered most prayers for a relative to recover from cancer, then cancer would no longer be a problem for humans to solve. ' And then what would we find to do with our time?
Not all theologians go as far as Swinburne. Nevertheless, the remarkable suggestion that the God Hypothesis is simple can be found in other modern theological writings. Keith Ward, then Regius Professor of Divinity at Oxford, was very clear on the matter in his 1996 book God, Chance and Necessity:
As a matter of fact, the theist would claim that God is a very elegant, economical and fruitful explanation for the
150
'1 H K G O 1) I) F I. U S I O X
existence of the universe. It is economical because it attributes the existence and nature of absolutely every- thing in the universe to just one being, an ultimate cause which assigns a reason for the existence of everything, including itself. It is elegant because from one key idea - the idea of the most perfect possible being - the whole nature of God and the existence of the universe can be intelligibly explicated.
Like Swinburne, Ward mistakes what it means to explain some-
thing, and he also seems not to understand what it means to say of
something that it is simple. I am not clear whether Ward really
thinks God is simple, or whether the above passage represented a
temporary 'for the sake of argument' exercise. Sir John
Polkinghorne, in Science and Christian Belief, quotes Ward's earlier
criticism of the thought of Thomas Aquinas: 'Its basic error is in
supposing that God is logically simple - simple not just in the sense
that his being is indivisible, but in the much stronger sense that
what is true of any part of God is true of the whole. It is quite
coherent, however, to suppose that God, while indivisible, is inter-
nally complex. ' Ward gets it right here. Indeed, the biologist Julian
Huxley, in 1912, defined complexity in terms of 'heterogeneity of
parts', by which he meant a particular kind of functional
71 indivisibility.
Elsewhere, Ward gives evidence of the difficulty the theological mind has in grasping where the complexity of life comes from. He quotes another theologian-scientist, the biochemist Arthur Peacocke (the third member of my trio of British religious scientists), as postulating the existence in living matter of a 'propensity for increased complexity'. Ward characterizes this as 'some inherent weighting of evolutionary change which favours complexity'. He goes on to suggest that such a bias 'might be some weighting of the mutational process, to ensure that more complex mutations occurred'. Ward is sceptical of this, as well he should be. The evolutionary drive towards complexity comes, in those lineages where it comes at all, not from any inherent propensity for increased complexity, and not from biased mutation. It comes from natural selection: the process which, as far as we know, is the only
WHY THHRB ALMOST CERTAINLY IS NO COD 151
process ultimately capable of generating complexity out of simplicity. The theory of natural selection is genuinely simple. So is the origin from which it starts. That which it explains, on the other hand, is complex almost beyond telling: more complex than any- thing we can imagine, save a God capable of designing it.
AN INTERLUDE AT CAMBRIDGE
At a recent Cambridge conference on science and religion, where I put forward the argument I am here calling the Ultimate 747 argument, I encountered what, to say the least, was a cordial failure to achieve a meeting of minds on the question of God's simplicity. The experience was a revealing one, and I'd like to share it.
First I should confess (that is probably the right word) that the conference was sponsored by the Templeton Foundation. The audience was a small number of hand-picked science journalists from Britain and America. I was the token atheist among the eighteen invited speakers. One of the journalists, John Horgan, reported that they had each been paid the handsome sum of $15,000 to attend the conference, on top of all expenses. This surprised me. My long experience of academic conferences included no instances where the audience (as opposed to the speakers) was paid to attend. If I had known, my suspicions would immediately have been aroused. Was Templeton using his money to suborn science journalists and subvert their scientific integrity? John Horgan later wondered the same thing and wrote an article about
72
his whole experience. In it he revealed, to my chagrin, that my
advertised involvement as a speaker had helped him and others to overcome their doubts:
The British biologist Richard Dawkins, whose partici- pation in the meeting helped convince me and other fellows of its legitimacy, was the only speaker who denounced religious beliefs as incompatible with science, irrational, and harmful. The other speakers - three
152 THE GOD I)EI,USIGN
agnostics, one Jew, a deist, and 12 Christians (a Muslim philosopher canceled at the last minute) - offered a per- spective clearly skewed in favor of religion and Christianity.
Horgan's article is itself endearingly ambivalent. Despite his mis- givings, there were aspects of the experience that he clearly valued (and so did I, as will become apparent below). Horgan wrote:
My conversations with the faithful deepened my appreci- ation of why some intelligent, well-educated people embrace religion. One reporter discussed the experience of speaking in tongues, and another described having an intimate relationship with Jesus. My convictions did not change, but others' did. At least one fellow said that his faith was wavering as a result of Dawkins's dissection of religion. And if the Templeton Foundation can help bring about even such a tiny step toward my vision of a world without religion, how bad can it be?
Horgan's article was given a second airing by the literary
John Brockman on his 'Edge' website (often described as an on-line scientific salon) where it elicited varying responses, including one from the theoretical physicist Freeman Dyson. I responded to Dyson, quoting from his acceptance speech when he won the Templeton Prize. Whether he liked it or not, by accepting the Templeton Prize Dyson had sent a powerful signal to the world. It would be taken as an endorsement of religion by one of the world's most distinguished physicists.
'I am content to be one of the multitude of Christians who do not care much about the doctrine of the Trinity or the historical truth of the gospels. '
But isn't that exactly what any atheistic scientist would say, if he wanted to sound Christian? I gave further quotations from Dyson's acceptance speech, satirically interspersing them with imagined questions (in italics) to a Templeton official:
agent
WHY T H E R K A L. M O S T C R R T A I N I. Y IS NO CO I) 153
Oh, you want something a bit more profound, as well? How about. . .
'I do not make any clear distinction between mind and God. God is what mind becomes when it has passed beyond the scale of our comprehension. '
Have I said enough yet, and can I get back to doing physics now? Oh, not enough yet? OK then, how about this:
'Even in the gruesome history of the twentieth century, I see some evidence of progress in religion. The two individuals who epitomized the evils of our century, Adolf Hitler and Joseph Stalin, were both avowed atheists. '*
Can I go now?
Dyson could easily refute the implication of these quotations from his Templeton acceptance speech, if only he would explain clearly what evidence he finds to believe in God, in something more than just the Einsteinian sense which, as I explained in Chapter 1, we can all trivially subscribe to. If I understand Horgan's point, it is that Templeton's money corrupts science. I am sure Freeman Dyson is way above being corrupted. But his acceptance speech is still unfortunate if it seems to set an example to others. The Templeton Prize is two orders of magnitude larger than the induce- ments offered to the journalists at Cambridge, having been explicitly set up to be larger than the Nobel Prize. In Faustian vein, my friend the philosopher Daniel Dennett once joked to me, 'Richard, if ever you fall on hard times . . . '
For better or worse, I attended two days at the Cambridge con- ference, giving a talk of my own and taking part in the discussion of several other talks. I challenged the theologians to answer the point that a God capable of designing a universe, or anything else, would have to be complex and statistically improbable. The strongest response I heard was that I was brutally foisting a scientific epistemology upon an unwilling theology, f Theologians had always defined God as simple. Who was I, a scientist, to dictate
* This calumny is dealt with in Chapter 7.
f This accusation is reminiscent of 'NOMA', whose overblown claims I dealt with in Chapter 2.
154 T H E G O I) D R I, U S I O N
to theologians that their God had to be complex? Scientific arguments, such as those I was accustomed to deploying in my own field, were inappropriate since theologians had always maintained that God lay outside science.
I did not gain the impression that the theologians who mounted this evasive defence were being wilfully dishonest. I think they were sincere. Nevertheless, I was irresistibly reminded of Peter Medawar's comment on Father Teilhard de Chardin's The Phenomenon of Man, in the course of what is possibly the greatest negative book review of all time: 'its author can be excused of dis- honesty only on the grounds that before deceiving others he has
73
taken great pains to deceive himself'. The theologians of my
Cambridge encounter were defining themselves into an epistemological Safe Zone where rational argument could not reach them because they had declared by fiat that it could not. Who was I to say that rational argument was the only admissible kind of argument? There are other ways of knowing besides the scientific, and it is one of these other ways of knowing that must be deployed to know God.
The most important of these other ways of knowing turned out to be personal, subjective experience of God. Several discussants at Cambridge claimed that God spoke to them, inside their heads, just as vividly and as personally as another human might. I have dealt with illusion and hallucination in Chapter 3 ('The argument from personal experience'), but at the Cambridge conference I added two points. First, that if God really did communicate with humans that fact would emphatically not lie outside science. God comes bursting through from whatever other-worldly domain is his natural abode, crashing through into our world where his messages can be intercepted by human brains - and that phenomenon has nothing to do with science? Second, a God who is capable of send- ing intelligible signals to millions of people simultaneously, and of receiving messages from all of them simultaneously, cannot be, whatever else he might be, simple. Such bandwidth! God may not have a brain made of neurones, or a CPU made of silicon, but if he has the powers attributed to him he must have something far more elaborately and non-randomly constructed than the largest brain or the largest computer we know.
W H V T H t R t A I MO S T C E R T A I N I. Y I S N O G 0 1) 155
Time and again, my theologian friends returned to the point that there had to be a reason why there is something rather than nothing. There must have been a first cause of everything, and we might as well give it the name God. Yes, I said, but it must have been simple and therefore, whatever else we call it, God is not an appropriate name (unless we very explicitly divest it of all the baggage that the word 'God' carries in the minds of most religious believers). The first cause that we seek must have been the simple basis for a self-bootstrapping crane which eventually raised the world as we know it into its present complex existence. To suggest that the original prime mover was complicated enough to indulge in intelligent design, to say nothing of mindreading millions of humans simultaneously, is tantamount to dealing yourself a perfect hand at bridge. Look around at the world of life, at the Amazon rainforest with its rich interlacement of lianas, bromeliads, roots and flying buttresses; its army ants and its jaguars, its tapirs and peccaries, treefrogs and parrots. What you are looking at is the statistical equivalent of a perfect hand of cards (think of all the other ways you could permute the parts, none of which would work) - except that we know how it came about: by the gradual- istic crane of natural selection. It is not just scientists who revolt at mute acceptance of such improbability arising spontaneously; com- mon sense balks too. To suggest that the first cause, the great unknown which is responsible for something existing rather than nothing, is a being capable of designing the universe and of talking to a million people simultaneously, is a total abdication of the responsibility to find an explanation. It is a dreadful exhibition of self-indulgent, thought-denying skyhookery.
I am not advocating some sort of narrowly scientistic way of thinking. But the very least that any honest quest for truth must have in setting out to explain such monstrosities of improbability as a rainforest, a coral reef, or a universe is a crane and not a skyhook. The crane doesn't have to be natural selection. Admittedly, nobody has ever thought of a better one. But there could be others yet to be discovered. Maybe the 'inflation' that physicists postulate as occupying some fraction of the first yoctosecond of the universe's existence will turn out, when it is better understood, to be a cosmological crane to stand alongside Darwin's biological one. Or
156 THE GOD DELUSION
maybe the elusive crane that cosmologists seek will be a version of Darwin's idea itself: either Smolin's model or something similar. Or maybe it will be the multiverse plus anthropic principle espoused by Martin Rees and others. It may even be a superhuman designer - but, if so, it will most certainly not be a designer who just popped into existence, or who always existed. If (which I don't believe for a moment) our universe was designed, and a fortiori if the designer reads our thoughts and hands out omniscient advice, forgiveness and redemption, the designer himself must be the end product of some kind of cumulative escalator or crane, perhaps a version of Darwinism in another universe.
The last-ditch defence by my critics in Cambridge was attack. My whole world-view was condemned as 'nineteenth-century'. This is such a bad argument that I almost omitted to mention it. But regrettably I encounter it rather frequently. Needless to say, to call an argument nineteenth-century is not the same as explaining what is wrong with it. Some nineteenth-century ideas were very good ideas, not least Darwin's own dangerous idea. In any case, this par- ticular piece of namecalling seemed a bit rich coming, as it did, from an individual (a distinguished Cambridge geologist, surely well advanced along the Faustian road to a future Templeton Prize) who justified his own Christian belief by invoking what he called the historicity of the New Testament. It was precisely in the nineteenth century that theologians, especially in Germany, called into grave doubt that alleged historicity, using the evidence-based methods of history to do so. This was, indeed, swiftly pointed out by the theologians at the Cambridge conference.
In any case, I know the 'nineteenth-century' taunt of old. It goes with the 'village atheist' gibe. It goes with 'Contrary to what you seem to think Ha Ha Ha we don't believe in an old man with a long white beard any more Ha Ha Ha. ' All three jokes are code for something else, just as, when I lived in America in the late 1960s, 'law and order' was politicians' code for anti-black prejudice. * What, then, is the coded meaning of 'You are so nineteenth-century' in the context of an argument about religion? It is code for: 'You are so crude and unsubtle, how could you be so insensitive and ill- mannered as to ask me a direct, point-blank question like "Do you believe in miracles? " or "Do you believe Jesus was born of a
* In Britain 'inner cities' had the equivalent coded meaning, prompting Auberon Waugh's wickedly hilarious reference to 'inner cities of both sexes'.
WHY THERE ALMOST CERT AINL Y IS NO GOD 157
virgin? " Don't you know that in polite society we don't ask such questions? That sort of question went out in the nineteenth century. ' But think about why it is impolite to ask such direct, factual questions of religious people today. It is because it is em- barrassing! But it is the answer that is embarrassing, if it is yes.
The nineteenth-century connection is now clear. The nineteenth century is the last time when it was possible for an educated person to admit to believing in miracles like the virgin birth without embarrass- ment. When pressed, many educated Christians today are too loyal to deny the virgin birth and the resurrection. But it embarrasses them because their rational minds know it is absurd, so they would much rather not be asked. Hence, if somebody like me insists on asking the question, it is I who am accused of being 'nineteenth- century'. It is really quite funny, when you think about it.
I left the conference stimulated and invigorated, and reinforced in my conviction that the argument from improbability - the 'Ultimate 747' gambit - is a very serious argument against the existence of God, and one to which I have yet to hear a theolo- gian give a convincing answer despite numerous opportunities and invitations to do so. Dan Dennett rightly describes it as 'an un- rebuttable refutation, as devastating today as when Philo used it to trounce Cleanthes in Hume's Dialogues two centuries earlier. A sky- hook would at best simply postpone the solution to the problem,
74
but Hume couldn't think of any cranes, so he caved in. ' Darwin,
of course, supplied the vital crane. How Hume would have loved it.
This chapter has contained the central argument of my book, and so, at the risk of sounding repetitive, I shall summarize it as a series of six numbered points.
1
2
One of the greatest challenges to the human intellect, over the centuries, has been to explain how the complex, improbable appearance of design in the universe arises.
The natural temptation is to attribute the appearance of design to actual design itself. In the case of a man-made artefact such as a watch, the designer really was an intelligent engineer. It is tempting to apply the same logic to an eye or a wing, a spider or a person.
158 THE GOD DFLUS)ON
3 The temptation is a false one, because the designer hypothesis immediately raises the larger problem of who designed the designer. The whole problem we started out with was the problem of explaining statistical improbability. It is obviously no solution to postulate something even more improbable. We need a 'crane', not a 'skyhook', for only a crane can do the business of working up gradually and plausibly from simplicity to otherwise improbable complexity.
4 The most ingenious and powerful crane so far discovered is Darwinian evolution by natural selection. Darwin and his successors have shown how living creatures, with their spectacular statistical improbability and appearance of design, have evolved by slow, gradual degrees from simple beginnings. We can now safely say that the illusion of design in living creatures is just that - an illusion.
5 We don't yet have an equivalent crane for physics. Some kind of multiverse theory could in principle do for physics the same explanatory work as Darwinism does for biology. This kind of explanation is superficially less satisfying than the biological version of Darwinism, because it makes heavier demands on luck. But the anthropic principle entitles us to postulate far more luck than our limited human intuition is comfortable with.
6 We should not give up hope of a better crane arising in physics, something as powerful as Darwinism is for biology. But even in the absence of a strongly satisfying crane to match the biological one, the relatively weak cranes we have at present are, when abetted by the anthropic principle, self-evidently better than the self-defeating skyhook hypothesis of an intelligent designer.
If the argument of this chapter is accepted, the factual premise
of religion - the God Hypothesis - is untenable. God almost cer- tainly does not exist. This is the main conclusion of the book so far. Various questions now follow. Even if we accept that God doesn't exist, doesn't religion still have a lot going for it? Isn't it consoling?
WHY THERi; ALMOST CERTAINLY iS NO (,()[) 159
Doesn't it motivate people to do good? If it weren't for religion, how would we know what is good? Why, in any case, be so hostile? Why, if it is false, does every culture in the world have religion? True or false, religion is ubiquitous, so where does it come from? It is to this last question that we turn next.
CHAPTER 5 The roots of religion
To an evolutionary psychologist, the universal extravagance of religious rituals, with their costs in time, resources, pain and privation, should suggest as vividly as a mandrill's bottom that religion may be adaptive.
MAREK KOHN
T H E R O O T S OF R K 1.
i G I () N 163
THE DARWINIAN IMPERATIVE
Everybody has their own pet theory of where religion comes from and why all human cultures have it. It gives consolation and comfort. It fosters togetherness in groups. It satisfies our yearning to understand why we exist. I shall come to explanations of this kind in a moment, but I want to begin with a prior question, one that takes precedence for reasons we shall see: a Darwinian ques- tion about natural selection.
Knowing that we are products of Darwinian evolution, we should ask what pressure or pressures exerted by natural selection originally favoured the impulse to religion. The question gains urgency from standard Darwinian considerations of economy. Religion is so wasteful, so extravagant; and Darwinian selection habitually targets and eliminates waste. Nature is a miserly accountant, grudging the pennies, watching the clock, punishing the smallest extravagance. Unrelentingly and unceasingly, as Darwin explained, 'natural selection is daily and hourly scrutinis- ing, throughout the world, every variation, even the slightest; rejecting that which is bad, preserving and adding up all that is good; silently and insensibly working, whenever and wherever opportunity offers, at the improvement of each organic being'. If a wild animal habitually performs some useless activity, natural selection will favour rival individuals who devote the time and energy, instead, to surviving and reproducing. Nature cannot afford frivolous jeux d'esprit. Ruthless utilitarianism trumps, even if it doesn't always seem that way.
On the face of it, the tail of a peacock is a jeu d'esprit par excellence. It surely does no favours to the survival of its possessor. But it does benefit the genes that distinguish him from his less spectacular rivals. The tail is an advertisement, which buys its place in the economy of nature by attracting females. The same is true of the labour and time that a male bower bird devotes to his bower: a sort of external tail built of grass, twigs, colourful berries, flowers and, when available, beads, baubles and bottle caps. Or, to choose an example that doesn't involve advertising, there is 'anting': the odd habit of birds, such as jays, of 'bathing' in an ants' nest or
164 THE COD DELUSION
otherwise applying ants to the feathers. Nobody is sure what the
benefit of anting is - perhaps some kind of hygiene, cleaning out
parasites from the feathers; there are various other hypotheses,
none of them strongly supported by evidence. But uncertainty as to
details doesn't - nor should it - stop Darwinians from presuming,
with great confidence, that anting must be 'for' something. In this
case common sense might agree, but Darwinian logic has a par-
ticular reason for thinking that, if the birds didn't do it, their
statistical prospects of genetic success would be damaged, even if
we don't yet know the precise route of the damage. The conclusion
follows from the twin premises that natural selection punishes
wastage of time and energy, and that birds are consistently observed
to devote time and energy to anting. If there is a one-sentence man-
ifesto of this 'adaptationist' principle, it was expressed - admittedly
in somewhat extreme and exaggerated terms - by the distinguished
Harvard geneticist Richard Lewontin: 'That is the one point which
I think all evolutionists are agreed upon, that it is virtually impos-
sible to do a better job than an organism is doing in its own
75
environment. ' If anting wasn't positively useful for survival and
reproduction, natural selection would long ago have favoured individuals who refrained from it. A Darwinian might be tempted to say the same of religion; hence the need for this discussion.
To an evolutionist, religious rituals 'stand out like peacocks in a sunlit glade' (Dan Dennett's phrase). Religious behaviour is a writ- large human equivalent of anting or bower-building. It is time-consuming, energy-consuming, often as extravagantly ornate as the plumage of a bird of paradise. Religion can endanger the life of the pious individual, as well as the lives of others. Thousands of people have been tortured for their loyalty to a religion, persecuted by zealots for what is in many cases a scarcely distinguishable alter- native faith. Religion devours resources, sometimes on a massive scale. A medieval cathedral could consume a hundred man- centuries in its construction, yet was never used as a dwelling, or for any recognizably useful purpose. Was it some kind of architec- tural peacock's tail? If so, at whom was the advertisement aimed? Sacred music and devotional paintings largely monopolized medieval and Renaissance talent. Devout people have died for their gods and killed for them; whipped blood from their backs, sworn
THE ROOTS OF RELIGION 165
themselves to a lifetime of celibacy or to lonely silence, all in the service of religion. What is it all for? What is the benefit of religion? By 'benefit', the Darwinian normally means some enhancement to the survival of the individual's genes. What is missing from this is the important point that Darwinian benefit is not restricted to the genes of the individual organism. There are three possible alter- native targets of benefit. One arises from the theory of group selection, and I'll come to that. The second follows from the theory that I advocated in The Extended Phenotype: the individual you are watching may be working under the manipulative influence of genes in another individual, perhaps a parasite. Dan Dennett reminds us that the common cold is universal to all human peoples in much the same way as religion is, yet we would not want to
suggest that colds benefit us. Plenty of examples are known of animals manipulated into behaving in such a way as to benefit the transmission of a parasite to its next host. I encapsulated the point in my 'central theorem of the extended phenotype': 'An animal's behaviour tends to maximize the survival of the genes "for" that behaviour, whether or not those genes happen to be in the body of the particular animal performing it. '
Third, the 'central theorem' may substitute for 'genes' the more general term 'replicators'. The fact that religion is ubiquitous prob- ably means that it has worked to the benefit of something, but it may not be us or our genes. It may be to the benefit of only the religious ideas themselves, to the extent that they behave in a some- what gene-like way, as replicators. I shall deal with this below, under the heading 'Tread softly, because you tread on my memes'. Meanwhile, I press on with more traditional interpretations of Darwinism, in which 'benefit' is assumed to mean benefit to individual survival and reproduction.
Hunter-gatherer peoples such as Australian aboriginal tribes presumably live in something like the way our distant ancestors did. The New Zealand/Australian philosopher of science Kim Sterelny points up a dramatic contrast in their lives. On the one hand aboriginals are superb survivors under conditions that test their practical skills to the uttermost. But, Sterelny goes on, intelligent as our species might be, we are perversely intelligent. The very same peoples who are so savvy about the natural world and how to
166 THE C,()D I)ELUSION
survive in it simultaneously clutter their minds with beliefs that are palpably false and for which the word 'useless' is a generous under- statement. Sterelny himself is familiar with aboriginal peoples of Papua New Guinea. They survive under arduous conditions where food is hard to come by, by dint of 'a legendarily accurate under- standing of their biological environment. But they combine this understanding with deep and destructive obsessions about female menstrual pollution and about witchcraft. Many of the local cultures are tormented by fears of witchcraft and magic, and by the violence that accompanies those fears. ' Sterelny challenges us to
76
explain 'how we can be simultaneously so smart and so dumb'. Though the details differ across the world, no known culture lacks some version of the time-consuming, wealth-consuming, hostility-provoking rituals, the anti-factual, counter-productive fantasies of religion. Some educated individuals may have abandoned religion, but all were brought up in a religious culture from which they usually had to make a conscious decision to
depart. The old Northern Ireland joke, 'Yes, but are you a Protestant atheist or a Catholic atheist? ', is spiked with bitter truth. Religious behaviour can be called a human universal in the same way as heterosexual behaviour can. Both generalizations allow individual exceptions, but all those exceptions understand only too well the rule from which they have departed. Universal features of a species demand a Darwinian explanation.
Obviously, there is no difficulty in explaining the Darwinian advantage of sexual behaviour. It is about making babies, even on those occasions where contraception or homosexuality seems to belie it. But what about religious behaviour? Why do humans fast, kneel, genuflect, self-flagellate, nod maniacally towards a wall, crusade, or otherwise indulge in costly practices that can consume life and, in extreme cases, terminate it?
DIRECT ADVANTAGES OF RELIGION
There is a little evidence that religious belief protects people from stress-related diseases. The evidence is not strong, but it would not
T H E R O O T S ()1
;
R fc L I G I O N 167
be surprising if it were true, for the same kind of reason as faith- healing might turn out to work in a few cases. I wish it were not necessary to add that such beneficial effects in no way boost the truth value of religion's claims. In George Bernard Shaw's words, 'The fact that a believer is happier than a skeptic is no more to the point than the fact that a drunken man is happier than a sober one. '
Part of what a doctor can give a patient is consolation and re- assurance. This is not to be dismissed out of hand. My doctor doesn't literally practise faith-healing by laying on of hands. But many's the time I've been instantly 'cured' of some minor ailment by a reassuring voice from an intelligent face surmounting a stethoscope. The placebo effect is well documented and not even very mysterious. Dummy pills, with no pharmacological activity at all, demonstrably improve health. That is why double-blind drug trials must use placebos as controls. It's why homoeopathic remedies appear to work, even though they are so dilute that they have the same amount of active ingredient as the placebo control - zero molecules. Incidentally, an unfortunate by-product of the encroachment by lawyers on doctors' territory is that doctors are now afraid to prescribe placebos in normal practice. Or bureaucracy may oblige them to identify the placebo in written notes to which the patient has access, which of course defeats the object. Homoeopaths may be achieving relative success because they, unlike orthodox practitioners, are still allowed to administer placebos - under another name. They also have more time to devote to talking and simply being kind to the patient. In the early part of its long history, moreover, homoeopathy's reputation was inadvertently enhanced by the fact that its remedies did nothing at all - by contrast with orthodox medical practices, such as blood- letting, which did active harm.
Is religion a placebo that prolongs life by reducing stress? Possibly, although the theory must run a gauntlet of sceptics who point out the many circumstances in which religion causes rather than relieves stress. It is hard to believe, for example, that health is improved by the semi-permanent state of morbid guilt suffered by a Roman Catholic possessed of normal human frailty and less than normal intelligence. Perhaps it is unfair to single out the Catholics. The American comedian Cathy Ladman observes that 'All religions
168 T H E Ci O D I) E L U S 1 O N
are the same: religion is basically guilt, with different holidays. ' In any case, I find the placebo theory unworthy of the massively pervasive worldwide phenomenon of religion. I don't think the reason we have religion is that it reduced the stress levels of our ancestors. That's not a big enough theory for the job, although it may have played a subsidiary role. Religion is a large phenomenon and it needs a large theory to explain it.
Other theories miss the point of Darwinian explanations altogether. I'm talking about suggestions like 'religion satisfies our curiosity about the universe and our place in it', or 'religion is consoling'. There may be some psychological truth here, as we shall see in Chapter 10, but neither is in itself a Darwinian explanation. As Steven Pinker pointedly said of the consolation theory, in How the Mind Works: 'it only raises the question of why a mind would evolve to find comfort in beliefs it can plainly see are false. A freez- ing person finds no comfort in believing he is warm; a person face-to-face with a lion is not put at ease by the conviction that it is a rabbit. ' At the very least, the consolation theory needs to be trans-
lated into Darwinian terms, and that is harder than you might think. Psychological explanations to the effect that people find some belief agreeable or disagreeable are proximate, not ultimate, explanations.
Darwinians make much of this distinction between proximate and ultimate. The proximate explanation for the explosion in the cylinder of an internal combustion engine invokes the sparking plug. The ultimate explanation concerns the purpose for which the explosion was designed: to impel a piston from the cylinder, thereby turning a crankshaft. The proximate cause of religion might be hyperactivity in a particular node of the brain. I shall not pursue the neurological idea of a 'god centre' in the brain because I am not concerned here with proximate questions. That is not to belittle
them. I recommend Michael Shermer's How We Believe: The Search for God in an Age of Science for a succinct discussion, which includes the suggestion by Michael Persinger and others that visionary religious experiences are related to temporal lobe epilepsy.
But my preoccupation in this chapter is with Darwinian ultimate explanations. If neuroscientists find a 'god centre' in the brain, Darwinian scientists like me will still want to understand the
T H 1-; R O O T S O F R E I 1 C 1 O N 169
natural selection pressure that favoured it. Why did those of our ancestors who had a genetic tendency to grow a god centre survive to have more grandchildren than rivals who didn't? The Darwinian ultimate question is not a better question, not a more profound question, not a more scientific question than the neurological proximate question. But it is the one I am talking about here.
Nor are Darwinians satisfied by political explanations, such as 'Religion is a tool used by the ruling class to subjugate the under- class. ' It is surely true that black slaves in America were consoled by promises of another life, which blunted their dissatisfaction with this one and thereby benefited their owners. The question of whether religions are deliberately designed by cynical priests or rulers is an interesting one, to which historians should attend. But it is not, in itself, a Darwinian question. The Darwinian still wants to know why people are vulnerable to the charms of religion and therefore open to exploitation by priests, politicians and kings.
A cynical manipulator might use sexual lust as a tool of political power, but we still need the Darwinian explanation of why it works. In the case of sexual lust, the answer is easy: our brains are set up to enjoy sex because sex, in the natural state, makes babies. Or a political manipulator might use torture to achieve his ends. Once again, the Darwinian must supply the explanation for why torture is effective; why we will do almost anything to avoid intense pain. Again it seems obvious to the point of banality, but the Darwinian still needs to spell it out: natural selection has set up the perception of pain as a token of life-threatening bodily damage, and programmed us to avoid it. Those rare individuals who cannot feel pain, or don't care about it, usually die young of injuries which the rest of us would have taken steps to avoid. Whether it is cynically exploited, or whether it just manifests itself spontaneously, what ultimately explains the lust for gods?
GROUP SELECTION
Some alleged ultimate explanations turn out to be - or avowedly are - 'group-selection' theories. Group selection is the controversial
170 T H E G O D D E I. U S I O N
idea that Darwinian selection chooses among species or other groups of individuals. The Cambridge archaeologist Colin Renfrew suggests that Christianity survived by a form of group selection because it fostered the idea of in-group loyalty and in-group brotherly love, and this helped religious groups to survive at the expense of less religious groups. The American group-selection apostle D. S. Wilson independently developed a similar suggestion at more length, in Darwin's Cathedral.
Here's an invented 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 rival tribes whose gods
urge peace and harmony, or tribes with no gods at all. Warriors
who unshakeably believe that a martyr's death will send them
straight to paradise fight bravely, and willingly give up their lives.
So tribes with this kind of religion are more likely to survive in
inter-tribal warfare, steal the conquered tribe's livestock and seize
their women as concubines. Such successful tribes prolifically
spawn daughter tribes that go off and propagate more daughter
tribes, all worshipping the same tribal god. The idea of a group
spawning daughter groups, like a beehive throwing off swarms, is
not implausible, by the way. The anthropologist Napoleon
Chagnon mapped just such fissioning of villages in his celebrated
study of the 'Fierce People', the Yanomamo of the South American
77 jungle.
Chagnon is not a supporter of group selection, and nor am I. There are formidable objections to it. A partisan in the controversy, I must beware of riding off on my pet steed Tangent, far from the main track of this book. Some biologists betray a confusion between true group selection, as in my hypothetical example of the god of battles, and something else which they call group selection but which turns out on closer inspection to be either kin selection or reciprocal altruism (see Chapter 6).
Those of us who belittle group selection admit that in principle it can happen. The question is whether it amounts to a significant force in evolution. When it is pitted against selection at lower levels - as when group selection is advanced as an explanation for individual self-sacrifice - lower-level selection is likely to be stronger. In our hypothetical tribe, imagine a single self-interested
THE ROOTS OF RELIGION 171
warrior in an army dominated by aspiring martyrs eager to die for the tribe and earn a heavenly reward. He will be only slightly less likely to end up on the winning side as a result of hanging back in the battle to save his own skin. The martyrdom of his comrades will benefit him more than it benefits each one of them on average, because they will be dead. He is more likely to reproduce than they are, and his genes for refusing to be martyred are more likely to be reproduced into the next generation. Hence tendencies towards martyrdom will decline in future generations.
This is a simplified toy example, but it illustrates a perennial problem with group selection. Group-selection theories of in- dividual self-sacrifice are always vulnerable to subversion from within. Individual deaths and reproductions occur on a faster timescale and with greater frequency than group extinctions and fissionings. Mathematical models can be crafted to come up with special conditions under which group selection might be evolution- arily powerful. These special conditions are usually unrealistic in nature, but it can be argued that religions in human tribal group- ings foster just such otherwise unrealistic special conditions. This is an interesting line of theory, but I shall not pursue it here except to concede that Darwin himself, though he was normally a staunch advocate of selection at the level of the individual organism, came as close as he ever came to group selectionism in his discussion of human tribes:
When two tribes of primeval man, living in the same country, came into competition, if the one tribe included (other circumstances being equal) a greater number of courageous, sympathetic, and faithful members, who were always ready to warn each other of danger, to aid and defend each other, this tribe would without doubt succeed best and conquer the other . . . Selfish and contentious people will not cohere, and without coherence nothing can be effected. A tribe possessing the above qualities in a high degree would spread and be victorious over other tribes; but in the course of time it would, judging from all
past history, be in turn overcome by some other and still
78
more highly-endowed tribe.
172 T H ? . G O D I) E I, U S 1 O N
To satisfy any biological specialists who might be reading this, I should add that Darwin's idea was not strictly group selection, in the true sense of successful groups spawning daughter groups whose frequency might be counted in a metapopulation of groups. Rather, Darwin visualized tribes with altruistically co-operative members spreading and becoming more numerous in terms of numbers of individuals. Darwin's model is more like the spread of the grey squirrel in Britain at the expense of the red: ecological replacement, not true group selection.
RELIGION AS A BY-PRODUCT OF SOMETHING ELSE
In any case, I want now to set aside group selection and turn to my own view of the Darwinian survival value of religion. I am one of an increasing number of biologists who see religion as a by-product of something else. More generally, I believe that we who speculate about Darwinian survival value need to 'think by-product'. When we ask about the survival value of anything, we may be asking the wrong question. We need to rewrite the question in a more helpful way. Perhaps the feature we are interested in (religion in this case) doesn't have a direct survival value of its own, but is a by-product of something else that does. I find it helpful to introduce the by- product idea with an analogy from my own field of animal behaviour.
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, under that provocative name, wonder how on earth natural selection could favour it. My point is that we must rewrite the question before we can even attempt an intelligent answer. It isn't suicide. Apparent suicide emerges as an inadvertent side-effect or by-product of something else. A by-product of . . . what? Well, here's one possibility, which will serve to make the point.
Artificial light is a recent arrival on the night scene. Until
T H I', R O () T S OF R K I. I G I O N 173
recently, the only night lights on view were the moon and the stars. They are at optical infinity, so rays coming from them are parallel. This fits them for use as compasses. Insects are known to use celestial objects such as the sun and the moon to steer accurately in a straight line, and 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 of this kind: 'Steer a course such that the light rays hit your eye at an angle of 30 degrees. ' Since insects have compound eyes (with straight tubes or light guides radiating out from the centre of the eye like the spines of a hedgehog), this might amount in practice to something as simple as keeping the light in one particular tube or ommatidium.
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 applying a 30-degree (or any acute angle) rule of thumb to a nearby candle, as though it were the moon at optical infinity, will steer the moth, via a spiral trajectory, into the flame. Draw it out for yourself, using some par- ticular acute angle such as 30 degrees, and you'll produce an elegant logarithmic spiral into the candle.
i same!
Theism claims that every other object which exists is caused to exist and kept in existence by just one sub- stance, God. And it claims that every property which every substance has is due to God causing or permitting it to exist. It is a hallmark of a simple explanation to postulate few causes. There could in this respect be no
WHY THKRK ALVI OS I CERTAINLY IS NO (,()]) 149
simpler explanation than one which postulated only one cause. Theism is simpler than polytheism. And theism postulates for its one cause, a person [with] infinite power (God can do anything logically possible), infinite knowledge (God knows everything logically possible to know), and infinite freedom.
Swinburne generously concedes that God cannot accomplish feats that are logically impossible, and one feels grateful for this forbearance. Having said that, there is no limit to the explanatory purposes to which God's infinite power is put. Is science having a little difficulty explaining X? No problem. Don't give X another glance. God's infinite power is effortlessly wheeled in to explain X (along with everything else), and it is always a supremely simple explanation because, after all, there is only one God. What could be simpler than that?
Well, actually, almost everything. A God capable of con- tinuously monitoring and controlling the individual status of every particle in the universe cannot be simple. His existence is going to need a mammoth explanation in its own right. Worse (from the point of view of simplicity), other corners of God's giant consciousness are simultaneously preoccupied with the doings and emotions and prayers of every single human being - and whatever intelligent aliens there might be on other planets in this and 100 billion other galaxies. He even, according to Swinburne, has to decide continuously not to intervene miraculously to save us when we get cancer. That would never do, for, 'If God answered most prayers for a relative to recover from cancer, then cancer would no longer be a problem for humans to solve. ' And then what would we find to do with our time?
Not all theologians go as far as Swinburne. Nevertheless, the remarkable suggestion that the God Hypothesis is simple can be found in other modern theological writings. Keith Ward, then Regius Professor of Divinity at Oxford, was very clear on the matter in his 1996 book God, Chance and Necessity:
As a matter of fact, the theist would claim that God is a very elegant, economical and fruitful explanation for the
150
'1 H K G O 1) I) F I. U S I O X
existence of the universe. It is economical because it attributes the existence and nature of absolutely every- thing in the universe to just one being, an ultimate cause which assigns a reason for the existence of everything, including itself. It is elegant because from one key idea - the idea of the most perfect possible being - the whole nature of God and the existence of the universe can be intelligibly explicated.
Like Swinburne, Ward mistakes what it means to explain some-
thing, and he also seems not to understand what it means to say of
something that it is simple. I am not clear whether Ward really
thinks God is simple, or whether the above passage represented a
temporary 'for the sake of argument' exercise. Sir John
Polkinghorne, in Science and Christian Belief, quotes Ward's earlier
criticism of the thought of Thomas Aquinas: 'Its basic error is in
supposing that God is logically simple - simple not just in the sense
that his being is indivisible, but in the much stronger sense that
what is true of any part of God is true of the whole. It is quite
coherent, however, to suppose that God, while indivisible, is inter-
nally complex. ' Ward gets it right here. Indeed, the biologist Julian
Huxley, in 1912, defined complexity in terms of 'heterogeneity of
parts', by which he meant a particular kind of functional
71 indivisibility.
Elsewhere, Ward gives evidence of the difficulty the theological mind has in grasping where the complexity of life comes from. He quotes another theologian-scientist, the biochemist Arthur Peacocke (the third member of my trio of British religious scientists), as postulating the existence in living matter of a 'propensity for increased complexity'. Ward characterizes this as 'some inherent weighting of evolutionary change which favours complexity'. He goes on to suggest that such a bias 'might be some weighting of the mutational process, to ensure that more complex mutations occurred'. Ward is sceptical of this, as well he should be. The evolutionary drive towards complexity comes, in those lineages where it comes at all, not from any inherent propensity for increased complexity, and not from biased mutation. It comes from natural selection: the process which, as far as we know, is the only
WHY THHRB ALMOST CERTAINLY IS NO COD 151
process ultimately capable of generating complexity out of simplicity. The theory of natural selection is genuinely simple. So is the origin from which it starts. That which it explains, on the other hand, is complex almost beyond telling: more complex than any- thing we can imagine, save a God capable of designing it.
AN INTERLUDE AT CAMBRIDGE
At a recent Cambridge conference on science and religion, where I put forward the argument I am here calling the Ultimate 747 argument, I encountered what, to say the least, was a cordial failure to achieve a meeting of minds on the question of God's simplicity. The experience was a revealing one, and I'd like to share it.
First I should confess (that is probably the right word) that the conference was sponsored by the Templeton Foundation. The audience was a small number of hand-picked science journalists from Britain and America. I was the token atheist among the eighteen invited speakers. One of the journalists, John Horgan, reported that they had each been paid the handsome sum of $15,000 to attend the conference, on top of all expenses. This surprised me. My long experience of academic conferences included no instances where the audience (as opposed to the speakers) was paid to attend. If I had known, my suspicions would immediately have been aroused. Was Templeton using his money to suborn science journalists and subvert their scientific integrity? John Horgan later wondered the same thing and wrote an article about
72
his whole experience. In it he revealed, to my chagrin, that my
advertised involvement as a speaker had helped him and others to overcome their doubts:
The British biologist Richard Dawkins, whose partici- pation in the meeting helped convince me and other fellows of its legitimacy, was the only speaker who denounced religious beliefs as incompatible with science, irrational, and harmful. The other speakers - three
152 THE GOD I)EI,USIGN
agnostics, one Jew, a deist, and 12 Christians (a Muslim philosopher canceled at the last minute) - offered a per- spective clearly skewed in favor of religion and Christianity.
Horgan's article is itself endearingly ambivalent. Despite his mis- givings, there were aspects of the experience that he clearly valued (and so did I, as will become apparent below). Horgan wrote:
My conversations with the faithful deepened my appreci- ation of why some intelligent, well-educated people embrace religion. One reporter discussed the experience of speaking in tongues, and another described having an intimate relationship with Jesus. My convictions did not change, but others' did. At least one fellow said that his faith was wavering as a result of Dawkins's dissection of religion. And if the Templeton Foundation can help bring about even such a tiny step toward my vision of a world without religion, how bad can it be?
Horgan's article was given a second airing by the literary
John Brockman on his 'Edge' website (often described as an on-line scientific salon) where it elicited varying responses, including one from the theoretical physicist Freeman Dyson. I responded to Dyson, quoting from his acceptance speech when he won the Templeton Prize. Whether he liked it or not, by accepting the Templeton Prize Dyson had sent a powerful signal to the world. It would be taken as an endorsement of religion by one of the world's most distinguished physicists.
'I am content to be one of the multitude of Christians who do not care much about the doctrine of the Trinity or the historical truth of the gospels. '
But isn't that exactly what any atheistic scientist would say, if he wanted to sound Christian? I gave further quotations from Dyson's acceptance speech, satirically interspersing them with imagined questions (in italics) to a Templeton official:
agent
WHY T H E R K A L. M O S T C R R T A I N I. Y IS NO CO I) 153
Oh, you want something a bit more profound, as well? How about. . .
'I do not make any clear distinction between mind and God. God is what mind becomes when it has passed beyond the scale of our comprehension. '
Have I said enough yet, and can I get back to doing physics now? Oh, not enough yet? OK then, how about this:
'Even in the gruesome history of the twentieth century, I see some evidence of progress in religion. The two individuals who epitomized the evils of our century, Adolf Hitler and Joseph Stalin, were both avowed atheists. '*
Can I go now?
Dyson could easily refute the implication of these quotations from his Templeton acceptance speech, if only he would explain clearly what evidence he finds to believe in God, in something more than just the Einsteinian sense which, as I explained in Chapter 1, we can all trivially subscribe to. If I understand Horgan's point, it is that Templeton's money corrupts science. I am sure Freeman Dyson is way above being corrupted. But his acceptance speech is still unfortunate if it seems to set an example to others. The Templeton Prize is two orders of magnitude larger than the induce- ments offered to the journalists at Cambridge, having been explicitly set up to be larger than the Nobel Prize. In Faustian vein, my friend the philosopher Daniel Dennett once joked to me, 'Richard, if ever you fall on hard times . . . '
For better or worse, I attended two days at the Cambridge con- ference, giving a talk of my own and taking part in the discussion of several other talks. I challenged the theologians to answer the point that a God capable of designing a universe, or anything else, would have to be complex and statistically improbable. The strongest response I heard was that I was brutally foisting a scientific epistemology upon an unwilling theology, f Theologians had always defined God as simple. Who was I, a scientist, to dictate
* This calumny is dealt with in Chapter 7.
f This accusation is reminiscent of 'NOMA', whose overblown claims I dealt with in Chapter 2.
154 T H E G O I) D R I, U S I O N
to theologians that their God had to be complex? Scientific arguments, such as those I was accustomed to deploying in my own field, were inappropriate since theologians had always maintained that God lay outside science.
I did not gain the impression that the theologians who mounted this evasive defence were being wilfully dishonest. I think they were sincere. Nevertheless, I was irresistibly reminded of Peter Medawar's comment on Father Teilhard de Chardin's The Phenomenon of Man, in the course of what is possibly the greatest negative book review of all time: 'its author can be excused of dis- honesty only on the grounds that before deceiving others he has
73
taken great pains to deceive himself'. The theologians of my
Cambridge encounter were defining themselves into an epistemological Safe Zone where rational argument could not reach them because they had declared by fiat that it could not. Who was I to say that rational argument was the only admissible kind of argument? There are other ways of knowing besides the scientific, and it is one of these other ways of knowing that must be deployed to know God.
The most important of these other ways of knowing turned out to be personal, subjective experience of God. Several discussants at Cambridge claimed that God spoke to them, inside their heads, just as vividly and as personally as another human might. I have dealt with illusion and hallucination in Chapter 3 ('The argument from personal experience'), but at the Cambridge conference I added two points. First, that if God really did communicate with humans that fact would emphatically not lie outside science. God comes bursting through from whatever other-worldly domain is his natural abode, crashing through into our world where his messages can be intercepted by human brains - and that phenomenon has nothing to do with science? Second, a God who is capable of send- ing intelligible signals to millions of people simultaneously, and of receiving messages from all of them simultaneously, cannot be, whatever else he might be, simple. Such bandwidth! God may not have a brain made of neurones, or a CPU made of silicon, but if he has the powers attributed to him he must have something far more elaborately and non-randomly constructed than the largest brain or the largest computer we know.
W H V T H t R t A I MO S T C E R T A I N I. Y I S N O G 0 1) 155
Time and again, my theologian friends returned to the point that there had to be a reason why there is something rather than nothing. There must have been a first cause of everything, and we might as well give it the name God. Yes, I said, but it must have been simple and therefore, whatever else we call it, God is not an appropriate name (unless we very explicitly divest it of all the baggage that the word 'God' carries in the minds of most religious believers). The first cause that we seek must have been the simple basis for a self-bootstrapping crane which eventually raised the world as we know it into its present complex existence. To suggest that the original prime mover was complicated enough to indulge in intelligent design, to say nothing of mindreading millions of humans simultaneously, is tantamount to dealing yourself a perfect hand at bridge. Look around at the world of life, at the Amazon rainforest with its rich interlacement of lianas, bromeliads, roots and flying buttresses; its army ants and its jaguars, its tapirs and peccaries, treefrogs and parrots. What you are looking at is the statistical equivalent of a perfect hand of cards (think of all the other ways you could permute the parts, none of which would work) - except that we know how it came about: by the gradual- istic crane of natural selection. It is not just scientists who revolt at mute acceptance of such improbability arising spontaneously; com- mon sense balks too. To suggest that the first cause, the great unknown which is responsible for something existing rather than nothing, is a being capable of designing the universe and of talking to a million people simultaneously, is a total abdication of the responsibility to find an explanation. It is a dreadful exhibition of self-indulgent, thought-denying skyhookery.
I am not advocating some sort of narrowly scientistic way of thinking. But the very least that any honest quest for truth must have in setting out to explain such monstrosities of improbability as a rainforest, a coral reef, or a universe is a crane and not a skyhook. The crane doesn't have to be natural selection. Admittedly, nobody has ever thought of a better one. But there could be others yet to be discovered. Maybe the 'inflation' that physicists postulate as occupying some fraction of the first yoctosecond of the universe's existence will turn out, when it is better understood, to be a cosmological crane to stand alongside Darwin's biological one. Or
156 THE GOD DELUSION
maybe the elusive crane that cosmologists seek will be a version of Darwin's idea itself: either Smolin's model or something similar. Or maybe it will be the multiverse plus anthropic principle espoused by Martin Rees and others. It may even be a superhuman designer - but, if so, it will most certainly not be a designer who just popped into existence, or who always existed. If (which I don't believe for a moment) our universe was designed, and a fortiori if the designer reads our thoughts and hands out omniscient advice, forgiveness and redemption, the designer himself must be the end product of some kind of cumulative escalator or crane, perhaps a version of Darwinism in another universe.
The last-ditch defence by my critics in Cambridge was attack. My whole world-view was condemned as 'nineteenth-century'. This is such a bad argument that I almost omitted to mention it. But regrettably I encounter it rather frequently. Needless to say, to call an argument nineteenth-century is not the same as explaining what is wrong with it. Some nineteenth-century ideas were very good ideas, not least Darwin's own dangerous idea. In any case, this par- ticular piece of namecalling seemed a bit rich coming, as it did, from an individual (a distinguished Cambridge geologist, surely well advanced along the Faustian road to a future Templeton Prize) who justified his own Christian belief by invoking what he called the historicity of the New Testament. It was precisely in the nineteenth century that theologians, especially in Germany, called into grave doubt that alleged historicity, using the evidence-based methods of history to do so. This was, indeed, swiftly pointed out by the theologians at the Cambridge conference.
In any case, I know the 'nineteenth-century' taunt of old. It goes with the 'village atheist' gibe. It goes with 'Contrary to what you seem to think Ha Ha Ha we don't believe in an old man with a long white beard any more Ha Ha Ha. ' All three jokes are code for something else, just as, when I lived in America in the late 1960s, 'law and order' was politicians' code for anti-black prejudice. * What, then, is the coded meaning of 'You are so nineteenth-century' in the context of an argument about religion? It is code for: 'You are so crude and unsubtle, how could you be so insensitive and ill- mannered as to ask me a direct, point-blank question like "Do you believe in miracles? " or "Do you believe Jesus was born of a
* In Britain 'inner cities' had the equivalent coded meaning, prompting Auberon Waugh's wickedly hilarious reference to 'inner cities of both sexes'.
WHY THERE ALMOST CERT AINL Y IS NO GOD 157
virgin? " Don't you know that in polite society we don't ask such questions? That sort of question went out in the nineteenth century. ' But think about why it is impolite to ask such direct, factual questions of religious people today. It is because it is em- barrassing! But it is the answer that is embarrassing, if it is yes.
The nineteenth-century connection is now clear. The nineteenth century is the last time when it was possible for an educated person to admit to believing in miracles like the virgin birth without embarrass- ment. When pressed, many educated Christians today are too loyal to deny the virgin birth and the resurrection. But it embarrasses them because their rational minds know it is absurd, so they would much rather not be asked. Hence, if somebody like me insists on asking the question, it is I who am accused of being 'nineteenth- century'. It is really quite funny, when you think about it.
I left the conference stimulated and invigorated, and reinforced in my conviction that the argument from improbability - the 'Ultimate 747' gambit - is a very serious argument against the existence of God, and one to which I have yet to hear a theolo- gian give a convincing answer despite numerous opportunities and invitations to do so. Dan Dennett rightly describes it as 'an un- rebuttable refutation, as devastating today as when Philo used it to trounce Cleanthes in Hume's Dialogues two centuries earlier. A sky- hook would at best simply postpone the solution to the problem,
74
but Hume couldn't think of any cranes, so he caved in. ' Darwin,
of course, supplied the vital crane. How Hume would have loved it.
This chapter has contained the central argument of my book, and so, at the risk of sounding repetitive, I shall summarize it as a series of six numbered points.
1
2
One of the greatest challenges to the human intellect, over the centuries, has been to explain how the complex, improbable appearance of design in the universe arises.
The natural temptation is to attribute the appearance of design to actual design itself. In the case of a man-made artefact such as a watch, the designer really was an intelligent engineer. It is tempting to apply the same logic to an eye or a wing, a spider or a person.
158 THE GOD DFLUS)ON
3 The temptation is a false one, because the designer hypothesis immediately raises the larger problem of who designed the designer. The whole problem we started out with was the problem of explaining statistical improbability. It is obviously no solution to postulate something even more improbable. We need a 'crane', not a 'skyhook', for only a crane can do the business of working up gradually and plausibly from simplicity to otherwise improbable complexity.
4 The most ingenious and powerful crane so far discovered is Darwinian evolution by natural selection. Darwin and his successors have shown how living creatures, with their spectacular statistical improbability and appearance of design, have evolved by slow, gradual degrees from simple beginnings. We can now safely say that the illusion of design in living creatures is just that - an illusion.
5 We don't yet have an equivalent crane for physics. Some kind of multiverse theory could in principle do for physics the same explanatory work as Darwinism does for biology. This kind of explanation is superficially less satisfying than the biological version of Darwinism, because it makes heavier demands on luck. But the anthropic principle entitles us to postulate far more luck than our limited human intuition is comfortable with.
6 We should not give up hope of a better crane arising in physics, something as powerful as Darwinism is for biology. But even in the absence of a strongly satisfying crane to match the biological one, the relatively weak cranes we have at present are, when abetted by the anthropic principle, self-evidently better than the self-defeating skyhook hypothesis of an intelligent designer.
If the argument of this chapter is accepted, the factual premise
of religion - the God Hypothesis - is untenable. God almost cer- tainly does not exist. This is the main conclusion of the book so far. Various questions now follow. Even if we accept that God doesn't exist, doesn't religion still have a lot going for it? Isn't it consoling?
WHY THERi; ALMOST CERTAINLY iS NO (,()[) 159
Doesn't it motivate people to do good? If it weren't for religion, how would we know what is good? Why, in any case, be so hostile? Why, if it is false, does every culture in the world have religion? True or false, religion is ubiquitous, so where does it come from? It is to this last question that we turn next.
CHAPTER 5 The roots of religion
To an evolutionary psychologist, the universal extravagance of religious rituals, with their costs in time, resources, pain and privation, should suggest as vividly as a mandrill's bottom that religion may be adaptive.
MAREK KOHN
T H E R O O T S OF R K 1.
i G I () N 163
THE DARWINIAN IMPERATIVE
Everybody has their own pet theory of where religion comes from and why all human cultures have it. It gives consolation and comfort. It fosters togetherness in groups. It satisfies our yearning to understand why we exist. I shall come to explanations of this kind in a moment, but I want to begin with a prior question, one that takes precedence for reasons we shall see: a Darwinian ques- tion about natural selection.
Knowing that we are products of Darwinian evolution, we should ask what pressure or pressures exerted by natural selection originally favoured the impulse to religion. The question gains urgency from standard Darwinian considerations of economy. Religion is so wasteful, so extravagant; and Darwinian selection habitually targets and eliminates waste. Nature is a miserly accountant, grudging the pennies, watching the clock, punishing the smallest extravagance. Unrelentingly and unceasingly, as Darwin explained, 'natural selection is daily and hourly scrutinis- ing, throughout the world, every variation, even the slightest; rejecting that which is bad, preserving and adding up all that is good; silently and insensibly working, whenever and wherever opportunity offers, at the improvement of each organic being'. If a wild animal habitually performs some useless activity, natural selection will favour rival individuals who devote the time and energy, instead, to surviving and reproducing. Nature cannot afford frivolous jeux d'esprit. Ruthless utilitarianism trumps, even if it doesn't always seem that way.
On the face of it, the tail of a peacock is a jeu d'esprit par excellence. It surely does no favours to the survival of its possessor. But it does benefit the genes that distinguish him from his less spectacular rivals. The tail is an advertisement, which buys its place in the economy of nature by attracting females. The same is true of the labour and time that a male bower bird devotes to his bower: a sort of external tail built of grass, twigs, colourful berries, flowers and, when available, beads, baubles and bottle caps. Or, to choose an example that doesn't involve advertising, there is 'anting': the odd habit of birds, such as jays, of 'bathing' in an ants' nest or
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otherwise applying ants to the feathers. Nobody is sure what the
benefit of anting is - perhaps some kind of hygiene, cleaning out
parasites from the feathers; there are various other hypotheses,
none of them strongly supported by evidence. But uncertainty as to
details doesn't - nor should it - stop Darwinians from presuming,
with great confidence, that anting must be 'for' something. In this
case common sense might agree, but Darwinian logic has a par-
ticular reason for thinking that, if the birds didn't do it, their
statistical prospects of genetic success would be damaged, even if
we don't yet know the precise route of the damage. The conclusion
follows from the twin premises that natural selection punishes
wastage of time and energy, and that birds are consistently observed
to devote time and energy to anting. If there is a one-sentence man-
ifesto of this 'adaptationist' principle, it was expressed - admittedly
in somewhat extreme and exaggerated terms - by the distinguished
Harvard geneticist Richard Lewontin: 'That is the one point which
I think all evolutionists are agreed upon, that it is virtually impos-
sible to do a better job than an organism is doing in its own
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environment. ' If anting wasn't positively useful for survival and
reproduction, natural selection would long ago have favoured individuals who refrained from it. A Darwinian might be tempted to say the same of religion; hence the need for this discussion.
To an evolutionist, religious rituals 'stand out like peacocks in a sunlit glade' (Dan Dennett's phrase). Religious behaviour is a writ- large human equivalent of anting or bower-building. It is time-consuming, energy-consuming, often as extravagantly ornate as the plumage of a bird of paradise. Religion can endanger the life of the pious individual, as well as the lives of others. Thousands of people have been tortured for their loyalty to a religion, persecuted by zealots for what is in many cases a scarcely distinguishable alter- native faith. Religion devours resources, sometimes on a massive scale. A medieval cathedral could consume a hundred man- centuries in its construction, yet was never used as a dwelling, or for any recognizably useful purpose. Was it some kind of architec- tural peacock's tail? If so, at whom was the advertisement aimed? Sacred music and devotional paintings largely monopolized medieval and Renaissance talent. Devout people have died for their gods and killed for them; whipped blood from their backs, sworn
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themselves to a lifetime of celibacy or to lonely silence, all in the service of religion. What is it all for? What is the benefit of religion? By 'benefit', the Darwinian normally means some enhancement to the survival of the individual's genes. What is missing from this is the important point that Darwinian benefit is not restricted to the genes of the individual organism. There are three possible alter- native targets of benefit. One arises from the theory of group selection, and I'll come to that. The second follows from the theory that I advocated in The Extended Phenotype: the individual you are watching may be working under the manipulative influence of genes in another individual, perhaps a parasite. Dan Dennett reminds us that the common cold is universal to all human peoples in much the same way as religion is, yet we would not want to
suggest that colds benefit us. Plenty of examples are known of animals manipulated into behaving in such a way as to benefit the transmission of a parasite to its next host. I encapsulated the point in my 'central theorem of the extended phenotype': 'An animal's behaviour tends to maximize the survival of the genes "for" that behaviour, whether or not those genes happen to be in the body of the particular animal performing it. '
Third, the 'central theorem' may substitute for 'genes' the more general term 'replicators'. The fact that religion is ubiquitous prob- ably means that it has worked to the benefit of something, but it may not be us or our genes. It may be to the benefit of only the religious ideas themselves, to the extent that they behave in a some- what gene-like way, as replicators. I shall deal with this below, under the heading 'Tread softly, because you tread on my memes'. Meanwhile, I press on with more traditional interpretations of Darwinism, in which 'benefit' is assumed to mean benefit to individual survival and reproduction.
Hunter-gatherer peoples such as Australian aboriginal tribes presumably live in something like the way our distant ancestors did. The New Zealand/Australian philosopher of science Kim Sterelny points up a dramatic contrast in their lives. On the one hand aboriginals are superb survivors under conditions that test their practical skills to the uttermost. But, Sterelny goes on, intelligent as our species might be, we are perversely intelligent. The very same peoples who are so savvy about the natural world and how to
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survive in it simultaneously clutter their minds with beliefs that are palpably false and for which the word 'useless' is a generous under- statement. Sterelny himself is familiar with aboriginal peoples of Papua New Guinea. They survive under arduous conditions where food is hard to come by, by dint of 'a legendarily accurate under- standing of their biological environment. But they combine this understanding with deep and destructive obsessions about female menstrual pollution and about witchcraft. Many of the local cultures are tormented by fears of witchcraft and magic, and by the violence that accompanies those fears. ' Sterelny challenges us to
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explain 'how we can be simultaneously so smart and so dumb'. Though the details differ across the world, no known culture lacks some version of the time-consuming, wealth-consuming, hostility-provoking rituals, the anti-factual, counter-productive fantasies of religion. Some educated individuals may have abandoned religion, but all were brought up in a religious culture from which they usually had to make a conscious decision to
depart. The old Northern Ireland joke, 'Yes, but are you a Protestant atheist or a Catholic atheist? ', is spiked with bitter truth. Religious behaviour can be called a human universal in the same way as heterosexual behaviour can. Both generalizations allow individual exceptions, but all those exceptions understand only too well the rule from which they have departed. Universal features of a species demand a Darwinian explanation.
Obviously, there is no difficulty in explaining the Darwinian advantage of sexual behaviour. It is about making babies, even on those occasions where contraception or homosexuality seems to belie it. But what about religious behaviour? Why do humans fast, kneel, genuflect, self-flagellate, nod maniacally towards a wall, crusade, or otherwise indulge in costly practices that can consume life and, in extreme cases, terminate it?
DIRECT ADVANTAGES OF RELIGION
There is a little evidence that religious belief protects people from stress-related diseases. The evidence is not strong, but it would not
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be surprising if it were true, for the same kind of reason as faith- healing might turn out to work in a few cases. I wish it were not necessary to add that such beneficial effects in no way boost the truth value of religion's claims. In George Bernard Shaw's words, 'The fact that a believer is happier than a skeptic is no more to the point than the fact that a drunken man is happier than a sober one. '
Part of what a doctor can give a patient is consolation and re- assurance. This is not to be dismissed out of hand. My doctor doesn't literally practise faith-healing by laying on of hands. But many's the time I've been instantly 'cured' of some minor ailment by a reassuring voice from an intelligent face surmounting a stethoscope. The placebo effect is well documented and not even very mysterious. Dummy pills, with no pharmacological activity at all, demonstrably improve health. That is why double-blind drug trials must use placebos as controls. It's why homoeopathic remedies appear to work, even though they are so dilute that they have the same amount of active ingredient as the placebo control - zero molecules. Incidentally, an unfortunate by-product of the encroachment by lawyers on doctors' territory is that doctors are now afraid to prescribe placebos in normal practice. Or bureaucracy may oblige them to identify the placebo in written notes to which the patient has access, which of course defeats the object. Homoeopaths may be achieving relative success because they, unlike orthodox practitioners, are still allowed to administer placebos - under another name. They also have more time to devote to talking and simply being kind to the patient. In the early part of its long history, moreover, homoeopathy's reputation was inadvertently enhanced by the fact that its remedies did nothing at all - by contrast with orthodox medical practices, such as blood- letting, which did active harm.
Is religion a placebo that prolongs life by reducing stress? Possibly, although the theory must run a gauntlet of sceptics who point out the many circumstances in which religion causes rather than relieves stress. It is hard to believe, for example, that health is improved by the semi-permanent state of morbid guilt suffered by a Roman Catholic possessed of normal human frailty and less than normal intelligence. Perhaps it is unfair to single out the Catholics. The American comedian Cathy Ladman observes that 'All religions
168 T H E Ci O D I) E L U S 1 O N
are the same: religion is basically guilt, with different holidays. ' In any case, I find the placebo theory unworthy of the massively pervasive worldwide phenomenon of religion. I don't think the reason we have religion is that it reduced the stress levels of our ancestors. That's not a big enough theory for the job, although it may have played a subsidiary role. Religion is a large phenomenon and it needs a large theory to explain it.
Other theories miss the point of Darwinian explanations altogether. I'm talking about suggestions like 'religion satisfies our curiosity about the universe and our place in it', or 'religion is consoling'. There may be some psychological truth here, as we shall see in Chapter 10, but neither is in itself a Darwinian explanation. As Steven Pinker pointedly said of the consolation theory, in How the Mind Works: 'it only raises the question of why a mind would evolve to find comfort in beliefs it can plainly see are false. A freez- ing person finds no comfort in believing he is warm; a person face-to-face with a lion is not put at ease by the conviction that it is a rabbit. ' At the very least, the consolation theory needs to be trans-
lated into Darwinian terms, and that is harder than you might think. Psychological explanations to the effect that people find some belief agreeable or disagreeable are proximate, not ultimate, explanations.
Darwinians make much of this distinction between proximate and ultimate. The proximate explanation for the explosion in the cylinder of an internal combustion engine invokes the sparking plug. The ultimate explanation concerns the purpose for which the explosion was designed: to impel a piston from the cylinder, thereby turning a crankshaft. The proximate cause of religion might be hyperactivity in a particular node of the brain. I shall not pursue the neurological idea of a 'god centre' in the brain because I am not concerned here with proximate questions. That is not to belittle
them. I recommend Michael Shermer's How We Believe: The Search for God in an Age of Science for a succinct discussion, which includes the suggestion by Michael Persinger and others that visionary religious experiences are related to temporal lobe epilepsy.
But my preoccupation in this chapter is with Darwinian ultimate explanations. If neuroscientists find a 'god centre' in the brain, Darwinian scientists like me will still want to understand the
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natural selection pressure that favoured it. Why did those of our ancestors who had a genetic tendency to grow a god centre survive to have more grandchildren than rivals who didn't? The Darwinian ultimate question is not a better question, not a more profound question, not a more scientific question than the neurological proximate question. But it is the one I am talking about here.
Nor are Darwinians satisfied by political explanations, such as 'Religion is a tool used by the ruling class to subjugate the under- class. ' It is surely true that black slaves in America were consoled by promises of another life, which blunted their dissatisfaction with this one and thereby benefited their owners. The question of whether religions are deliberately designed by cynical priests or rulers is an interesting one, to which historians should attend. But it is not, in itself, a Darwinian question. The Darwinian still wants to know why people are vulnerable to the charms of religion and therefore open to exploitation by priests, politicians and kings.
A cynical manipulator might use sexual lust as a tool of political power, but we still need the Darwinian explanation of why it works. In the case of sexual lust, the answer is easy: our brains are set up to enjoy sex because sex, in the natural state, makes babies. Or a political manipulator might use torture to achieve his ends. Once again, the Darwinian must supply the explanation for why torture is effective; why we will do almost anything to avoid intense pain. Again it seems obvious to the point of banality, but the Darwinian still needs to spell it out: natural selection has set up the perception of pain as a token of life-threatening bodily damage, and programmed us to avoid it. Those rare individuals who cannot feel pain, or don't care about it, usually die young of injuries which the rest of us would have taken steps to avoid. Whether it is cynically exploited, or whether it just manifests itself spontaneously, what ultimately explains the lust for gods?
GROUP SELECTION
Some alleged ultimate explanations turn out to be - or avowedly are - 'group-selection' theories. Group selection is the controversial
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idea that Darwinian selection chooses among species or other groups of individuals. The Cambridge archaeologist Colin Renfrew suggests that Christianity survived by a form of group selection because it fostered the idea of in-group loyalty and in-group brotherly love, and this helped religious groups to survive at the expense of less religious groups. The American group-selection apostle D. S. Wilson independently developed a similar suggestion at more length, in Darwin's Cathedral.
Here's an invented 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 rival tribes whose gods
urge peace and harmony, or tribes with no gods at all. Warriors
who unshakeably believe that a martyr's death will send them
straight to paradise fight bravely, and willingly give up their lives.
So tribes with this kind of religion are more likely to survive in
inter-tribal warfare, steal the conquered tribe's livestock and seize
their women as concubines. Such successful tribes prolifically
spawn daughter tribes that go off and propagate more daughter
tribes, all worshipping the same tribal god. The idea of a group
spawning daughter groups, like a beehive throwing off swarms, is
not implausible, by the way. The anthropologist Napoleon
Chagnon mapped just such fissioning of villages in his celebrated
study of the 'Fierce People', the Yanomamo of the South American
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Chagnon is not a supporter of group selection, and nor am I. There are formidable objections to it. A partisan in the controversy, I must beware of riding off on my pet steed Tangent, far from the main track of this book. Some biologists betray a confusion between true group selection, as in my hypothetical example of the god of battles, and something else which they call group selection but which turns out on closer inspection to be either kin selection or reciprocal altruism (see Chapter 6).
Those of us who belittle group selection admit that in principle it can happen. The question is whether it amounts to a significant force in evolution. When it is pitted against selection at lower levels - as when group selection is advanced as an explanation for individual self-sacrifice - lower-level selection is likely to be stronger. In our hypothetical tribe, imagine a single self-interested
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warrior in an army dominated by aspiring martyrs eager to die for the tribe and earn a heavenly reward. He will be only slightly less likely to end up on the winning side as a result of hanging back in the battle to save his own skin. The martyrdom of his comrades will benefit him more than it benefits each one of them on average, because they will be dead. He is more likely to reproduce than they are, and his genes for refusing to be martyred are more likely to be reproduced into the next generation. Hence tendencies towards martyrdom will decline in future generations.
This is a simplified toy example, but it illustrates a perennial problem with group selection. Group-selection theories of in- dividual self-sacrifice are always vulnerable to subversion from within. Individual deaths and reproductions occur on a faster timescale and with greater frequency than group extinctions and fissionings. Mathematical models can be crafted to come up with special conditions under which group selection might be evolution- arily powerful. These special conditions are usually unrealistic in nature, but it can be argued that religions in human tribal group- ings foster just such otherwise unrealistic special conditions. This is an interesting line of theory, but I shall not pursue it here except to concede that Darwin himself, though he was normally a staunch advocate of selection at the level of the individual organism, came as close as he ever came to group selectionism in his discussion of human tribes:
When two tribes of primeval man, living in the same country, came into competition, if the one tribe included (other circumstances being equal) a greater number of courageous, sympathetic, and faithful members, who were always ready to warn each other of danger, to aid and defend each other, this tribe would without doubt succeed best and conquer the other . . . Selfish and contentious people will not cohere, and without coherence nothing can be effected. A tribe possessing the above qualities in a high degree would spread and be victorious over other tribes; but in the course of time it would, judging from all
past history, be in turn overcome by some other and still
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more highly-endowed tribe.
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To satisfy any biological specialists who might be reading this, I should add that Darwin's idea was not strictly group selection, in the true sense of successful groups spawning daughter groups whose frequency might be counted in a metapopulation of groups. Rather, Darwin visualized tribes with altruistically co-operative members spreading and becoming more numerous in terms of numbers of individuals. Darwin's model is more like the spread of the grey squirrel in Britain at the expense of the red: ecological replacement, not true group selection.
RELIGION AS A BY-PRODUCT OF SOMETHING ELSE
In any case, I want now to set aside group selection and turn to my own view of the Darwinian survival value of religion. I am one of an increasing number of biologists who see religion as a by-product of something else. More generally, I believe that we who speculate about Darwinian survival value need to 'think by-product'. When we ask about the survival value of anything, we may be asking the wrong question. We need to rewrite the question in a more helpful way. Perhaps the feature we are interested in (religion in this case) doesn't have a direct survival value of its own, but is a by-product of something else that does. I find it helpful to introduce the by- product idea with an analogy from my own field of animal behaviour.
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, under that provocative name, wonder how on earth natural selection could favour it. My point is that we must rewrite the question before we can even attempt an intelligent answer. It isn't suicide. Apparent suicide emerges as an inadvertent side-effect or by-product of something else. A by-product of . . . what? Well, here's one possibility, which will serve to make the point.
Artificial light is a recent arrival on the night scene. Until
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recently, the only night lights on view were the moon and the stars. They are at optical infinity, so rays coming from them are parallel. This fits them for use as compasses. Insects are known to use celestial objects such as the sun and the moon to steer accurately in a straight line, and 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 of this kind: 'Steer a course such that the light rays hit your eye at an angle of 30 degrees. ' Since insects have compound eyes (with straight tubes or light guides radiating out from the centre of the eye like the spines of a hedgehog), this might amount in practice to something as simple as keeping the light in one particular tube or ommatidium.
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 applying a 30-degree (or any acute angle) rule of thumb to a nearby candle, as though it were the moon at optical infinity, will steer the moth, via a spiral trajectory, into the flame. Draw it out for yourself, using some par- ticular acute angle such as 30 degrees, and you'll produce an elegant logarithmic spiral into the candle.
