The Selfish Gene

Many critics, especially vociferous ones learned in philosophy as I have discovered, prefer to read a book by title only.

The gene is the unit in the sense of replicator. The organism is the unit in the sense of vehicle.

Personifying genes, if done with due care and caution, often turns out to be the shortest route to rescuing a Darwinian theorist drowning in muddle.

As soon as he reaches it he should give up and preferably let himself be eaten by his litter-mates or his parents.

What should we have done, fiddled the equations?

Its reputation for contentiousness took years to grow until, by now, it is widely regarded as a work of radical extremism.

If you push novelty of language and metaphor far enough, you can end up with a new way of seeing.

The chimpanzee and the human share about 99.5 per cent of their evolutionary history, yet most human thinkers regard the chimp as a malformed, irrelevant oddity while seeing themselves as stepping-stones to the Almighty.

We are survival machines—robot vehicles blindly programmed to preserve the selfish molecules known as genes.

I have long felt that biology ought to seem as exciting as a mystery story, for a mystery story is exactly what biology is.

If superior creatures from space ever visit earth, the first question they will ask, hi order to assess the level of our civilization, is: 'Have they discovered evolution yet?'

Let us try to teach generosity and altruism, because we are born selfish.

I am not concerned here with the psychology of motives. I am not going to argue about whether people who behave altruistically are 'really' doing it for secret or subconscious selfish motives.

Indeed, since the insect head is the seat of some inhibitory nerve centres, it is possible that the female improves the male's sexual performance by eating his head.

If it is species that are competing in what Darwin called the struggle for existence, the individual seems best regarded as a pawn in the game, to be sacrified when the greater interest of the species as a whole requires it.

But group extinction is a slow process compared with the rapid cut and thrust of individual competition.

A human foetus, with no more human feeling than an amoeba, enjoys a reverence and legal protection far in excess of those granted to an adult chimpanzee.

Darwin's 'survival of the fittest' is really a special case of a more general law of survival of the stable.

The earliest form of natural selection was simply a selection of stable forms and a rejection of unstable ones.

But bacteria and the rest of us are late-comers, and in those days large organic molecules could drift unmolested through the thickening broth.

We tend to regard erratic copying as a bad thing, and in the case of human documents it is hard to think of examples where errors can be described as improvements.

Evolution is something that happens, willy-nilly, in spite of all the efforts of the replicators (and nowadays of the genes) to prevent it happening.

Now they swarm in huge colonies, safe inside gigantic lumbering robots, sealed off from the outside world, communicating with it by tortuous indirect routes, manipulating it by remote control.

It is as though, in every room of a gigantic building, there was a book-case containing the architect's plans for the entire building.

A body is the genes' way of preserving the genes unaltered.

This means that any one individual body is just a temporary vehicle for a short-lived combination of genes.

What happens is that, during the manufacture of the sperm, single pages, or rather multi-page chunks, are detached and swapped with the corresponding chunks from the alternative volume.

It is as though the architect's plans were written out, not on discrete pages, but on 46 rolls of ticker tape.

The sperm was one of several millions, a vast armada of tiny vessels, and together they sailed into your mother.

A piece of chromosome detaches itself at both ends, turns head over heels, and reattaches itself in the inverted position.

Neighbouring cistrons on the same chromosome form a tightly-knit troupe of travelling companions who seldom fail to get on board the same vessel when meiosis time comes around.

It leaps from body to body down the generations, manipulating body after body in its own way and for its own ends, abandoning a succession of mortal bodies before they sink in senility and death.

The genes are not destroyed by crossing-over, they merely change partners and march on. Of course they march on. That is their business. They are the replicators and we are their survival machines.

The gene is the basic unit of selfishness.

Many a good gene gets into bad company, and finds itself sharing a body with a lethal gene, which kills the body off in childhood.

No doubt some of your cousins and great-uncles died in childhood, but not a single one of your ancestors did. Ancestors just don't die young!

According to this theory then, senile decay is simply a by-product of the accumulation in the gene pool of late-acting lethal and semi-lethal genes, which have been allowed to slip through the net of natural selection simply because they are late-acting.

Why did sex, that bizarre perversion of straightforward replication, ever arise in the first place?

The simplest way to explain the surplus DNA is to suppose that it is a parasite, or at best a harmless but useless passenger, hitching a ride in the survival machines created by the other DNA.

I prefer to think of the body as a colony of genes, and of the cell as a convenient working unit for the chemical industries of the genes.

When seen in highly speeded-up film, climbing plants look like active animals.

Although the width of an axon is microscopic, its length may be many feet: there are single axons which run the whole length of a giraffe's neck.

Nothing remotely approaching consciousness needs to be postulated, even though a layman, watching its apparently deliberate and purposeful behaviour, finds it hard to believe that the missile is not under the direct control of a human pilot.

The genes too control the behaviour of their survival machines, not directly with their fingers on puppet strings, but indirectly like the computer programmer.

The results were nearly disastrous for mankind, for the intentions of the Andromedans were not universally altruistic, and the computer was well on the way to dictatorship over the world before the hero eventually finished it off with an axe.

The currency used in the casino of evolution is survival, strictly gene survival, but for many purposes individual survival is a reasonable approximation.

All we have to believe is that those individuals whose genes build brains in such a way that they tend to gamble correctly are as a direct result more likely to survive.

One way of discovering whether it is a good plan is to try and see, but it is undesirable to use this test for all the tentative plans dreamed up, if only because the supply of young men prepared to die 'for their country' is exhaustible, and the supply of possible plans is very large.

The trouble with overt trial is that it takes time and energy. The trouble with overt error is that it is often fatal.

The susceptible strains are susceptible because they do not practise this hygienic infanticide.

The genes are master programmers, and they are programming for their lives.

The angler is telling a lie, exploiting the little fish's tendency to approach wriggling worm-like objects.

As we shall see, we must even expect that children will deceive their parents, that husbands will cheat on wives, and that brother will lie to brother.

Animals fight with gloved fists and blunted foils. Threat and bluff take the place of deadly earnest.

Remember that we are picturing the animal as a robot survival machine with a pre-programmed computer controlling the muscles.

Hawks always fight as hard and as unrestrainedly as they can, retreating only when seriously injured.

If only everybody would agree to be a dove, every single individual would benefit.

An ESS is stable, not because it is particularly good for the individuals participating in it, but simply because it is immune to treachery from within.

A retaliator behaves like a hawk when he is attacked by a hawk, and like a dove when he meets a dove.

In the war of attrition both contestants pay the price but only one of them gets the goods.

Anybody who betrayed, by the merest flicker of a whisker, that he was beginning to think of throwing in the sponge, would be at an instant disadvantage.

A simple analogy is to humans who settle a dispute quickly and without fuss by tossing a coin.

By simply moving the two tubes from one end of the tank to the other, Tinbergen was able to dictate which male attacked and which retreated.

He used a model cricket to beat up real crickets. After this treatment the real crickets became more likely to lose fights against other real crickets.

The lion genes 'want' the meat as food for their survival machine. The antelope genes want the meat as working muscle and organs for their survival machine.

Selection at the low level of the single gene can give the impression of selection at some higher level.

Well-integrated bodies exist because they are the product of an evolutionarily stable set of selfish genes.

The key point of this chapter is that a gene might be able to assist replicas of itself that are sitting in other bodies.

A gene could prosper in the gene pool if it 'said' the equivalent of: 'Body, if A is drowning as a result of trying to save someone else from drowning, jump in and rescue A.'

The relatedness between two brothers is 1/2, since half the genes possessed by one brother will be found in the other.

A third cousin is not far from being equivalent to any old Tom, Dick, or Harry as far as an altruistic gene is concerned.

The whole point of Hamilton's argument is that the distinction between family and non-family is not hard and fast, but a matter of mathematical probability.

When a man throws a ball high in the air and catches it again, he behaves as if he had solved a set of differential equations in predicting the trajectory of the ball.

What really happens is that die gene pool becomes filled widi genes diat influence bodies in such a way diat they behave as if diey had made such calculations.

Animals have to be given by their genes a simple rule for action, a rule that does not involve all-wise cognition of the ultimate purpose of the action, but a rule that works nevertheless, at least in average conditions.

The rule's 'definition' of a member of the school who is drowning might be something like: 'A long thing thrashing about and choking near the surface.'

I see this as a double mistake, since the adopter not only wastes her own time; she also releases a rival female from the burden of child-rearing, and frees her to have another child more quickly.

So the gene for cheating the system would spread through the population, and the nice friendly baby-sitting circle would break down.

Although the parent/child relationship is no closer genetically than the brother/sister relationship, its certainty is greater.

The poor father is much more vulnerable to deception. It is therefore to be expected that fathers will put less effort than mothers into caring for young.

In a species in which children have a longer average life expectancy than parents, any gene for child altruism would be labouring under a disadvantage.

The one thing that cannot be evolutionarily stable is a pure caring strategy.

They express a preference for 'natural' methods of population limitation, and a natural method is exactly what they are going to get. It is called starvation.

Even in apparently faithful monogamous species, the female may be wedded to a male's territory rather than to him personally.

For Wynne-Edwards, epideictic behaviour is deliberate massing in crowds to facilitate population estimation.

They are practising birth-control in order to maximize the number of surviving children they actually have, an aim which is the very opposite of that which we normally associate with birth-control.

The welfare state is perhaps the greatest altruistic system the animal kingdom has ever known. But any altruistic system is inherently unstable, because it is open to abuse by selfish individuals, ready to exploit it.

The best strategy for a gambler may sometimes be a wait-and-hope strategy, rather than a bull-at-a-gate strategy.

Obviously, if a female is presented with reliable evidence that a famine is to be expected, it is in her own selfish interests to reduce her own birth-rate.

If starlings are estimating population size by the volume of noise in a winter roost, it would pay each individual to shout as loudly as possible, in order to sound more like two starlings than one.

When a child uses up some of its mother's milk, the amount of milk consumed is measured not in pints, not in calories, but in units of detriment to other children of the same mother.

Indeed it may pay her to feed him to his brothers and sisters, or to eat him herself, and use him to make milk.

The difference between the abrupt change of life in women and the gradual fading out of fertility in men suggests that there is something genetically 'deliberate' about the menopause—that it is an 'adaptation'.

Have you ever heard a litter of piglets squealing to be first on the scene when the mother sow lies down to feed them? Or little boys fighting over the last slice of cake?

The runt should die gracefully and willingly. He can benefit his genes most by doing so.

The principle of this ruthless tactic is the same as that of the hijacker threatening to blow up an aeroplane, with himself on board, unless he is given a ransom.

As soon as he hatches out, while he is still blind, naked, and otherwise helpless, he scythes and slashes his foster brothers and sisters to death: dead brothers do not compete for food!

The blood may chill at the thought, but could this be what baby swallows do to each other?

Translating into gene language, a gene for fratricide could conceivably spread through the gene pool, because it has 100 per cent chance of being in the body of the fratricidal individual, and only a 50 per cent chance of being in the body of his victim.

There is really only one entity whose point of view matters in evolution, and that entity is the selfish gene.

But the young are in a strong position to lie, because they know exactly how hungry they are, while the parent can only guess whether they are telling die truth or not.

If there is a human moral to be drawn, it is that we must teach our children altruism, for we cannot expect it to be part of their biological nature.

The advantage to an individual of producing small, rapidly moving gametes would be that he could afford to make a larger number of gametes, and therefore could potentially have more children.

The honest ones became eggs, and the exploiters became sperms.

Those who are producing nothing but daughters are assured of a safe few grandchildren, but this is nothing compared to the glorious genetic possibilities that open up before anyone specializing in sons.

The female sex is exploited, and the fundamental evolutionary basis for the exploitation is the fact that eggs are larger than sperms.

In this way a male mouse destroys his potential step-children, and renders his new wife receptive to his own sexual advances.

The unpleasant truth is that in some circumstances an advantage accrues to the partner who deserts first, whether it is the father or the mother.

A business man should never say 'I have already invested so much in the Concorde airliner (for instance) that I cannot afford to scrap it now.'

In a population in which all the females are fast, philanderer genes will spread like wildfire.

Building a nest may be less romantic than slaying a dragon or swimming the Hellespont, but it is much more useful.

There is a macabre sense in which the unfortunate male mantis can be said to invest in his children.

The male is inevitably provided with an opportunity to take the prior decision to desert, closing the female's options, and forcing her to decide whether to leave the young to certain death, or whether to stay with it and rear it.

In a society where males compete with each other to be chosen as he-men by females, one of the best things a mother can do for her genes is to make a son who will turn out in his turn to be an attractive he-man.

A male bird with a long and cumbersome tail is showing off to females that he is such a strong he-man that he can survive in spite of his tail.

A gene that makes males develop a handicap, such as a long tail, becomes more numerous in the gene pool because females choose males who have handicaps.

What shall it profit a male if he shall gain the whole world, and lose his immortal genes?

A male on the other hand can never get enough copulations with as many different females as possible: the word excess has no meaning for a male.

In the case of birds of paradise, we decided that females are drab because they do not need to compete for males.

There will be a ceaseless migration in from the edges of an aggregation towards the centre.

If an acoustic engineer were asked to design a sound that a predator would find it hard to approach, he would produce something very like the real alarm calls of many small song-birds.

Translated roughly into English it means: 'Look how high I can jump, I am obviously such a fit and healthy gazelle, you can't catch me, you would be much wiser to try and catch my neighbour who is not jumping so high!'

The death of a single sterile worker bee is no more serious to its genes than is the shedding of a leaf in autumn to the genes of a tree.

If such a monstrous queen ever has to move from the royal cell she rides in state on the backs of squadrons of toiling workers.

It follows that a hymenopteran female is more closely related to her full sisters than she is to her offspring of either sex.

If we are right to picture the workers as the farmers and the queen as their brood mare, presumably the workers will be successful in achieving their 3: i ratio.

The slaves are, of course, blissfully ignorant of the fact that they are unrelated to the queen and to the brood that they are tending.

The workers use their mother as a more efficient manufacturer of copies of their own genes than they would be themselves.

It has been suggested diat some aphids have evolved a backside that looks and feels like an ant's face, die better to attract ants.

We are gigantic colonies of symbiotic genes.

B is a cheat, an individual who accepts the benefit of other individuals' altruism, but who does not pay it back, or who pays it back insufficiently.

If a population arrives at an ESS that drives it extinct, then it goes extinct, and that is just too bad.

One might expect that a large fish would craftily wait until he had been thoroughly cleaned, and then gobble up the cleaner.

It is even possible that man's swollen brain, and his predisposition to reason mathematically, evolved as a mechanism of ever more devious cheating, and ever more penetrating detection of cheating in others.

Fashions in dress and diet, ceremonies and customs, art and architecture, engineering and technology, all evolve in historical time in a way that looks like highly speeded up genetic evolution, but has really nothing to do with genetic evolution.

When you plant a fertile meme in my mind you literally parasitize my brain, turning it into a vehicle for the meme's propagation in just the way that a virus may parasitize the genetic mechanism of a host cell.

The 'everlasting arms' hold out a cushion against our own inadequacies which, like a doctor's placebo, is none the less effective for being imaginary.

If a single phrase of Beethoven's ninth symphony is sufficiently distinctive and memorable to be abstracted from the context of the whole symphony, and used as the call-sign of a maddeningly intrusive European broadcasting station, then to that extent it deserves to be called one meme.

The computers in which memes live are human brains.

The meme for blind faith secures its own perpetuation by the simple unconscious expedient of discouraging rational inquiry.

Socrates may or may not have a gene or two alive in the world today, as G. C. Williams has remarked, but who cares? The meme-complexes of Socrates, Leonardo, Copernicus and Marconi are still going strong.

We, alone on earth, can rebel against the tyranny of the selfish replicators.

It is so simple that I have known clever men misunderstand it completely, thinking that there must be more to it!

That is why the game is called a dilemma, why it seems so maddeningly paradoxical, and why it has even been proposed that there ought to be a law against it.

The successive rounds of the game give us the opportunity to build up trust or mistrust, to reciprocate or placate, forgive or avenge.

My 'Grudger' is an example of this; it has a good memory for faces, and although fundamentally cooperative it defects if the other player has ever defected before.

The winning strategy, remarkably, was the simplest and superficially least ingenious of all.

It seems pretty convincing that nice guys do well in this game.

This was because the field now included more subtle nasty strategies capable of preying ruthlessly upon such an out-and-out softy.

Because, in the world of Darwinism, winnings are not paid out as money; they are paid out as offspring.

So any other nice strategy, like die totally saintly Always Cooperate, although admittedly it will not enjoy a positive selective advantage over Tit for Tat, can nevertheless drift into the population without being noticed.

If only die population could just manage, by random drift, to get itself over die knife-edge, it could coast down die slope to die Tit for Tat side, and everyone would do much better at die banker's (or 'nature's') expense.

It is as though there were a secret passage underneath the knife-edge. But that secret passage contains a one-way valve: there is an asymmetry.

There is a banker paying out money, and it is possible for the two players to link arms and laugh all the way to the bank.

As well they might, since 'my learned friend and I' are cooperating very nicely all the way to the bank.

Referee Ron Challis watched helpless as the players pushed the ball around with little or no challenge to the man in possession.

I will probably be anxious to get my defection in first. Especially since I may fear that you are fearing that I...

Suddenly a salvo arrived but did no damage. Naturally both sides got down and our men started swearing at the Germans, when all at once a brave German got on to his parapet and shouted out 'We are very sorry about that; we hope no one was hurt.'

To the high command they conveyed aggression, but to the enemy they conveyed peace.

The fig is a dark indoor hothouse for flowers, an indoor pollination chamber.

A given amount of blood adds more hours to the life of a highly starved bat than to a less starved one.

They rise above the bonds of kinship, forming their own lasting ties of loyal blood-brotherhood.

DNA is cocooned in protein, swaddled in membranes, shielded from the world and invisible to natural selection.

Whenever, in a wild population, a t allele happens to arise by mutation, it immediately spreads like a brushfire.

The phenotypic effects of a gene need to be thought of as all the effects that it has on the world.

Yet we take a spider web for granted, as a nuisance in the house rather than as one of the wonders of the world.

If it is legitimate to speak of a gene as affecting the wrinkliness of a pea or the nervous system of an animal (all geneticists think it is) then it must also be legitimate to speak of a gene as affecting the hardness of the stones in a caddis house.

It is as if the genes reached outside their 'own' body and manipulated the world outside.

The two sets of genes can be expected to 'pull together' for just the same reasons as all the genes of one individual organism normally pull together.

Our own genes cooperate with one another, not because they are our own but because they share the same outlet—sperm or egg—into the future.

The rabies virus is transmitted in saliva when one animal bites another. In dogs, one of the symptoms of the disease is that normally peaceful and friendly animals become ferocious biters, foaming at the mouth.

I am looking at a photograph of an adult dunnock, so small in comparison to its monstrous foster-child that it has to perch on its back in order to feed it.

Its nervous system is being controlled, as irresistibly as if it were a helpless drug addict, or as if the cuckoo were a scientist plugging electrodes into its brain.

She seeks out the host queen, and rides about on her back while she quiedy performs, to quote Edward Wilson's artfully macabre understatement, 'die one act for which she is uniquely specialized: slowly cutting off die head of her victim'.

For ants, matricide is an act of special genetic madness and formidable indeed must be die drug that drives diem to it.

Replicators don't behave, don't perceive the world, don't catch prey or run away from predators; they make vehicles that do all those things.

If fluke genes were passed on in snail eggs and sperms, the two bodies would evolve to become as one flesh.

Why did those ancient replicators give up the cavalier freedom of the primeval soup and take to swarming in huge colonies?

The fertilized egg is a narrow bottleneck which, during embryonic development, widens out into the trillions of cells of an adult elephant.

The old object is too weighed down with the clutter of history.

It does not inherit its parent's heart and remould it into a new (and possibly improved) heart.

In bottle-wrack, the individual plant will be a unit with a genetic identity, will deserve the name individual.

The two phenomena, bottlenecked life cycles and discrete organisms, go hand in hand. As each evolves, it reinforces the other. The two are mutually enhancing, like the spiralling feelings of a woman and a man during the progress of a love affair.

The whole world is criss-crossed with causal arrows joining genes to phenotypic effects, far and near.

At this the Professor of Entomology growled from the front row, as if it were the most obvious thing to have overlooked: 'Haven't you tried cutting their heads off?'

But a major new mutation in basic embryological plan can also open up new floodgates of radiating evolution for millions of years to come.

What on earth do you think you are, if not a robot, albeit a very complicated one?

Influences from the external environment too are indispensable; after all, legs are actually made of food!

A lineage of copies would exist if we xeroxed a page of a book, then xeroxed the xerox, then xeroxed the xerox of the xerox, and so on.

Orgel and Crick hit the nail on the head when they make the analogy between selfish DNA and cuckoo eggs: cuckoo eggs, after all, escape detection by looking exactly like host eggs.

A desperate fling, which the computer contemptuously brushes aside ... The ultimate humiliation.

Perhaps consciousness arises when the brain's simulation of the world becomes so complete that it must include a model of itself.

The hardware of the brain is fundamentally parallel, like that of the Edinburgh machine. And it runs software designed to create an illusion of serial processing: a serially processing virtual machine riding on top of parallel architecture.

Predicting what is going to happen in the inanimate world is a piece of cake compared with predicting what is going to happen in the social world.

A nightingale's song is not information, not even deceitful information. It is persuasive, hypnotic, spellbinding oratory.

He might as well have used the example of a French chef boiling lobsters alive to preserve the flavour.

Only under these conditions did a really serious, prolonged fight break out.

The so-called 'slave' pig, the one that did all the work, was the pig that was usually dominant.

Progressive evolution may be not so much a steady upward climb as a series of discrete steps from stable plateau to stable plateau.

They have extra-big front legs which make them look almost scorpion-like; and they have sharp horns pointing forward from the head.

Moreover, being a true clone, the aphids are no more 'social' than the cells of your body.

A snail shell is an exquisite logarithmic spiral, but where does the snail keep its log tables; how indeed does it read them, since the lens in its eye lacks 'linguistic support' for calculating m, the coefficient of refraction?

However rare my lethal recessives may be in the population at large, and however rare my sister's lethal recessives may be in the population at large, there is a disquietingly high chance that hers and mine are the same.

They preferred first cousins over both full siblings and unrelated birds.

The great point about being a young ant, as opposed to a young mammal, is that it doesn't matter whether your father is dead (indeed, he almost certainly is dead!).

You could be forgiven for thinking the opposite: a generation has grown up, especially in America, that scatters the name 'group selection' around like confetti.

Charnov's point is that the conflict is a walk-over for the parents for the very good reason that only the parents see it as a conflict at all!

This is one of the places in the book where my tone swung too far towards the cynical, selfish view of life.

The key idea here is that a small initial difference between the sexes can be self-enhancing: selection can start with an initial, slight difference and make it grow larger and larger.

Briefly, then, we can draw two conclusions: (a) that the battle of sexes has much in common with predation; and (b) that the behaviour of lovers is oscillating like the moon, and unpredictable as the weather.

But sexual selection really can have the embarrassing property of chasing an ever-driving 'optimum'.

Hamilton pictures cycles of counteradaptation and counter-counteradaptation endlessly rolling through time and forever perversely updating the definition of the 'best' rabbit.

It is as though males are forced by the females to evolve clinical thermometers permanently sticking out of their mouths, clearly displayed for females to read.

The hydraulic advertisement gains its effectiveness precisely because erection sometimes fails.

Most worrying for me, these include my colleague Alan Grafen who, as has been said in print before, 'has the most annoying habit of always being right'.

A male's genes, after all, are immersed in his internal biochemistry and far better placed than female genes to respond to his quality.

An advertising system is chosen precisely because it actually has the effect of reducing the success of the advertiser—all other things being held equal.

I find the prospect rather worrying, because it means that theories of almost limitless craziness can no longer be ruled out on commonsense grounds.

Perhaps the large individuals perform a valuable role by storing up their faeces in the body when food is plentiful, so that they can act as an emergency larder when food is scarce—a sort of constipated commissariat.

The difference between a solitary individual and its gregarious incarnation is as great as the difference between two ant castes.

The symphony becomes identified with this one tune. If people then become disenchanted with the tune, they think that they dislike the whole symphony.

If you take uniformly heterozygous individuals and cross them, either with each other or with one of the homozygous parental strains, all hell breaks loose, genetically speaking.

Each ounce of food invested in a sibling brings back just the same return on investment, genetically speaking, as it would if invested in a child.

Robert Brett has calculated that a single mole rat, working on its own, would have to search so long to find a single tuber that it would wear its teeth out with digging.

My purpose was to cut the gene down to size, rather than to sculpt a grand theory of human culture.

The mutant meme has taken over another vehicle.

What if just a few of us were to start singing 'God saves our gracious Queen'?

If the spread of Hamilton's meme was really like a gathering epidemic, the points on a cumulative logarithmic graph should fall on a single straight line.

My chagrin turned to glee, therefore, when I chanced upon an old stencilled bibliography that I had handed to the students at an Oxford lecture in 1970.

My software doctors, on the other hand, will be, like lawyers, solving man-made problems that should never have existed in the first place.

Religious faith deserves a chapter to itself in the annals of war technology, on an even footing with the longbow, the warhorse, the tank, and the hydrogen bomb.

We, that is our brains, are separate and independent enough from our genes to rebel against them.

Territorial defence in the speckled wood butterfly (Pararge aegeria): the resident always wins.

HAMILTON, W. D. (1975) Gamblers since life began: barnacles, aphids, elms.

KREBS,). R. and DAWKINS, R. (1984) Animal signals: mind-reading and manipulation.

Selfish DNA: the ultimate parasite.

ZAHAVI, A. (1975) Mate selection—a selection for a handicap.

I chose not to break the flow of the book with literature citations.

DNA: 'selfish' 44-5, 182, 275, (63, 145); domain of danger 167, (86); domestic bliss strategy 149, 153-5.

meme 192-201, 322-31, (20) complex 197-9 computer 329-30 definition 192 exponential spread 326-8 hardware 323, (58) good one 322-3 scientific 325 pool 192-3

primeval soup 14, 45, 192, 196, (144) Prisoner's Dilemma 183, 203, (12, 17°, 173) iterated 206 indefinitely long 224

Surely even the most gullible naturalist must have asked himself how such altruism could have become part of the behavioural repertoire of the species, having regard to the fact that the genetic make-ups conducive to it must have perished with their possessors in this grand demographic auto-da-fe.

There is indeed truth enough for a dozen sermons in the schoolboy aphorism that 'a chicken is the egg's way of making another egg.'

Now they go by the name of genes and we are their survival machines.

What conjurers do with mirrors is nothing to what nature, if Dawkins is right, does with no more promising a starting material than congealed primeval soup.

In a textbook of game theory one sees no more of games than one sees of circles and triangles in a textbook of modern geometry.

Typical vehicles are the bodies of dogs, fruitflies and people.

Many critics, especially vociferous ones learned in philosophy as I have discovered, prefer to read a book by title only.

The gene is the unit in the sense of replicator. The organism is the unit in the sense of vehicle.

Personifying genes, if done with due care and caution, often turns out to be the shortest route to rescuing a Darwinian theorist drowning in muddle.

As soon as he reaches it he should give up and preferably let himself be eaten by his litter-mates or his parents.

Its reputation for contentiousness took years to grow until, by now, it is widely regarded as a work of radical extremism.

The chimpanzee and the human share about 99.5 per cent of their evolutionary history, yet most human thinkers regard the chimp as a malformed, irrelevant oddity while seeing themselves as stepping-stones to the Almighty.

We are survival machines—robot vehicles blindly programmed to preserve the selfish molecules known as genes.

I have long felt that biology ought to seem as exciting as a mystery story, for a mystery story is exactly what biology is.

If superior creatures from space ever visit earth, the first question they will ask, hi order to assess the level of our civilization, is: 'Have they discovered evolution yet?'

A human foetus, with no more human feeling than an amoeba, enjoys a reverence and legal protection far in excess of those granted to an adult chimpanzee.

Darwin's 'survival of the fittest' is really a special case of a more general law of survival of the stable.

The earliest form of natural selection was simply a selection of stable forms and a rejection of unstable ones.

But bacteria and the rest of us are late-comers, and in those days large organic molecules could drift unmolested through the thickening broth.

It leaps from body to body down the generations, manipulating body after body in its own way and for its own ends, abandoning a succession of mortal bodies before they sink in senility and death.

The genes too control the behaviour of their survival machines, not directly with their fingers on puppet strings, but indirectly like the computer programmer.

The trouble with overt trial is that it takes time and energy. The trouble with overt error is that it is often fatal.

Remember that we are picturing the animal as a robot survival machine with a pre-programmed computer controlling the muscles.

Hawks always fight as hard and as unrestrainedly as they can, retreating only when seriously injured.

If only everybody would agree to be a dove, every single individual would benefit.

An ESS is stable, not because it is particularly good for the individuals participating in it, but simply because it is immune to treachery from within.

The key point of this chapter is that a gene might be able to assist replicas of itself that are sitting in other bodies.

A third cousin is not far from being equivalent to any old Tom, Dick, or Harry as far as an altruistic gene is concerned.

If starlings are estimating population size by the volume of noise in a winter roost, it would pay each individual to shout as loudly as possible, in order to sound more like two starlings than one.

The runt should die gracefully and willingly. He can benefit his genes most by doing so.

The advantage to an individual of producing small, rapidly moving gametes would be that he could afford to make a larger number of gametes, and therefore could potentially have more children.

There will be a ceaseless migration in from the edges of an aggregation towards the centre.

It follows that a hymenopteran female is more closely related to her full sisters than she is to her offspring of either sex.

When you plant a fertile meme in my mind you literally parasitize my brain, turning it into a vehicle for the meme's propagation in just the way that a virus may parasitize the genetic mechanism of a host cell.

The meme for blind faith secures its own perpetuation by the simple unconscious expedient of discouraging rational inquiry.

We, alone on earth, can rebel against the tyranny of the selfish replicators.

It is so simple that I have known clever men misunderstand it completely, thinking that there must be more to it!

That is why the game is called a dilemma, why it seems so maddeningly paradoxical, and why it has even been proposed that there ought to be a law against it.

The successive rounds of the game give us the opportunity to build up trust or mistrust, to reciprocate or placate, forgive or avenge.

My 'Grudger' is an example of this; it has a good memory for faces, and although fundamentally cooperative it defects if the other player has ever defected before.

The winning strategy, remarkably, was the simplest and superficially least ingenious of all.

It seems pretty convincing that nice guys do well in this game.

A given amount of blood adds more hours to the life of a highly starved bat than to a less starved one.

DNA is cocooned in protein, swaddled in membranes, shielded from the world and invisible to natural selection.

The phenotypic effects of a gene need to be thought of as all the effects that it has on the world.

Replicators don't behave, don't perceive the world, don't catch prey or run away from predators; they make vehicles that do all those things.

Most worrying for me, these include my colleague Alan Grafen who, as has been said in print before, 'has the most annoying habit of always being right'.

What if just a few of us were to start singing 'God saves our gracious Queen'?

If the spread of Hamilton's meme was really like a gathering epidemic, the points on a cumulative logarithmic graph should fall on a single straight line.

meme 192-201, 322-31, (20) complex 197-9 computer 329-30 definition 192 exponential spread 326-8 hardware 323, (58) good one 322-3 scientific 325 pool 192-3

primeval soup 14, 45, 192, 196, (144) Prisoner's Dilemma 183, 203, (12, 17°, 173) iterated 206 indefinitely long 224

Surely even the most gullible naturalist must have asked himself how such altruism could have become part of the behavioural repertoire of the species, having regard to the fact that the genetic make-ups conducive to it must have perished with their possessors in this grand demographic auto-da-fe.

There is indeed truth enough for a dozen sermons in the schoolboy aphorism that 'a chicken is the egg's way of making another egg.'