The Greatest Show on Earth: The Evidence for Evolution

by Richard Dawkins

But nature never overbreeds for anything. Nature gets the balance right. The world is full of genes for getting the balance right: that is why they are there!

We wouldn’t need our fighters if you didn’t have your bombers. You wouldn’t need your missiles if we didn’t have ours. We could both save billions if we halved our armaments spending and put the money into ploughshares. And now, having halved our arms budget and reached a stable stand-off, let’s halve it again.

The problem is that natural selection doesn’t ‘step in’, natural selection doesn’t look into the future,fn5 and natural selection doesn’t choose between rival groups.

[N]ature is neither kind nor unkind.6 She is neither against suffering, nor for it. Nature is not interested in suffering one way or the other unless it affects the survival of DNA.

A virus exists for the sole purpose of making more viruses. Well, the same is ultimately true of tigers and snakes, but there it doesn’t seem so futile. The tiger and the snake may be DNA-replicating machines but they are beautiful, elegant, complicated, expensive DNA-replicating machines.

Futility? What nonsense. Sentimental, human nonsense. Natural selection is all futile. It is all about the survival of self-replicating instructions for self-replication.

Suffering is a by-product of evolution by natural selection, an inevitable consequence that may worry us in our more sympathetic moments but cannot be expected to worry a tiger – even if a tiger can be said to worry about anything at all – and certainly cannot be expected to worry its genes.

Theologians worry about the problems of suffering and evil, to the extent that they have even invented a name, ‘theodicy’ (literally, ‘justice of God’), for the enterprise of trying to reconcile it with the presumed beneficence of God. Evolutionary biologists see no problem, because evil and suffering don’t count for anything, one way or the other, in the calculus of gene survival.

Brains are built with a rule of thumb such as, ‘If you experience the sensation of pain, stop whatever you are doing and don’t do it again.’

Natural selection is ‘against’ individuals over-ruling the warning sensations of pain. Natural selection ‘wants’ us to survive, or more specifically, to reproduce, and be blowed to country, ideology or their non-human equivalents. As far as natural selection is concerned, little red flags will be favoured only if they are never over-ruled.

It must be kept alive to provide fresh meat for the growing wasp larva feeding inside. And the larva, for its part, takes care to eat the internal organs in a judicious order. It begins by taking out the fat bodies and digestive organs, leaving the vital heart and nervous system till last – they are necessary, you see, to keep the caterpillar alive. As Darwin so poignantly wondered, what kind of beneficent designer would have dreamed that up? I don’t know whether caterpillars can feel pain. I devoutly hope not. But what I do know is that natural selection would in any case take no steps to dull their pain, if the job could be accomplished more economically by simply paralysing their movements.

Thus, from the war of nature,1 from famine and death,fn1 the most exalted object which we are capable of conceiving, namely, the production of the higher animals, directly follows. There is grandeur in this view of life, with its several powers, having been originally breathed into a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved.

it may not be a logical deduction,2 but to my imagination it is far more satisfactory to look at such instincts as the young cuckoo ejecting its foster-brothers, – ants making slaves, – the larvae of ichneumonidae feeding within the live bodies of caterpillars, – not as specially endowed or created instincts, but as small consequences of one general law, leading to the advancement of all organic beings, namely, multiply, vary, let the strongest live and the weakest die.

The difference between life and non-life is a matter not of substance but of information. Living things contain prodigious quantities of information.

The genetic database will become a storehouse of information about the environments of the past, environments in which ancestors survived and passed on the genes that helped them to do so. To the extent that present and future environments resemble those of the past (and mostly they do), this ‘genetic book of the dead’ will turn out to be a useful manual for survival in the present and future.

Your brain includes collective memories inherited non-genetically from past generations, handed down by word of mouth, or in books or, nowadays, on the internet.

The world in which you and I live is richer by far because of those who went before us and inscribed their impacts on the database of human culture: Newton and Marconi, Shakespeare and Steinbeck, Bach and the Beatles, Stephenson and the Wright brothers, Jenner and Salk, Curie and Einstein, von Neumann and Berners-Lee. And, of course, Darwin.

These tidal cycles are especially important for marine and coastal organisms, and people have rather implausibly wondered whether some kind of species memory of our marine ancestry survives in our monthly reproductive cycles. That may be far-fetched, but it is a matter for intriguing speculation how different life would be if we had no orbiting moon.7 It has even been suggested, again implausibly in my opinion, that life without the moon would be impossible.

The Second Law of Thermodynamics states that, although energy can be neither created nor destroyed, it can – must, in a closed system – become more impotent to do useful work: that is what it means to say that ‘entropy’ increases.

This is not a violation of the Second Law, for energy is constantly being fed in from the sun.

If someone points out to you that your pet theory of the universe is in disagreement with Maxwell’s equations – then so much the worse for Maxwell’s equations. If it is found to be contradicted by observation – well, these experimentalists do bungle things sometimes. But if your theory is found to be against the second law of thermodynamics I can give you no hope; there is nothing for it but to collapse in deepest humiliation.

The whole system, whether we are talking about life, or about water rising into the clouds and falling again, is finally dependent on the steady flow of energy from the sun.

While never actually disobeying the laws of physics and chemistry – and certainly never disobeying the Second Law – energy from the sun powers life, to coax and stretch the laws of physics and chemistry to evolve prodigious feats of complexity, diversity, beauty, and an uncanny illusion of statistical improbability and deliberate design.

We know a great deal about how evolution has worked ever since it got started, much more than Darwin knew. But we know little more than Darwin did about how it got started in the first place.

Darwin went on to say, ‘It is mere rubbish, thinking at present of the origin of life; one might as well think of the origin of matter.’ He didn’t rule out the possibility that the problem would eventually be solved (indeed, the problem of the origin of matter largely has been solved) but only in the distant future: ‘It will be some time before we see “slime, protoplasm, etc” generating a new animal.’

‘It is often said that all the conditions for the first production of a living organism are now present, which could ever have been present. But if (and oh! what a big if!) we could conceive in some warm little pond, with all sorts of ammonia and phosphoric salts, light, heat, electricity, etc, present, that a proteine compound was chemically formed ready to undergo still more complex changes, at the present day such matter would be instantly devoured or absorbed, which would not have been the case before living creatures were formed.’

Even if ‘the conditions for the first production of a living organism’ are still present, any such new production would be ‘instantly devoured or absorbed’ (presumably by bacteria, we would today have good reason to add), ‘which would not have been the case before living creatures were formed’.

Oxygen flooded into the atmosphere as a pollutant, even a poison, until natural selection shaped living things to thrive on the stuff and, indeed, suffocate without it.

Darwin meant something more particular by ‘endless’. As we look back on the history of life, we see a picture of never-ending, ever-rejuvenating novelty. Individuals die; species, families, orders and even classes go extinct. But the evolutionary process itself seems to pick itself up and resume its recurrent flowering, with undiminished freshness, with unabated youthfulness, as epoch gives way to epoch.

My overwhelming impression, while staring into the computer screen and breeding biomorphs, whether coloured or black, and when breeding arthromorphs, was that it never became boring. There was a sense of endlessly renewed strangeness. The program never seemed to get ‘tired’, and nor did the player.

In 1989 I wrote a paper called ‘The evolution of evolvability’9 in which I suggested that not only do animals get better at surviving, as the generations go by: lineages of animals get better at evolving. What does it mean to be ‘good at evolving’?

How is it that we find ourselves not merely existing but surrounded by such complexity, such elegance, such endless forms most beautiful and most wonderful?

Not only does life need at least one star to provide energy. Stars are also the furnaces in which the majority of the chemical elements are forged, and you can’t have life without a rich chemistry.

Without green plants to outnumber us at least ten to one there would be no energy to power us.

Without the ever-escalating arms races between predators and prey, parasites and hosts, without Darwin’s ‘war of nature’, without his ‘famine and death’ there would be no nervous systems capable of seeing anything at all, let alone of appreciating and understanding it.

We are surrounded by endless forms, most beautiful and most wonderful, and it is no accident, but the direct consequence of evolution by non-random natural selection – the...