The Electronic Telegraph 11 May 1995 SCIENCE
CHARLES DARWIN lost his faith with the help of a wasp. "I cannot persuade myself," Darwin wrote, "that a beneficent and omnipotent God would have designedly created the Ichneumonidae with the express intention of their feeding within the living bodies of caterpillars." Actually, Darwin's gradual loss of faith, which he downplayed for fear of upsetting his devout wife Emma, had more complex causes.His reference to the Ichneumonidae was aphoristic. The macabre habits to which he referred are shared by their cousins the digger wasps. A female digger wasp not only lays her egg in a caterpillar (or grasshopper or bee) so that her larva can feed on it. According to Fabre she also carefully guides her sting into each ganglion of the prey's central nervous system so as to paralyse it but not kill it. This way, the meat keeps fresh.
It is not known whether the paralysis acts as a general anaesthetic, or if it is like curare in just freezing the victim's ability to move. If the latter, the prey might be aware of being eaten alive from inside, but unable to move a muscle to do anything about it. This sounds savagely cruel but nature is not cruel, only pitilessly indifferent. This is one of the hardest lessons for humans to learn. We cannot accept that things might be neither good nor evil, neither cruel nor kind, but simply indifferent to all suffering, lacking all purpose.
The river of my new book's title is a river of DNA and it flows through time, not space. DNA is the hereditary chemical that characterises every living thing by carrying its genetic specifications. This is a river of information not of bones and tissues: a river of abstract instructions for building bodies, not a river of solid bodies themselves. The information passes through bodies, and affects them, but it is not affected by them on its way through.
But there is more to it than this. To be good at surviving, a gene must be good at working together with the other genes in the same species - the same river. To survive in the long run, a gene must be a good companion. It must do well in the company of, or against the background of, the other genes in the same river. Genes of another species are in a different river. They do not have to get on well together: not in the same sense, anyway, for they do not have to share the same bodies.
The feature that defines a species is that all members of any one species have the same river of genes flowing through them, and all the genes in a species have to be prepared to be good companions of one another. A new species comes into existence when an existing species divides into two. The river of genes forks in time.
From a gene's point of view, speciation, the origin of new species, is the long goodbye. After a brief period of partial separation, the two rivers go their separate ways for ever, or until one or other dries extinct into the sand. Secure within the banks of either river, the water is mixed and remixed by sexual recombination. But water never leaps its banks to contaminate the other river.
After a species has divided, the two sets of genes are no longer companions. They no longer meet in the same bodies and they are no longer required to get on well together. There is no longer any intercourse between them - and intercourse here means literally sexual intercourse between their temporary vehicles, their bodies.
When we think of the divide that leads to all the mammals, as opposed to, say, the stream that led to the grey squirrel, it is tempting to imagine something on a grand Mississippi/Missouri scale. The mammal branch we are talking about is, after all, destined to branch and branch and branch again until it produces all the mammals from pigmy shrew to elephant, from moles underground to monkeys atop the canopy.
It is only with hindsight that we see the ancestral mammal as a mammal at all. In those days it would have been just another species of mammal-like reptile, not markedly different from perhaps a dozen other small, snouty, insectivorous morsels of dinosaur-food.
Natural selection is concerned only with the narrow present - with the survival of DNA through millions of successive present moments, strung out along millions of branches of the river of DNA. Natural selection is as indifferent to the distant future of the race as it is indifferent to the suffering of the individuals being selected. For, to return to our pessimistic beginning, when the utility function - that which is being maximised - is DNA survival, this is not a recipe for happiness.
If nature were kind, she would at least make the minor concession of anaesthetising caterpillars before they are eaten alive from within. But nature is neither kind nor unkind. 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.
The total amount of suffering per year in the natural world is beyond all decent contemplation. During the minute that it takes me to compose this sentence, thousands of animals are being eaten alive, others are running for their lives, whimpering with fear, others are being slowly devoured from within by rasping parasites, thousands of all kinds are dying of starvation, thirst and disease. It must be so.
If there is ever a time of plenty, this very fact will automatically lead to an increase in population until the natural state of starvation and misery is restored. Theologians worry away at the "Problem of Evil" and a related Problem of Suffering. On the day that I originally wrote this paragraph, the newspapers were filled with one of those heartrending disasters, the tragic crash of a busload of children.
The paper went on to quote one priest: "The simple answer is that we do not know why there should be a God who lets these awful things happen. But the horror of the crash, to a Christian, confirms the fact that we live in a world of real values: positive and negative. If the universe was just electrons, there would be no problem of evil or suffering."
On the contrary, if the universe were just electrons and selfish genes, meaningless tragedies are exactly what we should expect, along with equally meaningless good fortune. Such a universe would be neither evil nor good in intention. It would manifest no intentions of any kind.
In a universe of blind physical forces and genetic replication, some people are going to get hurt, other people are going to get lucky, and you won't find any rhyme or reason in it, or any justice. The universe that we observe has precisely the properties we should expect if there is, at bottom, no design, no purpose, no evil and no good, nothing but blind, pitiless indifference. As that unhappy poet A E Housman put it:
For Nature, heartless, witless Nature
Will neither know nor care.
DNA neither knows nor cares. DNA just is. And we dance to its music.
© 1995 by Richard Dawkins.
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