The Greatest Show on Earth (39 page)

‘FROM THE WAR OF NATURE, FROM FAMINE AND DEATH’

Clear-headed as ever, Darwin recognized the moral paradox at the heart of his great theory. He didn’t mince words – but he offered the mitigating reflection that nature has no evil intentions. Things simply follow from ‘laws acting all around us’, to quote an earlier sentence from the same paragraph. He had said something similar at the end of Chapter 7 of The Origin:it may not be a logical deduction, 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.
I’ve already mentioned Darwin’s revulsion – widely shared by his contemporaries – in the face of the female ichneumon wasp’s habit of stinging its victim to paralyse but not kill it, thereby keeping the meat fresh for its larva as it eats the live prey from within. Darwin, you’ll remember, couldn’t persuade himself that a beneficent creator would conceive such a habit. But with natural selection in the driving seat, all becomes clear, understandable and sensible. Natural selection cares naught for any comfort. Why should it? For something to happen in nature, the only requirement is that the same happening in ancestral times assisted the survival of the genes promoting it. Gene survival is a sufficient explanation for the cruelty of wasps and the callous indifference of all nature: sufficient – and satisfying to the intellect if not to human compassion.
Yes, there is grandeur in this view of life, and even a kind of grandeur in nature’s serene indifference to the suffering that inexorably follows in the wake of its guiding principle, survival of the fittest. Theologians may here wince at this echo of a familiar ploy in theodicy, in which suffering is seen as an inevitable correlate of free will. Biologists, for their part, will find ‘inexorably’ by no means too strong when they reflect – perhaps along the lines of my ‘red flag’ meditation of the previous chapter – on the biological function of the capacity to suffer. If animals aren’t suffering, somebody isn’t working hard enough at the business of gene survival.
Scientists are human, and they are as entitled as anyone to revile cruelty and abhor suffering. But good scientists like Darwin recognize that truths about the real world, however distasteful, have to be faced. Moreover, if we are going to admit subjective considerations, there is a fascination in the bleak logic that pervades all of life, including wasps homing in on the nerve ganglia down the length of their prey, cuckoos ejecting their foster brothers (‘Thow mortherer of the heysugge on y braunche’), slave-making ants, and the single-minded – or rather zero-minded – indifference to suffering shown by all parasites and predators. Darwin was bending over backwards to console when he concluded his chapter on the struggle for survival with these words:
All that we can do, is to keep steadily in mind that each organic being is striving to increase at a geometrical ratio; that each at some period of its life, during some season of the year, during each generation or at intervals, has to struggle for life, and to suffer great destruction. When we reflect on this struggle, we may console ourselves with the full belief, that the war of nature is not incessant, that no fear is felt,* that death is generally prompt, and that the vigorous, the healthy, and the happy survive and multiply.
Shooting the messenger is one of humanity’s sillier foibles, and it underlies a good slice of the opposition to evolution that I mentioned in the Introduction. ‘Teach children that they are animals, and they’ll behave like animals.’ Even if it were true that evolution, or the teaching of evolution, encouraged immorality, that would not imply that the theory of evolution was false. It is quite astonishing how many people cannot grasp this simple point of logic. The fallacy is so common it even has a name, the argumentum ad consequentiam – X is true (or false) because of how much I like (or dislike) its consequences.

‘THE MOST EXALTED OBJECT WHICH WE ARE CAPABLE OF CONCEIVING’

Is ‘the production of the higher animals’ really ‘the most exalted object which we are capable of conceiving’? Most exalted? Really? Are there not more exalted objects? Art? Spirituality? Romeo and Juliet? General Relativity? The Choral Symphony? The Sistine Chapel? Love?
You have to remember that, for all his personal modesty, Darwin nursed high ambitions. On his world-view, everything about the human mind, all our emotions and spiritual pretensions, all arts and mathematics, philosophy and music, all feats of intellect and of spirit, are themselves productions of the same process that delivered the higher animals. It is not just that without evolved brains spirituality and music would be impossible. More pointedly, brains were naturally selected to increase in capacity and power for utilitarian reasons, until those higher faculties of intellect and spirit emerged as a by-product, and blossomed in the cultural environment provided by group living and language. The Darwinian world-view does not denigrate the higher human faculties, does not ‘reduce’ them to a plane of indignity. It doesn’t even claim to explain them at the sort of level that will seem particularly satisfying, in the way that, say, the Darwinian explanation of a snake-mimicking caterpillar is satisfying. It does, however, claim to have wiped out the impenetrable – not even worth trying to penetrate – mystery that must have dogged all pre-Darwinian efforts to understand life.
But Darwin doesn’t need any defence from me, and I’ll pass over the question of whether the production of the higher animals is the most exalted object we can conceive, or merely a very exalted object. What, however, of the predicate? Does the production of the higher animals ‘directly follow’ from the war of nature, from famine and death? Well, yes, it does. It directly follows if you understand Darwin’s reasoning, but nobody understood it until the nineteenth century. And many still don’t understand it, or perhaps are reluctant to do so. It is not hard to see why. When you think about it, our own existence, together with its post-Darwinian explicability, is a candidate for the most astonishing fact that any of us are called upon to contemplate, in our whole life, ever. I’ll come to that shortly.

‘HAVING BEEN ORIGINALLY BREATHED’

I have lost count of the irate letters I have received from readers of a previous book, taking me to task for, as the writers think, deliberately omitting the vital phrase, ‘by the Creator’ after ‘breathed’? Am I not wantonly distorting Darwin’s intention? These zealous correspondents forget that Darwin’s great book went through six editions. In the first edition, the sentence is as I have written it here. Presumably bowing to pressure from the religious lobby, Darwin inserted ‘by the Creator’ in the second and all subsequent editions. Unless there is a very good reason to the contrary, when quoting On the
Origin of Species I always quote the first edition. This is partly because my own copy of that historic print run of 1,250 is one of my most precious possessions, given me by my benefactor and friend Charles Simonyi. But it is also because the first edition is the most historically important. It is the one that thumped the Victorian solar plexus and drove out the wind of centuries. Moreover, later editions, especially the sixth, pandered to more than public opinion. In an attempt to respond to various learned but misguided critics of the first edition, Darwin backtracked and even reversed his position on a number of important points that he had actually got right in the first place. So, ‘having been originally breathed’ it is, with no mention of any Creator.
It seems that Darwin regretted this sop to religious opinion. In a letter of 1863 to his friend the botanist Joseph Hooker, he said, ‘But I have long regretted that I truckled to public opinion, and used the Pentateuchal term of creation, by which I really meant “appeared” by some wholly unknown process.’ The ‘Pentateuchal term’ Darwin is referring to here is the word ‘creation’. The context, as Francis Darwin explains in his 1887 edition of his father’s letters, was that Darwin was writing to thank Hooker for the loan of a review of a book by Carpenter, in which the anonymous reviewer had spoken of ‘a creative force . . . which Darwin could only express in Pentateuchal terms as the primordial form “into which life was originally breathed”’. Nowadays, we should dispense even with the ‘originally breathed’. What is it that is supposed to have been breathed into what? Presumably the intended reference was to some kind of breath of life,*
but what might that mean? The harder we look at the border between life and non-life, the more elusive does the distinction become. Life, the animate, was supposed to have some sort of vibrant, throbbing quality, some vital essence – made to sound yet more mysterious when dropped into French: élan vital.† Life, it seemed, was made of a special living substance, a witch’s brew called ‘protoplasm’. Conan Doyle’s Professor Challenger, a fictional character even more preposterous than Sherlock Holmes, discovered that the Earth was living, a kind of giant sea urchin whose shell was the crust that we see, and whose core consisted of pure protoplasm. Right up to the middle of the twentieth century, life was thought to be qualitatively beyond physics and chemistry. No longer. The difference between life and non-life is a matter not of substance but of information. Living things contain prodigious quantities of information. Most of the information is digitally coded in DNA, and there is also a substantial quantity coded in other ways, as we shall see presently.
In the case of DNA, we understand pretty well how the information content builds up over geological time. Darwin called it natural selection, and we can put it more precisely: the non-random survival of information that encodes embryological recipes for that survival. Self-evidently it is to be expected that recipes for their own survival will tend to survive. What is special about DNA is that it survives not in its material self but in the form of an indefinite series of copies. Because there are occasional errors in the copying, new variants may survive even better than their predecessors, so the database of information encoding recipes for survival will improve as time goes by. Such improvements will be manifest in the form of better bodies and other contrivances and devices for the preservation and propagation of the coded information. On the ground, the preservation and propagation of DNA information will normally mean the survival and reproduction of bodies containing it. It was at the level of bodies, their survival and reproduction, that Darwin himself worked. The coded information within them was implicit in his world-view, but not made explicit until the twentieth century.
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. The repository of that information will, at any one moment, reside in individual bodies, but in the longer term, where reproduction is sexual and DNA is shuffled from body to body, the database of survival instructions will be the gene pool of a species.
Each individual’s genome, in any one generation, will be a sample from the species database. Different species will have different databases because of their different ancestral worlds. The database in the gene pool of camels will encode information about deserts and how to survive in them. The DNA in mole gene pools will contain instructions and hints for survival in dark, moist soil. The DNA in predator gene pools will increasingly contain information about prey animals, their evasive tricks and how to outsmart them. The DNA in prey gene pools will come to contain information about predators and how to dodge and outrun them. The DNA in all gene pools contains information about parasites and how to resist their pernicious invasions.
Information on how to handle the present so as to survive into the future is necessarily gleaned from the past. Non-random survival of DNA in ancestral bodies is the obvious way in which information from the past is recorded for future use, and this is the route by which the primary database of DNA is built up. But there are three further ways in which information about the past is archived in such a way that it can be used to improve future chances of survival. These are the immune system, the nervous system, and culture. Along with wings, lungs and all the other apparatus for survival, each of the three secondary information-gathering systems was ultimately prefigured by the primary one: natural selection of DNA. We could together call them the four ‘memories’.
The first memory is the DNA repository of ancestral survival techniques, written on the moving scroll that is the gene pool of the species. Just as the inherited database of DNA records the recurrent details of ancestral environments and how to survive them, the immune system, the ‘second memory’, does the same thing for diseases and other insults to the body during the individual’s own lifetime. This database of past diseases and how to survive them is unique to each individual and is written in the repertoire of proteins that we call antibodies – one population of antibodies for each pathogen (disease-causing organism), precisely tailored by past ‘experience’ with the proteins that characterize the pathogen. Like many children of my generation, I had measles and chickenpox. My body ‘remembers’ the ‘experience’, the memories being embodied in antibody proteins, along with the rest of my personal database of previously vanquished invaders. I have fortunately never had polio, but medical science has cleverly devised the technique of vaccination for planting false memories of diseases never suffered. I shall never contract polio, because my body ‘thinks’ it has done so in the past, and my immune system database is equipped with the appropriate antibodies, ‘fooled’ into making them by the injection of a harmless version of the virus. Fascinatingly, as the work of various Nobel Prize-winning medical scientists has shown, the immune system’s database is itself built up by a quasi-Darwinian process of random variation and non-random selection. But in this case the non-random selection is selection not of bodies for their capacity to survive, but of proteins within the body for their capacity to envelop or otherwise neutralize invading proteins.
The third memory is the one we ordinarily think of when we use the word: the memory that resides in the nervous system. By mechanisms that we don’t yet fully understand, our brains retain a store of past experiences to parallel the antibody ‘memory’ of past diseases and the DNA ‘memory’ (for so we can regard it) of ancestral deaths and successes. At its simplest, the third memory works by a trial-and-error process that can be seen as yet another analogy to natural selection. When searching for food, an animal may ‘try’ various actions. Though not strictly random, this trial stage is a reasonable analogy to genetic mutation. The analogy to natural selection is ‘reinforcement’, the system of rewards (positive reinforcement) and punishments (negative reinforcement). An action such as turning over dead leaves (trial) turns out to yield beetle larvae and woodlice hiding under the leaves (reward). The nervous system has a rule that says, ‘Any trial action that is followed by reward should be repeated. Any trial action that is followed by nothing, or, worse, followed by punishment, for example pain, should not be repeated.’
But the brain’s memory goes much further than this quasi-Darwinian process of non-random survival of rewarded actions, and elimination of punished actions, in the animal’s repertoire. The brain’s memory (no need for inverted commas here, because it is the primary meaning of the word) is, at least in the case of human brains, both vast and vivid. It contains detailed scenes, represented in an internal simulacrum of all five senses. It contains lists of faces, places, tunes, social customs, rules, words. You know it well from the inside, so there is no need for me to spend my words evoking it, except to note the remarkable fact that the lexicon of words at my disposal for writing, and the identical, or at least heavily overlapping, dictionary at your disposal for reading, all reside in the same vast neuronal database, along with the syntactic apparatus for arranging them into sentences and deciphering them.
Furthermore, the third memory, the one in the brain, has spawned a fourth. The database in my brain contains more than just a record of the happenings and sensations of my personal life – although that was the limit when brains originally evolved. 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.
All four memories are part of, or manifestations of, the vast super-structure of apparatus for survival which was originally, and primarily, built up by the Darwinian process of non-random DNA survival.