Читать книгу Why Us?: How Science Rediscovered the Mystery of Ourselves - James Fanu Le - Страница 10

‘Alone in that vastness, lit by the feeble beam of our lamps, we were seized by a strange feeling. Everything was so beautiful, so fresh, almost too much so. Time was abolished, as if the tens of thousands of years that separated us from the producers of these paintings no longer existed. It seemed as if they had just created these masterpieces. Suddenly we felt like intruders. Deeply impressed, we were weighed down by the feeling that we were not alone; the artists’ souls and spirits surrounded us. We thought we could feel their presence.’

Jean-Marie Chauvet on discovering the world’s oldestpaintings, from 30,000 BC

The beginning for ourselves, Homo sapiens – modern, thoughtful, argumentative, reflective, creative man – can be pinpointed with remarkable accuracy to 35,000 BC, or thereabouts, in south-west Europe. Here, in the shadow of the snow-topped Pyrenees that separate what is now southern France from northern Spain, flourished the first and most enduring of all human civilisations, a vibrant, unified, coherent culture, transmitted from generation to generation for an astonishing twenty-five thousand years. This palaeolithic (Stone Age) civilisation, created by the first truly modern Europeans, was more long-lasting than any that have succeeded it: ten times longer than the 2,500-year reign of the pharaohs in Egypt, twenty-five times longer than the thousand years of Graeco-Roman antiquity.

The historical lineage of our species stretches much further back, into the almost unimaginably distant past of five or six million years ago, but those more ancient predecessors left nothing behind other than some precious and much-argued-over skulls, bones and teeth, and the stone implements, scrapers, blades and axe-heads with which they hunted and butchered their prey.

Homo sapiens, or ‘Cromagnon man’, as this first representative of our species is known (so named after the Cro-Magnon – ‘Big Hole’ – rock shelter where his remains were first unearthed in 1868), was something else. His arrival in south-west France signalled a cultural explosion of technological innovation and artistic expression that has characterised the human race ever since. And he was the first, too, to leave behind an image of himself, so though thirty-five thousand years separate us, we can readily make his acquaintance. Fly, or catch the train, to Paris, and take the Metro westwards to the suburban station of St Germain-en-Laye. Emerging from the entrance, you cannot miss the impressive moated château of the Musée Nationale d’Antiquités, home to the largest of all archaeological collections. Few tourists make it this far out of the city, and you may be virtually alone as you stride past the first few display cabinets with their serried ranks of those familiar – if not exactly thrilling – stone implements. And then suddenly, without warning, your eyes are caught by the face of a teenage girl fashioned from the glistening ivory of a mammoth’s tusk, so small and delicate she could easily nestle in the palm of your hand (see overleaf). Her triangular-shaped face with its long, straight nose and deep-set eyes emerges from a slender, graceful neck framed by flowing locks of braided hair. She is the ‘Dame de Brassempouy’, the first human portrait, unearthed in 1895 by the French archaeologist Édouard Piette from amongst a pile of mammoth and rhinoceros bones that covered the floor of a cave a few kilometres outside the village of Brassempouy in southern France, after which she is named. Her air of youthful innocence is complemented by a second sculpted object in the same cabinet, of similar size and from the same site, that exemplifies that other timeless image of womanhood – the mature and childbearing. It may only be a broken fragment, but her prominent breasts and fleshy thighs are unmistakably those of a fertile woman.

This youthful teenager and this mature woman, the first images of modern humanity, are both visual and tactile, their polished surfaces testimony to the countless generations whose hands caressed that braided hair and felt those fleshy contours. They subvert the customary perception of man’s trajectory from a primitive past to a civilised present by compelling us to recognise how little has changed. The cultural history of our species may stretch back thirty-five thousand years, but from its earliest beginnings to the present day it is clearly ‘of a piece’.

And there is yet more to the Dame de Brassempouy than this invaluable perspective. Her immediate predecessors in Europe, the beetle-browed, thick-necked Neanderthals (so named after the Neander valley in Germany where their remains were first unearthed), were no more capable of creating so exquisite an object than were the very earliest humans who traversed the savannah plains of Africa several million years previously. Now, those Neanderthals had many virtues. They were tough and intelligent enough to survive for quarter of a million years in the hostile environments of the recurring Ice Ages that periodically swept across the continent, and they had a brain capacity slightly larger than our own. But they left not a single such image behind. The Dame de Brassempouy thus focuses our attention with exceptional clarity on that most important of questions: What happened in the transition to modern man? What is it that sets us apart, why should we be so different?

The Cromagnons’ arrival in south-western Europe was the culmination of an unexplained diaspora that 100,000 years earlier had impelled modern Homo sapiens to leave his African homeland and spread outwards to every corner of the earth. It was cold, of course, as throughout the tens of thousands of years of Cromagnon civilisation the ice cap several hundred miles to the north expanded and retreated. But they found shelter from the icy winds in the rocky south-facing valleys of the Dordogne and the Pyrenees. They had fire to warm themselves and animal furs for clothing, sewn together with the aid of ivory needles and held in place by exquisite ivory buttons. They lived in communities of several hundred spread out in separate dwelling places, and with a total population of probably little more than twenty thousand. They danced, as we know from the swinging breasts of an exquisite thirty-thousand-year-old statuette of a naked woman, and played music, fashioning drums from mammoth bones, clicking castanets from jawbones and flutes from the hollow bones of birds, which, with a whistle head attached, can be made to produce strong, clear notes. They wore jewellery and beads made from a few highly prized materials – certain types of seashells and animal teeth – which they traded over large distances. And they were great technical innovators. While their predecessors’ stone tools had scarcely changed in a million years, the Cromagnons prodigiously extended their sources of food supply by inventing both the spear-thrower and the harpoon. They invented oil lamps to illuminate the interiors of their caves, the drill that could put an ‘eye’ in a needle, and rope to bind their tents together.

And they had a passion for art. ‘We are justified in asserting they devoted themselves, intensely and continuously, to the creation of pictorial, graphic and sculptural works,’ writes the Italian art historian Paolo Graziosi. This is not the conventional version of primitive Stone Age art, where ‘stick’ men pursue their quarry with bows and spears, but is comparable to the art of the Italian Renaissance, with a naturalistic style that ‘sought to express reality in its deep unchanging essence’. Their powers of observation were so acute that ‘we know, for example, that the extinct rhinoceros of Ice Age Europe was adorned with a shaggy coat’, writes Ian Tattersall of the American Museum of Natural History, and that the extraordinary Megalocerus giganticus, a deer with vast antlers, had a darkly coloured hump behind its shoulders.

The Cromagnons’ artistic legacy takes two forms: ‘portable’ art, mostly sculptures and engravings on ivory and antler horn; and the distinctly ‘non-portable’ vast frescoes that covered the walls and ceilings of their cavernous cathedrals concealed in the depths of the mountainsides, in which they ‘mastered the problems of presenting three dimensions in two, and in giving a sensation of movement’.

And what movement! As archaeologist John Pfeiffer recalls on first glimpsing the ‘incomparable splendour’ of the painted caves at Lascaux in southern France:

It is pitch dark inside, and then the lights are turned on. Without prelude, before the eye has had a chance to look at any single feature, you see it whole, painted in red, black and yellow, a burst of animals, a procession dominated by huge creatures with horns. The animals form two lines converging from left and right, seeming to stream into a funnel mouth, towards and into a dark hole which marks the way into a deeper gallery.

It is not possible to convey the full range of the Cromagnons’ artistic virtuosity, so three striking examples must suffice. The first is the sculpted handle of a spear-thrower, fashioned from a reindeer’s antler, that shows a young ibex looking round at a large faecal stool emerging from its rectum, on which two birds are perched. The tautness of the animal’s neck muscles is beautifully conveyed in this humorous image, which must have been popular as several others, virtually identical, have since been discovered.

Next comes a fresco painting of a pride of lions from the Chauvet cave of the opening quotation to this chapter, whose ‘richly embellished chambers’ also feature mammoth, rhinoceros and an ‘exquisitely painted’ panel of horses’ heads. But these lions are the most impressive of all, showing how the Cromagnons had mastered the three-dimensional sense of perspective, with heavy paint-strokes beneath the neck adding depth to the image.

Thirdly there is a bison’s head (see overleaf), full of gravitas, sculpted from clay, from around 15,000 BC, that would be a masterpiece in any age. One can hardly imagine that it was created 14,500 years before the Golden Age of sculpture of classical Athens. Indeed, when compared to the sculpted head of an ox being led in sacrificial procession on the Parthenon frieze, one could almost be forgiven for thinking they were rendered by the same hand.

So there we have it, three artistic masterpieces, each of which conveys something of the profundity of the mind of these first representatives of our species, their humour and pathos, and their deep appreciation of the character of the animals with which they shared the world and which they so masterfully portrayed.

For the archaeologists of the nineteenth century, few things were quite as perplexing as the possibility that these wonderful expressions of human intelligence could have been created by Stone Age cave dwellers. It seemed inconceivable that man could have been capable of such artistic virtuosity in so distant a past, so when the Marquis de Sautola stumbled across the first of the painted caves at Altamira in northern Spain – after his eight-year-old daughter drew his attention to a parade of bison on the ceiling with the famous phrase ‘Mira, Papa, bueyez!’ (Look, Papa, oxen!’) – no one believed him. His lecture to the International Congress of Archaeology in Lisbon in 1880 in which he described his findings was ‘met with incredulity and an abrupt and contemptuous dismissal’. The Altamira paintings were never acknowledged as authentic in his lifetime – rather, their exceptional quality was presumptive evidence that he must have faked them. The Marquis died a disillusioned man, yet any condemnation of his harsh treatment by his archaeological contemporaries is a judgement of hindsight. Their scepticism was not unreasonable, given that the proposition that Stone Age man might have been capable of creating such great art itself seemed unreasonable.

Nowadays we know better. The sensational recent discoveries of man’s earliest ancestors – in particular the two near-complete fossilised skeletons, ‘Lucy’ and ‘Turkana Boy’ – mark the first two distinct stages of Man’s Ascent, his decision to stand upright and his prodigiously enlarging brain. The ‘cultural explosion’ of Cromagnon man’s artistic achievement marks the culminating phase of that evolutionary trajectory, determined by the third of those distinctly human attributes – the faculty of language. And yet, the drama of that evolutionary trajectory now appears, in the light of the findings of the New Genetics and the Decade of the Brain, more perplexing even than it would have seemed to those sceptical nineteenth-century archaeologists. This is ‘the riddle of the ascent of man’.

The common understanding of man’s evolutionary heritage begins with Charles Darwin’s On the Origin of Species of 1859, extended to incorporate ‘ourselves’ in The Descent of Man, published twelve years later, with its central claim that the near-infinite diversity of shape, form and attributes of living things all evolved from the first and simplest form of life, self-assembled from ‘all sorts of ammonia and phosphoric salts’ in ‘some warm little pond’ on the earth’s surface several billion years ago. The modern interpretation of Darwin’s theory is, briefly, as follows. The major determinants of what makes a fish a fish, or a bird a bird, are the instructions carried within the twenty thousand (plus or minus) genes formed by the sequence of just four chemicals (best imagined, as suggested, as four coloured discs, green, red, blue and yellow) strung out along the Double Helix within the nucleus of each and every cell. These genetic instructions are then passed on in the sperm and egg at the moment of conception to ensure that the offspring of fish will be fish and birds, birds. Those individual genes replicate themselves with astonishing accuracy every time the cell divides, but very occasionally a mistake, or ‘mutation’, may creep in: so a green disc (say) is substituted for a red one, thus subtly altering the genetic instructions. Most of the time this does not matter, or is detrimental, but very occasionally the ‘chance mutation’ in those genetic instructions may confer some biological advantage, maximising the carriers’ chances of survival in the struggle for existence. Their offspring in turn are likely to inherit their parent’s advantageous genetic variation, and as the process continues from generation to generation, the characteristics of species will be gradually transformed, step by step, in favour of those which are best suite d (or ‘adapted’) to their environment. Thus fish are adapted to life underwater because over millions of generations ‘nature’ has ‘selected’ (hence ‘natural selection’) those whose random changes in their genes have maximised their swimming potential, while birds are good at flying because the same process has maximised their aerodynamic capabilities. Put another way, all of life has ‘descended with modification’ from that common ancestor.

And man, Darwin argued in The Descent of Man, is no exception. Indeed, there is probably no more persuasive evidence for his evolutionary theory than the striking physical similarities between man and his primate cousins, which point inexorably to their having ‘descended by modification’ from some common ape-like ancestor. Man has survived and prospered because nature, in ‘selecting’ the genetic mutations that would cause him to stand upright and acquire that much larger brain, conferred so considerable a biological advantage as to maximise his chances of survival. Certainly man’s much superior intellectual faculties might seem to set him apart. Nonetheless, our primate cousins, like ourselves, exhibit similar emotions of jealousy, suspicion and gratitude; they make choices, recall past events and are capable (to a degree) of reason. Hence the superiority of the human mind, Darwin argued, represents a continuum – it is a difference of ‘degree but not of kind’.

Details aside, one single, powerful image captures this profoundly influential interpretation of man’s origins. Darwin’s close friend and advocate Thomas Huxley, in an illustration to his book Evidence as to Man’s Place in Nature (1863), placed the skeletons of chimpanzees, gorillas and man in sequence, transforming their striking physical similarities into a powerful narrative of the rise of man from knuckle-walking chimp to upstanding Homo sapiens. The same image, expanded with a series of ‘hominid’ intermediaries, and reproduced (often humorously) in numerous different guises, would become one of the most familiar, and certainly influential, icons of the twentieth century. The ‘Descent’ of man by modification from his ape-like ancestors, it implied, was in reality the story of his ‘Ascent’ to his pre-eminent position in the grand order of life. And so the major archaeological discoveries of the last fifty years have shown it to be.

The discovery of the fossilised bones of Cromagnon man in 1868, together with those of his beetle-browed Neanderthal predecessors, would roll back man’s evolutionary history 200,000 years or more. It was not however till the 1930s that the first evidence of the more distant stages would begin to emerge, and not till the 1970s, when the first of two near-complete fossilised skeletons was unearthed in the harsh landscape of central Africa, that Darwin’s hypothesised transition from that ape-like common ancestor to Homo sapiens would be vindicated.

Those two near-complete skeletons were, first, the three-and-a-half-million-year-old ‘Lucy’, or Australopithecus afarensis to give her her scientific name, whose discovery had such a powerful and emotional effect on Donald Johanson and Tom Gray (‘…we hugged each other, sweaty and smelly, howling and hugging in the heat-shimmering gravel’), as already described. One set of fossilised remains can look remarkably like another, but the vital clue, and the source of their exhilaration, lies in the sharp upward angle of the head of the femur, or upper thigh bone, that locates the centre of gravity of the human skeleton in the small area enclosed by two feet placed together – confirming that Lucy was the first of our most distant ancestors to stand upright.

Lucy’s novel method of locomotion would be confirmed soon after with the discovery of an amazing series of three sets of footprints left behind in the volcanic ash of the Laetoli region of northern Tanzania three and a half million years ago, that provide a most moving insight into the human relationships of those distant ancestors.

‘The footprint records a normal positioning of the left and right feet with human-like big toes,’ writes British neurologist John Eccles.

The special feature is that one individual followed the other, placing its feet accurately in the preceding footsteps. The third was smaller and walked closely to the left following the slightly wavy walk of the larger. We can interpret this as showing that two of the group [mother and child?] walked together holding hands, while another [sibling?] followed accurately placing its feet into the footsteps of the leader. We are given a privileged view of a family taking a walk on the newly formed volcanic ash 3.6 million years ago, just as we might do on soft sand left by the receding tide!

Ten years later, in 1984, near the ancient Lake Turkana in Kenya, the famous palaeontologist Richard Leakey discovered a further near-complete skeleton, ‘Turkana Boy’, an adolescent of the species Homo erectus from around 1.6 million years ago, with a skull intermediate in size between Lucy and ourselves – reflecting that second unique evolutionary characteristic of the human species, his prodigiously enlarging brain.

Turkana Boy’s ‘people’, Homo erectus, were the first to make tools, reflecting that manual dexterity which is a further unique attribute of humans, made possible by the seemingly trivial evolutionary advantage of lengthening the thumb by an extra inch to make it ‘opposable’, allowing it to ‘speak to’ the other four digits.

‘In man the most precise function that the hand is capable of is to place the tip of the thumb in opposition to the tip of the index finger, so they make maximum contact,’ writes the British anatomist John Napier. ‘In this position small objects can be manipulated with an unlimited potential for fine pressure adjustments or minute directional corrections. This is the hallmark of mankind. No non-human primate can replicate it.

This extra inch of the human thumb transforms the grasping power of the hand of our primate cousins into the vast repertoire of the gripping precision of the human hand that would, eventually, allow man to paint and sculpt and record, through the written word, his experiences, without which his history would have disappeared completely into the dark abyss of time.

We cannot know precisely how or why the enlarging brain of Homo erectus released the hand’s (till then, hidden) potential of both grasping and gripping, but we can see its consequences readily enough in his stone tools. Palaeontologists who have taught themselves the technique of stone napping (as it is known) discovered that the necessary skill lies in finding the right-shaped ‘core’ stone, which is then percussed by a hammer stone at precisely the right angle and with a controlled degree of force so as to produce fragments of the right size and sharp enough to cut open the skin of his prey.

There is something immensely moving about the diminutive Lucy, no more than five feet tall, and the strapping Turkana Boy. Their bones may be silent, but nonetheless they speak to us across those aeons of time. What, one wonders, when they looked upwards at that clear African sky at night, did they make of its thousands of shimmering stars and the drama of the waxing and waning of the moon?

It is impossible to exaggerate the importance of those skeletal remains to our understanding of evolutionary heritage, confirming the linear sequence of our predecessors just as Darwin had postulated. Five million years ago the antecedents of Lucy and her tribe forsook the safety of the forest to walk upright on the savannah of central Africa. Two million years passed, and the ever-expanding brain of Homo erectus allowed for the incremental increase in intelligence necessary to fashion tools from stone, and to undertake those extraordinary migrations of tens of thousands of miles that would take him through what is now the Middle East into Asia, and as far as northern China and Indonesia. Then a further million and a half years elapsed before the emergence of Homo sapiens, who from his base in Africa would undertake a second great wave of global migration, this time as far as Australia, across the Bering Straits to America, and up into Europe and the southern Pyrenees, where Cromagnon man would found the first human civilisation.

Thanks to Donald Johanson, Richard Leakey and many others, we now possess the factual evidence for man’s evolutionary ascent, culminating in those images of deer and bison on the ceiling of that Altamira cave whose technical virtuosity so astonished the Marquis de Sautola. There is no deep mystery about our origins. The massively overwhelming prevailing view taught in virtually every school and university in the Western world insists that Darwin’s evolutionary theory of natural selection explains us and our ancestors. ‘Our own existence [that] once presented the greatest of all mysteries is a mystery no longer. Darwin solved it,’ observes the evolutionary biologist Richard Dawkins. ‘We no longer have to resort to superstition … it is absolutely safe to say that anyone who claims not to believe in evolution is ignorant, stupid or insane.’ And how could it not be so? What other conceivable explanation might there be? There is none. That, one would think, should be the end of the matter.

And yet, the more that time has passed since those definitive discoveries of Lucy and Turkana Boy, the more perplexing that evolutionary trajectory seems to be. The Ascent of Man captured in Thomas Huxley’s famous image is no longer a theoretical idea: it is concretely realised in Lucy’s sharp-angled femur and Turkana Boy’s much larger skull; but the more one reflects on what is involved in standing upright or acquiring a larger brain, the less convincing Darwin’s proposed mechanism of natural selection appears to be. Further, the suddenness of the cultural explosion that signalled the arrival of Cromagnon man argues against a progressive, gradualist evolutionary transformation. It suggests rather some dramatic event – as if a switch were thrown, the curtain rose, and there was man at the centre of the stage of world events. The findings of the New Genetics and the Decade of the Brain make it much more difficult to set such doubts aside. The trivial genetic differences that separate our primate cousins from ourselves seem quite insufficient to account for those physical differences that set us apart. Similarly, the elusive workings of the human brain would seem to defy any simple evolutionary explanation.