Man is a singular creature. He has a set of gifts which make him unique among the animals so that, unlike them, he is not a figure in the landscape, he is the shape of the landscape. This is the Pacific Ocean. The California Indians used to say that at full moon the fish came and danced on these beaches. And it’s true that there is a local variety of fish, the grunion, that comes up out of the water and lays its eggs above the high tide mark. The females bury themselves tail first in the sand, and the males gyrate or dance around them and fertilize the eggs as they are being laid. The full moon is important because it gives nine or ten days between these very high tides and the next ones that will wash the hatched fish out to sea again.
Every landscape in the world is full of these exact and beautiful adaptations by which an animal fits into its environment like one cogwheel into another. Millions of years of evolution have shaped the grunion to fit and sit exactly with the tides. But nature, that is evolution, has not fitted man to any specific environment. On the contrary, by comparison with the grunion, he has a rather crude survival kit. And yet this is the paradox of the human condition, one that fits him to all environments. His imagination, his reason, his emotional subtlety and toughness make it possible for him not to accept the environment, but to change it. And that series of inventions by which man from age to age has remade his environment is a different kind of evolution—not biological, but cultural evolution. I call that brilliant sequence of cultural peaks the Ascent of Man.
Of course it’s tempting—very tempting to a scientist—to hope that the most original achievements of the mind are also the most recent. And we do indeed have cause to be proud of some modern work. Think of the unraveling of the code of heredity in the DNA spiral, or the work going forward on the special faculties of the human brain. Think of the philosophic insight that saw into the theory of relativity, or the minute behavior of matter on the atomic scale. Yet human achievement, and science in particular, is not a museum of finished constructions. It’s a progress in which the first experiments of the alchemists also have a formative place, and the sophisticated arithmetic that the Mayan astronomers of Central America invented for themselves independently of the old world.
The stonework of Machu Picchu in the Andes and the geometry of the Alhambra are constructions as arresting and important for their people as the architecture of DNA for us. In every age there is a turning point, a new way of seeing and asserting the coherence of the world. It’s frozen in the statues on Easter Island that put a stop to time, and in the medieval clocks in Europe that once also seemed to say the last word about the heavens forever.
There’s nothing in modern chemistry more unexpected than putting together alloys with new properties. That was discovered about the birth of Christ in South America, and long before that in Asia. Splitting and fusing the atom both derive conceptually from a discovery made in prehistory: that stone and all matter has a structure along which it can be split and put together in new arrangements. And man-made biological inventions almost as early: agriculture. The domestication of wild wheat, for example, and the improbable idea of taming and then riding the horse.
So these programs or essays are a journey through intellectual history; a personal journey to the high points of man’s achievement—what the poet Yeats called monuments of unaging intellect. Where should one begin? With the creation: with the creation of man himself. Charles Darwin pointed the way. It’s almost certain now that man first evolved in Africa near the equator. This is a possible area. The valley of the river Omo in Ethiopia near Lake Rudolph. The ancient stories used to put the creation of man into a golden age and a beautiful legendary landscape. If I were telling the story of Genesis now, I should be standing in the Garden of Eden. But this is manifestly not the Garden of Eden. And yet I am at the navel of the world, at the birthplace of man, here in the East African Rift Valley near the equator. And if this ever was a Garden of Eden, why, it withered millions of years ago.
I’ve chosen this place because it has a unique structure. In this valley was laid down over the last four million years layer upon layer of volcanic dust. Four million years ago, three million years ago, over two million years ago, somewhat under two million years ago. And then the Rift Valley buckled it, so that now it makes a map in time which we see stretching into the distance. These cliffs are the strata on edge. In the foreground the bottom level, four million years old. And beyond that the next lowest, well over three million years old. The remains of a creature like man appear beyond that. And the remains of the animals that lived at the same time.
The animals are a surprise, because it turns out that they have changed so little. This is the topi antelope now. The ancestor of man that hunted its ancestor two million years ago would at once recognize the topi today. But he would not recognize the hunter today, black or white, as his own descendant.
Among the animals, the hunter has changed as little as the hunted. The serval cat is still powerful in pursuit, and the oryx is still swift in flight. Both perpetuate the same relation between their species as they did long ago. Human evolution began when the African climate changed to drought. The lakes shrank, the forest thinned out to savanna. When animals like Grévy's zebra were adapted to the dry savanna, it became a trap in time as well as space. They stayed where they were and much as they were. The most gracefully adapted of all these animals is surely Grant's gazelle. Yet that lovely leap never took it out of the savanna.
In a parched African landscape like this at Omo, man first put his foot to the ground. That seems a pedestrian way to begin the Ascent of Man. And yet it’s crucial. Two million years ago, the first certain ancestor of man walked with a foot which is almost indistinguishable from the foot of modern man. The fact is that when he put his foot on the ground and walked upright, man made a commitment to a new integration of life, and therefore of the limits. The one to concentrate on, of course, is the head. This is what it looked like just over two million years ago. It’s a historic skull. It wasn’t found here at Omo, but south of the equator, at a place called Taung, by an anatomist called Raymond Dart. It’s a baby five to six years old, and the skull has been badly twisted. Yet Dart instantly recognized two extraordinary features. One is that the foramen magnum—that’s the hole in the skull that the spinal cord comes up through to the brain—is upright, so that this was a child that held its head up. And the other is the teeth. The teeth are always telltale. They’re small, they’re square. These are still the child’s nook teeth. They are not the great fighting canines that the apes have. That means that this was a creature that was going to forage with its hands and not its mouth that was probably eating meat—raw meat—and almost certainly making tools, pebble tools, stone choppers, to carve it to hunt. Dart called this creature Australopithecus. It’s not a name that I like. It just means southern ape.
For me, the little Australopithecus baby has a personal history. In 1950, when its humanity was by no means accepted, I was asked to do a piece of mathematics. Could I combine a measure of the size of the teeth with their shape so as to discriminate it from the teeth of apes? I’d never held a fossil skull in my hands, and I was by no means an expert on teeth. But it worked pretty well. And it transmitted to me a sense of excitement which I remember this instance. I, at over 40, having spent a lifetime on doing abstract mathematics about the shapes of things, suddenly saw my knowledge reach back two million years and shine a searchlight into the history of man. That was phenomenal. And from that moment I was totally committed to thinking about what makes man what he is—in the scientific work that I’ve done since then, the literature that I’ve written, and in these programs. I don’t know how the Taung baby began life, but to me it still remains the primordial infant from which the whole adventure of man began.
The human baby, the human being, is a mosaic of animal and angel. For example, the reflex that makes the baby kick is already there in the womb. Every mother knows that. And it’s there in all vertebrates. Here, at eleven months, it urges the baby to crawl. That brings in new movements, and they then lay down and consolidate the pathways in the brain (the cerebellum) that will form a whole repertoire of subtle, complex movements and make them second nature to him. Now the cerebellum is in control. All that the conscious mind has to do is to issue the command. And at fourteen months the command is: stand.
What are the physical gifts that man must share with the animals, and what gifts make him different? The starting response of the runner is the same as the flight response of the gazelle. He seems all animal in action. The heartbeat goes up. The heart is pumping five times as much blood as normal, and 90% of it is for the muscles. He needs 20 gallons of air a minute now to aerate his blood. That shows up as heat in infrared films. The blue or light zones are hottest, the red or dark zones are cooler. The main chemical action is to get energy for the muscles by burning sugar there. But three quarters of that is lost as heat. At this speed, the chemical burn up in the muscles is too fast to be complete. The waste products of incomplete burning now foul up the blood. This is what causes fatigue and blocks the muscle action until the blood can be cleaned with fresh oxygen.
All that, in one way or another, is the normal metabolism of an animal in flight. But the runner was not in flight. The shot that set him off was the starter’s pistol. And what he was experiencing deliberately was not fear but exaltation. The runner is like the child at play. His actions are an adventure in freedom. And the only purpose of this breathless chemistry was to explore the limits of his own strength. There are physical differences between man and the other animals, even between man and the apes. The athlete grasps his pole, for example, with an exact grip that no ape can quite match. Yet such differences are secondary by comparison with the overriding difference, which is that the athlete is an adult whose behavior is not driven by his immediate environment. In themselves, his actions make no practical sense at all. They are an exercise that is not directed to the present. The athlete’s mind is fixed ahead of him, building up his skill, and he vaults in imagination into the future.
The pole vaulter is a capsule of human abilities. The grasp of the hand, the arch of the foot, the muscles of shoulder and pelvis, the pole itself in which energy is stored and released like a bow firing an arrow. It’s the invention of the pole, the concentration of the mind at the moment before leaping, which gives it the stamp of humanity. If I’m to take the Ascent of Man back to its beginnings in the animal, it’s the evolution of the head and skull that has to be traced. Unhappily, over the 50 million years or so to be talked about, there are only six or seven essentially distinct skulls so that, in order to trace the continuity, I’m putting them on a computer which will lead from one to the next.
Begin 50 million years ago with this small tree-dwelling creature, a lemur, whose skull is being turned upside down. You can see the foramen magnum at the back. This is a creature that hung, not held, its head on the spine. And it has the essential marks of the primates—that is the family of monkey, ape, and man. From the whole skeleton, we know that it has fingernails, not claws. It has a thumb that can oppose, at least in part, the hand. And it has in the skull the two features that really mark the beginning of man: the snout is short, the eyes are widely spaced. That means that there has been selection against the sense of smell and in favor of the sense of vision. From that, man begins.
In the next 20 million years, the line that leads to the monkeys branches away from the main line to the apes and man. This creature is on the main line 30 million years ago. He’s large, yet still lives in the trees. But from now on, the ancestors of the apes and man spend part of their time on the ground.
This is ten million years on, a classical find: Proconsul. The brain is markedly larger. The eyes are now fully forward in stereoscopic vision. They tell us how the ape-and-man line was moving. But alas, this creature is on a branch line, the ape line. The teeth show us that it is an ape because the way in which the jaw is locked by the big canines is not man-like. It’s the change in the teeth that signals the separation of the line that leads to man.
This creature is fourteen million years old and we only have pieces of the jaw. But it’s clear that the teeth are level and more human.
There is now a blank in the fossil record for about ten million years. Then, perhaps five million years ago, we come certainly to the relatives of man. This is a cousin of man—not in the direct line to us; a heavily built Australopithecus who is a vegetarian. The teeth that survive are pitted by the fine grit that he picked up with the roots that he ate. His cousin on the line to man is lighter, visibly so in the jaw, and is probably a meat eater. This is the nearest thing to what used to be called the missing link: Australopithecus from Africa, a grown female. The Taung child with which I began this program would have grown up to be like this: fully erect, walking, and with a large brain, between a pound and a pound and a half. That’s the size of the brain of a big ape now. But of course this was a small creature, standing only four feet high.
Indeed, recent finds by Richard Leakey suggest that, by two million years ago, the brain was larger even than that. And with that larger brain the ancestors of man made two inventions, for one of which we have visible evidence, and for the other influential evidence. First, the visible invention.
Two million years ago, Australopithecus made stone jaws like this, where a simple blow has put an edge on the pebble. And for the next million years, man in his further evolution did not change this type of tool. The ancestors of man had a short thumb, so they could only hold this tool in a power grip and use it like that. It’s a meat eater’s tool.
The other invention is social. Skulls and skeletons of Australopithecus that we found in large numbers show that most of them died before they were twenty. That means that there must have been many orphans. And Australopithecus must have had a long childhood, as all the primates do. By the age of ten they were still children. Therefore, there must have been a social organization which adopted them, made them part of the community, educated them. That’s a great step towards cultural evolution.
At what point can we say that the precursors of man become man himself? That’s a delicate question. Such changes do not take place overnight, and it would be foolish to try and make them see more certain than they really were, or to argue about names. Two million years ago we were not yet men, but a million years ago we were. Because by then there appears a creature who can be called Homo: Homo erectus.
He spread far beyond Africa. That’s Peking Man, 400,000 years old, the first creature that used fire. The changes in Homo erectus are substantial over a million years, but they seem gradual. This is Neanderthal Man. He already has a three-pound brain as large as modern man. Probably some lines of Neanderthal Man died out, but it seems likely that a line in the Middle East went on directly to us Homo sapiens. Somewhere in the last million years or so, man made a change in the quality of his tools, which presumably points to some biological refinement in the hand, and especially in the brain controlling the hand. He makes tools which require much finer manipulation in the making, and of course in the use.
The evolution of the brain, of the hand, of the eyes, of the feet, the whole human frame, makes a mosaic of special gifts. Man is not the most majestic of the creatures. Long before the mammals even, the dinosaurs were far more splendid. But he has what no other animal possesses: a jigsaw of faculties which alone, over 3,000 million years of life, make him creative. Every animal leaves traces of what it was. Man alone leaves traces of what he created.
From the ancestral Australopithecus onwards, the family of man ate some meat—small animals at first, larger ones later. Meat is a more concentrated protein than plant, and eating meat cuts down the bulk and the time spent in eating by two thirds. But a slow creature like man can stalk, pursue, and corner a savanna animal that is adapted for flight only by cooperation. Hunting requires conscious planning and organization by means of language as well as special weapons. The hunt is a communal undertaking, of which the climax—but only the climax—is the kill.
Hunting cannot support a growing population in one place. The limit for the savanna was not more than two people to the square mile. At that density, the total land surface of the Earth could only support the present population of California, about 20 millions, and could not support the population of Great Britain. The choice for the hunters was brutal: starve or move. They moved away over prodigious distances.
By a million years ago, they were in North Africa. By 700,000 years ago, they were in Java. By 400,000 years ago, they had marched north to China in the east and Europe in the west. These incredible migrations made man from an early time a widely dispersed species, even though his total numbers were quite small, perhaps one million. What is even more forbidding is that man moved into the north just when the climate there was turning to ice.
In that great cold the ice, as it were, grew out of the ground. The Northern climate had been temperate for immemorial ages—literally for several hundred million years. Yet, just when Homo erectus settled in China and Northern Europe, a sequence of three separate ice ages began. The first was at its fiercest when Peking Man lived in caves 400,000 years ago. It’s no surprise to find fire used in those caves for the first time.
The ice moved south and retreated three times, and the land changed each time. The ice caps at their largest contained so much of the Earth’s water that the level of the sea fell 400 feet. In the second ice age, over 200,000 years ago, Neanderthal man with his big brain became important. The cultures of man that we recognize began to form in the most recent ice age within the last 100,000 years. That is when we find the elaborated tools that point to sophisticated forms of hunting: the spear-thrower, for example, and the baton that may be a straightening tool. The fully barbed harpoon, and of course the flint master tools that were needed to make the hunting tools. Man survived the fierce test of the ice ages because he had the flexibility of mind to recognize inventions and turn them into community property.
Evidently the ice ages worked a profound change in the way man could live. They forced him to depend less on plants and more on animals. The rigors of hunting on the edge of the ice also changed the strategy of hunting. It became less attractive to stalk single animals, however large. The better alternative was to follow herds of animals, and not to lose them; to learn to anticipate, and in the end to adopt their habits, including their wandering migrations. This is a peculiar adaptation, the trans-humans’ mode of life on the move. The only people that still live in this way are the Lapps in the extreme north of Scandinavia, who follow the reindeer as they did during the ice age. There are 30,000 people and 300,000 reindeer, and their way of life is coming to an end even now as we watch it. The herds go on their own migration across the fjords from one icy pasture of lichen to another, and the Lapps go with them. But the Lapps are not herdsmen. They do not control the reindeer. They have not domesticated it. They simply move where the herds move.
The Lapps have some of the traditional inventions for controlling single animals that other cultures also discovered. For example, they make some males manageable as draft animals by castrating them. It’s a strange relation. The Lapps are entirely dependent on the reindeer. They eat the meat—a pound a head each every day. They use the sinews and fur and hides and bones. They drink the milk. They even use the antlers. And yet the Lapps are freer than the reindeer, because their mode of life is a cultural adaptation and not a biological one. The adaptation that the Lapps have made, the trans-humans’ life on the move in a landscape of ice, is a choice that they can change. It’s not irreversible, as biological mutations are.
Making a shelter from reindeer hides is an adaptation that the Lapps can change tomorrow. Most of them are doing so now. But you cannot change the color of your skin. Why are the Lapps white? Man began with a dark skin. The sunlight makes vitamin D in his skin, and if he had been white in Africa it would make too much. But in the North man needs to let in all the sunlight there is to make enough vitamin D. And natural selection therefore favored those with whiter skins.
The biological differences between different communities are on this modest scale. The Lapps have not lived by biological adaptation, but by invention, by the imaginative use of the reindeer’s habits and all its products, by turning it into a draft animal, by artifacts, and the sledge. Surviving in the ice did not depend on skin color. The Lapps have survived, man survived the ice ages, by the master invention of all: fire.
Fire is the symbol of the hearth. And from the time Homo sapiens began to leave the mark of his hand 30,000 years ago, the hearth was the cave. For at least a million years, man—in some recognizable form—lived as a forager and a hunter. We have almost no monuments of that immense period of prehistory, so much longer than any history that we record. Only at the end of that time, on the edge of the European ice sheet, we find (in caves like Altamira here, and elsewhere in Spain and southern France) the record of what dominated the mind of man, the hunter. There we see what made his world and preoccupied him: knowledge of the animal that he lived by and stalked.
And yet, when we reflect, what is remarkable is not that there are such few monuments, but that there any at all. Man is a puny, slow, awkward, unarmed animal. He had to invent a pebble, a flint, a knife, a spear. But why do these scientific inventions which were essential to his survival [???] from an early time add those arts that now astonish us? Decorations with animal shapes. Why above all did he come to caves like this, live in them, and then make paintings of animals not where he lived, but in places that were dark, secret, remote, hidden, inaccessible?
The obvious thing to say is that in these places the animal was magical. But magic is a word which explains nothing. It says that man believed he had power, but what power? Here I can only give you my personal view. I think that the power that we see expressed here for the first time is the power of the forward-looking imagination. In these paintings the hunter was made familiar with dangers which he knew he had to face, but to which he had not yet come. When the hunters were brought here into the secret dark, and the light was suddenly flashed on the pictures, he saw the bison as he would have to face him. He saw the running deer. He saw the turning boar. The moment of fear was made present to him. His spear arm flexed with an experience which he would have and which he needed not to be afraid of.
We also look here through the telescope of the imagination. The imagination is a telescope in time. We are looking back at the experiences of the past. The men who made these paintings, the men who were present, looked through that telescope forward. They looked along the Ascent of Man. Because what we call cultural evolution is essentially a constant growing and widening of the human imagination. The men who made the weapons and the men who made the paintings were doing the same thing: anticipating a future as only man can do, inferring what is to come from what is here. All over these caves the print of the hand says that: this is my mark, this is Man.