The Ascent of Man (38 page)

And wee said nothing, all the day.

But O alas, so long, so farre,

Our bodies why doe wee forbeare?

This Extasic doth unperplex

(We said) and tell us what we love.

Loves mysteries in soules doe grow,

But yet the body is his booke.

I begin this last essay in Iceland because it is the seat of the oldest democracy in Northern Europe. In the natural amphitheatre of Thingvellir, where there were never any buildings, the Allthing of Iceland (the whole community of the Norsemen of Iceland) met each year to make laws and to receive them. And this began about
AD
900, before Christianity arrived,
at a time when China was a great empire, and Europe was the spoil of princelings and robber barons. That is a remarkable beginning to democracy.

But there is something more remarkable about this misty, inclement site. It was chosen because the farmer who had owned it had killed, not another farmer but a slave, and had been outlawed. Justice was seldom so even-handed in slave-owning cultures.
Yet justice is a universal of all cultures. It is a tightrope that man walks, between his desire to fulfil his wishes, and his acknowledgement of social responsibility. No animal is faced with this dilemma: an animal is either social or solitary. Man alone aspires to be both in one, a social solitary. And to me that is a unique biological feature. That is the kind of problem that engages me in my
work on human specificity, and that I want to discuss.

It is something of a shock to think that justice is part of the biological equipment of man. And yet it is exactly that thought which took me out of physics into biology, and that has taught me since that a man’s life, a man’s home, is a proper place in which to study his biological uniqueness.

It is natural that by tradition biology is
thought of in a different way: that the likeness between man and the animals is what dominates it. Back before the year
AD
200 the great classic author of antiquity in medicine, Claudius Galen, studied, for example, the forearm in man. How did he study it? By dissecting the forearm in a Barbary ape. That is how you have to begin, necessarily using the evidence of the animals, long before the theory
of evolution comes to justify the analogy. And to this day the wonderful work on animal behaviour by Konrad Lorenz naturally makes us seek for likeness between the duck and the tiger and man; or B. F. Skinner’s
psychological work on pigeons and rats. They tell us something about man. But they cannot tell us everything. There must be something unique about man because otherwise, evidently, the
ducks would be lecturing about Konrad Lorenz, and the rats would be writing papers about B. F. Skinner.

Let us not beat about the bush. The horse and the rider have many anatomical features in common. But it is the human creature that rides the horse, and not the other way about. And the rider is a very good example, because man was not created to ride the horse. There is no wiring inside the
brain that makes us horse riders. Riding a horse is a comparatively recent invention, less than five thousand years old. And yet it has had an immense influence, for instance on our social structure.

The plasticity of human behaviour makes that possible. That is what characterises us; in our social institutions, of course, but for me, naturally, above all in books, because they are the permanent
product of the total interests of the human mind. They come to me like the memory of my parents: Isaac Newton, the great man dominating the Royal Society at the beginning of the eighteenth century, and William Blake, writing the
Songs of Innocence
late in the eighteenth century. They are two aspects of the one mind, and both are what behavioural biologists call species-specific.

How can I put this most simply? I wrote a book recently called
The Identity of Man
. I never saw the cover of the English edition until the book reached me in print. And yet the artist had understood exactly what was in my mind, by putting on the cover a drawing
of the brain and the
Mona Lisa
, one on top of the other. In his action he demonstrated what the book said. Man is unique not because he does science, and he is unique not because he does art, but because science and art equally are expressions of his marvellous plasticity of mind. And the
Mona Lisa
is a very good example, because after all what did Leonardo do for much of his life? He drew anatomical
pictures, such as the baby in the womb in the Royal Collection at Windsor. And the brain and the baby is exactly where the plasticity of human behaviour begins.

I have an object which I treasure: a cast of the skull of a child that is two million years old, the Taung baby. Of course, it is not strictly a human child. And yet if she – I always think of her as a girl – if she had lived long enough,
she might have been my ancestor. What distinguishes her little brain from mine? In a simple sense, the size. That brain, if she had grown up, would have weighed perhaps a little over a pound. And my brain, the average brain today, weighs three pounds.

I am not going to talk about the neural structures, about one-way conduction in nervous tissues, or even about the old brain and the new, because
that apparatus is what we share with many animals. I am going to talk about the brain as it is specific to the human creature.

The first question we ask is, is the human brain a better computer – a more complex computer? Of course, artists in particular tend to think of the brain as a computer. So in his
Portrait of Dr Bronowski
Terry Durham has symbols of the spectrum and the computer, because
that is how an artist imagines a scientist’s brain. But of course that cannot be right. If the brain were a computer, then it would be carrying out a pre-wired set of actions in an inflexible sequence.

By way of example, think of a very beautiful piece of animal behaviour described in my
friend Dan Lehrman’s work on the mating of the ring-dove. If the male coos in the right way, if he bows in the right way, then the female explodes in excitement, all her hormones squirt, and she goes through a sequence as part of which she builds a perfect nest. Her actions are exact in detail and order, yet they are untaught, and therefore invariable; the ring-dove never changes them. Nobody ever
gave her any set of bricks to learn to build a nest. But you could not get a human being to build anything unless the child had put together a set of bricks. That is the beginning of the Parthenon and the Taj Mahal, of the dome at Sultaniyeh and the Watts Towers, of Machu Picchu and the Pentagon.

We are not a computer that follows routines laid down at birth. If we are any kind of machine, then
we are a learning machine, and we do our important learning in specific areas of the brain. Thus you see that the brain has not just blown up to two or three times its size during its evolution. It has grown in quite special areas: where it controls the hand, for instance, where speech is controlled, where foresight and planning are controlled. I shall ask you to look at them one by one.

Consider
the hand first. The recent evolution of man certainly begins with the advancing development of the hand, and the selection for a brain which is particularly adept at manipulating the hand. We feel the pleasure of that in our actions, so that for the artist the hand remains a major symbol: the hand of Buddha, for instance,
giving man the gift of humanity in a gesture of calm, the gift of fearlessness.
But also for the scientist the hand has a special gesture: we can oppose the thumb to the fingers. Well, the apes can do that. But we can oppose the thumb precisely to the forefinger, and that is a special human gesture. And it can be done because there is an area in the brain so large that I can best describe its size to you in the following way: we spend more grey matter in the brain manipulating
the thumb than in the total control of the chest and the abdomen.

I remember as a young father tiptoeing to the cradle of my first daughter when she was four or five days old, and thinking, ‘These marvellous fingers, every joint so perfect, down to the finger nails. I could not have designed that detail in a million years’. But of course it is exactly a million years that
it took me, a million years that it took mankind, for the hand to drive the brain and for the brain to feed back and drive the hand to reach its present stage of evolution. And that takes place in a quite specific place in the brain. The whole of the hand is essentially monitored by a part of the brain that can be marked out, near the top of the head.

Take next an even more specifically human
part of the brain which does not exist in animals at all: for speech. That is localised in two connected areas of the human brain; one area is close to the hearing centre, and the other lies forward and higher, in the frontal lobes. Is that pre-wired? Yes, in one sense, because if we do not have the speech centres intact we cannot speak at all. And yet, does it have to be learned? Of course it does.
I speak English, which I only learned at the age of thirteen; but I could not speak English if I had not before learned language. You see, if you leave a child speaking no language until the age of thirteen, then it is almost impossible for it to learn at all. I speak English because I learned Polish at the age of two. I have forgotten every word of Polish, but I learned
language
. Here as in other
human gifts the brain is wired to learn.

The speech areas are very peculiar in another way that is human. You know that the human brain is not symmetrical in its two halves. The evidence is familiar to you in the observation that, unlike other animals, men are markedly right-handed or left-handed. Speech also is controlled on one side of the brain, but the side does not vary. Whether you are
right-handed or left-handed, speech is almost certainly on the left. There are exceptions, in the same way that there are people who have their heart on the right, but the exceptions are rare: by and large speech is in areas in the left half of the brain. And what is in the matching areas on the right? We do not exactly know, so far. We do not exactly know what the right-hand side of the brain does
in those areas which are devoted to speech on the left. But it looks as if they take the input that comes by way of the eye – the map of a two-dimensional world on the retina – and turn it or organise it into a three-dimensional picture. If that is right, then in my view it is clear that speech is also a way of organising the world into its parts and putting them together again like movable images.