Kitabı oku: «Why Us?: How Science Rediscovered the Mystery of Ourselves»

1 Science Triumphant, Almost

‘The real voyage of discovery consists not in seeking new lands, but in seeing with new eyes.’

Marcel Proust

We live in the Age of Science, whose lengthy roll-call of discoveries and technical innovations has immeasurably changed our lives for the better. Within living memory children succumbed in their thousands every year from polio and whooping cough, telephones were a rarity, colour television was yet to be invented and the family would gather every evening around the wireless after supper to listen to the news.

Since then, the therapeutic revolution of the post-war years has reduced death in infancy to its irreducible minimum, while ensuring that most now live out their natural lifespan; the electronic revolution has prodigiously extended both the capacity of the human mind, with computers of ever smaller size and greater power, and its horizons, with the Hubble telescope circling in orbit around the earth, relaying back from the far reaches of the cosmos sensational images of its beauty and grandeur.

The landmarks of this post-war scientific achievement are familiar enough: for medicine, there are antibiotics and the pill, heart transplants and test tube babies (and much else besides); for electronics, the mobile phone and the Internet; for space exploration, the Apollo moon landing of 1969 and the epic journey of Voyagers I and II to the far reaches of our solar system. But these last fifty years have witnessed something yet more remarkable still – a series of discoveries that, combined together, constitute the single most impressive intellectual achievement of all time, allowing us to ‘hold in our mind’s eye’ the entire sweep of the history of the universe from its beginning till now. That history, we now know, starts fifteen thousand million years ago (or thereabouts) with the Big Bang, ‘a moment of glory too swift and expansive for any form of words [when] a speck of matter became in a million millionth of a second something at least ten million million million times bigger’. Eleven thousand million years pass, and a massive cloud of gas, dust, pebbles and rocks in a minor galaxy of that (by now) vast universe coalesces around a young sun to create the planets of our solar system. Another thousand million years pass, the surface of the earth cools and the first forms of life emerge from some primeval swamp of chemicals. Yet another two and a half thousand million years elapse till that moment a mere(!) five million years ago when the earliest of our ancestors first walked upright across the savannah plains of central Africa.

And again, within living memory we knew none of this, neither how the universe came into being, nor its size and composition; neither how our earth was born, nor how its landscape and oceans were created; neither the timing of the emergence of life, nor the ‘universal code’ by which all living things reproduce their kind; neither the physical characteristics of our earliest ancestors, nor the details of their evolutionary transformation to modern man. Now we do, and holding this historical sweep ‘in our mind’s eye’ it is possible to appreciate the intellectual endeavour that underpins it will never, can never, be surpassed. How astonishing to realise that today’s astronomers can detect the distant echoes of that ‘moment of glory’ of the Big Bang all those billions of years ago, and capture in those astonishing images transmitted from the Hubble telescope the very processes that brought our solar system into existence. How astonishing that geologists should have discovered that massive plates of rock beneath the earth’s surface, moving at the rate of a centimetre a year, should have formed its continents and oceans, the mountains and valleys of the snow-capped Himalayas thrust upwards by the collision of the Indian subcontinent with the Asian landmass. How astonishing, too, that biologists should now understand the internal workings of the microscopic cell, and how the arrangements of the same four molecules strung out along the elegant spiral of the Double Helix contain the ‘master plan’ of every living thing that has ever existed.

It is impossible to convey the intellectual exhilaration of such momentous discoveries, but the account by Donald Johanson of finding the first near-complete skeleton of our three-and-a-half-million-year-old hominid ancestor ‘Lucy’ conveys something of the emotions felt by so many scientists over the past fifty years.

Tom [Gray] and I had surveyed for a couple of hours. It was now close to noon, and the temperature was approaching 110. We hadn’t found much: a few teeth of a small extinct horse; part of the skull of an extinct pig, some antelope molars, a bit of a monkey jaw …

‘I’ve had it,’ said Tom. ‘When do we head back to camp?’

But as we turned to leave, I noticed something lying on the ground part way up the slope.

‘That’s a bit of a hominid arm,’ I said.

‘Can’t be. It’s too small. Has to be monkey of some kind.’

We knelt to examine it.

‘Much too small,’ said Gray again.

I shook my head. ‘Hominid.’

‘What makes you so sure?’ he said.

‘That piece right next to your hand. That’s hominid too.’

‘Jesus Christ,’ said Gray. He picked it up. It was the back of a small skull. A few feet away was part of a femur; a thigh bone. ‘Jesus Christ,’ he said again. We stood up and began to see other bits of bone on the slope. A couple of vertebrae, part of a pelvis – all of them hominid. An unbelievable, impermissible thought flickered through my mind. For suppose all these fitted together? Could they be parts of a single extremely primitive skeleton? No such skeleton has ever been found – anywhere.

‘Look at that,’ said Gray. ‘Ribs.’

A single individual.

‘I can’t believe it,’ I said, ‘I just can’t believe it.’

‘By God you’d better believe it!’ shouted Gray. His voice went up into a howl. I joined him. In that 110 degree heat we began jumping up and down. With nobody to share our feelings, we hugged each other, sweaty and smelly, howling and hugging in the heat-shimmering gravel, the small brown remains of what now seemed almost certain to be parts of a single hominid skeleton lying all around us.

Momentous events have multiple causes, and the source of this so recent and all-encompassing delineation of the history of our universe stretches back across the centuries. It is impossible to hope to convey the intellectual brilliance and industry of those who brought this extraordinary enterprise to fruition, whose major landmarks are summarised here as the Thirty Definitive Moments of the past six decades.

TABLE 1

Science Triumphant 1945–2001: Thirty Definitive Moments

The triumph of science, one might suppose, is virtually complete. What, during these times, have we learned from the humanities – philosophy, say, theology or history – that begins to touch the breadth and originality of this scientific achievement and the sheer extraordinariness of its insights? What, one might add, have the humanities done that begins to touch the medical therapeutic revolution of the post-war years or the wonders of modern technology?

That history of our universe as revealed in the recent past draws on many disciplines: cosmology and astronomy obviously, the earth and atmospheric sciences, biology, chemistry and genetics, anthropology and archaeology, and many others. But science is also a unified enterprise, and these areas of enquiry all ‘hang together’ to reveal the coherent story outlined above. There remained, however, two great unknowns, two final obstacles to a truly comprehensive theory that would also explain our place in that universe.

The first is how it is that we, like all living things, reproduce our kind with such precision from one generation to the next. The ‘instructions’, as is well recognised, come in the form of genes strung out along the two intertwining strands of the Double Helix in the nucleus of every cell. But the question still remained: How do those genes generate that near-infinite diversity and beauty of form, shape and size, and behaviour that distinguish one form of life from another? How do they fashion from a single fertilised human egg the unique physical features and mind of each one of us?

The second of these ‘great unknowns’ concerned the workings of the brain, and the human brain in particular. To be sure, neurologists have over the past hundred years identified the functions of its several parts – with the frontal lobes as the ‘centre’ of rational thought and emotion, the visual cortex at the back, the speech centre in the left hemisphere and so on. But again the question remained: How does the electrical firing of the brain’s billions of nerves ‘translate’ into our perception of the sights and sounds of the world around us, our thoughts and emotions and the rich inner landscape of personal memories?

These two substantial questions had remained unresolved because both the Double Helix and the brain were inaccessible to scientific scrutiny: the Double Helix, with its prodigious amount of genetic information, comes packed within the nucleus of the cell, a mere one five thousandth of a millimetre in diameter; while the blizzard of electrical activity of the billions of neurons of the brain is hidden within the confines of the bony vault of the skull. But then, in the early 1970s, a series of technical innovations would open up first the Double Helix and then the brain to scientific investigation, with the promise that these final obstacles to our scientific understanding of ourselves might soon be overcome. We will briefly consider each in turn.