Facebook Twitter



The 20th century will be remembered for three broad innovations: unprecedented means to save, prolong and enhance life; unprecedented means to destroy life, including for the first time putting our global civilization at risk; and unprecedented insights into the nature of ourselves and the universe. All three of these developments have been brought forth by science and technology, a sword with two razor-sharp edges.

SAVING, PROLONGING AND ENHANCING HUMAN LIFE: Until about 10,000 years ago, with the invention of agriculture and the domestication of animals, the human food supply was limited to fruits and vegetables in the natural environment, and game animals.But the sparsity of naturally grown foodstuffs was such that the Earth could maintain no more than about 10 million or so of us. In contrast, by the end of the 20th century, there will be 6 billion people. That means that 99.9 percent of us owe our lives to agricultural technology and the science that underlies it - plant and animal genetics and behavior, chemical fertilizers, pesticides, preservatives, plows, combines and other agricultural implements, irrigation - and refrigeration in trucks, railway cars, stores and homes.

Many of the most striking advances in agricultural technology - including the "Green Revolution" - are products of the 20th century. Through urban and rural sanitation, clean water, other public health measures, acceptance of the germ theory of disease, antibiotics and other pharmaceuticals, genetics and molecular biology, medical science has enormously improved the well-being of people all over the world - but especially in the developed countries. Smallpox has been eradicated worldwide; the area of the Earth in which malaria flourishes shrinks year by year; and diseases I remember from my childhood, such as whooping cough, scarlet fever and polio, are almost gone today.

Among the most important 20th century inventions are comparatively inexpensive birth-control methods, which for the first time permit women safely to control their reproductive destinies and are working toward the emancipation of half of the human species. They permit major declines in the perilously increasing populations in many countries without requiring oppressive restrictions on sexual activity.

It is also true that the chemicals and radiation produced by our technology have induced new diseases and are implicated in cancer. The global proliferation of cigarettes leads to an estimated 3 million deaths a year (all of course preventable). By 2020, the number is estimated by the World Health Organization to reach 10 million a year.

But technology has given much more than it has taken away. The clearest sign of this is that life expectancy in the United States and Western Europe in 1901 was about 45 years, while today it is approaching 80 years, a little more for women, a little less for men.

Life expectancy is probably the single most effective index of quality of life: If you're dead, you're probably not having a good time. That said, there are still a billion of us without enough to eat, and 40,000 children dying needlessly every day on our planet.

Through radio, television, phonographs, audiotape players, compact discs, telephones, fax machines and computer information networks, technology has profoundly changed the face of popular culture. It has made possible the pros and cons of global entertainment, of multinational corporations with loyalties to no particular country, transnational affinity groups, and direct access to the political and religious views of other cultures.

As we saw in the highly attenuated rebellion at Tiananmen Square and the one at the "White House" in Moscow, faxes, telephones and computer networks can be powerful tools of political upheaval.

The introduction of mass-market paperback books in the 1940s has brought the world's literature and the insights of its greatest thinkers, present and past, into the lives of ordinary people.

Along with progress in literacy, such trends are the allies of Jeffersonian democracy. On the other hand, what passes for literacy in America in the late 20th century is a very rudimentary knowledge of the English language, and television in particular tends to seduce the mass population away from reading. In pursuit of the profit motive, it has dumbed itself down to lowest-common-denominator programming - instead of rising up to teach and inspire.

The use of potentially life-saving technology differs from nation to nation. The United States, for example, has the highest infant mortality of any industrial nation. It has more young black men in prison than in college. Its students routinely perform poorly on standardized science and mathematics tests when compared with students of the same age in other countries.

The disparity in real incomes between the rich and the poor and the decline of the middle class have been growing swiftly over the past decade and a half. High-technology industry has been fleeing American shores. After leading the world in almost all these respects in midcentury, there are some signs of decline in the United States at century's end. The quality of leadership can be pointed to, but so can the dwindling penchant for critical thinking and political action in its citizens.

TOTALITARIAN AND MILITARY TECHNOLOGY: The means of making war, of mass killings, of the annihilations of whole peoples, has reached unprecedented levels in the 20th century. In 1901, there were no military aircraft or missiles, and the most powerful artillery could loft a shell a few miles and kill a handful of people. By the second third of the 20th century, some 70,000 nuclear weapons had been accumulated.

Many of them were fitted to strategic rocket boosters, fired from silos or submarines, able to reach virtually any part of the world, and each warhead powerful enough to destroy a large city.

Today we are in the throes of major arms reductions, both in warheads and delivery systems, by the United States and the former Soviet Union. Were all present treaties - even those not yet ratified - implemented, the United States and Russia would still have enough weapons to destroy every city on the planet twice over. The climatic effects of a global thermonuclear war seem to be sufficient to destroy the global civilization and perhaps the human species.

Formidable arsenals are also in the possession of Britain, France, China and Israel, with Pakistan, India and many other nations able to assemble nuclear weapons on short notice. In addition, horrendously deadly chemical and biological weapons are in many lands worldwide. In a century bubbling over with fanaticism, ideological certainty and mad leaders, this accumulation of unprecedentedly lethal weapons does not bode well for the human future.

More than 150 million human beings have been killed in warfare and by the direct orders of national leaders in the 20th century.

Our technology has become so powerful that not only on purpose but also inadvertently we can alter th environment on a large scale and threaten many species on earth, our own included. Chlorofluorocarbons and bromine compounds attack the protective ozone layer. The burning of fossil fuels produces global warming, which is likely to reach serious proportions by the end of the next century. We destroy an acre of forest every second and exterminate a species of life every day.

The simple fact is we are performing unprecedented experiments on the global environment and in general hoping against hope that the problems will solve themselves and go away.

Ethnocentric and xenophobic vendettas have been rife on every continent. Systematic attempts to annihilate whole ethnic groups have occurred - most notably in Nazi Germany, but also in Rwanda, the former Yugoslavia and elsewhere. Similar tendencies have existed throughout human history, but only in the 20th century has technology made killing on such a scale practical.

Strategic bombing, missiles and long-range artillery have the "advantage" that the combatants need not come face-to-face with the agony they have worked. Their consciences need not trouble them.

The global military budget at the end of the 20th century is close to a trillion dollars a year. Think of how much human good could be purchased for even a fraction of that.

THE REVELATIONS OF SCIENCE: Every branch of science has made stunning advances in the 20th century. The very foundations of physics have been revolutionized by the special and general theories of relativity and by quantum mechanics. It was in this century that the nature of atoms - with protons and neutrons in a central nucleus and electrons in a surrounding cloud - was first understood, when the constituent components of protons and neutrons, the quarks, were first glimpsed, and when a host of exotic abort-lived elementary particles first bonged up under the ministrations of high-energy accelerators and cosmic rays.

Fission and fusion have made possible the corresponding nuclear weapons, fission power plants (a not unmixed blessing), and the prospect of fusion power plants. An understanding of radioactive decay has given us definitive knowledge of the age of the Earth (about 4.6 billion years) and of the time of the origin of life on our planet (roughly 4 billion years ago).

Some mass extinctions of life in the past are now understood to have been caused by immense mantle plumes gushing up through the surface and generating lava seas where solid land once stood. Others are due to the impact of large comets or near-Earth asteroids igniting the skies and changing the climate.

In the next century, at the very least we ought to be inventorying comets and asteroids to see if any of them has our name on it.

One cause for scientific celebration in the 20th century is the discovery of the nature and function of DNA, deoxyribonucleic acid - the key molecule responsible for heredity in humans and in most other plants and animals. We have learned to read the genetic code, and in increasing numbers of organisms we have mapped all the genes and know what functions of the organisms most of them are in charge of.

Geneticists are well on their way to mapping the human genome - an accomplishment with enormous potential for both good and evil. The most significant aspect of the DNA story is that the fundamental processes of life are fully understandable in terms of physics and chemistry.

Physics and chemistry, coupled with the most powerful computers on Earth, have tried to understand the climate and general circulation of the Earth's atmosphere through time.

This powerful tool is used to evaluate the future consequences of the continued emission of carbon dioxide and other greenhouse gases into the Earth's atmosphere; meanwhile, much easier, meteorological satellites permit weather prediction at least days in advance, avoiding billions of dollars in crop failures every year.

At the beginning of the 20th century, astronomers were stuck at the bottom of an ocean of turbulent air and left to peer at distant worlds. By the end of the 20th century, great telescopes are in Earth's orbit peering at the heavens in gamma rays, X-rays, ultraviolet light, visible light, infrared light and radio waves.

Marconi's first radio broadcast across the Atlantic Ocean occurred in 1901. We have now used radio to communicate with four spacecraft beyond the outermost known planet of our solar system, and to bear the natural radio emission from quasars 8 billion and 10 billion light-years away.

Exploratory spacecraft have been launched to study 70 worlds and to land on three of them. The century has seen the almost mythic accomplishment of sending 12 humans to the moon and bringing them, and over a hundred kilograms of moon rocks, back safely. Robotic craft have confirmed that Venus, driven by a massive greenhouse effect, has a surface temperature of almost 900 degrees Fahrenheit; that 4 billion years ago Mars had an Earth-like climate; that organic molecules are falling from the sky of Saturn's moon Titan like manna from heaven; that comets are perhaps a quarter organic matter.

Four of our spacecraft are on their way to the stars. Other planets have recently been found around other stars. Our Sun is revealed to be in the remote outskirts of a vast, lens-shaped galaxy comprising some 400 billion other suns.

At the beginning of the century, it was thought that the Milky Way was the only galaxy. We now recognize that there are a hundred billion others, all fleeing one from another as if they are the remnants of an enormous explosion, the Big Bang. Exotic denizens of the cosmic zoo have been discovered that were not even dreamed of at the turn of the century - pulsars, quasars, black holes.

But I see the emergence in our consciousness of a universe of a magnificence, and an intricate, elegant order far beyond anything our ancestors imagined. And if much about the universe can be understood in terms of a few simple laws of nature, those wishing to believe in God can certainly ascribe those beautiful laws to a Reason underpinning all of nature.

My own view is that it is far better to understand the universe as it really is than to pretend to a universe as we might wish it to be.

Whether we will acquire the understanding and wisdom necessary to come to grips with the scientific revelations of the 20th century will be the most profound challenge of the 21st.