Dreams of Earth and Sky (35 page)

Blackett said in 1948 that the Soviet proposal for abolishing nuclear weapons without enforcement should have been accepted. If his advice had been followed, we would have been in a situation like the one in 1972 when the United States, the United Kingdom, and the Soviet Union signed a treaty abolishing biological weapons. Before the treaty was signed, the large stockpiles of American and British biological weapons had been destroyed. After the treaty was signed, the Soviet Union cheated on a massive scale and continued to maintain a large clandestine stockpile. Today the biological weapons treaty is still in force and we still have reason to suspect that Russia may be cheating. The question now is whether we are better off with the treaty or without it. Is it better to have a world with biological weapons illegal and well hidden in clandestine facilities, or a world with large stockpiles of biological weapons openly deployed and vulnerable to theft?

Opinions may be divided on the value of the treaty, but there is at least a reasonable argument to be made for keeping it in force. The same argument was made by Blackett for accepting the 1946 Soviet proposal for prohibiting nuclear weapons. If we had accepted the Soviet proposal, we would be living in a world with nuclear weapons legally prohibited but secretly manufactured and hidden away in various places around the world. Would that world be less dangerous than the world of huge stockpiles openly deployed in which we have lived for the last sixty years? Blackett answered yes to that question.
It is time now for the world to ask the question again and decide whether Blackett was right.

Looking back with seventy years of hindsight, we can see clearly that Churchill was deluded. Central to his vision of the world was the power and glory of the British Empire. He fought his wars for the preservation of the empire. The young people who fought for Britain in World War II were not fighting for the empire. They knew that the empire was crumbling and most of them were happy to see it swept away. That was why they voted in 1945 to sweep Churchill away. They knew that Churchill was living in the past, out of touch with the real world. I have a vivid memory of the British general election of 1950, when Attlee was running for reelection after five years of slow recovery from the war. Attlee came to Birmingham, where I was then living, to give a campaign speech to a large crowd. He spoke at length about the social programs that the Labour Party had carried out during his tenure, the big improvements in public housing and public education, and the National Health Service. The crowd listened to this without much enthusiasm. Then at the end of his speech, Attlee said, “We gave freedom to India,” and the crowd responded with loud and long cheering. Giving freedom to India was the one thing that Churchill would never have done. Attlee won the election.

When Churchill returned for his second term as prime minister, he recognized that the empire was fading and based his nuclear policy on another illusion, the special relationship between Britain and America. During World War II he had enjoyed a special relationship with Franklin Roosevelt, with frequent telephone calls and many personal meetings. His friendship with Roosevelt was a crucial part of his war strategy. It allowed him to think of himself as one of the Big Three, deciding the fate of the world in conferences with Roosevelt and Stalin. After returning to office in 1951, he tried to reestablish
his special relationship with presidents Truman and Eisenhower. Truman and Eisenhower found his personal advances annoying and gently pushed him off. After the British hydrogen bomb was demonstrated in 1957, sharing of nuclear secrets was successfully reestablished, but Churchill’s belief that this would perpetuate Britain’s status as a Great Power remained an illusion.

The big question that Farmelo does not try to answer is whether it makes sense for Britain to have nuclear weapons. Two famous scientists answered this question with a resounding no. One was Patrick Blackett. The other was Joseph Rotblat, a Polish nuclear physicist who went with the British contingent to Los Alamos. Rotblat was the only scientist who left the bomb project in 1944 as soon as he heard that the Germans were not working on a bomb. He served for most of a long life as leader of the Pugwash movement, an international alliance of scientists concerned about war and weapons. For his efforts as a peacemaker he won the Nobel Peace Prize in 1995.

Just as Rotblat is unique as a Los Alamos scientist who walked out of the brotherhood of bomb-makers for reasons of conscience, the Republic of South Africa is unique as a country possessing nuclear weapons and unilaterally destroying them. The South Africans have set a splendid example for other countries possessing nuclear weapons to follow. Nobody gives South Africans diminished respect because they walked out of the nuclear club. The United Kingdom is now in an excellent position to gain respect and save money by following the South African example.

SCIENCE CONSISTS OF
facts and theories. Facts and theories are born in different ways and are judged by different standards. Facts are supposed to be true or false. They are discovered by observers or experimenters. A scientist who claims to have discovered a fact that turns out to be wrong is judged harshly. One wrong fact is enough to ruin a career.

Theories have an entirely different status. They are free creations of the human mind, intended to describe our understanding of nature. Since our understanding is incomplete, theories are provisional. Theories are tools of understanding, and a tool does not need to be precisely true in order to be useful. Theories are supposed to be more or less true, with plenty of room for disagreement. A scientist who invents a theory that turns out to be wrong is judged leniently. Mistakes are tolerated, so long as the culprit is willing to correct them when nature proves them wrong.

Brilliant Blunders
, by Mario Livio,
*
is a lively account of five wrong theories proposed by five great scientists during the last two
centuries. These examples give for nonexpert readers a good picture of the way science works. The inventor of a brilliant idea cannot tell whether it is right or wrong. Livio quotes the psychologist Daniel Kahneman describing how theories are born: “We can’t live in a state of perpetual doubt, so we make up the best story possible and we live as if the story were true.” A theory that began as a wild guess ends as a firm belief. Humans need beliefs in order to live, and great scientists are no exception. Great scientists produce right theories and wrong theories, and believe in them with equal conviction.

The essential point of Livio’s book is to show the passionate pursuit of wrong theories as a part of the normal development of science. Science is not concerned only with things that we understand. The most exciting and creative parts of science are concerned with things that we are still struggling to understand. Wrong theories are not an impediment to the progress of science. They are a central part of the struggle.

The five chief characters in Livio’s drama are Charles Darwin, William Thomson (Lord Kelvin), Linus Pauling, Fred Hoyle, and Albert Einstein. Each of them made major contributions to the understanding of nature, and each believed firmly in a theory that turned out to be wrong. Darwin explained the evolution of life with his theory of natural selection of inherited variations, but believed in a theory of blending inheritance that made the propagation of new variations impossible. Kelvin discovered basic laws of energy and heat, and then used these laws to calculate an estimate of the age of the earth that was too short by a factor of fifty. Pauling discovered the chemical structure of protein, the active component of all living tissues, and proposed a completely wrong structure for DNA, the passive component that carries hereditary information from parent to offspring.

Hoyle discovered the process by which the heavier elements essential
for life, such as carbon, nitrogen, oxygen, and iron, are created by nuclear reactions in the cores of massive stars. He then proposed a theory of the history of the universe known as steady-state cosmology, which has the universe existing forever without any big bang at the beginning, and stubbornly maintained his belief in the steady state long after observations proved that the big bang really happened.

Finally, Einstein discovered the great theory of space and time and gravitation known as general relativity, and then added to the theory an additional component later known as dark energy. Einstein afterward withdrew his proposal of dark energy, believing that it was unnecessary. Long after Einstein’s death, observations have proved that dark energy really exists, so that Einstein’s addition to the theory was right and his withdrawal was wrong.

Each of these examples shows in a different way how wrong ideas can be helpful or unhelpful to the search for truth. No matter whether wrong ideas are helpful or unhelpful, they are in any case unavoidable. Science is a risky enterprise, like other human enterprises such as business and politics and warfare and marriage. The more brilliant the enterprise, the greater the risks. Every scientific revolution requires a shift from one way of thinking to another. The pioneer who leads the shift has an imperfect grasp of the new way of thinking and cannot foresee its consequences. Wrong ideas and false trails are part of the landscape to be explored.

Darwin’s wrong idea was the blending theory of inheritance, which supposed the qualities inherited by offspring to be a blend of the qualities of the parents. This was the theory of inheritance generally accepted by plant breeders and animal breeders in Darwin’s time. Darwin accepted it as a working hypothesis because it was the only theory available. He accepted it reluctantly because he knew that it was unsatisfactory in two ways. First, it failed to explain the frequent
cases of hereditary throwback, when a striking hereditary feature such as red hair or musical talent skips a generation from grandparent to grandchild. Second, it failed to allow a rare advantageous variation to spread from a single individual to an entire population of animals, as required by his theory of the origin of species. With blending inheritance, any rare advantageous variation would be quickly diluted in later generations and would lose its selective advantage. For both of these reasons, Darwin knew that the theory of blending inheritance was inadequate, but he did not have any acceptable alternative when he published
The Origin of Species
in 1859.

Nine years later, when Darwin published another book,
The Variation of Animals and Plants Under Domestication
, he had abandoned the blending inheritance theory as inconsistent with the facts. He replaced it with another theory that he called pangenesis. Pangenesis said that the inheritance of qualities from parent to offspring was not carried in the seeds alone but in all the cells of the parent. Somehow the cells of the parent produced little granules that were collected by the seeds. The granules then instructed the seeds how to grow. For the rest of his life Darwin continued to believe in pangenesis, but it was another brilliant blunder, no better than blending inheritance and equally inconsistent with the facts.

Like Darwin’s theories of blending heredity and pangenesis, Kelvin’s wrong calculation of the age of the earth and Pauling’s wrong structure for DNA were speculations requiring blindness to obvious facts. Kelvin based his calculation on his belief that the mantle of the earth was solid and could transfer heat from the interior to the surface only by conduction. We now know that the mantle is partially fluid and transfers most of the heat by the far more efficient process of convection, which carries heat by a massive circulation of hot rock moving upward and cooler rock moving downward. Kelvin lacked our modern knowledge of the structure and dynamics of the earth,
but he could see with his own eyes the eruptions of volcanoes bringing hot liquid from deep underground to the surface. His skill as a calculator seems to have blinded him to messy processes such as volcanic eruptions that could not be calculated.

Similarly, Pauling guessed a wrong structure for DNA because he assumed that a pattern that worked for protein would also work for DNA. He was blind to the gross chemical differences between protein and DNA. Francis Crick and James Watson, paying attention to the differences, found the correct structure for DNA one year after Pauling missed it.

Hoyle’s wrong theory of the universe had a different status from the other mistakes, because he was a young rebel when he proposed it. The steady-state universe was from the beginning a minority view. The decisive evidence against it was the discovery in 1964 of the microwave radiation pervading the universe. The microwave radiation had been predicted to exist as a relic of the hot big bang. The radiation proved that the hot big bang really happened and that the universe had a violent beginning. After that discovery, Hoyle was almost alone, preaching the steady-state gospel to a small band of disciples.

Einstein, the last of Livio’s five blunderers, is an exception to all rules. He is widely quoted as saying that his addition of dark energy to the theory of gravitation was his biggest blunder. Livio has carefully examined the evidence and has come to the conclusion that Einstein never made this statement. The evidence points strongly to George Gamow as the guilty party. Gamow was another brilliant blunderer with a reputation for making up colorful stories. Einstein’s real biggest blunder happened when he changed his mind and dropped dark energy from his theory. Nature proved him wrong fifty years after his death, when it revealed that three quarters of the total mass of the universe is dark energy.

Einstein invented a steady-state model of the universe many years
before Hoyle. This steady-state model was discovered recently by a group of Irish scientists in an unpublished Einstein manuscript. Einstein abandoned the idea and never published it, probably because he found that steady-state theories are contrived and artificial. When Hoyle noisily promoted the steady-state cosmology twenty years later, Einstein never mentioned that he had discovered and discarded it long before. Einstein must have recognized it quickly as a brilliant blunder, clever but not likely to be correct. (I am indebted to the Irish scientist Cormac O’Raifeartaigh for information about the discovery of the Einstein manuscript.)