Dreams of Earth and Sky

by Freeman Dyson

  The most durable of the glorified technologies was the medieval horse carrying a knight in armor. The knight was armed with a heavy lance pointing forward. The tactic by which the knight was supposed to win battles was a cavalry charge, the horses and lances overwhelming foot soldiers with irresistible force. Weinberg examines the evidence and finds that successful cavalry charges were rare. More often, foot soldiers defeated the charge by moving out of the way of the horses or by occupying strong defensive positions. After the charge was over and the knights were dispersed, foot soldiers could defeat them individually by force of numbers.

  Weinberg describes with scholarly relish several historic battles in which foot soldiers defeated cavalry. In spite of these repeated calamities, the knight on his horse remained the emblem of military virtue throughout the long centuries of the Middle Ages. Kings and emperors spent their fortunes and gave land to their feudal dependents to pay for knights and horses. In times of peace, the knights and horses exercised their military skills by competing with one another in splendid tournaments. The display of fine armor and equestrian skill became an end in itself, pursued by knights and armorers without much regard for military effectiveness. Making a grand spectacle in tournaments was more important than winning battles against peasants armed with bows and arrows. According to the customs of the Middle Ages, a knight who survived a defeat by peasants could usually return home without dishonor, after paying a ransom appropriate to his rank in the feudal hierarchy. The ransom might ruin his feudal estate but would not ruin his military career.

  Weinberg finds a historic continuity between the medieval hero worship of the knight on horseback and the modern hero worship of men riding invincible machines. He tells the sad story of the Dreadnought, a British battleship that was launched in 1905, the brainchild of Sir John Fisher. Fisher was an anomaly in the Royal Navy, a technical expert who had risen to the rank of First Sea Lord. Unlike other Sea Lords, he understood the technologies of gunnery and torpedoes. The Dreadnought was the fulfillment of his dream to build a ship that was technologically supreme, faster and more heavily armed than any ship afloat, outrunning and outgunning any possible opponent.

  In 1905 Britannia still ruled the waves. My father was then at the Royal Naval College at Osborne, teaching music to naval cadets. The sons of the British aristocracy were trained at Osborne to become officers of the Royal Navy, just as they had been trained in past centuries to become warriors on horseback. My father had two future kings, Edward VIII and George VI, singing in his boy choir. He enjoyed the welcoming message emblazoned on a banner above the main entrance to the college: “There is nothing the Royal Navy cannot do.” He shared the prevalent admiration for the Royal Navy and for Sir John Fisher. The Royal Navy was then bigger and stronger than any two other navies combined. Without the Dreadnought, Britain would probably have stayed ahead of other navies for a long time.

  But the Dreadnought attracted intense public attention all over the world. It made the rest of the Royal Navy seem suddenly worthless. After 1905, the only ships that counted politically were dreadnoughts. The Kaiser decided to build dreadnoughts, and Britain had to build more dreadnoughts to keep up with Germany. A serious naval arms race had begun, which continued with increasing intensity until World War I broke out in 1914. The dreadnoughts had destroyed Britain’s naval superiority. They made the British and German navies appear to be equal. They may have helped significantly to upset the political balance of Europe and to precipitate the tragedy of 1914.

  After World War I began, the British and German dreadnoughts did not play an important part. They engaged each other only once, at the inconclusive Battle of Jutland in 1916. The decisive struggle between the two navies began in 1917, when German submarines almost cut off Britain’s vital war supplies by destroying vast numbers of merchant ships, and British destroyer escorts barely succeeded in sinking enough submarines so that convoys of merchant ships could survive. If the Kaiser had built more submarines instead of dreadnoughts, he might have won the war, and if the British had built more destroyers they might have won it sooner. But the mystique of the invincible battleship lasted through World War I and afterward, until it was finally demolished by the victories of aircraft carriers in World War II.

  Already in World War I, the myth of the battleship was being displaced by the new mythology of air power. The first airman hero was the Red Baron, the German Manfred von Richthofen, who flew his red triplane flamboyantly over the western front. After a year and a half of spectacular combat, he was killed, but he remained a durable hero. Meanwhile Hugh Trenchard, a less flamboyant but more important airman hero, emerged on the British side. Trenchard was the commander of the Royal Flying Corps, at that time subordinate to the army and engaged in tactical operations in France. Trenchard flew low over the western front and saw with his own eyes the miseries of the soldiers in their muddy trenches. He had dreams of a different kind of war, in which the agonies of the western front would be avoided. In his dreams he would fly his airplanes not to France but to Germany. He would bring the war to the German homeland and win it there. His airmen would destroy the German war industries without help from the army. They would attack the German war leaders directly in Berlin and save the lives of the millions of young men in the trenches.

  After World War I ended, Trenchard turned his dreams into reality. The Royal Flying Corps became the Royal Air Force, with independent authority to fight its own wars. Trenchard remained in command. When Hitler came to power in Germany, Britain had to prepare for World War II with a serious program of rearmament. Trenchard had retired as chief of the Royal Air Force, but his views prevailed. The decision was made in 1936 that Britain’s primary instrument for fighting the next war would be the Royal Air Force Bomber Command. Bomber Command would be a huge force of heavy bombers, designed for the strategic bombing of Germany and not for tactical support of the army. Never again would Britain fight a war in trenches. Hitler would be defeated in the air over Berlin. At the same time, while these decisions were being implemented in Britain, similar decisions were made in the US, with the airman Billy Mitchell playing the role of Trenchard. The US also believed in victory through air power and built a large force of strategic bombers.

  Hitler did not believe in strategic bombers. Neither did the leaders of Japan and the Soviet Union. As a result, strategic bombers had a minor part in the outcome of World War II. I was at the headquarters of Bomber Command in the winter of 1943–1944 when we launched the series of sixteen massive attacks on Berlin that were intended to “knock Hitler out of the war” without the unpleasantness of invading France. Bomber Command had finally grown to the size that the planners of 1936 had specified. The crews and the machines were ready for action. This was our opportunity to win the war in the air over Berlin, as Trenchard had imagined in 1917. We failed miserably. Persistent winter clouds over the city made accurate bombing impossible. Three thousand of our young men died in the attacks. Our losses of bombers grew heavier as the German fighters improved their skills and tactics.

  The population of Berlin kept the city functioning, and the German war industries continued to increase their production. By January 1944 it was clear to us at Bomber Command headquarters that the Battle of Berlin was lost. In the last year of the war, after we had successfully invaded France and the Mariana Islands, our bombers were finally able to destroy the cities of Germany and Japan, but the decisive battles happened earlier and were fought by armies and navies. “Victory Through Air Power” turned out to be an illusion. If we had been better prepared to fight with armies and navies, we would probably have won the war sooner.

  After this summary of world history dominated by illusions of military glory, Weinberg comes to the politics of the present day. He finds it still dominated by military illusions. Here I particularly recommend his chapters on political themes: “The Growing Nuclear Danger,” “Ambling Toward Apocalypse,” and “The Wrong Stuff.” Since 1945 the dominating illusion has been nuclear wea
pons. The possession of nuclear weapons now gives people and governments an illusion of power, like the illusions of knights on horseback in the Middle Ages, dreadnoughts in 1905, and strategic bombing in 1936. The United States is repeatedly engaged in costly wars that drag on inconclusively, and we have never found a way to use nuclear weapons effectively. It seems that nuclear weapons cannot be used for any sane military purpose. They are effective for destroying cities and for killing large numbers of people indiscriminately, and for nothing else.

  According to Weinberg, the existence of tens of thousands of nuclear weapons is the chief danger to United States security in the modern world. So long as these weapons exist, technical accidents and political miscalculations can easily escalate into an orgy of nuclear killing that would destroy our civilization. No other catastrophe could be as nearly total and as permanent as this one. To get rid of these weapons is more important to our survival than any other objective of our foreign policy.

  Second to nuclear weapons, the next most dangerous military illusion is missile defense, a system of defensive rockets or other high-technology weaponry capable of shooting down incoming nuclear missiles. To many people who understand the danger and the uselessness of nuclear weapons, missile defense seems to be a preferable alternative. If a strategy based on nuclear weapons is unsafe and immoral, then a strategy based on active defense against nuclear weapons might be better for our safety as well as for our morality. For forty years, the United States made fruitless efforts to develop a defense against nuclear missiles, and for forty years Weinberg vigorously opposed these efforts. He argues that national security based on missile defense is even more illusory than security based on nuclear weapons. Missile defense can be defeated by concealing real nuclear warheads in a swarm of cheap decoys that look like warheads. In the arms race between offensive missiles and missile defense, the defense can never win because the defender can never know in advance what the offense will do.

  The illusion of missile defense decreases our security because it encourages every government possessing nuclear weapons to accumulate larger numbers to overcome possible defenses. I have argued in the past that missile defense might actually be helpful if it were part of a totally defensive strategy, with defenses giving everyone some reassurance of safety as offensive nuclear forces are reduced to zero. I agree with Weinberg that our present efforts to develop missile defense, while also maintaining an offensive nuclear strategy, are worse than useless. Missile defense conforms to the historical pattern of military illusions, combining technical failure with political folly.

  A third political folly that Weinberg attacks is the manned exploration of space. He looks at manned space missions in the context of the history of astronomy. Astronomy is the oldest science. For 2,500 years, astronomy led mankind to a true understanding of the way the universe works. From the beginning, instruments were the key to understanding. The first astronomical instrument was the gnomon, a simple vertical post whose shadow allowed the Babylonians and the Greeks to measure time and angle with some precision. The legacy of Babylonian mathematics still survives in the sixtyfold ratios of our units of time: hours and minutes and seconds. After the gnomon came the sundial, the telescope, the chronometer, the computer, and the spacecraft.

  Now we are living in a golden age of astronomy, when for the first time our instruments give us a clear view of the entire universe, out in space to the remotest galaxies, back in time all the way to the beginning. Our instruments are telescopes on tops of mountains and on spacecraft in orbit, increasing their capabilities by leaps and bounds as our data-handling skills improve. It takes us only about ten years to build a new generation of instruments that give us radically sharper and deeper views of everything in the sky.

  Weinberg contrasts this ongoing triumph of scientific instruments with the abject failure of the American program of manned missions. Our unmanned missions to explore the planets and stars and galaxies have made us truly at home in the universe, while our manned missions after the Apollo program to land on the moon have been scientifically fruitless. Forty years after Apollo, the manned program is still stuck aimlessly in low orbit around the earth, while politicians debate what it should try to do next.

  American scientists mostly share Weinberg’s view of space. They see the unmanned exploration of space as a success and the manned exploration as a failure. I was lucky to be exposed to a different view in March 2009 when I watched a Russian space launch. The launch was a public ceremony in which the whole community participated. In Russia you do not go into space to do science. You go into space because it is a part of human destiny. To be a cosmonaut is a vocation rather than a profession. Konstantin Tsiolkovsky, the schoolteacher who worked out the mathematics of interplanetary rocketry in the nineteenth century, said, “The earth is the cradle of the mind, but we cannot live forever in a cradle.” It may take us a few centuries to get to the planets, but we are on our way. We will keep going, no matter how long it takes.

  The American space culture as Weinberg articulates it is only half of the truth. The Russian space culture is the other half. If you think as Americans do, on a time scale of decades, then unmanned missions succeed and manned missions fail. The grandest unmanned missions, such as the Cassini mission now exploring the satellites of Saturn, take about one decade to build and another decade to fly. The grandest manned mission, the Apollo moon landing, ended after a decade and could not be sustained. The time scale of a decade is fundamentally right for unmanned missions and wrong for manned missions. If you think as Russians do, on a time scale of centuries, then the situation is reversed. Russian space science activities have failed to achieve much because they did not concentrate their attention on immediate scientific objectives. Russian manned mission activities, driven not by science but by a belief in human destiny, keep moving quietly forward. There is room for both cultures in our future. Space is big enough for both.

  After history and politics, Weinberg’s other main theme is science. He writes about science with the sensitivity of a teacher who has taught courses on Physics for Poets, emphasizing basic ideas and avoiding technical details. In this book there are no equations. Chapters with titles such as “Can Science Explain Everything? Anything?” and “The Future of Science, and the Universe” describe Weinberg’s philosophical conclusions and say little about the tools of his trade.

  His philosophy includes a streak of militant atheism. He has a strong aversion to all religious beliefs and a particularly intense dislike for organized religions such as Christianity and Islam. He quotes with approval the mathematician Paul Erdös, who never used the word “God” but instead spoke of the “Supreme Fascist.” He agrees with the statement of Thomas Jefferson: “The Christian God is a being of a terrific character—cruel, vindictive, capricious, and unjust.” After this eloquent condemnation of Christianity, Weinberg’s chapter “A Deadly Certitude” ends with an even sharper condemnation of Islam. The chapter is a review of Richard Dawkins’s book The God Delusion (2006). Weinberg concludes:

  Dawkins treats Islam as just another deplorable religion, but there is a difference. The difference lies in the extent to which religious certitude lingers on in the Muslim world, and in the harm it does.… I share Dawkins’s lack of respect for all religions, but in our times it is folly to disrespect them all equally.

  I find it ironic that Weinberg, after declaring so vehemently his hostility to religious beliefs, emerges in his writing about science as a man of faith. He believes passionately in the possibility of a final theory. He wrote a book with the title Dreams of a Final Theory† in which the notion of a final theory permeates his thinking. A final theory means a set of mathematical rules that describe with complete generality and complete precision the way the physical universe behaves. Complete generality means that the rules are obeyed everywhere and at all times. Complete precision means that any discrepancies between the rules and the results of experimental measurements will be due to the limited accuracy of t
he measurements.

  For Weinberg, the final theory is not merely a dream to inspire his brilliant work as a mathematical physicist exploring the universe. For him it is an already existing reality that we humans will soon discover. It is a real presence, hidden in the motions of atoms and galaxies, waiting for us to find it. The faith that a final theory exists, ruling over the operations of nature, strongly influences his thinking about history and ethics as well as his thinking about science.

  I have profound respect for Weinberg as a scientist. I also have profound respect for his faith, although I do not share it. I accept the possibility that he may be right and I may be wrong. I do not forget the disagreement we had forty-four years ago about a hypothetical particle called the W. In chapter 21 I tell the story of this disagreement. The letter W does not stand for Weinberg, but it was Weinberg who imagined it before it was discovered. Weinberg believed that the W particle must exist, because he needed it as an essential component of the theory with which he unified the weak forces in nature. I believed that the W particle could not exist because its existence would contradict a mathematical argument that I held dear. His belief was based on physical intuition, mine on mathematical calculation. A few years later the W particle was directly observed. My mathematical argument turned out to be irrelevant. I was happy to celebrate Weinberg’s triumph, and consoled myself with a quotation from my favorite poet, William Blake: “To be an Error and to be Cast Out is a Part of God’s Design.” Blake had another piece of wisdom, “Opposition is true Friendship,” which made it easy for us to remain friends. As members of the scientific community, we can disagree passionately about facts and theories and still be friends.