Why would anybody want to write another book about Albert Einstein? Why would anybody want to read it? These are two separate questions, but both of them have satisfactory answers. In spite of the large number of books already written about Einstein, there is still room for one more.
There were several good reasons for writing this book. Yale University Press is publishing a big series of short biographies under the heading “Jewish Lives.” Among the twenty already published are Sigmund Freud, Franz Kafka, Sarah Bernhardt, Mark Rothko, and Leon Trotsky. Among the twenty-five announced as forthcoming are Benjamin Disraeli, Bob Dylan, Jesus, and Moses. Einstein obviously belongs on this list.
John Reed in his eyewitness report, Ten Days That Shook the World, describing the Bolshevik Revolution in Petrograd in 1917, proclaimed Leon Trotsky to be “the greatest Jew since Jesus.” Over the last hundred years, Einstein has displaced Trotsky as the second-brightest star of the Jewish pantheon. It would be absurd to display a gallery of famous Jews without putting Einstein in a prominent place. Another reason this Einstein book is welcome is that it is short. Most of the earlier books are much longer, with detailed and lengthy accounts of Einstein’s personal life and scientific thinking. The time is now ripe for a short book, summarizing briefly the well-known facts about Einstein’s rocky road as a husband and father and scientist, and emphasizing his lasting importance as a politician and a philosopher. This book is accurate and well balanced. It presents Einstein’s Jewish heritage as he saw it himself, not as the core of his being, but as a historical accident bringing inescapable responsibilities.
The reasons for reading this book are also simple. The majority of famous scientists have books written about them that are of interest to historians and specialists. The scientists remain famous for a few decades and then gradually fade. The books contain almost all the information about them that is worth preserving. But there are a few scientists whose lives and thoughts are of perennial interest, because they permanently changed our way of thinking. To the few belong Galileo and Newton and Darwin, and now Einstein. For the select few, there will be no end to the writing of books. New books will need to be written and read, because these people had enduring ideas that throw light on new problems as the centuries go by.
The later chapters of Steven Gimbel’s book describe Einstein’s deep involvement with the Zionist movement, promoting the settlement of Jews in Palestine. Einstein saw these settlements as a benefit both to Jews and to Arabs, giving Jews a place to live and prosper, and giving Arabs a chance to share the blessings of progress and prosperity. In 1929, when some Palestinian Arabs organized a violent opposition to Jewish settlement and killed some Jews, the British colonial government suppressed the rebellion and enforced a peaceful coexistence of Jews and Arabs. But Einstein understood that this enforced coexistence could not last. He wrote an article with the title “Jew and Arab” from which Gimbel quotes:
The first and most important necessity is the creation of a modus vivendi with the Arab people. Friction is perhaps inevitable, but its evil consequences must be overcome by organized cooperation, so that the inflammable material may not be piled up to the point of danger. The absence of contact in every-day life is bound to produce an atmosphere of mutual fear and distrust, which is favorable to such lamentable outbursts of passion as we have witnessed. We Jews must show above all that our own history of suffering has given us sufficient understanding and psychological insight to know how to cope with this problem of psychology and organization: the more so as no irreconcilable differences stand in the way of peace between Jews and Arabs in Palestine. Let us therefore above all be on our guard against blind chauvinism of any kind, and let us not imagine that reason and common-sense can be replaced with British bayonets.
Einstein worked with Chaim Weizmann, the leader of the Zionist organization, to raise money for the settlements and for the foundation of the Hebrew University of Jerusalem. But while he worked with Weizmann as a fund-raiser, he disagreed fundamentally with Weizmann’s aims for the future. In the early days, before Israel existed, Einstein was opposed to the idea of a Jewish state. Weizmann aimed from the beginning to establish a Jewish state in Palestine, and he lived long enough to see his dreams come true, serving as the first president of the State of Israel. After the State of Israel was established, Einstein gave it his full support. But he said that a peaceful and permanent presence of Jews in Palestine could only be possible if they worked side by side with Arabs under conditions of social and political equality.
Einstein felt a deep personal responsibility for the actions of the Jewish community to which he never wholeheartedly belonged. He tried with all his strength to stop the Jewish people from becoming another nationalistic culture glorifying military strength, like the militaristic German culture that he had hated as a child and repudiated as a teenager when he renounced his German citizenship. He continued to support Israel while severely criticizing it. At the end of his life, when he had become an American citizen, he felt an equally deep responsibility for the actions of the American community to which he never wholeheartedly belonged. He had gone through the ritual of naturalization, but he remained an alien spirit in America.
He saw the American people, after their victory over Germany and Japan, sliding into the same militaristic arrogance that overcame the German people after their victory over France in 1871. He had experienced in Berlin in 1914 the insane enthusiasm with which the German people, including his scientist friends and colleagues, welcomed the outbreak of World War I. He saw the same insanity taking root in America, with patriotic citizens imagining that the possession of nuclear weapons would give America the power to rule the world. Just as he spoke out against the militarization of Israel, he spoke out against the militarization of America. He spoke with particular clarity against the delusion that staying ahead in the race to develop nuclear weapons could give America a permanent national security.
Gimbel quotes an excerpt from Einstein’s statement reacting to President Truman’s announcement in 1950 that the United States was developing a hydrogen bomb:
The arms race between the United States and the Soviet Union, initiated originally as a preventive measure, assumes hysterical proportions. On both sides, means of mass destruction are being perfected with feverish haste and behind walls of secrecy. And now the public has been advised that the production of the hydrogen bomb is the new goal which will probably be accomplished. An accelerated development toward this end has been solemnly proclaimed by the President. If these efforts should prove successful, radioactive poisoning of the atmosphere and, hence, annihilation of all life on earth will have been brought within the range of what is technically possible. The weird aspect of this development lies in its apparently inexorable character. Each step appears as the inevitable consequence of the one that went before. And at the end, looming ever clearer, lies general annihilation.
These words have had a lasting impact. Many world leaders, civilian and military, have made similar statements during the subsequent sixty years. More importantly, the governments of powerful countries have behaved cautiously, showing by their actions that they do not consider victory in a major war to be a meaningful objective. Wars continue to be fought, but they are mostly local in scale and extended in time, as different as possible from a nuclear holocaust that could destroy half the world in a few hours. Military leaders in all countries have learned that nuclear weapons are not very useful. They are effective for murdering huge numbers of people in a short time, but not for winning real battles in real wars. For almost all situations in local wars, nuclear weapons are too big and the targets are too small.
From 1945 until the end of his life in 1955, Einstein saw the abolition of nuclear weapons as a necessary objective. Abolition was for him the only way to save mankind from the threat of nuclear destruction. He was not sure how abolition could be achieved. Sometimes he spoke of a world government with power to stop nuclear activities in every country. Sometimes he spoke of formal agreements between existing governments. Sometimes he spoke about abolishing war as well as abolishing nuclear weapons. He understood that any abolition of war or of weapons would require a radical change in our way of thinking.
The essential first step, before any abolition agreement could be effective, was to educate the public. The public and the political leaders must understand that nuclear weapons were not only intolerably dangerous but also militarily useless. Once these facts of life were clearly understood, there would be a fighting chance that an abolition agreement could work. Einstein did whatever he could in his final years to educate the public.
In the last month of his life, he joined with Bertrand Russell to make a public statement that he did not live to see published. Here are its concluding words:
In view of the fact that in any future world war nuclear weapons will certainly be employed, and that such weapons threaten the continued existence of mankind, we urge the Governments of the world to realize, and to acknowledge publicly, that their purposes cannot be furthered by a world war, and we urge them, consequently, to find peaceful means for the settlement of all matters of dispute between them.
After the Russell-Einstein manifesto was published, there grew out of it an organization called the Pugwash movement, bringing together scientists from East and West to discuss the problems of war and weapons. The name Pugwash came from the small town in eastern Canada where the first meeting was held in 1957. Since that time, meetings have been held in many countries, continuing up to the present day. The basic idea of the meetings is that science gives to scientists of all countries a common language, so that they can understand one another even when talking about political and human problems having little to do with science.
Politicians and diplomats have much greater difficulty in understanding one another. Scientists have long experience of working together in an international enterprise that pays no attention to national or ideological differences. At the beginning, Bertrand Russell himself presided over the Pugwash meetings. After Russell retired, the leadership was taken over by Joseph Rotblat, a Polish nuclear physicist who worked at Los Alamos and became famous as the only scientist who walked out of Los Alamos for reasons of conscience in 1944, when it became known that Germany did not have a serious nuclear weapons project. General Leslie Groves let him go after he promised not to tell his friends the reason for his departure. Rotblat ran the Pugwash meetings for forty years. He won the respect of all the participants and many of their governments.
I attended several of the early Pugwash meetings under the auspices of Russell and Rotblat. At that time they were acting as a valuable back channel for exchanging views between the American and Soviet governments, when the official diplomatic channel was blocked by ideological disagreements. The two dominant personalities were Leó Szilárd on the American side and Vladimir Pavlichenko on the Soviet side. Szilárd was an old friend of Einstein from Einstein’s Berlin days. He wrote the letter that Einstein signed in 1939, warning President Roosevelt that nuclear weapons were a possibility, that uranium was the crucial material for their manufacture, and that it was important to keep the rich uranium ores of the Belgian Congo out of the hands of Hitler.
Szilárd had also tried in vain to deliver an appeal to President Truman in 1945, urging him to give Japan warning and an opportunity to surrender before dropping nuclear bombs on Japanese cities. Pavlichenko was the KGB man on the Soviet side, sent to Pugwash conferences along with the scientists to make sure that they did not deviate from the Soviet line. He was highly intelligent and well informed about technical and political questions. He knew far more than the scientists about the actions and intentions of his own government.
Szilárd immediately recognized Pavlichenko as the man to talk to when serious issues were discussed. Any proposal made to Pavlichenko would reach high levels in the Soviet government. Szilárd had friends at high levels in the American government, and so this unlikely pair, the Hungarian rebel and the KGB apparatchik, worked fruitfully together to carry messages in both directions. Now, fifty years later, Pugwash meetings are carrying messages between Israel and hostile Arab states in the Middle East, and between India and Pakistan in Asia. The hope expressed by Einstein is still alive, that our way of thinking could one day change, and abolition of war and weapons could become possible.
Less than half of Gimbel’s book is about Einstein’s politics. The rest of it is about his science and his philosophy. In this review I reverse the proportions, giving more space to politics and less to philosophy. Einstein’s philosophy grew directly out of his science. During the ten years from 1905 to 1915, he created a new view of the physical universe, including atoms and light-quanta, space and time, electromagnetism and gravitation, with all their motions and interactions governed by precise mathematical laws. His theories were tested by observation and experiment and found to be correct. On the basis of this dazzling success, he built a philosophy.
A philosophy for Einstein meant a general view of nature into which the scientific details can fit. His philosophy describes nature as a single layer of observable objects with strict causality governing their movements. If the state of affairs at the present time is precisely known, then the laws of nature allow the state at a future time to be precisely predicted. The uncertainty of our knowledge of the future arises only from the uncertainty of our knowledge of the past and present. I call this view of nature the classical philosophy, since all objects obey the laws of classical physics.
Ten years after Einstein completed his theories, Werner Heisenberg and Erwin Schrödinger invented quantum mechanics, describing the behavior of atoms and light-quanta in a radically different way. Experiments confirmed that quantum mechanics gives a true picture of atomic processes that Einstein’s theories could not explain. Niels Bohr worked out a philosophy, generally known as the Copenhagen interpretation, to explain quantum mechanics. I prefer to call it the dualistic philosophy, since it describes the universe as consisting of two layers. The first layer is the classical world of Einstein, with objects that are directly observable but no longer predictable. They have become unpredictable because they are driven by events in the second layer that we cannot see. The second layer is the quantum world, with states that are not directly observable but obey simple laws. For example, the laws of the second layer decree that every particle travels along every possible path with a probability that depends in a simple way on the path.
The two layers are connected by probabilistic rules, so that the quantum state of an object tells us only the probabilities that it will do various things. The dualistic philosophy allows us to divide our knowledge of nature into facts and probabilities. Observation of the first layer gives us facts about what happened in the past, but only gives us probabilities about what may happen in the future. The future is uncertain because the processes in the second layer are unobservable. The power and the beauty of quantum mechanics arise from the fact that the physical laws in the second layer are precisely linear.
All points in a linear theory are equal, and a linear space has perfect symmetry about any of its points. As a result of the linearity of the laws, the second layer possesses a wealth of marvelous symmetries that are only partially visible in the first layer. For example, in the first layer, symmetries between space and time are only partly visible. In daily life, we do not mix up inches with seconds or miles with days. In the second layer, as the result of Paul Dirac’s elegant equation describing the quantum behavior of the electron, the mixing of space with time in the electron’s movements would be clearly visible. But we do not live in the second layer, and so the mixing is hidden from us.
The dualistic philosophy gives a natural frame for the new sciences of particle physics and relativistic cosmology that emerged in the twentieth century after Einstein and Bohr were dead. The new sciences are dominated by mathematical symmetries that are exact in the second layer and approximate in the first layer. The dualistic philosophy seems to me to represent accurately our present state of knowledge. It says that the classical world and the quantum world are both real, but the way they fit together is not yet completely understood. The dualistic philosophy is flexible enough to accept unexpected discoveries and conceptual revolutions.
Now, eighty years after the dualistic philosophy was invented by Bohr, it is generally regarded by the younger generation of physicists as obsolete. The younger generation mostly rejects duality and accepts what I call the quantum-only philosophy. The quantum-only philosophy says that the classical world is an illusion and only the quantum world exists. The concept of a classical world arose because the effects of quantum mechanics are rapidly erased by a phenomenon known as decoherence. Decoherence hides the quantum world by destroying rapidly the waves arising from quantum effects. After the waves have disappeared, whatever is left obeys classical laws and looks like a classical world. According to the quantum-only philosophy, the marvelous harmony of Einstein’s classical universe is only an approximation, valid when quantum waves happen to be small enough to be neglected.
To summarize the present situation, there are three ways to understand philosophically our observations of the physical universe. The classical philosophy of Einstein has everything in a single layer obeying classical laws, with quantum processes unexplained. The quantum-only philosophy has included everything in a single layer obeying quantum laws, with the astonishing solidity and uniqueness of the classical illusion unexplained. The dualistic philosophy gives reality impartially to the classical vision of Einstein and to the quantum vision of Bohr, with the details of the connection between the two layers unexplained. All three philosophies are tenable, and all three are incomplete. I prefer the dualistic philosophy because I give equal weight to the insights of Einstein and Bohr. I do not believe that the celestial harmonies discovered by Einstein are an accidental illusion.
Einstein in real life was not only a great politician and a great philosopher. He was also a great observer of the human comedy, with a robust sense of humor. The third side of Einstein’s personality is not emphasized by Gimbel, but was an important cause of his immense popularity. He came as an observer to my boarding school in England in 1931, a few years before I arrived there. He was in England as the guest of Frederick Lindemann, an Oxford physicist who was also a friend and adviser to Winston Churchill.
Lindemann took him to the school to meet one of the boys who was a family friend. The boy was living in Second Chamber, in an ancient building where the walls are ornamented with marble memorials to boys who occupied the rooms in past centuries. Einstein and Lindemann wandered by mistake into the adjoining First Chamber, which had been converted from a living room to a bathroom. In First Chamber, the marble memorials were preserved, but underneath them on the walls were hooks where boys had hung their smelly football clothes. Einstein surveyed the scene for a while in silence, and then said: “Now I understand: the spirits of the departed pass over into the trousers of the living.”