Birds and Frogs

Selected Papers of Freeman Dyson, 1990–2014

Freeman J Dyson

• Publisher: WSPC
• Year: 2015
• ISBN:
  9789814602884
• Topic: Matemáticas
• Subtopic: Matemáticas general

This book is a sequel to the volume of selected papers of Dyson up to 1990 that was published by the American Mathematical Society in 1996. The present edition comprises a collection of the most interesting writings of Freeman Dyson, all personally selected by the author, from the period 1990–2014.

The five sections start off with an Introduction, followed by Talks about Science, Memoirs, Politics and History, and some Technical Papers. The most noteworthy is a lecture entitled Birds and Frogs to the American Mathematical Society that describes two kinds of mathematicians with examples from real life. Other invaluable contributions include an important tribute to C. N. Yang written for his retirement banquet at Stony Brook University, as well as a historical account of the Operational Research at RAF Bomber Command in World War II provocatively titled A Failure of Intelligence. The final section carries the open-ended question of whether any conceivable experiment could detect single gravitons to provide direct evidence of the quantization of gravity — Is a Graviton Detectable? Various possible graviton-detectors are examined.

This invaluable compilation contains unpublished lectures, and surveys many topics in science, mathematics, history and politics, in which Freeman Dyson has been so active and well respected around the world.

Contents:

• Introduction and Commentary
• Talks about Science
• Memoirs
• Politics and History
• Technical Papers

Readership: Students of physics and mathematics and all members of the general public interested in science.
Dyson;Papers;Lectures;Von Neumann;Yang;Oklo;Graviton;Prisoner's Dilemma Key Features:

• Contains portraits of remarkable people that the author has known, descriptions of ethical dilemmas that he has encountered, and speculations concerning the future of life and the future of human society

SECTION 1

INTRODUCTION AND COMMENTARY

CHAPTER 1

INTRODUCTION

I am grateful to Dr. K. K. Phua at World Scientific Publishing Company for publishing this collection of papers from my later years. It is a sequel to two earlier volumes, “Selected Papers of Freeman Dyson with Commentary”, published by the American Mathematical Society in 1996, and “From Eros to Gaia”, published by Pantheon Books in 1992. The two earlier collections contained technical and non-technical papers separately. This collection contains both non-technical and technical papers. For the convenience of readers, the non-technical papers are divided into popular science (Section 2), memoirs of people I have known (Section 3), and public affairs (Section 4), and the technical papers are put together at the end (Section 5). During the last 24 years, roughly half of my working hours have been devoted to scientific problems and half to human problems. I spend half my time calculating and half writing.

In this commentary I discuss the papers in chronological order. The starting-point is the year 1990, when I was more concerned than usual with human problems. I gave some public lectures on various ethical problems that were emerging from the successes and failures of modern science. I was invited to summarize these lectures in an essay, “Science in Trouble”, published in the American Scholar, a literary magazine edited by Joseph Epstein. The essay is item (4.1) in this collection. It marks the start of my career as a social critic. It begins with an aggressive statement: “Trouble comes to science on three levels: personal, local and global”. On each level I found ethical problems threatening the future of the scientific enterprise. The essay was widely read and widely resented. Never in my life as a writer have I received such a barrage of angry letters from readers. I had successfully gored a number of sacred cows. I wrote in response to thank my critics, telling them that the purpose of criticism is not to compel agreement but to provoke argument.

Returning to my roots in England, I contributed item (3.1) to the bicentennial celebration of the self-taught mathematician George Green at the University of Nottingham. Green was the son of a miller in Nottingham, and as a child he had to spend long hours in a revolving room at the top of the windmill, adjusting the pitch of the blades to the strength and direction of the wind. Somehow he got hold of the works of the French mathematicians Laplace and Lagrange, and studied them in the windmill when the wind was quiet. He invented Green’s Functions, which are useful devices for solving dynamical equations. He introduced French analytical methods to England, where nothing much had been done in mathematics since the death of Newton. The windmill still stands, now converted into a science museum and educational center for the local schoolchildren. Julian Schwinger and I were invited to talk at the celebration, since we had both made intensive use of Green’s Functions in our development of quantum electrodynamics. We spoke about the revolution in physics that happened in the 1940s when Green’s Functions were applied to quantum theory. The final act of the celebration was the dedication of a memorial tablet to Green in Westminster Abbey, with a picture of the windmill.

Item (3.2) is a short piece published by the American Philosophical Society to celebrate the astronomer James Bradley. I call him the inventor of modern science because he was the first person who ever measured anything to six-figure accuracy. He trained his assistant Charles Mason to achieve this level of accuracy, and Mason put his skill to good use when he surveyed the Mason–Dixon line separating Maryland from Pennsylvania.

The years 1990–2006 were the final years of a fifty-year friendship and collaboration with the Indian–French mathematical physicist Madan Lal Mehta. Mehta’s brilliant work on the theory of random matrices attracted me to work on that subject in 1960. He was born in India in 1932, moved to France in 1958 and became a French citizen in 1971. I invited him to come as a member to the Institute for Advanced Study for the year 1962–1963, and we collaborated intensively from that time forward. The constant exchange of messages and ideas with Mehta was one of the main joys of my life as a scientist.

One of Mehta’s elegant contributions to random matrix theory was a paper, “A non-linear differential equation and a Fredholm determinant”, published in the Journal de Physique in 1992. That paper stimulated my response, item (5.1). It was appropriately published in the volume, “Chen Ning Yang, a Great Physicist of the Twentieth Century”, edited by Shing-Tung Yao, celebrating the seventieth birthday of Yang. At the beginning of my paper, I explain why the dedication to Yang is appropriate. The paper imitates the style of the classic calculation of the long-range order of a two-dimensional Ising ferromagnet, published by Yang in 1952. I remarked that imitation is the sincerest form of flattery, even if it comes forty years late.

In my paper (5.1), I used Mehta’s system of nonlinear equations to find the asymptotic behavior of the eigenvalues of a random matrix when the number of levels is large and the distortion of the series by external forces is also large. The crystalline long-range order of the eigenvalues is exactly described by Jacobian elliptic functions instead of by the sines and cosines that appear in previously known examples of random-matrix eigenvalue distributions. I had found a new asymptotic form for a function known as the Fifth Painlevé Trancendent, defined in a classic paper by the French mathematician P. Painlevé in 1902. My paper is an extreme example of mathematical baroque style applied to an unimportant physical problem. It was my farewell tribute to the beauty of random matrix theory and to the unique personality of Mehta.

Mehta loved to travel around the world with little money and few worldly possessions, adapting easily to alien cultures. In 1993, already over sixty years old and not in the best of health, he made a classic journey overland from Beijing through Tibet to India, traveling like a native on buses and trucks, and when necessary on foot. One section of the trip was a bus-ride from Golmud, in China north of Tibet, to Lhasa, crossing the central Tibetan plateau. That was before the modern railway over the plateau was built. He told us with pride that the Tibetans and Chinese on the bus were mostly suffering from altitude sickness, but he was not. After retiring from his position in France, he returned to his home in India and died there in 2006.

For the academic year 1995–1996, the French particle physicist Thibault Damour was a visiting member at the Institute for Advanced Study, and item (5.2) is the result of our collaboration. We analyzed the evidence from isotope ratios of rare-earth nuclei in the ancient fission reactors at Oklo in West Africa, looking for effects of any possible variation of the constants of nature during the two billion years since the reactors were operating. Alexandr Shlyakhter had the idea of looking for such evidence when he was a student in Leningrad in 1976. He showed that the isotope ratios give far stronger bounds on the variation of constants than any other evidence. We confirmed Shlyakhter’s results and made them more precise. Shlyakhter emigrated from the Soviet Union and came to MIT in 1989. I spoke to him a few times by telephone but never met him. In the year 1998, I heard the devastating news that he was struggling with a brain tumor, and in 2000 he died.

In 1994 I retired from my position as active Professor and became Professor Emeritus at the Institute for Advanced Study. This meant that I remained a member of the Institute community but was free to travel and take other jobs. I spent the Fall of 1994 as visiting professor at Dartmouth College, invited by my historian friend Martin Sherwin. Martin and I taught a course together called “The Nuclear Age”. He was then already hard at work on the book, “American Prometheus”, a biography of Robert Oppenheimer finally published in 2005. The term at Dartmouth strengthened my interest in history and gave me a chance to interact strongly with undergraduates. In 1999, I spent a term teaching at Gustavus Adolphus College in Minnesota. There I taught a “Science and Society” course with Professor Larry Potts, focussed on ethical problems of biotechnology rather than on nuclear weapons. My reception at Gustavus Adolphus was especially friendly, because the campus had been half destroyed by a huge tornado one year earlier. We were living and working in half-destroyed buildings, sharing the hardships and helping each other to survive.

In 1998, I was actively engaged in revising my book, “Origins of Life”, originally published in 1985, for a second edition to be published in 1999. Biology had moved ahead rapidly in the intervening years, but I found that the origin of life remained an unsolved problem, as mysterious as ever. The main theme of my book was the hypothesis that life began twice, first with garbage-bag creatures lacking exact replication, and second with parasitic replicators using the garbage-bag creatures for life support. This theme did not need to be changed when the book was revised. It remains today a plausible hypothesis, without evidence either to contradict or to confirm it. Item (2.1) is a public lecture given at the Jet Propulsion Laboratory, summarizing the thoughts that went into the new edition of the book.

Item (3.3) is a banquet speech, celebrating my friend Yang Chen Ning on the occasion of his retirement from Stony Brook in 1999. I called attention to three outstanding qualities of Yang that are rarely combined. First, a marvelous mathematical skill, enabling him to solve technical problems. Second, a deep understanding of nature, enabling him to ask important questions. Third, a community spirit, enabling him to play a major role in the rebirth of Chinese civilization. Together, these three qualities make him what he is, a conservative revolutionary who values the past and leads the way to the future.

Item (4.2) is the acceptance speech given at the Washington National Cathedral when I won the Templeton Prize for Progress in Religion. In the speech, I asked the question why I won the prize, but I did not answer it. I still do not know the answer. I am one of a large number of scientists who find no conflict between science and religion, provided that each side treats the other with respect. Unfortunately, public attention is concentrated on a minority of militant fundamentalists and militant atheists who enjoy attacking each other. They distract attention from the majority of believers and unbelievers who are glad to live together in peace. In Washington, I was speaking for the majority.

In 2000, I spent three weeks as visiting lecturer at the University of Canterbury at Christchurch, New Zealand. I gave six public lectures of which item (4.3) was one. It arose from an essay by Michael Armstrong, published in “Outlook” in 1983, describing in detail the way Tolstoy taught the village children on his estate. “Outlook” was a little magazine devoted to the education of young children. It was founded in 1970 by David Hawkins, the philosopher who served as Oppenheimer’s personal assistant at Los Alamos. I subscribed to it from the beginning until it died in 1986. The Armstrong essay, with the title, “Tolstoy on education: The pedagogy of freedom”, gave me the idea for a talk comparing Tolstoy with Napoleon. Before starting his village school, Tolstoy traveled around Europe examining the systems of public education established by Napoleon. Tolstoy was horrified by what he saw, and resolved to make his school as different as possible from the Napoleonic model. The clash between Tolstoy and Napoleon is sharp, not only in the education of children but also in our views of history, science and ethics. In all these areas, Napoleon works from the top down, Tolstoy from the bottom up. I am on the side of Tolstoy.

Item (5.3) is a little piece of recreational mathematics and needs no explanation. Item (4.4) is a personal meditation about childhood, spoken on a television program in Amsterdam directed by Wim Kayzer. Kayzer had the program published in a book, “Het Boek van de Schoonheid en de Troost”, with the English contributions translated into Dutch. He intended to publish an English version, “The Book of Beauty and Consolation”, with the Dutch contributions translated into English. The English version never appeared, and this is the first publication of my remarks in English. Of all the items here collected, this is my favorite.

Item (5.4) is a serious discussion of the foundations of quantum mechanics, written for a symposium in 2002 honoring John Wheeler. I describe four thought-experiments that lead me to the conclusion that quantum mechanics cannot be a complete description of nature. In my opinion, a complete description of nature must contain a classical world and a quantum world. Roughly speaking, the classical world describes the past and deals with facts, while the quantum world describes the future and deals with probabilities. The simplest example of this double description is a uranium atom. The wave-function of an out-going alpha-particle tells us the probability that the atom will decay tomorrow. But the wave-function cannot state the fact that the atom decayed yesterday. Only a dualistic picture of the universe can describe my four thought-experiments consistently. Of course, I do not expect these arguments to convert the modern quantum-experts to my point of view. We all agree about the practical consequences of quantum theory while continuing to disagree about the philosophical interpretation.

Item (5.5), written in collaboration with Jeremy Bernstein, is a piece of work done 44 years earlier when we worked together on Project Orion, a spaceship propelled by nuclear bombs. The basic feasibility of the project depends on the opacity of the bomb debris. The debris is supposed to transfer momentum to the ship without transferring too much energy. This is possible only if the debris is highly opaque to its own radiation. We studied the question, how large can the opacity of matter be, without violating the laws of physics, at a given density and temperature. The answer is simple. The maximum opacity is independent of density and inversely proportional to temperature. It turned out that for our spaceship, a mixture of light elements would provide an opacity close to the maximum. We published our work 44 years later because it is relevant to radiation transport in highly evolved stars.

The next three items are autobiographical. Item (2.2) is a description of my childhood and education, published as a chapter in a book, “When we were kids: How a child becomes a scientist”, edited by John Brockman. Item (3.4) describes a meeting with Enrico Fermi in 1953, when he demolished in twenty minutes my theoretical explanation of his experimental results. He showed his greatness as a physicist by seeing intuitively that my theory of meson-proton scattering could not be right. He did me an enormous favor by saving me and my students from years of fruitless calculations.

Item (4.5) is an account of the failure of the Operational Research Section of the Royal Air Force Bomber Command, where I worked for the last two years of World War II. I call it a failure because we never solved the two main problems that faced the command. The first problem was bombing accuracy. To destroy important military targets such as oil-refineries required accuracy of a few hundred meters, while the actual accuracy until the last few months of the war was several kilometers. This problem was finally solved, not by the Operational Research Section, but by innovative tactics invented by the aircrew of 5 Group. The second problem was bomber losses. The losses were of the order of five per cent for operations over Germany. The campaign was enormously costly in human lives as well as in industrial resources. The main cause of losses in the later years of the war was fighter aircraft with guns firing vertically upward. A fighter directly below could destroy a bomber without being seen. Our Research Section never guessed that this was our main problem and only learned about it after the war was over. These two failures are typical of failures of intelligence systems in more recent wars. Intelligence systems tend to fail because they are designed to convey information from war-fighters to analysts far from the fighting, and they convey very little information back to the war-fighters who might use it effectively.

Item (3.5) is a memoir of Edward Teller written for the National Academy of Sciences. I enjoyed writing it because I had enjoyed working with Teller and remained his friend for fifty years. I tried as best I could to present a balanced picture of his faults and virtues, to counteract the efforts of his political enemies to demonize him. His three closest friends, Ernest Lawrence, Enrico Fermi and John von Neumann, great scientists who could have written memoirs with more authority than mine, all died young.

Item (4.6) is a talk that I gave to the Medina Seminar, an annual event at Princeton University. Each year, a group of distinguished judges comes for two days of intellectual refreshment. The judges are a highly intelligent and critical audience. I spoke about the proper balance between individual rights and group rights. My thoughts on this subject were stimulated by Caroline Humphrey, an anthropologist who is fluent in Russian. She had given a talk to the American Philosophical Society about the difficulty of translating the English word “Freedom” into Russian. There are three Russian words that are used to translate “Freedom”, and none of them has the right meaning. The problem arises from the fact that the ideas of freedom in English and Russian culture are basically different. In English, freedom means the right of an individual to live without coercion by the community. In Russian, freedom means the right of a community to manage its own affairs. This is why many people in Russia believe that they had more freedom in the days of Stalin than they have today. Starting from this linguistic problem, I discussed the delicate relation between individual and group rights in law, and between individual selection and group selection in evolutionary biology. American laws and customs are exceptional in giving precedence to the individual, while the majority of laws and customs in other societies give precedence to the community. If we are to live together in peace, we must understand our differences and be prepared to make compromises.

Item (2.3) gave its title to the book. I wrote an essay with this title for the American Mathematical Society. It was supposed to be a lecture in honor of Albert Einstein, to be given at the meeting of the Society in Vancouver. I got sick and never gave the lecture, but it was published in the American Mathematical Society Notices, and later, revised and translated into Russian, in the Uspekhi Fizicheskikh Nauk. The version published here is the English text used for the Russian translation. The birds and frogs in the essay are the two kinds of mathematician that I have encountered during my working life. But not all birds and frogs are mathematicians. They can be people in all walks of life. Birds are those who fly high and survey the landscape over a wide area. Frogs are those who stay on the ground and solve one problem at a time. Not only in science but in other human enterprises such as literature and politics, birds and frogs play leading roles and both are needed. That is why the title is appropriate for the book as a whole.

Items (2.4) and (4.7) were two talks written at the same time for different audiences, a scientific talk for an unscientific audience a...

Table of contents

• Cover
• Halftitle
• Title
• Copyright
• Contents
• Section 1. Introduction and Commentary
• Section 2. Talks about Science
• Section 3. Memoirs
• Section 4. Politics and History
• Section 5. Technical Papers
• Index