Part III: Life among the Physicists

Chapter 8. Los Alamos

1943–1945

During the late spring of 1943, I wrote to von Neumann about the possibility of war work. I knew he was involved, because his letters often came from Washington rather than from Princeton. I was not happy with teaching, although I did a lot of mathematics, wrote papers, organized colloquia, and taught war-related courses. Still it seemed a waste of my time; I felt I could do more for the war effort.

One day Johnny answered with an intimation that there was interesting work going on — he could not tell me where. From Princeton he said he was going west via Chicago, and suggested that I come to the Union Station there to talk to him since he had two hours between trains. That was in the early fall of 1943.

I went and, sure enough, Johnny appeared. What caught my attention were the two men escorting him, looking a bit like “gorillas.” They were obviously guards, and that impressed me; he must be an important figure to rate this, I decided. One of the men went to do something about his railroad ticket, and we talked in the meantime.

Johnny said that there was some very exciting work going on in which I could possibly be of good use; he still could not tell me where it was taking place, but he traveled rather often from Princeton to that location.

I don’t know why — by pure chance or one of these incredible coincidences or prophetic insights? — but I answered jokingly, “Well, as you know, Johnny, I don’t know much about engineering or experimental physics, in fact I don’t even know how the toilet flusher works, except that it is a sort of autocatalytic effect.” At this I saw him wince and his expression become quizzical. Only later did I discover that indeed the word autocatalytic was used in connection with schemes for the construction of an atomic bomb.

Then another coincidence occurred. I said, “Recently I have been looking at some work on branching processes.” There was a paper by a Swedish mathematician about processes in which particles multiply quite like bacteria, for example. It was prewar work, and an elegant theory of probabilistic processes. That, too, could have had something to do with the mathematics of neutron multiplication. And again he looked at me almost with suspicion or wonder and smiled wanly.

The Wisconsin astronomer Joel Stebbins, whom I saw occasionally, had told me about some work going on with uranium and about the release of energy from very heavy elements. I wondered if, subconsciously, this prompted my remarks.

During this meeting at the station, Johnny and I also discussed what seemed a general lack of imagination in the scientific community’s planning of work useful for the war effort — especially in computations for hydrodynamics and aerodynamics. I pointed out my doubts about the age of some of the main participants (people over forty-five seemed to me at that time old). Johnny agreed there were obvious elements of senility. As usual, we tried to lighten our sadness with jocular comments, observing that someone should establish a “gerontological” society, whose members would be scientists interested in war work and afflicted with premature or “galloping” senility.

Since Johnny could not or would not tell me where he was going except that it was to the Southwest, I remembered an old Jewish story about two Jews on a train in Russia. One asks the other, “Where are you going?” and the second replies, “To Kiev.” Whereupon the first says, “You liar, you tell me you are going to Kiev so I would think you are going to Odessa. But I know you are going to Kiev, so why do you lie?” And I told Johnny, “I know you can’t tell me, but you say you are going Southwest in order that I should think that you are going Northeast. But I know you are going Southwest, so why do you lie?” He laughed. We talked a while longer about the war situation, politics, and the world; then his two companions reappeared and he left.

I saw him once more, I think, in Chicago, before I received an official invitation to join an unidentified project that was doing important work, the physics having something to do with the interior of stars. The letter inviting me was signed by the famous physicist Hans Bethe. It came together with a letter from the personnel department with details of the appointment, salary, clearance procedures, indications on how to get there, and so forth. I accepted immediately with excitement and eagerness.

The pay was slightly above my university salary, but on a twelve-month basis — around $5,000, if I remember correctly. The professional physicists like Bethe who were there already received little more than their university salaries. I learned later that a chemist from Harvard, George Kistiakowski, had the allegedly astronomical salary of $9,000 or $10,000.

I informed my university of this opportunity to join an obviously important war project and secured a leave of absence for the duration.

A student of mine, Joan Hinton, had left for an unknown destination a few weeks before. Joan was taking a course I gave in classical mechanics. One day she appeared in my office in North Hall to ask if I could give her an examination three or four weeks before the end of the term so that she could start some war work. She produced a letter from Professor Ingraham, the chairman, authorizing me to do that. She was a good student, a rather eccentric girl, blonde, sturdy, good-looking. Her uncle was G. I. Taylor, the English physicist. She was also a great-granddaughter of George Boole, the famous nineteenth-century logician. I wrote a number of questions on the back of an envelope; Joan took some sheets of paper, sat down on the floor with her notebook, wrote out her exam, passed, and disappeared from Madison.

Soon after, other people I knew well began to vanish one after the other, without saying where — cafeteria acquaintances, young physics professors and graduate students like David Frisch, and his wife Rose, who was a graduate student in my calculus class, Joseph McKibben, Dick Taschek, and others.

Finally I learned that we were going to New Mexico, to a place not far from Santa Fe. Never having heard about New Mexico, I went to the library and borrowed the Federal Writers’ Project Guide to New Mexico. At the back of the book, on the slip of paper on which borrowers signed their names, I read the names of Joan Hinton, David Frisch, Joseph McKibben, and all the other people who had been mysteriously disappearing to hush-hush war jobs without saying where. I had uncovered their destination in a simple and unexpected fashion. It is next to impossible to maintain absolute secrecy and security in war time.

This reminds me of another story. Since I knew Stebbins well, about a month after arriving at Los Alamos, I wrote to him. I did not say where I was but mentioned that in January or February I had seen the star Canopus on the horizon. Later it occurred to me that as an astronomer he could easily have deduced my latitude since this star of the Southern skies is not visible above the 38th parallel.

I shall pass over our problems in getting train reservations. Even with the priorities I had, our departure was delayed by about a month. On the train I had to offer a gratuity to the conductor to obtain a berth for Françoise, who was two months pregnant at the time. This was the first — and I think last — time in my life that I ’’bribed” anyone.

We arrived at a remote, lonely, unimpressive little whistle-stop — Lamy, New Mexico. To my infinite surprise, there to meet us was Jack Calkin, a mathematician I knew well. I had met him several years before at the University of Chicago and had seen him a number of times since. Calkin had been Johnny’s assistant and had gone with him to London to discuss probability problems in aerial-bombing patterns and methods. Just a few weeks before, he had joined the Manhattan Project. He was a tall, pleasant-looking man, with more savoir-faire than most mathematicians. Having heard that I was coming, he borrowed a car from the Army motor pool and drove to meet us at the train.

The sun shone brilliantly, the air was crisp and heady, and it was warm even though there was a lot of snow on the ground — a lovely contrast to the rigors of winter in Madison. Calkin drove us into Santa Fe, and we stopped for lunch at the Hotel La Fonda, where we sat at the low Spanish-style tables in the bar. After an interesting New-Mexico-style meal, we walked to a small doorway in a one-story building on a little street that bordered the central Plaza. In a modest suite of rooms, a smiling middle-aged lady invited me to fill out a few forms, turned a crank on a primitive desk machine, and produced the sheets of paper that were our passes to the Los Alamos Project. This inconspicuous little office was the entrance to the gigantic Los Alamos complex. The scene, very much like a British cloak-and-dagger mystery, brought memories of my boyhood fascination with such tales.

The project site was about forty miles northwest of Santa Fe. The ride was hair-raising, Jack having elected to show us the countryside by taking us on a short cut — a muddy track through sparse Mexican and Indian villages — until we came to the Rio Grande, which we crossed on a narrow wooden bridge.

The setting was romantic. We were going up and up into a strange, mysterious landscape of mesas, cliffs, piñon trees and brush. This became a forest of pines as we gained elevation. At a military gate in a barbed-wire fence, we showed our passes and drove on to a helter-skelter collection of one- and two-story wooden structures built along muddy, unpaved, narrow streets and paths.

We were assigned a small cottage by a pond (with the promise of larger quarters as soon as they were built). I then followed Jack to my first visit to the technical area.

We entered an office, where I was surprised to find Johnny deep in conversation with a man of middle stature, bushy eyebrows, an intense expression. He limped slightly as he paced back and forth in front of a blackboard. This was Edward Teller, to whom Johnny introduced me.

They were talking about things which I only vaguely understood. There were tremendously long formulae on the blackboard, which scared me. Seeing all these complications of analysis, I was dumbfounded, fearing I would never be able to contribute anything. However, when day after day the same equations remained and were not changed every few hours as I had expected, I regained my confidence and some hope of being able to add something to the theoretical work.

I understood snatches of their conversation, and an hour later, Johnny took me aside and explained to me formally and clearly the nature of the project and its status at the moment. The work in Los Alamos had started in earnest only about two or three months before. Von Neumann seemed very certain of its importance and radiated confidence about the ultimate success of the enterprise whose objective was the construction of an atomic bomb. He told me of all the possibilities which had been considered, of the problems relating to the assembling of fissionable materials, about plutonium (which did not yet physically exist even in the most microscopic quantities at Los Alamos). I remember very well, when a couple of months later I saw Robert Oppenheimer running excitedly down a corridor holding a small vial in his hand, with Victor Weisskopf trailing after him. He was showing some mysterious drops of something at the bottom of the vial. Doors opened, people were summoned, whispered conversations ensued, there was great excitement. The first quantity of plutonium had just arrived at the lab.

Needless to say, I soon ran across most of the Wisconsinites who had so mysteriously disappeared from Madison before us. I met Hans Bethe on the first day. I knew more about him than about Teller. I gradually met the entire group of theoretical and experimental physicists. I had known many mathematicians in Europe and in this country, but not as many physicists.

I had some knowledge of theoretical physics, despite the joke I had told Johnny about my not understanding even the autocatalytic action of a toilet. Astronomy, of course, had been my first interest, and then physics and mathematics. I had even given a course in classical mechanics at Harvard, but it is one thing to know about physics abstractly, and quite another to have a practical encounter with problems directly connected with experimental data, such as the very novel technology which was to come from Los Alamos.

I found out that the main ability to have was a visual, and also an almost tactile, way to imagine the physical situations, rather than a merely logical picture of the problems.

The feeling for problems in physics is quite different from purely theoretical mathematical thinking. It is hard to describe the kind of imagination that enables one to guess at or gauge the behavior of physical phenomena. Very few mathematicians seem to possess it to any great degree. Johnny, for example, did not have to any extent the intuitive common sense and “gut” feeling or penchant for guessing what happens in given physical situations. His memory was mainly auditory, rather than visual.

Another thing that seems necessary is the knowledge of a dozen or so physical constants, not merely of their numerical value, but a real feeling for their relative orders of magnitude and interrelations, and, so to speak, an instinctive ability to “estimate.”

I knew, of course, the values of constants like the velocity of light and maybe three or four other fundamental constants — the Planck constant h, a gas constant R, etc. Very soon I discovered that if one gets a feeling for no more than a dozen other radiation and nuclear constants, one can imagine the subatomic world almost tangibly, and manipulate the picture dimensionally and qualitatively, before calculating more precise relationships.

Most of the physics at Los Alamos could be reduced to the study of assemblies of particles interacting with each other, hitting each other, scattering, sometimes giving rise to new particles. Strangely enough, the actual working problems did not involve much of the mathematical apparatus of quantum theory although it lay at the base of the phenomena, but rather dynamics of a more classical kind — kinematics, statistical mechanics, large-scale motion problems, hydrodynamics, behavior of radiation, and the like. In fact, compared to quantum theory the project work was like applied mathematics as compared with abstract mathematics. If one is good at solving differential equations or using asymptotic series, one need not necessarily know the foundations of function space language. It is needed for a more fundamental understanding, of course. In the same way, quantum theory is necessary in many instances to explain the data and to explain the values of cross sections. But it was not crucial, once one understood the ideas and then the facts of events involving neutrons reacting with other nuclei.

Teller, in whose group I was supposed to work, talked to me on that first day about a problem in mathematical physics that was part of the necessary theoretical work in preparation for developing the idea of a “super” bomb, as the proposed thermonuclear hydrogen bomb was then called. The idea of thermonuclear reactions that would release enormous amounts of energy was, of course, older. Their role in the reactions in the interior of stars was discussed in theoretical papers in the 1930s by the physicists Geoffrey S. Atkinson and Fritz Houtermans. The idea of using a uranium fission explosion to trigger a thermonuclear reaction can be credited to Teller, Bethe, Konopinski, I believe, and perhaps some others.

Teller’s problem concerned the interaction of an electron gas with radiation, and it had more to do with the thermonuclear possibilities than with the assembly of the fission bomb, which was the main problem and work of Los Alamos. He guessed a formula for energy transfers connected with the so-called Compton effect about the rate of energy transfer. This formula, based on dimensional grounds and his intuition alone, was quite simple; he asked me to try to derive it more rigorously. As it was presented, there was no numerical factor in front. This seemed curious to me. I asked him explicitly about this a day or two later, and he said “Oh, the factor should be 1.”

This was the first technical problem in theoretical physics I had ever tackled in my life, and I approached it from a very elementary point of view. I read papers on statistical mechanics, on properties of the radiation field, and started working with rather naive and common-sense kinematic pictures. I tried some arithmetic and obtained a formula much like Teller’s, but with a numerical factor of about four in front as the rate of transfer. It was a messy little job. Edward was not satisfied with my rather elementary derivations.

Shortly after I had discussed this work with Teller, a young, more professional mathematical physicist, Henry Hurwitz, Jr., joined Teller’s group and with his much better mathematical techniques and experience in the special functions that were used in this type of problem, he obtained a formula, much more scholarly than mine, involving Bessel functions. Indeed, the exact numerical factor was not very different from four. If I remember correctly, it was a root of a certain Bessel function.

The idea was to have some thermonuclear material — deuterium — next to the fission bomb, and to let it ignite after the uranium bomb had exploded. How to do it in detail was the big problem, and it was by no means easy to see how such an arrangement would ignite and not just sputter and fizzle out. There was also, theoretically at least, the hazard of getting more of an explosion than intended and of having the whole atmosphere of the earth ignite! The well-known physicist Gregory Breit was involved in calculating the chances of the ignition of the atmosphere. These, of course, had to be zero before one could even think of tampering with thermonuclear reactions on earth.

I think it was Bethe, with Emil Konopinski, a well-known theoretical physicist, who suggested tritium instead of deuterium as a material easier to ignite, given the temperature of the fission bomb. Such an engineering suggestion from theoretical work came from his superb knowledge of theoretical nuclear physics.

Bethe was the head of the theoretical division, as it was called. Actually it was his and Robert F. Bacher’s papers in Reviews of Modern Physics which were used as the “bible” of the Los Alamos scientists, for they contained the bulk of the theoretical ideas and experimental facts known at the time. Bethe, now a Nobel Prize-winner for his earlier discovery of the mechanism of energy generation in the sun and other stars (the so-called carbon cycle), is, among other things, a virtuoso in the techniques of mathematical physics. As Feynman once put it, at Los Alamos he was, with his rigorous and definitive work, like a battleship moving steadily forward, surrounded by a flotilla of smaller vessels, the younger theoretical workers of the laboratory. He is one of the few persons for whom I merely had respect in the beginning but over the years have continuously developed liking and admiration.

When I first met Teller, he appeared youthful, always intense, visibly ambitious, and harboring a smoldering passion for achievement in physics. He was a warm person and clearly desired friendship with other physicists. Possessing a very critical mind, he also showed quickness, sense, and great determination and persistence. However, I think he also showed less feeling for true simplicity in the more fundamental levels of theoretical physics. To exaggerate a bit, I would say his talents were more in the direction of engineering, construction, and the surveying of existing methods. But undoubtedly he also had great ingenuity.

Teller was well known for his work on molecules, but he may have considered this as a sort of secondary field. I think it was the ease with which Gamow had new ideas without any technical arsenal at his disposal that pushed Teller into trying to emulate him and to attempt more fundamental work.

After he got into personal difficulties with Teller on the organizational features of the hydrogen work, Gamow later told me that before the war Teller was, in his view, a different person — helpful, willing, and able to work on other people’s ideas without insisting on everything having to be his own. According to Gamow, something changed in him after he joined the Los Alamos Project.

Of course, many physicists who were almost congenitally ivory-tower types got their heads turned with the sudden realization of not only the practical but worldwide historical importance of their work — not to mention the more trivial but obvious matter of the enormous sums of money and physical facilities that surpassed anything in their previous experience. Perhaps this played a role in the personality change of some principals; with Oppenheimer, the director, it may have had a bearing on his subsequent activities, career, ideas, and role as a universal sage. Like Teller, Oppenheimer may have had a feeling of inadequacy as compared with the creators of great new physical theories. He was equal to or even more brilliant and quick than Teller, but perhaps lacked the ultimate creative spark of originality. With his fantastic intelligence, he must have realized this himself. In speed of understanding and in critical ability, he probably surpassed Bethe or Fermi.

Teller wanted to have his own stamp on much of the essential work of Los Alamos, at first via his own approach to the fission bomb. He was pushing for milder explosions, dilution of material, etc. In spite of calculations by Konopinski and others that gave a poor outlook for some of these plans, he was trying by every means to have his own adopted. Collaboration with Bethe, who was head of the theoretical division, became increasingly difficult.

As disagreements between Teller and Bethe became more frequent and acute, Teller threatened to leave. Oppenheimer, who did not want to lose such a brilliant scientist, agreed to let him and his group work in a more future-oriented field, independent of the project’s main line. This is how Teller began to concentrate and organize the theoretical work for the “Super.” Konopinski, Weisskopf, Serber, Richard Feynman, William Rarita, and many others all had special contributions to make, but it was really Teller who kept the thing together and moving forward during the war.

After Fermi’s arrival, Teller’s group became a part of Fermi’s division. Fermi took great interest in the theoretical work on the thermonuclear reactions and H-bomb possibilities; at the end of the war he gave a series of lectures magnificently summarizing the work done until then — thanks mostly to the investigations of Teller and his group.

But even then, before the success of the atomic bomb itself, some of Teller’s actions gave clues to what led to much of the unpleasantness and waste of time in the so-called H-Bomb controversy.

Teller’s group was composed of a number of very interesting young physicists, younger even than Teller, Konopinski, or myself. It included Nick Metropolis, a Greek-American with a wonderful personality; Harold and Mary Argo, a husband-and-wife team, eager and talented; Jane Roeberg, a young woman who gave the impression of being competent; and a few others whose names I do not now remember.

There was, of course, much contact with other groups of physicists who were on the borderline of problems concerning the possibilities of a “super”; discussions with them were frequent, pleasant, and concerned many different branches of physics. One could hear about the pros and cons of the idea of implosion, which was new and vigorously debated in many of the offices. These discussions were completely open. Nothing was concealed from anybody who was a scientist.

The more formal way of letting people know what was going on was the weekly colloquia, which were held in a big hangar that also served as the movie theater. These talks covered progress of the work of the whole laboratory and the specific problems which the project encountered. They were run by Oppenheimer himself.

As for myself, after this first work on Edward’s problem, I spread out my interests to other related questions, one being the problem of statistics of neutron multiplication. This was more tangible for me from the purely mathematical side. I discussed such problems of branching and multiplying patterns with David Hawkins. We wrote a report on multiplicative branching processes, which had some practical application and relevance to the problem of the initial detonation of the bomb by a few neutrons. This problem was also studied by Stan Frankel and by Feynman, in a more technical and classical way. Our paper could be considered the beginning of what would come to be known in mathematics as branching processes theory, a sub-field of probability theory.

I also talked a lot with von Neumann and Calkin about problems of hydrodynamics, especially those concerning the process of implosion. Somewhat to my surprise I found my purely abstract intellectual habits as a mathematician immediately useful in the work with these more practical, special, and tangible problems. I have never felt the “gap” between the mode of thinking in pure mathematics and the thinking in physics, on which many mathematicians place so much stress. Anything amenable to mental analysis was congenial for me. I do not mean the distinction between rigorous thinking and more vague “imaginings”; even in mathematics itself, all is not a question of rigor, but rather, at the start, of reasoned intuition and imagination, and, also, repeated guessing. After all, most thinking is a synthesis or juxtaposition of advances along a line of syllogisms — perhaps in a continuous and persistent “forward’’ movement, with searching, so to speak “sideways,” in directions which are not necessarily present from the very beginning and which I describe as “sending out exploratory patrols” and trying alternative routes. It is all a multicolored thing, not very easy to describe in a way that a reader can appreciate. But I hope this kind of personal analysis of thinking in science is one of the possible interests of this book.

A discussion with von Neumann which I remember from early 1944 took several hours, and concerned ways to calculate the course of an implosion more realistically than the first attempts outlined by him and his collaborators. The hydrodynamical problem was simply stated, but very difficult to calculate — not only in detail, but even in order of magnitude.

In particular, the questions concerned values of certain numbers relating to compression versus pressure, and such. These had to be known, let us say within ten per cent or better, but the simplifications made in the outline of the calculations were of such a nature that they could not guarantee accuracy within a factor of two or three. All the ingenious shortcuts and theoretical simplifications which von Neumann and other mathematical physicists suggested, and which he tried to execute with the help of Calkin, seemed inadequate to me. In this discussion I stressed pure pragmatism and the necessity for attempting to get a heuristic survey of the general problem by simpleminded brute force — that is, more realistic, massive numerical work. At that time, in 1944, with the available computing facilities, the accuracy of the necessary numerical work could not be satisfactory. This was one of the first reasons for pressing for the development of electronic computers.

One of the charms and great attractions of life in Los Alamos in those days was the lunches at the Lodge, in the midst of friends. I was very surprised to find there and gradually to meet so many famous persons I had heard about.

Los Alamos was a very young place. At thirty-four, I was already one of the older people. What impressed me most was the very great competence of the younger people and the variety of their fields of specialization. It was almost like having an encyclopedia to look at, something that I so much like to do. I had the same feeling when talking to the young scientists around the laboratory. It is not the right expression perhaps but, roughly speaking, they were more accomplished in depth than in breadth. The older men, many of whom were European-born, had a more general knowledge. Yet science had become so ramified, specialization had proceeded so far, that it was quite difficult to retain knowledge of all the details and the overall view at the same time.

The younger scientists showed a lot of common sense in their own fields, but in general a great hesitation to engage in speculation outside their areas. Perhaps this stemmed from a fear of not being “absolutely right.” Many displayed a certain anti-philosophical spirit — not anti-intellectual, but anti-philosophical. This was perhaps because of the pragmatic nature of American attitudes.

I was also struck by the well-known American talent for cooperation, the team spirit, and how it contrasted with what I had known in continental Europe. I remembered how Jules Verne had anticipated this when he wrote about the collective effort needed for the organization of his “Voyage to the Moon.” People here were willing to assume minor roles for the sake of contributing to a common enterprise. This spirit of team work must have been characteristic of life in the nineteenth century and was what made the great industrial empires possible. One of its humorous side effects in Los Alamos was a fascination with organizational charts. At meetings, theoretical talks were interesting enough to the audience, but whenever an organizational chart was displayed, I could feel the whole audience come to life with pleasure at seeing something concrete and definite (“Who is responsible to whom,” etc.). Organization was and perhaps still is a great American talent, although this is written at a time when the so-called energy crisis appears to me to be more a crisis of momentum than of energy (a crisis of enterprise, solidarity, common spirit, determination, and cooperation for the common good).

It is difficult to describe for the general reader the intellectual flavor, the feeling, of a scientific “atmosphere.” There is no specific English word for this impression. Odor and smell have unpleasant connotations; perfume is artificial; aura is suggestive of mystery, of the supernatural. The younger scientists did not have much of an aura, they were bright young men, not geniuses. Perhaps only Feynman among the young ones had a certain aura.

Six or seven years younger than I, he was brilliant, witty, eccentric, original. I remember one day Bethe’s laughter shook the corridor walls, making me rush out of my office to see what was so funny. Three doors down in Bethe’s office, Feynman was standing — talking and gesticulating. He was telling the story of how he had failed his draft physical examination, re-enacting his now famous gesture: when a doctor asked him to show his hands, he chose to stretch them in front of him one with palm up, the other palm down. The doctor said, “The other side!” and he reversed both hands. This and other incidents of his physical examination had caused an explosion of laughter on the entire floor. It was on the first or second day in Los Alamos that I met Feynman, and remarked to him about my surprise that E = mc2 — which I of course believed in theoretically but somehow did not really “feel” — was, in fact, the basis of the whole thing and would bring about a bomb. What the whole Project was working on depended on those few little signs on paper. Einstein himself, when he was first told before the war about radioactive phenomena showing the equivalence of mass and energy, allegedly replied, “Ist das wirklich so? ist das wirklich so?” (Is that really so?)

Jokingly I told Feynman, “One day people will discover that a cubic centimeter of vacuum is really worth ten thousand dollars — it is equivalent to so much energy.” He immediately agreed and added, “Yes, but of course it will have to be pure vacuum!” Indeed, people now know about the polarization of vacuum. The force between two electrons or two protons is not e2/r2, but an infinite series of which this is the first term. It works on itself, like two almost-parallel mirrors, which show a reflection of a reflection of a reflection, ad infinitum.

Writing this reminds me of a feeling I once had when I visited the cyclotron in Chicago with Fermi. He took me around and made me walk through an incredibly heavy door, which he said “would flatten you into a piece of paper were it closed on you.” We walked between the poles of the magnet, and I reached into my pocket for the penknife with which I sometimes play. Suddenly it was jerked out of my hand when I touched it. The power of the vacuum! This made me physically conscious of the reality of “empty” space.

Feynman was also interested in many purely mathematical recreations not related to physics. I remember how he once gave an amusing talk about triangular numbers and managed to entertain everybody with his humor. At the same time, he was doing mathematics, and showing the foolishness of excessive cleverness and the irrationality of such strange interests.

One day he recited to me the following:

“I wonder why I wonder,

I wonder why I wonder why I wonder.

I wonder why I wonder why I wonder why,”

and so on.

It all depends on where you put the intonation, conveying a different meaning in every case. He did it marvelously in five or six styles, each with different stresses, as it were, most humorously.

Physically, Los Alamos consisted of a collection of two-and four-apartment buildings, temporary Army structures which turned out to be sturdy enough to survive for many years after the end of the war. To his everlasting credit, Oppenheimer insisted that they be laid out along the contours of the land, retaining as many trees as possible, instead of in the monotonous rectangular pattern of army camps and company towns. Still they were rather primitive, equipped with coal furnaces and coal stoves in the kitchens. People griped about the inadequacies of the housing situation, and wives had all sorts of complaints. But I found Los Alamos on the whole quite comfortable. The climate of New Mexico — Los Alamos in particular, at an elevation of seventy-two hundred feet — was one of the best I have ever lived in.

Placzek, a physicist who joined the project after the war, felt that east of the Rocky Mountains the United States was on the whole climatically uninhabitable, “unbewohnbar.” This is true especially for Europeans who are not accustomed to hot and muggy summers or to penetrating winter cold. In Cambridge, I used to tell my friends that the United States was like the little child in a fairy tale, at whose birth all the good fairies came bearing gifts, and only one failed to come. It was the one bringing the climate.

Soon after my arrival in Los Alamos I met David Hawkins, a young philosopher from Berkeley, one of the people Oppenheimer had brought with him to staff the administration of the Laboratory. We hit it off intellectually right away.

Hawkins is a tallish, blue-eyed, blond descendant of early New Mexico settlers. His father, Judge Hawkins, was a famous figure at the turn of the century. He was a lawyer and an official of the Territory, important in the Santa Fe Railroad operations. David was brought up in the small community of La Luz, in the southern part of the State. I mention this because later, when the bomb was exploded in the Jornada del Muerte desert near Alamagordo, David worried that blinding flashes or the heat and shock phenomena might be dangerous for people living in La Luz, some thirty or forty miles away, where his sister had her home.

Hawkins is a man of wide interests, with great breadth of knowledge, very good education, and a very logical mind. He regards scientific problems not as a narrow specialist, but from a general epistemological and philosophical point of view. To top it off, he is the most talented amateur mathematician I know. He told me that at Stanford he took some courses from Ouspenski, the Russian émigré specialist in probability and number theory, but he has not had any extensive training in mathematics. He has a very great natural feeling for it and a talent for manipulation. He is the most impressive of the non-professional mathematicians or physicists I have met anywhere in the world.

We discussed problems of neutron chain reactions and the probability problems of branching processes, or multiplicative processes, as we called them in 1944.

I was interested in the purely stylized problem of a branching tree of progeny from one neutron which may multiply, into zero (that is, the death of a neutron by absorption), or one (that just continues itself), or two or three or four (that is, causes the emergence of new neutrons), each possibility with a given probability. The problem is to follow the future course and the chain of possibilities through many generations.

Very early Hawkins and I detected a fundamental trick to help study such branching chains mathematically. The so-called characteristic function, a device invented by Laplace and useful for normal “addition” of random variables, turned out to be just the thing to study “multiplicative” processes. Later we found that observations to this effect had been made before us by the statistician Lotka, but the real theory of such processes, based on the operation of iteration of a function or of operators allied to the function (a more general process), was begun by us in Los Alamos, starting with a short report. This work was strongly generalized and broadened in 1947, after the war, by Everett and myself after he joined me in Los Alamos. Some time later, Eugene Wigner brought up a question of priorities. He was eager to note that we did this work quite a bit before the celebrated mathematician Andrei N. Kolmogoroff and other Russians and some Czechs had laid claim to having obtained similar results.

I liked Hawkins’s general curiosity, his almost unique knowledge of the fundamentals of several scientific theories — not only in the conceptual elements of physics but in biology and even economics. I liked his interest and genuinely original work in what was to become known as “information theory” after it became formalized by Wiener and especially by Claude Shannon. David applied to economic problems the mathematical ideas of von Neumann and Morgenstern in game theory.

Hawkins has since written several interesting papers and an excellent book on the philosophy of science, or rather on the philosophy of rational thinking, called The Language of Nature.

Hawkins’s position in Los Alamos at first was as a liaison between Oppenheimer’s office and the military. Some years later he wrote two volumes, since declassified, about the organization and the scientific history from the early days of Los Alamos until the end of the war. I did not know it at the time (and it was not obvious from conversations with him) that in the nineteen thirties he had been involved on the West Coast with communist sympathizer groups. That caused him great trouble before and during the McCarthy era, including hearings in Washington. He came out of it completely vindicated.

His wife, Frances, an extremely interesting person, became friendly with Françoise, and we saw each other a great deal. At the time of my illness in California in 1946, the Hawkinses were immensely helpful to us in caring for our daughter Claire, who was then an eighteen-month-old infant.

Hawkins left Los Alamos after the end of the war to take the post of professor of philosophy at the University of Colorado in Boulder, where he is today.

The Los Alamos community was completely different from any where I had ever lived and worked. Even Lwów, which had a dense concentration of people and where the mathematicians and university people were in daily contact and spent much time together in restaurants and coffee houses, did not have the degree of togetherness of Los Alamos. It was even more pronounced there because of the isolation and the smallness of the town, and the proximity of all the buildings. People visited each other constantly at all hours after work. What was novel to me was that these were not mathematicians (except von Neumann and two or three younger persons), but physicists, chemists, and engineers — psychologically quite different from my more inward-oriented mathematical colleagues. The variety and richness of the physicists was interesting and delightful to observe. On the whole, theoreticians and experimentalists differed in temperament.

It has been said that at lunch in Fuller Lodge one could see as many as eight or ten Nobel Prize-winners eating at the same time (Rabi, Lawrence, Fermi, Bloch, Bohr, Chadwick, and others). Their interests were wide because physics has more definite and obvious central problems than mathematics, which splits into many almost independent domains of thought. They considered not only the main problem — the construction of an atomic bomb and related physical questions about phenomena that would attend the explosion — the strictly project work — but also general questions about the nature of physics, the future of physics, the impact of nuclear experiments on the technology of the future, and contrastingly its influence on the future development of theory. Beyond this, I remember very many after-dinner discussions about the philosophy of science, and of course on the world situation, from daily progress on the war fronts to prospects of victory in the months to come.

The intellectual quality of so many interesting persons and their being constantly together was unique. In the entire history of science there had never been anything even remotely approaching such a concentration. The radar project in Cambridge, Massachusetts, proceeding at the same time, had some of these characteristics, but without the same intensity. It was more technological perhaps, and did not touch as many fundamental questions of physics.

Who were some of the luminaries of this fantastic assembly? Von Neumann, Fermi, Bethe, Bohr, Feynman, Teller, Oppenheimer, O. R. Frisch, Weisskopf, Segré, and many more. I have already tried to sketch the personalities of some of them and can describe a few more.

I first met Fermi when he arrived at Los Alamos, a few months after us, after the Chicago pile had been successfully completed. I remember sitting at lunch in Fuller Lodge before his arrival with six or seven people, including von Neumann and Teller. Teller said, “It is quite certain now that Enrico will arrive next week.” I had learned earlier that Fermi was referred to as “the pope” because of the infallibility of his pronouncements. So immediately I intoned: “Annuncio vobis gaudium maximum, papam habemus,” which is the classical way cardinals announce the election of a pope on the balcony overlooking St. Peter’s Square, after the white smoke comes out of the chimney in the Vatican. Johnny, who understood, explained this reference, and the allusion was applauded by the entire table.

Fermi was short, sturdily built, strong in arms and legs, and rather fast moving. His eyes, darting at times, would be fixed reflectively when he was considering some question. His fingers often nervously played with a pencil or a slide rule. He usually appeared in good humor, with a smile almost perpetually playing around his lips.

He would look at a questioner in an inquiring way. His conversation included many questions rather than expressions of opinion. His questions were formulated in such a way, however, that it was clear which way Fermi’s beliefs or guesses went. He would try to elucidate other persons’ thoughts by asking questions in a Socratic manner, yet more concretely than in Plato’s succession of problems.

Sublimated common sense characterized his thoughts. He had will power and control; and not obstinacy but persistence in following a line, all the while looking very carefully at possible ramifications. He would not neglect the opportunities that presented themselves, often by chance, from random observations in scientific work.

Once when we discussed another physicist, he characterized him as too systematically obstinate. Yet he also told me that he liked to work very systematically in an orderly fashion in order to keep everything under control. At the same time he had decided in his youth to spend at least one hour a day thinking in a speculative way. I liked this paradox of a systematic way of thinking unsystematically. Fermi had a whole arsenal of mental pictures, illustrations, as it were, of important laws or effects, and he had a great mathematical technique, which he used only when necessary. Actually it was more than mere technique; it was a method for dissecting a problem and attacking each part in turn. With our limited knowledge of introspection this cannot be explained at the present time. It is still an “art” rather than a “science.” I would say that Fermi was overwhelmingly rational. Let me explain what I mean: the special theory of relativity was strange, irrational, seen against the background of what was known before. There was no simple way to develop it through analogies with previous ideas. Fermi probably would not have tried to develop such a revolution.

I think he had a supreme sense of the important. He did not disdain work on the so-called smaller problems; at the same time, he kept in mind the order of importance of things in physics. This quality is more vital in physics than in mathematics, which is not so uniquely tied to ’’reality.” Strangely enough, he started as a mathematician. Some of his first papers with very elegant results were devoted to the problem of ergodic motion. When he wanted to, he could do all kinds of mathematics. To my surprise, once on a walk he discussed a mathematical question arising from statistical mechanics which John Oxtoby and I had solved in 1941.

Fermi’s will power was obvious, even to the extent of controlling his impulsive gestures. In my opinion, he deliberately avoided volatile Latin mannerisms, and perhaps by a conscious decision controlled gesticulations and avoided exclamations. But Enrico smiled and laughed very readily.

In all activities, scientific or otherwise, he had a mixture of semi-logical whimsical humor about common-sense points of view. When he played tennis, for instance, if he lost four games to six, he would say: “It does not count because the difference is less than the square root of the sum of the number of games.” (This is a measure of purely random fluctuations in statistics.)

He loved political discussions, and he loved trying — not too seriously — to foresee the future. He would ask people in a group to write down what they thought would happen, and put it in a sealed envelope to be opened a couple of months later. On the whole he was very pessimistic about the long-range outlook politically, concluding that humanity is still foolish and would destroy itself one day.

He could be also quite a tease. I remember his Italian inflections when he would taunt Teller with statements like: “Edward-a how com-a the Hungarians have not-a invented anything?” Once Segré, who was very fond of fishing on weekends in the streams of the Los Alamos mountains, was expounding on the subtleties of the art, saying that it was not easy to catch trout. Enrico, who was not a fisherman, said with a smile, “Oh, I see, Emilio, it is a battle of wits.”

In conversations with friends about the personalities of others, he tried to be entirely detached and objective, allowing little of personal or subjective opinions or feelings to surface. About himself, he had tremendous self-assurance. He knew that he had the touch as well as luck on top of his supreme common sense, enormous mathematical technique, and knowledge of physics.

Enrico was fond of walking; several times we walked all the way from Los Alamos down the walls of a canyon and along a stream to the Bandelier National Monument. It was a walk of seven or eight miles during which we had to cross the stream more than thirty times. The walk lasted several hours, and we discussed many subjects.

I should mention here one of my own peculiarities: I do not like walking uphill. I don’t really know why. Some people tell me that I tend to go too fast from impatience and get winded for that reason. I do not mind walking on level ground and I actually enjoy walking down hill. Years ago I bought a German travel guidebook called “One Hundred Downhill Walks in the Alps.” Certainly a humorous title.

After the war, on one of these downhill excursions in Frijoles Canyon, I told Fermi how in my last year of high school I was reading popular accounts of the work of Heisenberg, Schrödinger, and De Broglie on the new quantum theory. I learned that the solution of the Schrödinger equation gives levels of hydrogen atoms with a precision of six decimals. I wondered how such an artificially abstracted equation could work to better than one part in a million. A partial differential equation pulled out of thin air, it seemed to me, despite the appearances of derivation by analogies. I was relating this to Fermi, and at once he replied: “It [the Schrödinger equation] has no business being that good, you know, Stan.”

He went on to say that in the fall he intended to give a really logical introduction and derivation of quantum theory in his course at the University of Chicago. He apparently worked at it, but told me the next summer, when he returned to Los Alamos, “No, I didn’t succeed to my satisfaction in giving a really rational introduction to quantum theory.” It is not just a question of axioms as some naive purist might think. The question is why such and no other axiom? Any working algorithm can be axiomatized. How to introduce, justify, tie up or simplify the axioms, historically or conceptually, and how to base them on experiments — that is the problem.

Von Neumann and Fermi were really quite different in personality. Johnny was perhaps broader in his interests than Enrico. He had more specifically expressed interests in other fields, certainly, for example, in ancient history. Fermi did not show any great interest in or liking for the arts. I never remember him discussing music, painting, or literature. Current affairs, politics, yes; history, no. Von Neumann was interested in both. Fermi did not indulge in quotations or allusions, Latin or otherwise, although he liked epigrammatic formulations occasionally. But he did not display a gymnasium or lycée type of education or the resultant mental habits. His overwhelming characteristic was his Latin clarity. Von Neumann did not consciously insist on simplicity; on the contrary, he liked to show clever complications on occasion.

In their lectures to students or scientific gatherings, they demonstrated their different approaches. Johnny did not mind showing off brilliancy or special ingenuity; Fermi, on the contrary, always strived for the utmost simplicity, and when he talked everything appeared in a most natural, direct, bright, clear light. After students had gone home, they were often unable to reconstruct Fermi’s dazzlingly simple explanation of some phenomenon or his deceptively simple-looking idea on how to treat a physical problem mathematically. In contrast, von Neumann showed the effects of his sojourns at German universities. He was absolutely devoid of pomposity, but in his language structure he could be complicated, though perfect logic always gave a unique interpretation to his words.

They held high opinions of each other. I remember a discussion of some hydrodynamical problem Fermi had been thinking about. Von Neumann showed a way to consider it, using a formal mathematical technique. Fermi told me later with admiration, “He is really a professional, isn’t he!” As for von Neumann, he always took external evidences of success seriously; he was quite impressed by Fermi’s Nobel Prize. He also appreciated wistfully other people’s ability to get results by intuition or seemingly pure luck, especially by the apparent effortlessness of Fermi’s fundamental physics discoveries. After all, Fermi was perhaps the last all-around physicist in the sense that he knew the theory, did original work in many branches, and knew what experiments to suggest and even do himself; he was the last to be great both in theory and as an experimenter.

Niels Bohr, the discoverer of the quantized electron orbits in the atom and a great pioneer of quantum theory, was in Los Alamos for several months. He was not very old. To me at thirty-five, he seemed ancient, even though Bohr in his late fifties was very active and energetic, physically as well as mentally. He walked, skied, and hiked in the Los Alamos mountains. Somehow he seemed the embodiment of wisdom. (Wisdom, perhaps not genius in the sense of Newton or Einstein.) He knew what not to attempt and how much could be done without mathematics, which he left to others. This enormous wisdom is what I liked about him.

Departing from his usual caution about expressing opinions about other people, Fermi remarked once that when Bohr talked he sometimes gave the impression of a Catholic priest celebrating mass. It was an iconoclastic statement, since so many physicists are still under the spell of Bohr.

He had his own kind of genius that made him a great physicist but, to my mind, some of his students were almost benighted by his complementarity philosophy of “one can say this, but on the other hand one can…” or “one cannot say sharply what this means.” People without his great sense and intuitive wisdom were led astray and lost the precision and sharpness of their intellectual or scientific approach, in my opinion. But he still has many admirers. Victor F. Weisskopf is one.

It seems to me that as a philosophical guideline, complementarity is essentially negative. It can only console. Whether it can be positively useful other than in philosophical consolations is a question which troubles me.

Bohr’s speech was very difficult to understand, and anecdotes about him abound. Most of the time it was impossible to get his exact words. One day a young physicist, Ruby Scherr, was called on the public address system. Here I should explain that every day at periodic intervals the halls of the laboratory resounded with announcements and requests, the most frequent of which was a call for J. J. Gutierrez, who was a supply factotum and jack of all trades. Other calls were requests for the return of such and such an instrument, or even the Sears, Roebuck catalogue. One day among other announcements came one asking Ruby Scherr to please go to Nicholas Baker’s office. (Nicholas Baker was the pseudonym of Bohr for security reasons; Fermi’s was Farmer.) As Ruby Scherr tells the story, he went to the office, saw several physicists sitting around and obviously listening to a presentation by Bohr. Bohr stopped, mumbled a few incomprehensible sentences in the direction of Scherr, and suddenly ended with a crystal-clear three words: “Guess how much?” Scherr, who had not understood a word of the question, blushed with embarrassment, shook his head shyly and remained silent. After a moment Bohr again in a clear voice said “1041.” Whereupon everybody laughed. To this day, Scherr does not know what it was all about.

Another Bohr story illustrates the absentmindedness of scientists: it was well known throughout Los Alamos that Nicholas Baker was Niels Bohr; nevertheless, his true name was never supposed to be mentioned in public. At one colloquium, Weisskopf referred to “the well-known Bohr principle.” “Oh excuse me,” he fumbled, “the Nicholas Baker principle!” General laughter greeted this security breach.

Not all of us were unduly security conscious. Every scientist, old or young, had in his office a safe where secret documents had to be kept. Indeed, the Project must have had more safes than all the banks in New York. Once in Bohr’s office I watched him struggle to open his safe. The safes could be opened with a rather simple combination of three two-digit numbers. He tried and tried for a long time, finally succeeding. He pulled out the drawer and exclaimed delightedly: “I believe I have done enough for the day.” The story that Dick Feynman could open safes whose combinations had been forgotten by their owners is true. He apparently listened to the clicks of the tumblers and sometimes he guessed which combinations of digits of numbers like π or e in mathematics, or c, the velocity of light, or h, Planck’s constant, had been selected by the owners for the combinations.

One thing that relieved the repetition and alternation of work, intellectual discussions, evening gatherings, social family visits and dinner parties, was when a group of us would play poker about once a week. The group included Metropolis, Davis, Calkin, Flanders, Langer, Long, Konopinski, von Neumann (when he was in town), Kistiakowski sometimes, Teller, and others. We played for small stakes; the naïveté of the game and the frivolous discussions laced with earthy exclamations and rough language provided a bath of refreshing foolishness from the very serious and important business that was the raison d’être of Los Alamos.

In playing such a game, unless you are vitally interested in the game itself, and not merely in its relaxing qualities, you will not do well. Von Neumann, Teller, and I would think about completely unrelated subjects during the bidding or betting; consequently, more often than not we were the losers. Metropolis once described what a triumph it was to win ten dollars from John von Neumann, author of a famous treatise on game theory. He then bought his book for five dollars and pasted the other five inside the cover as a symbol of his victory. It may not be clear to non-scientists or non-mathematicians that one can do theoretical work in one’s head and pursue it quite intensely while literally carrying on some other more prosaic activity.

The Trinity test, Hiroshima, V-J Day, and the story of Los Alamos exploded over the world almost simultaneously with the A-Bomb. Publicity over the secret wartime Project filled the newspapers and its administrative heads were thrown in the limelight. In one newspaper interview out of many published the day after Hiroshima, E. O. Lawrence “modestly admitted,” according to the interviewer, “that he more than anyone else was responsible for the atomic bomb.” Similar statements by and about others filled the media. Oppenheimer was reported to have described his feelings after the unearthly light of the initial flash of the Trinity experiment by quoting from the Hindu epic, the Bhagavad Gita: “It flashed to my mind that I had become the Prince of Darkness, the destroyer of Universes.”

What is true is that as I was reading this item in a newspaper, something else flashed through my mind, a story of a “pension” in Berlin before the war. I told it immediately to Johnny, who was eating dinner in our house. The Berlin boarders were sitting around a table for dinner and dishes were passed for each person to help himself to his share. One man was taking most of the asparagus that was on the platter. Whereupon another man stood up shyly and said: “Excuse me, Mr. Goldberg, we also like asparagus!” And the expression “asparagus” became it code word in our private conversations for trying to obtain an unduly large share of credit for scientific work or any other accomplishment of a joint or group character. Johnny loved this story so much that in our humorous conversations we played on developing the theme. We would plan to write a twenty-volume treatise on “Asparagetics through the Ages.’’ Johnny would do “Die Asparagetics im Altertum” and I the final volume “Rückblick und Ausblick” in the manner of heavy German scholarship. Later, Carson Mark put his own stamp on these jokes by composing a song, “Oh, How I Love Asparagus,” to the tune of a current popular song.

But levities like these could hardly alleviate the general feeling of foreboding upon entering into the era of history that would be called the Atomic Age. The war was over, the world and the nation had to reorganize themselves. Life would never be the same.

Chapter 9. Southern California

1945–1946

The war was over and the world was emerging from the ashes. Many people left Los Alamos, either to return to their former universities like Hans Bethe, or to go to new academic positions like Weisskopf to MIT or Teller to Chicago. The government had not reached any decision yet about the fate of the wartime laboratory.

The University of Chicago took steps to start a great new center for nuclear physics, with Fermi, Teller and several others from the Manhattan District Project. Von Neumann, better than anyone else, it seems to me, argued that as a result of the role science had played in the winning of the war, the post-war academic world would not be recognizable in pre-1939 terms.

On the purely personal plane, I had no evidence that any member of my immediate family had survived (two cousins did reappear many years later, one in France, the other in Israel). Françoise had lost her mother in the concentration camp of Auschwitz. We were both American citizens now, the United States was our country, and the idea of returning to Europe never entered our heads. But the question of what job to return to from war work was very much on our minds.

I had some correspondence with Langer, who was then the chairman, about returning to Madison. He was very honest and open, and he told me with admirable frankness when I inquired about my chances for promotion and tenure: “No reason to beat around the bush, were you not a foreigner, it would be much easier and your career would develop faster.” So it seemed that my chances in Wisconsin were not very good, and I looked elsewhere. Elsewhere came in the form of a letter from an old Madison friend, Donald Hyers, who had become a professor at the University of Southern California in Los Angeles. Hyers was well established there, and he asked whether I would be interested in joining the faculty as an associate professor at a salary somewhat higher than the one in Madison. The university was small, not very strong academically, and certainly not a very prestigious place, but the professors there, he said, were engaged in vigorous attempts at improving the academic standing of the institution. He invited me for a visit, and I flew to Los Angeles in August of 1945.

This was the first time I saw that city, and it gave me a very strange impression. It was a different world from any I had known, climatically, architecturally, and otherwise. I mentioned this job possibility to Johnny, and although he was rather surprised at my interest in this rather modest opportunity, he did not react negatively. His tendency was to go along. I did not see much sense in marking time in Los Alamos after the war, so I accepted the USC offer.

In early September of 1945, I went to Los Angeles to look for housing and to prepare our move from Los Alamos. In the immediate postwar period, the housing situation in Los Angeles was critical. Since we did not own a car, we were restricted to searching for a house in the vicinity of the University. I used to say that any two points in Los Angeles were at least an hour’s drive apart, a “discrete” topological space. I managed to sublet for one semester a typical small Los Angeles house on a modest street lined with spindly palm trees. To me it seemed adequate, but it appeared rather miserable to Françoise. Nevertheless, we settled there temporarily for lack of anything better. I noticed that in our various moves from one habitat to the next all our material possessions, clothes, books, furnishings had a way of diminishing in transit. I used to say that they dwindled to 1/e, in analogy to the energy losses of particles in transit through “one mean free path.”

For the second semester of that academic year (1945–46), Hal and Hattie von Breton, good friends of the Hawkinses, invited us to stay in their summer cottage on Balboa Island across from Newport Beach. It was on the water, beautiful and comfortable — a wonderful change from the university neighborhood but a little too far for me to commute daily — so during the week I lived in a hotel near the campus and went home to the island on weekends. Françoise remained on Balboa with our baby daughter Claire, who had been born in Los Alamos the year before.

At USC I found the academic atmosphere somewhat restricted, rather anticlimactic after the intensity and the high level of science at Los Alamos. Everyone was full of good will, even if not terribly interested in “research.” The “teaching load” to which I was reluctantly returning was not too heavy. All in all, things looked promising had it not been for a violent illness which struck me suddenly. I had returned to Los Angeles from a mathematics meeting in Chicago with a miserable cold. It was a stormy day; on the walk from the bus to the house in Balboa the violent winds almost choked me. That same night I developed a fantastic headache. Never in my life had I experienced a headache of any kind; this was a new feeling altogether — the most severe pain I had ever endured, all-pervading and connected with a sensation of numbness creeping up from the breast bone to the chin. I remembered suddenly Plato’s description of Socrates after he was given the hemlock in prison; the jailor made him walk and told him that when the feeling of numbness starting in the legs reached his head he would die.

Françoise had difficulty in finding a doctor who would come to the island in the middle of the night. The one who finally came could not find anything visibly wrong and gave me a shot of morphine to alleviate the excruciating pain. The next morning I felt almost normal but with a lingering feeling of lassitude and an inability to express myself clearly, which came and went. Nevertheless, I returned to Los Angeles and gave my lectures at the university. The following night the violent headache reappeared. When I tried to telephone Françoise from my hotel room, I noticed that my speech was confused, that I was barely able to form words. I tried to talk around the expressions which would not come out and form equivalent ones, but it was mostly a meaningless mumble — a most frightening experience. Greatly alarmed by my incoherent phone call (I don’t know how I managed to remember the phone number at home), Françoise called the von Bretons and asked them to send a doctor to see me. In fact, two doctors appeared. Perplexed by my symptoms that came and went, they took me to Cedars of Lebanon hospital. A severe attack of brain troubles began, which was to be one of the most shattering experiences of my life. By the way, many of the recollections of what preceded my operation are hazy. Thanks to what Françoise told me later I was able to put it together.

For several days I underwent various tests — encephalograms, spinal taps, and the like. The encephalogram was peculiar. The doctors suspected a tumor, which could be benign or malignant. Dr. Rainey, a neurosurgeon pupil of Cushing, was called in and an operation was planned for the following day. Of all this I knew nothing, of course. I remember only trying to distract the nurse’s attention by telling her to look out of the window so I could read my chart. I saw there some alarming notation about C-3 which I suspected to mean the third convolution of the brain. Through all this I was overcome by an intense fear and began to think I was going to die. I considered my chances of surviving to be less than half. The aphasia was still present; much of the time when I tried to speak I uttered meaningless noises. I do not know why no one thought of ascertaining whether I could write instead of speak.

Françoise, alerted by the von Bretons, rushed all the way back from Balboa by taxi and arrived on the scene just as I was beginning to vomit bile, turning green and losing consciousness. She feared I was dying and made a frantic telephone call to the surgeon, who decided the operation should be performed immediately. This probably saved my life; the emergency operation relieved the severe pressure on my brain which was causing all the trouble. I remember that in my semi-conscious state my head was being shaved by a barber (he happened to be a Pole) who said a few words in Polish, to which I tried to reply. I remember also returning to consciousness briefly in a pre-operating room and wondering whether I was already in the morgue. I also remember hearing the noise of a drill. This was a true sensation as it turned out, for the doctors drilled a hole in my skull to take some last-minute X-rays. The surgeon performed a trepanation not knowing exactly where or what to look for. He did not find a tumor, but did find an acute state of inflammation of the brain. He told Françoise that my brain was bright pink instead of the usual gray. These were the early days of penicillin, which they applied liberally. A “window” was left on the brain to relieve the pressure which was causing the alarming symptoms.

I remained in a post-operative coma for several days. When I finally woke up, I felt not only better, but positively euphoric. The doctors pronounced me saved, even though they told Françoise to observe me for any signs of changes of personality or recurrence of the troubles which would have spelled brain damage or the presence of a hidden growth. I underwent more tests and examinations, and the illness was tentatively diagnosed as a kind of virus encephalitis. But the disquietude about the state of my mental faculties remained with me for a long time, even though I recovered speech completely.

One morning the surgeon asked me what 13 plus 8 were. The fact that he asked such a question embarrassed me so much that I just shook my head. Then he asked what the square root of twenty was, and I replied: about 4.4. He kept silent, then I asked, “Isn’t it?” I remember Dr. Rainey laughing, visibly relieved, and saying, “I don’t know.” Another time I was feeling my heavily bandaged head, and the doctor chided me saying the bacteria could infect the incision. I showed him I was touching a different place. Then I remembered the notion of a mean free path of neutrons and asked him if he knew what the mean free path of bacteria was. Instead of answering, he told me an unprintable joke about a man sitting on a country toilet and how the bacteria leaped from the splashing water. The nurses seemed to like me and offered all kinds of massages and back rubs and special diets, which helped my morale more than my physical condition (which was surprisingly good).

Many friends came to visit me. Jack Calkin, who was on leave on Catalina Island, appeared several times at the hospital. So did colleagues from the University. I remember the mathematician Aristotle Dimitrios Michael. He talked so agitatedly that I fell out of bed listening to him. This scared him very much. But I managed to scramble back even though I was still slightly numb on one side. Nick Metropolis came all the way from Los Alamos. His visit cheered me greatly. I found out that the security people in Los Alamos had been worried that in my unconscious or semi-conscious states I might have revealed some atomic secrets. There was also some question as to whether this illness (which was never properly diagnosed) might have been caused by atomic radiation. But in my case this was highly improbable, for I had never been close to radioactive material, having worked only with pencil and paper. University officials visited me, too. They seemed concerned about my ability to resume my teaching duties after I got well. People were acutely concerned about my mental faculties, wondering whether they would return in full. I worried myself a good deal about that, too; would my ability to think return in its entirety or would this illness leave me mentally impaired? Obviously in my profession, complete restoration of memory was of paramount importance. I was quite frightened, but in my self-analysis I noticed that I could imagine even greater states of panic. Logical thought processes are very much disturbed by fright. Perhaps it is nature’s way of blocking the process in times of danger to allow instinct to take over. But it seems to me that mere instincts, which reside in nerves and in muscle “programming,” are no longer sufficient to cope with the complicated situations facing modern man; some sort of reasoning ability is still needed in the face of most dangerous situations.

I regained my strength and faculties gradually and was allowed to leave the hospital after a few weeks. I obtained a leave of absence from the university.

I remember being discharged from the hospital. As I was preparing to leave, fully dressed for the first time, standing in the corridor with Françoise, Erdös appeared at the end of the hall. He did not expect to see me up, and he exclaimed: “Stan, I am so glad to see you are alive. I thought you were going to die and that I would have to write your obituary and our joint papers.” I was very flattered by his pleasure at seeing me alive, but also very frightened to realize that my friends had been on the brink of giving me up for dead.

Erdös had a suitcase with him and was just leaving after a visit to Southern California. He had no immediate commitments ahead and said, “You are going home? Good, I can go with you.” So we invited him to come with us to Balboa and stay awhile. The prospect of his company delighted me. Françoise was somewhat more dubious, fearing that it would tire me too much during the early part of my convalescence.

A mathematical colleague from USC drove us all back to the von Bretons’ house on Balboa Island. Physically, I was still very weak and my head had not yet healed. I was wearing a skullcap to protect the incision until my hair grew back, I remember having difficulty walking around the block the first few days, but gradually my strength returned, and soon I was walking a mile each day on the beach.

In the car on the way home from the hospital, Erdös plunged immediately into a mathematical conversation. I made some remarks, he asked me about some problem, I made a comment, and he said: “Stan, you are just like before.” These were reassuring words, for I was still examining my own mind trying to find out what I might have lost from my memory. Paradoxically, one can perhaps realize what topics one has forgotten. No sooner had we arrived than Erdös proposed a game of chess. Again I had mixed feelings: on one hand I wanted to try; on the other, I was afraid to in case I had forgotten the rules of the game and the moves of the pieces. We sat down to play. I had played a lot of chess in Poland and had more practice than he had, and I managed to win the game. But the feeling of elation that followed was immediately tempered by the thought that perhaps Paul had let me win on purpose. He proposed a second game. I agreed, although I felt tired, and won again. Whereupon it was Erdös who said, “Let us stop, I am tired.” I realized from the way he said it that he had played in earnest.

In the days that followed we had more and more mathematical discussions and longer and longer walks on the beach. Once he stopped to caress a sweet little child and said in his special language: “Look, Stan! What a nice epsilon.” A very beautiful young woman, obviously the child’s mother, sat nearby, so I replied, “But look at the capital epsilon.” This made him blush with embarrassment. In those days he was very fond of using expressions like SF (supreme fascist) for God, Joe (Stalin) for Russia, Sam (Uncle Sam) for the United States. These were for him objects of occasional scorn.

Gradually my self-confidence returned, but every time a new situation occurred in which I could test my returning powers of thought, I was beset by doubts and worries. For example, I received a letter from the Mathematical Society asking me if I would write for the Bulletin an obituary article on Banach, who had died in the fall of 1945. This again gave me reason to ponder. It seemed a little macabre after having barely escaped death myself to write about another’s demise. But I did it from memory, not having a library around, and sent in my article with apprehension, wondering if what I had written was weak or even nonsensical. The editors replied that the article would appear in the next issue. Yet my satisfaction and relief were again followed by doubt for I knew that all kinds of articles were printed, and I did not have such a high opinion of many of them. I still felt unsure that my thinking process was unimpaired.

Normally primitive or ’’elementary” thoughts are reactions to or consequences of external stimuli. But when one starts thinking about thinking in a sequence, I believe the brain plays a game — some parts providing the stimuli, the others the reactions, and so on. It is really a multi-person game, but consciously the appearance is of a one-dimensional, purely temporal sequence. One is only consciously aware of something in the brain which acts as a summarizer or totalizer of the process going on and that probably consists of many parts acting simultaneously on each other. Clearly only the one-dimensional chain of syllogisms which constitutes thinking can be communicated verbally or written down. Poincaré (and later Polya) tried to analyze the thought process. When I remember a mathematical proof, it seems to me that I remember only salient points, markers, as it were, of pleasure or difficulty. What is easy is easily passed over because it can be reconstituted logically with ease. If, on the other hand, I want to do something new or original, then it is no longer a question of syllogism chains. When I was a boy I felt that the role of rhyme in poetry was to compel one to find the unobvious because of the necessity of finding a word which rhymes. This forces novel associations and almost guarantees deviations from routine chains or trains of thought. It becomes paradoxically a sort of automatic mechanism of originality. I am pretty sure this “habit” of originality exists in mathematical research, and I can point to those who have it. This process of creation is, of course, not understood nor described well enough at present. What people think of as inspiration or illumination is really the result of much subconscious work and association through channels in the brain of which one is not aware at all.

It seems to me that good memory — at least for mathematicians and physicists — forms a large part of their talent. And what we call talent or perhaps genius itself depends to a large extent on the ability to use one’s memory properly to find the analogies, past, present and future, which, as Banach said, are essential to the development of new ideas.

I continue to speculate on the nature of memory and how it is built and organized. Although one does not know much at present about its physiological or anatomical basis, what gives a partial hint is how one tries to remember things which one has temporarily forgotten. There are several theories about the physical aspects of memory. Some neurologists or biologists say that it consists perhaps of permanently renewed currents in the brain, much as the first computer memories were built with sound waves in a mercury tank. Others say that it resides in chemical changes of RNA molecules. But whatever its mechanism, an important thing is to understand the access to our memory.

Experiments seem to indicate that the memory is complete in the sense that everything we experience or think about is stored. It is only the conscious access to it that is partial and varies from person to person. Some experiments have shown that by touching a certain spot in the brain a subject will seem to recall or even “feel” a situation that happened in the past — such as being at a concert and actually hearing a certain melody.

How is memory gradually built up during one’s conscious or even unconscious life and thought? My guess is that everything we experience is classified and registered on very many parallel channels in different locations, much as the visual impressions that are the result of many impulses on different cones and rods. All these pictures are transmitted together with connected impressions from other senses. Each such group is stored independently, probably in a great number of places under headings relevant to the various categories, so that in the visual brain there is a picture, and together with the picture something about the time, or the source, or the word, or the sound, in a branching tree which must have additionally a number of connecting loops. Otherwise one could not consciously try and sometimes succeed in remembering a forgotten name. In a computing machine, once the address of the position of an item in the memory is lost, there is no way to get at it. The fact that we succeed, at least on occasion, means that at least one member of the “search party” has hit a place where an element of the group is stored. Thus it is common to recall a last name once the first name has been recalled.

Then I thought, how about smell? Smell is something we sense; it is not related to any sound or picture. We do not know how to call it. It has no visual impact either. Does this contradict my guesses about simultaneous storage and connections? Then I remembered the famous incident related by Proust of the smell and taste of the “madeleine” (little cake). There are many descriptions in the literature of cases where a smell previously experienced and felt suddenly brings back a long-forgotten occasion when it was first associated with a place, or a person, many years before. So, perhaps on the contrary, this is another indication.

This feeling of analogy or association is necessary to place the set of impressions correctly on the suitable end points of a sequence of branches of a tree. And perhaps this is how people differ from each other in their memories. In some, more of these analogies are felt, stored, and better connected. Such analogies can be of an extremely abstract nature. I can conceive that a concrete picture, a visual sequence of dots and dashes, may bring back an abstract thought, which apparently in a mysterious coding had something in common with it. Some part of what is called mathematical talent may depend on the ability to see such analogies.

It is said that seventy-five percent of us have a dominant visual memory, twenty-five percent an auditory one. As for me, mine is quite visual. When I think about mathematical ideas, I see the abstract notions in symbolic pictures. They are visual assemblages, for example, a schematized picture of actual sets of points on a plane. In reading a statement like “an infinity of spheres or an infinity of sets,” I imagine a picture with such almost real objects, getting smaller, vanishing on some horizon.

It is possible that human thought codes things not in terms of words or syllogisms or signs, for most people think pictorially, not verbally. There is a way of writing abstract ideas in a kind of shorthand which is almost orthogonal to the usual ways in which we communicate with each other by means of the spoken or written word. One may call this a “visual algorithm.”

The process of logic itself working internally in the brain may be more analogous to a succession of operations with symbolic pictures, a sort of abstract analogue of the Chinese alphabet or some Mayan description of events — except that the elements are not merely words but more like sentences or whole stories with linkages between them forming a sort of meta- or super-logic with its own rules.

For me, some of the most interesting passages about the connections between the problem of time, as involved in the memory, and the physical or even mathematical meaning of it, whether it is classical or relativistic, were written, not by a physicist or a neurologist or a professional psychologist, but by Vladimir Nabokov in his book Ada. Some utterances by Einstein himself, as quoted in his biographies, show the great physicist’s wonder at what living in time means, since we experience only the present. But, in reality, we consist of permanent and immutable world lines in four dimensions.

With such thoughts and worries about the thinking process, I was recovering my physical strength during this period of convalescence. What comforted me the most was the receipt of an invitation to attend a secret conference in Los Alamos in late April. This became for me a true sign of confidence in my mental recovery. I could not be told on the telephone or by letter what the conference was about. Secrecy was most intense at that time, but I guessed correctly that it would be devoted to the problems of thermonuclear bombs.

The conference lasted several days. Many friends were present. Some had been directly involved, like Frankel, Metropolis, Teller, and myself; others were consultants, like von Neumann. Fermi was absent. The discussions were active and inquisitive. They began with a presentation by Fraenkel of some calculations on the work initiated by Teller during the war. They were not detailed or complete enough and required work on computers (not the MANIACs but other machines in operation at the Aberdeen Proving Grounds). These were the first problems attacked that way.

The promising features of the plan were noticed and to some extent confirmed, but there remained great questions about the initiation of the process and, once initiated, about its successful continuation.

(All this was to have great importance in a later lawsuit between Sperry Rand and Honeywell over the validity of patents involving computers. The claim was that computers were already in the public domain then because the government of the United States used them and therefore the patents granted later were invalid. I was one of many who were called to testify on this in 1971.)

I participated in all the Los Alamos meetings. They lasted for hours, mornings and afternoons, and I noticed with pleasure that I was not unduly tired.

I remember telling Johnny about my illness. “I was given up for dead,” I said, “and thought myself that I was already dead, except for a set of measure zero.” This purely mathematical joke amused him, he laughed and asked, ’’What measure?”

Edward Teller and Johnny were often together, and I joined them in private talks.

In one conversation they discussed the possibility of influencing the weather. They had in mind global changes, while I proposed more local interventions. For example, I remember asking Johnny whether hurricanes could not be diverted, attenuated, or dispersed with nuclear explosions. I wasn’t thinking of a point source, which is symmetrical, but several explosions in a line. I reasoned that the violence and enormous energy of a hurricane lies on top of a mass of air (the weather) which itself moves gently and slowly. I wondered if one could not, even ever so slightly, change its course in time and in trajectory on the slowmoving overall weather, thus making it avoid populated areas. There are, of course, many questions and objections about such an undertaking. One of the necessary conditions would be to make detailed computations on the course of the motion of the air masses, calculations which do not exist even now. Through the years Johnny and I occasionally talked about this with experts in hydrodynamics and meteorology.

The conference over, I returned to Los Angeles. Upon alighting from the plane, two FBI agents approached me, showed their identification and asked for permission to search my luggage. A copy of the very secret Metropolis and Frankel report was missing, and they wondered if I might have taken it by mistake. We searched, but I did not have it. Later I learned that everybody who had attended the conference had been contacted. The authorities were very nervous, for this was potentially of grave consequence. The missing document reappeared much later among some of Teller’s papers in a Los Alamos safe.

The time was rapidly approaching when I could resume teaching, but I was developing strongly negative feelings about Los Angeles. Rides through the streets where I had been driven in an ambulance reminded me of my recent illness. My feelings toward the University were colored by this, as well, and I was dissatisfied. I felt impatiently that it was not changing quickly enough from a glorified high school into a genuine institution of higher learning. I had disagreements with a dean about building up the academic level and increasing the staff. I was told he joked that he almost had a heart attack every time he saw me, even from a distance, so afraid was he that I was bringing him new proposals for expansion!

The best part of the University was the Hancock Library. It had an impressive building and some good books — but the building was better than the collection inside. The University had just acquired an old municipal library from Boston, and when I learned what it contained, I compared it to a priceless collection of hundredyearold Sears Roebuck catalogues. This sarcastic remark probably did not enhance my popularity.

Even though I had friends like Donald Hyers, and some new acquaintances among mathematicians, physicists, and chemists, with this growing disenchantment I wanted to leave. The Los Angeles experience had not been satisfactory.

Just then I received a telegram inviting me to return to Los Alamos in a better position and at a higher salary. It was signed by Bob Richtmyer and Nick Metropolis. Richtmyer had become head of the theoretical division.

This offer to return to Los Alamos to work among physicists and live once again in the exhilarating climate of New Mexico was a great relief for me. I replied immediately that I was interested in principle. When the telegram arrived at the laboratory, it read that I was interested “in principal.”

Chapter 10. Back at Los Alamos

1946–1949

Los Alamos was at about the lowest point in its existence. Yet on returning I found that there were a number of people who had decided to stay on and that the government wanted to keep the laboratory going and have it flourish. The laboratory was to continue studies and the development of atomic bombs.

After the war there was, of course, the question of possible new wars and the weaponry of the future. I was in favor of continuing strong armament policies if only not to run the risk of being overtaken by other nations. Johnny and others were apprehensive about Russia’s ability to obtain or to develop nuclear bombs, and about its intentions towards Western Europe. He was quite hawkish at that time (the words “hawks” and “doves” were not yet in use). He thought along the old historical lines of rivalries, power struggles, coalitions; he was for a Pax Americana more than some of our other physicist friends. He also foresaw early that the essential military problems would shift from the bombs themselves and their sizes and shapes to ways to deliver them — that is to say, to rocketry.

My own position was sort of halfway between him and the physicists who hoped to internationalize nuclear weapons. I thought it was naive to expect that the wolves would lie down with the lambs and felt that meaningful international agreements would take many years. One could not hope for an instant change in attitudes or in human nature itself. I distrusted the idea of the Atlantic Union as then proposed, feeling that some of the propaganda for it was too transparent. The hegemony disguised thinly under a general organization would merely raise fears and new hysterical reactions from the other side. However, I failed to realize fully the immense importance of nuclear armament and the influence it would have on the course of world events. One bomb, I told myself, was equal to a thousandplane raid. Yet I did not realize that the power of each such bomb could be still vastly increased, and that it was possible to manufacture thousands of them. This realization came later. I felt no qualms about returning to the laboratory to contribute to further studies of the development of atomic bombs. I would describe myself as having taken a middle course between completely naive idealism and extreme jingoism. I followed my instincts (or perhaps lack of instincts) and was mainly interested in the scientific aspects of the work. The problems of nuclear physics were very interesting and led into new regions of physics and astrophysics. Perhaps I also felt that technological sequels to scientific discoveries were inevitable. Finally I trusted the ultimate good sense of humanity. The Atomic Energy Act, as finally adopted, was much more satisfactory than the initial proposals which would have left the developments of atomic energy under the sole and complete control of the military. Françoise felt more dubious morally on instinctive and emotional grounds. I always felt that it was unwise for the scientists to turn away from problems of technology. This could leave it in the hands of dangerous and fanatical reactionaries. On the other hand, the idea of merely multiplying the number of bombs to infinity made no sense whatsoever since a small fraction of the stockpile would be sufficient to destroy all population centers on the globe even if it was assumed that a majority of the missiles failed to reach their targets. I also did not believe that Russia would invade Western Europe. This was one of the supposed reasons for superrearmament. From the Russian point of view, it seemed to me there was no possible advantage. Seeing that even in Poland, the Russians had trouble maintaining the regime, I could not see any gain for them in making West Germany communistic. On the contrary, if all of Germany were reunited under communism, it would have presented a tremendous threat to Russia. A united communist Germany would inevitably have tried to become “boss” of the communist world.

Upon our return to Los Alamos, we were given a different wartime apartment and remained in it only a few months. Jack Calkin, who was still there, lived across the street. The Hawkinses were also quite near, but were preparing to leave soon. Our resumption of a more natural, if more Spartan mode of life was a refreshing change from the rather artificial Los Angeles atmosphere.

As it turned out, I had not quite recovered all my strength from the severe illness. During the first few weeks I was back, I became tired after working only two or three hours in my office. Fortunately, this disappeared gradually, and I began to feel normal again. Apart from everything else, this illness had been a financial catastrophe. It had left me with a debt of about five thousand dollars in spite of health insurance. When, in Los Angeles, it appeared that I might die or remain permanently disabled or diminished, several of our Los Alamos friends and even persons who were merely acquaintances lent money to Françoise. This touched us very deeply. I repaid them as fast as I could. The rest took several years.

At that time, Adam, my brother, was brilliantly concluding his studies at Harvard, and came to visit us in Los Alamos. I, who had been conditioned by the prewar scarcity of jobs, was pessimistic about his chances of finding one. When I asked him what his plans were, he answered, “I’ll get an instructorship, of course.” I felt dubious. He must have read the skepticism in the expression on my face, because I saw in his eyes that he took me for a pessimistic old dodo. He was right, because he immediately obtained an instructor’s position at Harvard and has remained there ever since. He became an eminent professor of government, and is now director of the Center for Russian Studies. He is also a prolific and successful author of books on the history of communism. Among his best known are biographies of Lenin and Stalin.

Early in 1948 we had the opportunity to move to a wing of a house on “bathtub row” which had become vacant. We remained there until we left Los Alamos twenty years later. This was a group of some five or six houses which dated from the Los Alamos Ranch School days. They were the only houses with bathtubs — all the other structures had showers. During the war, these prize dwellings had been reserved for the director and other dignitaries. Fermi, Bethe, Weisskopf, and other important scientists had lived in the modest temporary wartime constructions.

This house was located directly across from the remodeled Lodge which served as the town’s hotel for VIPs and official visitors. We benefited enormously from this proximity. All our friends and acquaintances visiting Los Alamos were only a few steps away. It was easy for them to visit for a drink, a casual meal, or an hour spent on our terrace. Françoise called our house the Lodge annex. On their frequent visits to Los Alamos, Johnny and Klari particularly liked living in a little cottage just next door to our yard. The informality of all these get-togethers contributed a great deal to the pleasantness of our life in Los Alamos. No end of scientific, political and personal conversations took place there. A whole book could be written about them.

Bob Richtmyer had replaced Bethe as leader of the theoretical division. He took the place of Placzek, who had held the post for a few months after the war’s end. I had met Richtmyer during the war when he visited Los Alamos periodically from Washington where he worked in the patent office. He was tall, slim, intense, very friendly, and obviously a man of great general intelligence. He was interested in many areas of mathematics and mathematical physics. Later we learned about his intense musical interests, his great linguistic talents, and his specialized skills. For example, he was very good in cryptography. But he was so extremely reserved that I found it difficult to know him intimately even though we were and are on very friendly terms.

Norris Bradbury had replaced Oppenheimer as director of the laboratory. I had met him only briefly during the war. He was a pleasant, straightforward, matteroffact younger man, eager to take on the responsibility for continuing this extremely important work, even though he realized that it was not easy to step into the shoes of Robert Oppenheimer who was in the process of becoming a legendary figure.

Norris deserves all the credit for rescuing the project from a slow decline into a mere “ballistics” lab. It could easily have shrunk into the narrow confines of a weapons arsenal, not unlike some that remained in the California desert. Under his management the intellectual and technological level of the laboratory began to pick up slowly but surely. It became a solid and permanent place staffed by good scientists, with an increasingly broader range of interesting scientific problems and the fantastic prospects of atomic-age technology. (Now, under Harold Agnew’s direction, even more so.)

Norris was rather diffident in his approach to the scientists who had left. He felt that they should recognize by themselves how important for the country and the world it was for them to come back. As a result, although he wanted to, he did not like to ask people like Fermi or Bethe or Teller to visit. It was actually left to me, with his consent, to write such invitations, along with Carson Mark and Richtmyer. Thus, in a way I was instrumental in bringing Teller back to Los Alamos.

The laboratory began to expand again. The realization of the political importance of nuclear energy for peace and of nuclear weapons for defense made it again a most prominent vital spot in national affairs. High government officials were again frequent visitors. Jim Fisk, a former Junior Fellow at Harvard and friend of mine who had become involved in atomic energy activities and was high up in the Bell Telephone Research Labs, was one of them.

During the von Neumanns’ visits, we made excursions to Santa Fe and surrounding spots, frequently eating in the small local Spanish-American restaurants.

On the road to Santa Fe, each time we drove by a place called Totavi (really more a name than a place), I would launch into Latin and recite, “Toto, totare, totavi, totatum,” and he would add some form of the future. This was one of our nonsensical verbal games. Another childish one was to read road signs backwards. Johnny always read “pots” for stop” or ’’otla” for “alto” in Mexico.

Another game Johnny and Klari liked to play on that road was the Black Mesa game. Black Mesa was an Indian landmark in the Rio Grande Valley which was visible on and off on the way down from Los Alamos. The first one who spotted it called the other’s attention by exclaiming “Black Mesa!” and scored a point. The game went on from journey to journey, points being scored as in tennis with games and sets. They never seemed to forget from one trip to the next what the score was. Johnny always liked these brief verbal distractions from serious concentrated thought.

In the early years after the war, the AEC started to build an elegant, permanent structure for its offices and those of the security services, even before new and more comfortable housing was ready for the residents. Johnny remarked that this was entirely in the tradition of all government administrations through the ages, and he decided to call the building “El Palacio de Securita.” This was a good enough mixture of Spanish, Latin and Italian. So to go him one better, I immediately named a newly built church “San Giovanni delle Bombe.”

This is about the time we made up a “Nebech index.” Johnny had told me the classic story of the little boy who came home from school in pre-World-War-I Budapest and told his father that he had failed his final examination. The father asked him, “Why? What happened?” The boy replied, “We had to write an essay. The teacher gave us a theme: the past, the present, and the future of the Austro-Hungarian Empire.” The father asked, “So, what did you write?’’ and the boy answered, “I wrote: Nebech, nebech, nebech.” “That is correct,” his father said. “Why did you receive an F?” “I spelled nebech with two bb’s,” was the answer.

This gave me the idea of defining the nebech index of a sentence as the number of times the word nebech could be inserted in it and still be appropriate, though giving a different flavor to the meaning of the sentence according to the word it qualifies. For instance, one could argue that the most perfect “nebech three” sentence is Descartes’ statement: Cogito, ergo sum. One can say, Cogito nebech, ergo sum. Or Cogito, ergo nebech sum. Or Cogito, ergo sum nebech. Unfortunately this elegant example occurred to me only after Johnny’s death. Johnny and I used this index frequently during mathematical talks, physics meetings or political discussions. We would nudge one another, whisper “Nebech two” at a particular statement, and enjoy this greatly.

Now, if the reader is sufficiently mystified, I will explain that “nebech” is an untranslatable Yiddish expression, a combination of commiseration, scorn, drama, ridicule.

To try to give the flavor of the word, imagine the William Tell story as acted out in a Jewish school. In the scene where William Tell waits in hiding to shoot Gessler, an actor says, in Yiddish: “Through this street the Nebech must come.” It is obvious that Gessler is a Nebech since he will be the victim of William Tell. But if nebech had been in front of the word street, then the accent would be on street, indicating that it was not much of a street. To appreciate this may take years of apprenticeship.

Some months after I returned to Los Alamos, I invited my old friend and collaborator from Madison, C. J. Everett, to join me in the laboratory. He had remained in Madison through the war; I knew from our correspondence that he was getting tired of teaching, so I proposed to him to visit and renew our collaboration. He was the first and only person ever to arrive in Los Alamos by bus for an official interview. The project always paid for a roomette on the train, or plane fare, and his modesty caused a sensation. Shortly after the interview, he moved to Los Alamos with his wife and son and there began the continuation of our collaboration in probability theory and other mathematics, then our joint work on the H-bomb.

In Madison he was already a shy and retiring man, but as time passed he became more and more of a recluse. In the early days of his stay in Los Alamos, although he was reluctant to mingle with people, he could still be coaxed into coming to our house if one made the solemn promise that no one else would be there at the same time. Later he even refused to do that, and now the only place one can see him is in his little windowless cubicle of an office or in a carrel in the excellent laboratory library.

One of the laboratory routines was the preparation of a monthly progress report. Every staff member had to turn in a brief résumé of his work and research activity. I have already said that Everett had a very excellent sense of humor, and one month when we had been exceedingly busy with our own work he turned in a report which said only, “Great progress was made on last month’s progress report.”

Two seminar talks I gave shortly after my return turned out to have good or lucky ideas and led to successful further developments. One was on what was later called the Monte Carlo method, and the other was about some new possible methods of hydrodynamical calculations. Both talks laid the groundwork for very substantial activity in the applications of probability theory and in the mechanics of continua.

The hydrodynamical calculations were for problems in which there was no hope for closed formulae or explicit classical analysis solutions. They could be described as a sort of “brute force” calculations using fictitious “particles” that were really not the fluid elements but abstract points. Instead of considering individual material points of the fluid, it was a matter of’ using the coefficients of an infinite series into which the continuum was developed as abstract particles for a global description of the fluid. The whole motion is described by some infinite series whose terms are successively less important. Considering only the first few of them, one changed the partial differential equations of several variables (or the integral equations in several variables) into ordinary or totally different equations for a finite number of abstract “particles.’’ Some years later, the work of Francis Harlow in Los Alamos deepened, enlarged, and multiplied the scope of this approach to the calculations of motions of fluids or of compressible gases. These are now widely used. The possibilities of such methods have not yet been exhausted; they could play a great role in the calculations of air movements, weather prediction, astrophysical problems, problems of plasma physics, and others.

The second talk was on probabilistic calculations for a class of physical problems. The idea for what was later called the Monte Carlo method occurred to me when I was playing solitaire during my illness. I noticed that it may be much more practical to get an idea of the probability of the successful outcome of a solitaire game (like Canfield or some other where the skill of the player is not important) by laying down the cards, or experimenting with the process and merely noticing what proportion comes out successfully, rather than to try to compute all the combinatorial possibilities which are an exponentially increasing number so great that, except in very elementary cases, there is no way to estimate it. This is intellectually surprising, and if not exactly humiliating, it gives one a feeling of modesty about the limits of rational or traditional thinking. In a sufficiently complicated problem, actual sampling is better than an examination of all the chains of possibilities.

It occurred to me then that this could be equally true of all processes involving branching of events, as in the production and further multiplication of neutrons in some kind of material containing uranium or other fissile elements. At each stage of the process, there are many possibilities determining the fate of the neutron. It can scatter at one angle, change its velocity, be absorbed, or produce more neutrons by a fission of the target nucleus, and so on. The elementary probabilities for each of these possibilities are individually known, to some extent, from the knowledge of the cross sections. But the problem is to know what a succession and branching of perhaps hundreds of thousands or millions will do. One can write differential equations or integral differential equations for the “expected values,” but to solve them or even to get an approximative idea of the properties of the solution, is an entirely different matter.

The idea was to try out thousands of such possibilities and, at each stage, to select by chance, by means of a “random number” with suitable probability, the fate or kind of event, to follow it in a line, so to speak, instead of considering all branches. After examining the possible histories of only a few thousand, one will have a good sample and an approximate answer to the problem. All one needed was to have the means of producing such sample histories. It so happened that computing machines were coming into existence, and here was something suitable for machine calculation.

Computing machines came about through the confluence of scientific and technological developments. On one side was the work in mathematical logic, in the foundations of mathematics, in the detailed study of formal systems, in which von Neumann played such an important role; on the other was the rapid progress of technological discoveries in electronics which made it possible to construct electronic computers. They, in turn, provided such a quantitative increase in the speed of operation so much greater than the mechanical relay machines that it produced a qualitative change and vastly improved and enlarged the use of the tool. The results are now known to everyone: computers introduced a new age in heuristic research, in communication, and in making the space age possible.

The number of applications in exact science, in the natural sciences, and in everyday life is so great that one can talk of “the age of computers and automata” as having begun.

At that time the computers were merely in statu nascendi. As a joke I proposed to make Monte Carlo calculations by hiring several hundred Chinese from Taiwan, gather them on a boat, have each one sit with an abacus, or even just pencil and paper, and make them produce the random numbers by some actual physical process like throwing dice. Then someone would collect the results, and total the statistics into single answers.

Von Neumann played a leading role in the launching of electronic computers. His unique combination of gifts, his interests, and traits of character suited him for that role. I am thinking of his ability, and inclination to go through all the tedious details of program planning, of executing the minutiae of putting very large problems in a form treatable by a computer. It was his feeling for and knowledge of the details of mathematical logic systems and the theoretical structure of formal systems that enabled him to conceive of flexible programming. This was his great achievement. By suitable flow diagramming and programming, an enormous variety of problems became calculable on one machine with all connections fixed. Before his invention one had to pull out wires and reconnect plug boards each time a problem was changed.

The Monte Carlo method came into concrete form with its attendant rudiments of a theory after I proposed the possibilities of such probabilistic schemes to Johnny in 1946 during one of our conversations. It was an especially long discussion in a government car while we were driving from Los Alamos to Lamy. We talked throughout the trip, and I remember to this day what I said at various turns in the road or near certain rocks. (I mention this because it illustrates what may be multiple storing in the memory in the brain, just as one often remembers the place on the page where certain passages have been read, whether it is on the left- or right-hand page, up or down, and so on.) After this conversation we developed together the mathematics of the method. It seems to me that the name Monte Carlo contributed very much to the popularization of this procedure. It was named Monte Carlo because of the element of chance, the production of random numbers with which to play the suitable games.

Johnny saw at once its great scope even though in the first hour of our discussion he evinced a certain skepticism. But when I became more persuasive, quoting statistical estimates of how many computations were needed to obtain rough results with this or that probability, he agreed, eventually becoming quite inventive in finding marvelous technical tricks to facilitate or speed up these techniques.

The one thing about Monte Carlo is that it never gives an exact answer; rather its conclusions indicate that the answer is so and so, within such and such an error, with such and such probability — that is, with probability differing from one by such and such a small amount. In other words, it provides an estimate of the value of the numbers sought in a given problem.

I gave a lot of “propaganda” talks for this method all over the United States. Interest and improvements in the theory came rapidly. Here is an easy example of this procedure which I often selected: One may choose a computation of a volume of a region defined by a number of equations or inequalities in spaces of a high number of dimensions. Instead of the classical method of approximating everything by a network of points or cells, which would involve billions of individual elements, one may merely select a few thousand points at random and obtain by sampling an idea of the value one seeks.

The first questions concerned the production of the random or pseudo-random numbers. Tricks were quickly devised to produce them internally in the machine itself without relying on any outside physical mechanism. (Clicks from a radioactive source or from cosmic rays would have been very good but too slow.) Beyond the literal or “true” imitation of a physical process on electronic computers, a whole technique began to develop on how to study mathematical equations which on their face seem to have nothing to do with probability processes, diffusion of particles, or chain processes. The question was how to change such operator equations or differential equations into a form that would allow the possibility of a probabilistic interpretation. This is one of the main theses behind the Monte Carlo method, and its possibilities are not yet exhausted. I felt that in a way one could invert a statement by Laplace. He asserts that the theory of probability is nothing but calculus applied to common sense. Monte Carlo is common sense applied to mathematical formulations of physical laws and processes.

Much more generally, electronic computers were to change the face of technology. We discussed the many possibilities endlessly. But not even von Neumann could foresee their full economic or technological impact. These aspects of their development were still in their infancy so far as industrial applications were concerned when he died in 1957. Little did we know in 1946 that computing would become a fifty-billion-dollar industry annually by 1970.

Almost immediately after the war Johnny and I also began to discuss the possibilities of using computers heuristically to try to obtain insights into questions of pure mathematics. By producing examples and by observing the properties of special mathematical objects one could hope to obtain clues as to the behavior of general statements which have been tested on examples. I remember proposing in 1946 a calculation of a very great number of primitive roots of integers so that by observing the distributions one obtained enough statistical material on their appearance and on the combinatorial behavior to perhaps get some ideas of how to state and prove some possible general regularities. I do not think that this particular program has been advanced much until now. (In mathematical exploratory work on computers my collaborators were especially Myron Stein and Robert Schrandt.) In the following years in a number of published papers, I have suggested — and in some cases solved — a variety of problems in pure mathematics by such experimenting or even merely “observing.” The Gedanken Experimente, or Thought Experiments, of Einstein are possible and often useful in the purest part of mathematics. One of the papers outlining a field of exploration in “non-linear problems” was written in collaboration with Paul Stein. By now, a whole literature exists in this field.

Quite early, in fact only some months after the electronic computer called MANIAC became available in Los Alamos, I tried with a number of associates (Paul Stein, Mark Wells, James Kister, and William Walden) to code the machine to play chess. It was not so terribly difficult to code it to play correctly according to the rules. The real problem is that, even today, nobody knows how to put in its memory experiences of previous games and a general recognition of the quality of patterns and positions. Nevertheless it can be made to play so it can beat a rank amateur. We realized that the differences between playing poorly and playing well are much greater than teaching it to make legal moves and respond to obvious threats, and so on. This game was played on a six-by-six board without bishops (to shorten the time between moves). We wrote an article that appeared in the U.S. Chess Review and was soon reprinted by a Russian chess magazine. Stein, originally a physicist, “converted” to mathematics and became one of my closest collaborators.

Curiously the patterns of chess remind me of oriental rugs and also of something that laymen won’t understand — very complicated non-measurable sets. I think I am a fair chess player. When I first came to this country I played with other mathematicians for relaxation. In Los Alamos during the years after the war, friends and younger colleagues organized a chess club, and I played many games. The Los Alamos chess team on which I played board number one several times beat Santa Fe and even Albuquerque with their populations respectively three and fifteen times that of Los Alamos.

It was in 1949, after Teller’s return, that George Gamow, whom I had met briefly in Princeton before the war, came to Los Alamos for a lengthy visit. He was on a year’s leave from George Washington University in Washington. In physical appearance he was quite an impressive man, six feet three inches tall, slim in 1937 (by 1949 heavy set), blond, blue-eyed, youthful looking, full of good humor. He had a very characteristic shuffling way of’ walking with mincing steps. He was very different from the popular picture of the specialized, scholarly scientist — not at all the standard type of academic personage. There was nothing dry about him. A truly “three-dimensional” person, he was exuberant, full of life, interested in copious quantities of good food, fond of anecdotes, and inordinately given to practical jokes.

Almost at once we became friends and engaged in interminable discussions. In some ways our temperaments matched. He found something congenial in my way of thinking (or not thinking) about problems of physics along standard lines. He liked to approach different problems from many different directions in an unassuming, direct, and original way. He talked about himself a great deal. Generally he was one of the most egocentric persons I have known, yet paradoxically (because this combination is so rare) he was at the same time completely devoid of malice towards others.

It was he (and Edward U. Condon, independently and almost simultaneously), who started theoretical nuclear physics in a 1928 paper on the quantum theoretical explanation of radioactivity. In scientific research, he concentrated on a few given problems over a period of years, returning to the same questions time and again.

Banach once told me, “Good mathematicians see analogies between theorems or theories, the very best ones see analogies between analogies.” Gamow possessed this ability to see analogies between models for physical theories to an almost uncanny degree. In our ever-more-complicated and perhaps oversophisticated uses of mathematics, it was wonderful to see how far he could go using intuitive pictures and analogies from historical or even artistic comparisons. Another quality of his work was the nature of the topics with which he dealt. He never allowed his facility to carry him away from the essence of his subject in pursuit of unimportant details and elaborations. It was along the great lines of the foundations of physics, in cosmology, and in the recent discoveries in molecular biology that his ideas played an important role. His pioneering work in explaining the radioactive decay of atoms was followed by his theory of the explosive beginning of the universe, the “big bang” theory (he disliked the term by the way), and the subsequent formation of galaxies. The recent discovery of the radiation pervading the universe, corresponding to a temperature of some three degrees absolute, seems to confirm his prediction in 1948 concerning residual radiation from the big bang about ten billion years ago. This discovery came after his death in 1968.

Gamow, who was a complete layman in the field of biology (some of his detractors would say almost a charlatan), proposed, with his fantastically unerring instinct, some ideas about how the code really worked. I think he was the first to suggest that the sequence of the four substances of the DNA denoted by the letters A, C, T, G, expressed words, and how from these four letters one could build twenty or twenty-three amino acids which, in turn, considered as words, combined into phrases defining the structures of proteins. Gamow had this idea before anyone else. He even almost had the correct way (later found by Crick) of expressing the formation by triplets. At first he thought four were necessary. He was almost correct from the start.

One may see in his work, among other outstanding traits, perhaps the last example of amateurism in science on a grand scale.

An overwhelming curiosity about the scheme of things in nature, in the very large and in the very small, directed his work in nuclear physics and in cosmology.

The meaning, the origin and perhaps the variability in time of the fundamental physical constants like c (the velocity of light), h (the Planck constant), G (the gravitation constant) occupied his imagination and his efforts during the last years of his life.

The great unanswered questions concern the relations between masses of elementary particles and also the very large numbers which are the ratios between the nuclear, electrical, and gravitational forces. Gamow thought that these numbers could not have arisen as a result of an initial accident, and that they might be obtainable from topological or number-theoretical considerations. He believed in the final simplicity of a theory which one day would explain these numbers.

The French fictional detective Arsène Lupin, arch rival of Sherlock Holmes, said: “Il faut commencer à raisonner par le bon bout.” (You have to start thinking from the right end.) Gamow had a particularly great gift for this. He used models or similes; speaking mathematically he was guided by isomorphisms or homomorphisms. Abstruse ideas of quantum theory and the more palpable ideas between structures of classical physics were transformed or transfigured, not just by repetition, but by going to variables of higher time, to use technical mathematical terms again.

In 1954 Gamow and I happened to be in Cambridge, Massachusetts, at the same time. I was telling him about some of my speculations on the problems of evolution and the possibilities of calculating the rate of evolution of life. One day he came to see me and said: “Let’s go to Massachusetts General Hospital — there is an interesting biology seminar.” And we drove in his Mercedes. On the way I asked him who was talking. He said, “You are!” Apparently he had told the professors running the seminar that we would both talk about these speculations. And indeed we both did. On the way home I remarked, “Imagine, George, you and me trying to talk about biology! All these people, all these doctors in white smocks — they were ready to put us in straitjackets.”

In conversations during the last few months of his life he often returned to the consideration of schemata that might possibly throw light on the mystery of the elementary particles and the constants of physics. In a dream he had, which he related to his wife, Barbara, shortly before his death, he described the tantalizing experience of being in the company of such great spirits as Newton and Einstein and of discovering, as they had discovered, the extreme simplicity of the ultimate scientific truths.

At the same time that he delighted in cutting to the heart of things, he kept track of all his mundane activities in a very detailed and systematic way. From the first time I met him to the end, when we were both professors on the same campus in Boulder, I remember his collecting and putting in order all manner of snapshots and pictures of his various activities, markers as it were of scientific progress, vacation trips, discussions with friends. He also loved to compose photo-montages combining his own drawings with photographic cut-outs. These were intended as illustrations or caricatures of scientific discoveries.

All his writings are characterized by a natural flow of ideas, a simple uninvolved presentation, and an easy, never redundant, amusing but never frivolous style. He wrote easily, quickly, hardly ever rewriting, filling innumerable pages, each with only a few lines handwritten in enormous characters.

His now classic books on the history of physics and on the new ideas in the physical sciences show him to have been without malice or harsh judgment towards fellow physicists. He was sparing with real praise, reserving it only for the great achievements, but he never criticized or even pointed out mediocrity.

His popular books on science received great acclaim. Among the outstanding qualities of these works are simplicity of approach and the avoidance of unnecessary technical details that also distinguished his work in research.

His honesty made him write exactly the way he thought, embodying the precept of Descartes: ’’ordering one’s thoughts to analyze the complex by dissecting it into its simpler parts.”

One characteristic of Gamow, which was not perhaps directly visible but was easily deducible from his conversation and his creative activity, was his excellent memory. After dinner or at parties he loved to recite for the benefit of friends of Slavic origin long excerpts of Russian poetry; he could quote Pushkin or Lermontov by the hour. He also loved to use Russian proverbs.

Gamow had a ready wit and made many bons mots. He told me that the day he drove to Los Alamos for the first time, he noticed that “as one crosses the Rio Grande, and before one arrives at the Valle Grande [the Valle Grande is an extinct volcano of enormous dimensions in the mountains behind Los Alamos], one comes to the city of the Bomba Grande.”

In 1949 my approaching fortieth birthday appeared as a threatening landmark in my life. I always considered it ominous to be slipping into middle age. One’s feelings about age change with time, of course, but mathematicians have a reputation for peaking early, and many, myself included, have an admiration for youth. This Hellenic accent on youth is also something of an American obsession. From my earliest reading I admired Abel, the Norwegian genius who died at twenty-seven, and Galois, the creator of new ideas in algebra and group theory who died in a duel in Paris at the age of twenty-one. The greatest achievements of middle-aged men did not touch me as much. The tragedy, of course, is that as one gets older one tends to try to use old tricks in new situations; a sort of self-poisoning stops creativity. My friend Rota said he did not believe it was creativity that stopped but interest. That remark sparked a feeling of déjà vu. I agree in part. Maybe it is like boxing: it is not that the reactions slow down or that one is more easily fatigued; when boxers start having to think about what they are doing, they lose, because the reaction should be instinctive, quick automatic subroutines, so to speak.

Johnny used to say that after the age of twenty-six a mathematician begins to go downhill. When I met him he was just past that age. As time went on he extended the limit, but kept it always a little below his age. (For example, when near forty, he raised it to thirty-five.) This was characteristic of his rather self-effacing manner. He did not want to give the appearance of considering himself “in.” He knew that self-praise sounds ridiculous to others, and he would lean over backwards to appear modest. I, on the contrary, always took pleasure in boasting, especially about some of my own trivial accomplishments like athletics or winning at games. Children boast quite naturally. In the literature of antiquity, notably in Homer, heroes brag openly about their athletic prowess. Scientists sometimes boast by implication when they criticize or minimize the achievements of others.

Approaching forty and thinking about what I had accomplished up to that point, I was still very hopeful that much work lay ahead of me. Perhaps because much of what I had worked on or thought about had not yet been put in writing, I felt I still had things in reserve. Given this optimistic nature, I feel this way even now when I am past sixty.

Chapter 11. The “Super”

1949–1952

I was returning to Los Alamos from one of my frequent trips east when our monitoring systems detected the Russian A-bomb explosion. The news had not yet been made public. Immediately upon my arrival several friends — Metropolis, Calkin, and others — who met me at the little airport, greeted me with these items of news: (a) in a poker game the night before, Jack had won eighty dollars (an enormous sum for our kind of stakes), and (b) the Russians had detonated an atomic bomb. I considered this for a moment and said, of course, I believed (a). It was (b) that was true.

Johnny was in Los Alamos and he and Teller had been spending time together discussing this ominous development. I joined them in Johnny’s room at the Lodge. The general question was “What now?” At once I said that work should be pushed on the “super.” Teller nodded. Needless to say, that was on his mind also. They said they had been discussing how to go about it. The next day Teller left for Washington, perhaps to see Admiral Strauss, who was a member of the Atomic Energy Commission, to do what politicking he could there.

Strauss was one of the first AEC Commissioners. He was Jewish. Talking to him I noticed that he had the rather common — and to me pleasant — Jewish tendency to admire successful scientists. He possessed a sort of wistful appreciation of science, perhaps because he was not a scientist himself. In his early days on the Commission he had pushed for the development of a monitoring system to detect the presence of nuclear work anywhere in the world. This could be done by examining air samples from the atmosphere for the presence of certain gases which came from uranium fission. The idea came from Tony Turkevitch, a physical chemist from Chicago. I remember his mentioning such a plan in my presence in Los Alamos during the war.

To what extent Strauss’s counsel, influenced by Teller and von Neumann, contributed to President Truman’s decision to order full-speed work on the H-bomb, I do not know.

It has to be repeated here again that the work on the “super” had been going on efficiently and systematically. Norris Bradbury was directing the allocation of the theoretical effort. Some six months before this news from Russia, I mentioned to him that I had the impression that some people in Washington did not want this work to continue and Norris had said: “I’ll be damned if I’ll let anybody in Washington or any politicians tell me what work not to do.” I remember his smiling expression when he said it. This sentiment was not what is now called hawkish or motivated by political or military considerations; it referred purely to scientific and technological inquiry.

Theoretical work on the “super” had, as I have shown, continued all along after the “super” conference, but I do not think Teller wanted this publicized very much, for I think he either believed he was or wanted to be known as not only the main but the sole promoter, defender, and organizer of the work. Perhaps he felt that Bradbury, as head of the laboratory, would receive most of the credit for the future thermonuclear bomb, just as Oppenheimer had for the A-bomb, to the exclusion of the other scientists who had done the technical work. Indeed Teller had been and was the original proponent of intensive work on thermonuclear explosions in the United States.

This, of course, is my own interpretation of the reasons for the developments that followed. It may be substantiated in the existing literature, including the notorious Shepley-Blair account published in Life magazine, which contributed so much to the establishment of Teller as the “Father of the H-Bomb.” Their subsequent book was later discredited because of the misinformation it contained.

Shortly after President Truman’s announcement directing the AEC to proceed with work on the H-Bomb, E. O. Lawrence and Luis Alvarez visited Los Alamos from Berkeley and started discussions with Bradbury and then with Garnow, Teller, and myself about the ’feasibility of constructing a “super.” This visit played a part in the politics of this enterprise.

One of Teller’s first moves was to enlist a young physicist, Frédéric de Hoffmann, as his assistant. A native of Vienna, Freddy had come to the United States as a young boy before the war. He was young, clever, intelligent, and quick, but not what you might call a really original scientist. He became a sort of factotum, a jack of all trades for communications, contacts with administrators, and other duties. He carried Edward’s messages back and forth to Washington and also did some technical work. He was an ideal associate for Edward, who later could afford to be generous with credit for Freddy’s contributions, which would not detract from his own appearance as the almost exclusive originator, propagator, and executor of the project.

A first committee was formed to organize all work on the “super” and investigate all possible schemes for constructing it. The committee’s work was directed by Teller, as chairman, Gamow, and myself.

Several different proposals of ideas existed on how to initiate the thermonuclear reaction, using fission bombs as starter. One of Gamow’s was called “the cat’s tail.” Another was Edward’s original proposal. Gamow drew a humorous cartoon with symbolic representations of these various schemes. In it he squeezes a cat by the tail, I spit in a spittoon, and Teller wears an Indian fertility necklace, which according to Gamow is the symbol for the womb, a word he pronounced “vombb.” This cartoon has appeared among the illustrations in his autobiography, My World Line, published by The Viking Press in 1970.

Both Gamow and I showed a lot of independence of thought in our meetings, and Teller did not like this very much. Not too surprisingly, the original “super” directing committee soon ceased to exist. At a moment when both Gamow and I were out of town, Teller prevailed upon Bradbury to disband the committee and to replace it by another organizational entity. Gamow was quite put out by this. I did not care, but I wrote him, prophetically it seems, that great troubles would follow because of Edward’s obstinacy, his single-mindedness, and his overwhelming ambition. This letter, like all communications about work in Los Alamos, was “classified.” I expect it is still filed somewhere and perhaps some day may be included in some collection of documents from that period. Another such “indiscreet” letter is one I wrote to von Neumann in which I made fun of Edward’s attitude. This letter happens to be quoted in the second volume of the official history of the AEC, The Atomic Shield. In it I mention that an idea occurred to me which I had communicated to Edward. I added in jest that since Edward liked it very much perhaps that meant it would not work either.

At some time I outlined a possible detailed calculation which became the base of the work carried out by von Neumann on the newly built electronic computing machines with the help of Klari, as a programmer, and Cerda and Foster Evans, a husband-and-wife team of physicists who had joined the project after the war.

The wartime, or rather, immediate postwar Metropolis-Frankel calculation was very schematic compared to what I had in mind. More ambitious calculations of this sort had become possible since computers had improved both in speed and in the size of their memories. The steps outlined involved a fantastic number of’ arithmetical operations. Johnny said to me one day, “This computation will require more multiplications than have ever been done before by all of humanity.” But when I estimated roughly the number of multiplications performed by all the world’s school children in the last fifty years, I found that this number was larger by about a factor of ten!

Ours was the biggest problem ever, vastly larger than any astronomical calculation done to that date on hand computers, and it needed the most advanced electronic equipment available. By then von Neumann’s Princeton MANIAC was functioning and a duplicate version was being built in Los Alamos under the direction of Metropolis.

Still Teller kept on hinting that not enough work was being done on his original scheme for the ignition of the “super.” He kept insisting on certain special approaches of his own. I must admit that I became irritated by his insistence; in collaboration with my friend Everett one day I decided to try a schematic pilot calculation which could give an order of magnitude, at least, a “ballpark” estimate of the promise of his scheme.

Before we started this calculation of’ the progress of a thermonuclear reaction (burning in a mass of deuterium or deuterium-tritium mixture), Everett and I had done a lot of work on probability questions connected with the active assemblies of uranium and with neutron multiplications. We worked out a theory of multiplicative processes, as we called it. (Now the preferred name is “branching processes.”) This work followed the ideas developed in the report on branching processes written with David Hawkins during the war. But it elaborated, deepened, and extended them very greatly. The report of Hawkins and myself conisted of a few pages. The results of several months’ work with Everett were contained in three large reports of a hundred pages or more. The latter became the basis for much subsequent work, some of it done later independently by Russian and Czech scientists.

Within the formal organization of the laboratory, I was the leader of Group T-8, and Everett was its only member. Every day, in his office adjoining mine, we had done quite a lot of other mathematical work not necessarily connected with the current programmatic questions of Los Alamos and we would discuss the “universe” (Johnny’s expression), mathematical or otherwise.

Now we started to work each day for four to six hours with slide rule, pencil, and paper, making frequent quantitative guesses, and managed to get approximate results much more quickly than the gigantic problem, which was progressing slowly. Much of our work was done by guessing values of geometrical factors, imagining intersections of solids, estimating volumes, and estimating chances of points escaping. We did this repeatedly for hours, liberally sprinkling the guesses with constant slide-rule calculations. It was long and arduous work, the results of which gave a rather discouraging picture of the feasibility of the original “super” scheme. Our calculation showed its enormous practical difficulties and threw grave doubts on the prospects of Edward’s original approach to the initial ignition conditions of the “super.”

We proceeded something like this: each morning I would attempt to supply several guesses as to the value of certain coefficients referring to purely geometrical properties of the moving assembly involving the fate of the neutrons and other particles going through it and causing, in turn, more reactions. These estimates were interspersed with stepwise calculations of the behavior of the actual motions. The reader should realize that the real times for the individual computational steps were short, each less than a “shake,” and the spatial subdivisions of the material assembly very small in linear dimensions. Each step took a fraction of a “shake.” A “shake” was the name given in Los Alamos during the war to the time interval of 10-8 seconds. Another unit was that of a cross section called a “barn’’; it was 10–24 of a square centimeter, a terribly small area. The number of individual computational steps was therefore very large. We filled page upon page of calculations, much of it done by Everett. In the process he almost wore out his own slide rule, and when our results were achieved, after several months of work, Everett joked that “the grateful government could at least offer to buy him a new slide rule.” I do not know how many man-hours were spent on this problem.

To write the reports we enlisted the help of professional computers, Josephine Elliott among them. Even Françoise was pressed into service, grinding out untold numbers of arithmetical operations on desk calculators.

Lengthy as this process was, the work was finished several months before the Princeton electronic computer’s results started coming in. This so-to-speak homespun part of the H-bomb development was described in many official and popular accounts. It caught the public eye probably because of the certain appeal of its “man versus machine” element.

As our calculation progressed it naturally attracted quite a lot of attention among the physicists Teller was trying to interest in the “super” project, and also among those Bradbury had already enlisted for this work. Distinguished visitors would appear periodically to see how the calculations were going. John Wheeler’s first visits to Los Alamos date from about this period.

One day Fermi and Rabi came to our office, and we showed them the results which pointed to the mediocre progress of the reaction. These results could only be indicative and were by no means certain because of the crude approximations and guesses which we used in the place of voluminous numerical operations.

When it appeared that the technical difficulties of Teller’s original ideas could justify some of the scientific and political objections of certain physicists, and even perhaps the reluctance of the General Advisory Committee, Hans Bethe evidenced a renewed interest in the whole project and came to visit Los Alamos more often. With his wonderful virtuosity in mathematical physics and with his ability to solve analytical problems of nuclear physics he helped significantly. After all, it was Bethe who first suggested (Weizsäcker in Germany had reached the same conclusion independently) that nuclear reactions in the interior of the sun could be responsible for the sun’s energy generation and thus explain the radiation emitted by the sun and by other stars. Their original “carbon reaction mechanism” has been found not to be quite so exclusively responsible for the energy generation in all stars as was originally thought.

Teller was not easily reconciled to our results. I learned that the bad news drove him once to tears of frustration, and he suffered great disappointment. I never saw him personally in that condition, but he certainly appeared glum in those days, and so were other enthusiasts of the H-bomb project. Subdued and depressed, he would visit our offices periodically, and would attempt to prove us wrong by trying to find mistakes. Once he said, “There is a mistake here by a factor 104.” This especially annoyed Everett who did not have much self-confidence as a physicist but who, as a mathematician, amazingly enough never made mistakes. He used to say, “I never make mistakes” and this was true in that he never used a wrong sign or made simple numerical mistakes, as mathematicians often do. But each time he tried, Edward had to admit that it was he who was at fault in his arithmetic.

As the results of the von Neumann-Evans calculation on the big electronic Princeton machine slowly started to come in, they confirmed broadly what we had shown. There, in the course of the calculation, in spite of an initial, hopeful looking “flare up,” the whole assembly started slowly to cool down. Every few days Johnny would call in some results. “Icicles are forming,” he would say dejectedly.

These computations were the best one could do theoretically in those days. Because the existing experimental values for the constants which had to be applied in the calculations for the cross sections were uncertain, the project was still alive, but it was necessary to search for alternative approaches to ignition.

All along Johnny was emotionally involved in favor of the construction of an H-bomb. He hoped that in one way or another a good scheme would be found, and he never lost heart even when the mathematical results for the original approach were negative.

During this crucial period of uncertainty, I visited him in Princeton. Fermi happened to be there, too, on a brief visit, and we discussed the prospects all afternoon, during dinner in Johnny’s house, and all evening. The next day we talked with Oppenheimer. He knew about the results obtained by Everett and me. He seemed rather glad to learn of the difficulties, whereas von Neumann was still searching for ways to rescue the whole thing. Johnny outlined some hydrodynamical calculations. Fermi concurred. They came to estimate a certain velocity of expansion which seemed to me much too slow. With the experience of all the work I had done in the past months, I noticed that they had erred in assuming the density of liquid deuterium to be 1, whereas it is only a small fraction of 1. This error of per unit mass instead of per unit volume made the velocity appear indeed smaller and Johnny realized it and exclaimed: “Oh my! It is indeed much faster than a train.” Oppenheimer winked at me. He liked having the difficulties confirmed and enjoyed catching von Neumann and Fermi in a small and trivial arithmetic error.

My calculations with Everett concerned the first phase of the explosion, the problem of the initial ignition. An important part of the story has been overlooked in the official accounts and concerns some quite fundamental work that Fermi and I did following the first calculation of the progress of the reaction, its propagation and explosion. In numerous joint discussions we outlined the possibilities of propagation, assuming that some way or other (perhaps by the expenditure of large amounts of tritium) the initial ignition could be achieved. There again we had to use guesses in place of the enormously difficult detailed calculations that would have required computers even faster than those in existence. We did this again in time-step stages with intuitive estimates and marvelous simplifications introduced by Fermi.

The numerical work was done on desk computers with the assistance of a number of programmers from the laboratory’s computing group, managed by a good-humored New Yorker, Max Goldstein. Much to Max’s annoyance, Fermi wanted to encourage the girls to use slide rules; the machine precision was not really warranted because of our simplifications. But Max insisted on the usual routines with desk calculators. Reading from slide rules and using logarithms as Fermi did was much less accurate, but with his marvelous sense he had the ability to judge the right amount of’ accuracy which would be meaningful. The girls, who were merely making calculations without knowing the physics or general mathematics behind them, could not do that, of course, so in a way Max was quite right in insisting on the standard routines.

I particularly remember one of the programmers who was really beautiful and well endowed. She would come to my office with the results of the daily computation. Large sheets of paper were filled with numbers. She would unfold them in front of her low-cut Spanish blouse and ask, “How do they look?” and I would exclaim, “They look marvelous!” to the entertainment of Fermi and others in the office at the time.

A joint report was written by Fermi and myself. Enrico exercised very great caution in its conclusions. In fact, one conclusion stating the unpromising nature of the reaction as it was planned contained this sentence: “If the cross sections for the nuclear reactions could somehow be two or three times larger than what was measured and assumed, the reaction could behave more successfully.”

I believe this work with Fermi to have been even more important than the calculations made with Everett. It turned out to be basic to the technology of thermonuclear explosions. Fermi was satisfied with both its execution and with the fact that it put a limit to the size of such explosions. As he said: “One cannot make trees grow skyward indefinitely.”

In the meantime Teller continued to be very active both politically and organizationally at the moment when things looked at their worst for his original wartime “super” design, even with the modifications and improvements he and his collaborators had outlined in the intervening period.

Perhaps the change came with a proposal I contributed. I thought of a way to modify the whole approach by injecting a repetition of certain arrangements. Unfortunately, the idea or set of ideas involved is still classified and cannot be described here.

Psychologically it was perhaps precipitated by a memorandum from Darol Froman, an associate director of the laboratory, who asked various people what should be done with the whole “super” program. While expressing doubts about the validity of Teller’s insistence on his own particular scheme, I wrote to Froman that one should continue at all costs the theoretical work, that a way had to be found to extract great amounts of energy from thermonuclear reactions.

Shortly after responding I thought of an iterative scheme. After I put my thoughts in order and made a semi-concrete sketch, I went to Carson Mark to discuss it. Mark, who was by then head of the theoretical division, was already in charge of the very extensive theoretical work supporting Teller’s and Wheeler’s special groups. The same afternoon I went to see Norris Bradbury and mentioned this scheme. He quickly grasped its possibilities and at once showed great interest in pursuing it. The next morning, I spoke to Teller. I don’t think he had any real animosity toward me for the negative results of the work with Everett so damaging to his plans, but our relationship seemed definitely strained. At once Edward took up my suggestions, hesitantly at first, but enthusiastically after a few hours. He had seen not only the novel elements, but had found a parallel version, an alternative to what I had said, perhaps more convenient and generalized. From then on pessimism gave way to hope. In the following days I saw Edward several times. We discussed the problem for about half an hour each time. I wrote a first sketch of the proposal. Teller made some changes and additions, and we wrote a joint report quickly. It contained the first engineering sketches of the new possibilities of’ starting thermonuclear explosions. We wrote about two parallel schemes based on these principles. The report became the fundamental basis for the design of the first successful thermonuclear reactions and the test in the Pacific called “Mike.” A flurry of activity ensued. Teller lost no time in presenting these ideas, perhaps with most of the emphasis on the second half of our paper, at a General Advisory Committee meeting in Princeton which was to become quite famous because it marked the turning point in the development of the H-bomb. A more detailed follow-up report was written by Teller and de Hoffmann. New physicists were brought to Los Alamos, and work toward experimental verification started in earnest.

John Wheeler came to New Mexico to help Teller. He brought with him several of his brightest students. Among them was Ken Ford, with whom I was to do unrelated work later on. There was John Toll, now President of the State University of New York at Stony Brook, then a promising young physicist; Marshall Rosenbluth, who had been in Los Alamos during the war as a soldier with the SED; Ted Taylor, who contributed so many new ideas to atomic fission bombs; a brilliant mathematical physicist, Conrad Longmire; and other talented young people. Intense, fast work went on, and the plans for “Mike” were ready just a few months after our fateful conversation.

During their Los Alamos year, the Wheelers lived in a house next to ours and we saw them frequently. Wheeler was a very interesting type of physicist. To my mind, he had all the right desires for novelty in theoretical ideas without sticking too rigidly to preconceived notions and existing schemes. Sometimes he thought of outlandish-sounding schemes in physics or in cosmology, so much so that some of his ideas would strike me as lacking in an element of common sense or connection with possible experiments. Or perhaps they were, on the contrary, as Pauli once said about some ideas proposed by Heisenberg, “not crazy enough.” Wheeler’s great merit is his work on general relativity, pursued to extreme situations like black holes and beyond; he also has great didactical talents. Of his students, the best by far, I think, is Feynman. Long before, they wrote a very nice joint paper on a generalization of Mach’s principle.

Despite the great flurry of excellent experiments and the thermonuclear explosion itself, Teller continued to be dissatisfied and engaged in multiple activities in an effort to put still more of the work under his control. He expressed great unhappiness with the way Los Alamos handled the developments, though Bradbury and other senior members of the laboratory could see no other rational way of doing things. The rift grew so large that Teller put on all the political pressure he could muster to start a rival laboratory. Thanks largely to his influence with Lewis Strauss and the Commission in Washington, he obtained funds and authorization to start and staff another laboratory in Livermore, California, at about the time of the very successful “Mike” test which more than confirmed the possibilities. So Los Alamos went on to build the first H-bomb without him, while some of the first designs emanating from Livermore were quite unsuccessful. Johnny was aware of the feeling between the two laboratories. After the first unsuccessful Livermore try at a thermonuclear explosion in the Pacific proving grounds he laughed and said to me: “There will be dancing in the streets of Los Alamos tonight.”

Contrary to those people who were violently against the bomb on political, moral or sociological grounds, I never had any questions about doing purely theoretical work. I did not feel it was immoral to try to calculate physical phenomena. Whether it was worthwhile strategically was an entirely different aspect of the problem — in fact the crux of a historical, political or sociological question of the gravest kind — and had little to do with the physical or technological problem itself. Even the simplest calculation in the purest mathematics can have terrible consequences. Without the invention of the infinitesimal calculus most of our technology would have been impossible. Should we say therefore that calculus is bad?

I felt that one should not initiate projects leading to possibly horrible ends. But once such possibilities exist, is it not better to examine whether or not they are real? An even greater conceit is to assume that if you yourself won’t work on it, it can’t be done at all. I sincerely felt it was safer to keep these matters in the hands of scientists and people who are accustomed to objective judgments rather than in those of demagogues or jingoists, or even well-meaning but technically uninformed politicians. And when I reflected on the end results, they did not seem so qualitatively different from those possible with existing fission bombs. After the war it was clear that A-bombs of enormous size could be made. The thermonuclear schemes were neither very original nor exceptional. Sooner or later the Russians or others would investigate and build them. The political implications were unclear despite the hullabaloo and exaggerations on both sides. That single bombs were able to destroy the largest cities could render all-out wars less probable than they were with the already existing A-bombs and their horrible destructive power.

After completing this theoretical work I considered my job done and decided to change surroundings for a while. I accepted an invitation to spend a semester at Harvard as a visiting professor. It was the summer of 1951. The Fermis lived in the other half of our duplex. We saw them often. In September, as I was preparing to leave, I was packing and working on correspondence, books and papers and forgot to attend an important evening meeting in Bradbury’s office on the planning of future work and experiments. The next morning I learned that there had been a series of heated exchanges between Teller and Bradbury, and that some acrimonious remarks by other scientists present had been directed at Teller’s rather wild accusations. As I commented on this to Fermi, he replied with his usual serene imperturbability: “Why should you care, you are going away the day after tomorrow.” Some of my friends were greatly impressed by this display of olympian detachment. Rabi in particular admired Enrico’s logically calm attitudes.

The Oppenheimer Affair, which grew out of the violent hydrogen-bomb debate-even though the animosity between Strauss and Oppenheimer had personal and perhaps petty origins — did greatly affect the psychological and emotional role of scientists.

Once I asked Johnny whether he thought that Einstein would have actively defended Oppenheimer during the latter’s troubles. Johnny replied that he believed not; he thought Einstein had had genuinely mixed feelings about some of Oppenheimer’s actions and about the Affair.

It is hard to guess another’s motives. They may be the result of long-held convictions, political orientation, or even pet scientific or philosophical ideas. I believe, for example, that perhaps some of the reasons for Oppenheimer’s opposition to the development of the H-bomb were not exclusively on moral, philosophical, or humanitarian grounds. I might say cynically that he struck me as someone who, having been instrumental in starting a revolution (and the advent of nuclear energy does merit this appellation), does not contemplate with pleasure still bigger revolutions to come.

Anatole France tells somewhere that one day in a park in Paris he saw an old man sitting on a bench reading a newspaper. Suddenly a group of young students appeared, marching in parade formation and shouting revolutionary slogans. The old man became very agitated, shaking his cane and shouting: “Order! Police! Police! Stop!” France recognized the old man; in the past he had been a famous revolutionary.

Oppenheimer had many unusually strong, interesting qualities; but in some way he was a very sad man. The theoretical discussion which he proposed of the so-called neutron stars is one of his great contributions to theoretical physics, but its verification with the discoveries of pulsar stars, which are fast-rotating neutron stars, came years after his death.

It seems to me this was the tragedy of Oppenheimer. He was more intelligent, receptive, and brilliantly critical than deeply original. Also he was caught in his own web, a web not of politics but of phrasing. Perhaps he exaggerated his role when he saw himself as “Prince of Darkness, the destroyer of Universes.” Johnny used to say, “Some people profess guilt to claim credit for the sin.”

Many accounts of these events have been written. Some are exaggerated or distorted; others, like the official history of the AEC, are rather objective. But none can be complete yet, and of course the events as seen by the participants appear in different lights. This is my own account of the history of the H-bomb as I lived it and to the extent that I was directly involved in it.

Chapter 12. The Death of Two Pioneers

1952–1957

After the somewhat frantic work on the ’’super” first with Everett then with Fermi, and my return from the semester’s leave of absence at Harvard renewing contacts with old mathematical friends, my pre-occupations turned to other and more purely scientific problems.

Computers were brand-new; in fact the Los Alamos MANIAC was barely finished. The Princeton von Neumann machine had met with technical and engineering difficulties that had prolonged its perfection. The Los Alamos model had been luckier, for it was in the capable hands of James Richardson, an engineer in the Metropolis group.

As soon as the machines were finished, Fermi, with his great common sense and intuition, recognized immediately their importance for the study of problems in theoretical physics, astrophysics, and classical physics. We discussed this at length and decided to attempt to formulate a problem simple to state, but such that a solution would require a lengthy computation which could not be done with pencil and paper or with the existing mechanical computers. After deliberating about possible problems, we found a typical one requiring long-range prediction and long-time behavior of a dynamical system. It was the consideration of an elastic string with two fixed ends, subject not only to the usual elastic force of strain proportional to strain, but having, in addition, a physically correct small non-linear term. The question was to find out how this non-linearity after very many periods of vibrations would gradually alter the well-known periodic behavior of back and forth oscillation in one mode; how other modes of the string would become more important; and how, we thought, the entire motion would ultimately thermalize, imitating perhaps the behavior of fluids which are initially laminar and become more and more turbulent and convert their macroscopic motion into heat.

John Pasta, a recently arrived physicist, assisted us in the task of flow diagramming, programming, and running the problem on the MANIAC. Fermi had decided to try to learn how to code the machine by himself. In those days it was more difficult than now, when there are set rules, ready-made programs, and the procedure itself is automated. One had to learn many little tricks in those early days. Fermi learned them very quickly and taught me some, even though I already knew enough to be able to estimate what kind of problems could be done, their duration in number of steps, and the principles of how they should be executed.

Our problem turned out to have been felicitously chosen. The results were entirely different qualitatively from what even Fermi, with his great knowledge of wave motions, had expected. The original objective had been to see at what rate the energy of the string, initially put into a single sine wave (the note was struck as one tone), would gradually develop higher tones with the harmonics, and how the shape would finally become “a mess” both in the form of the string and in the way the energy was distributed among higher and higher modes. Nothing of the sort happened. To our surprise the string started playing a game of musical chairs, only between several low notes, and perhaps even more amazingly, after what would have been several hundred ordinary up and down vibrations, it came back almost exactly to its original sinusoidal shape.

I know that Fermi considered this to be, as he said, “a minor discovery.” And when he was invited a year later to give the Gibbs Lecture (a great honorary event at the annual American Mathematical Society meeting), he intended to talk about this. He became ill before the meeting, and his lecture never took place. But the account of this work, with Fermi, Pasta and myself as authors, was published as a Los Alamos report.

I should explain that the motion of a continuous medium like a string is studied on a machine by imagining the string to be composed of a finite number of particles — in our case, sixty-four or one hundred twenty-eight. (It is better to take a power of two for the number of elements, which is more convenient to handle on the computer.) These particles are connected to each other by forces which are not only linear in terms of their distance but by additional small non-linear quadratic terms. Then the machine quickly computes in short time-steps the motion of each of these points. After having computed this, it goes to the next time-step, computes the new positions, and so on for many times. There is absolutely no way to perform this numerical work with pencil and paper; it would literally take thousands of years. An analytic closed-form solution using the mathematical techniques of classical analysis of the nineteenth and twentieth centuries is also completely unlikely.

The results were truly amazing. There were many attempts to find the reasons for this periodic and regular behavior, which was to be the starting point of what is now a large literature on non-linear vibrations. Martin Kruskal, a physicist in Princeton, and Norman Zabuski, a mathematician at Bell Labs, wrote papers about it. Later, Peter Lax contributed signally to the theory. They made interesting mathematical analyses of problems of this sort. A mathematician will know that the so-called Poincaré return-type of dynamical system containing that many particles is terrifically long — on an astronomical scale — and the fact that it came back so soon to its original form is what is so surprising.

Another Los Alamos physicist, Jim Tuck, was curious to see if after this near return to the original position, another period started again from this condition and what it would be after a second “period.” With Pasta and Metropolis, he tried it again and, surprisingly, the thing came back, a percent or so less exactly. These continued and, after six or twelve such periods, it started improving again and a sort of superperiod appeared. Again this is most peculiar.

Other authors, among them several Russian mathematicians, have studied this problem and written papers about it. Last year I received a request from the Japanese Academy for permission to reprint the Fermi-Pasta-Ulam paper. I assented without hesitation and shortly thereafter a whole volume appeared containing studies of these questions by many authors.

I might say here that John Pasta was a very interesting person. A physicist by profession, he spent several years during the depression as a policeman on a beat in New York City. He joined my group in Los Alamos. On the whole very taciturn, he could occasionally make very caustic, humorous remarks. When Johnny became an AEC Commissioner, impressed by Pasta’s common sense, ability, and knowledge of the Los Alamos scene, he invited him to join the AEC in Washington.

As for James Tuck, he was a British physicist who had come to Los Alamos with the British Mission during the war. He had returned to Oxford after the war, but then came back to join the laboratory again. We collaborated on a method for obtaining energy from fusion in a non-explosive way and during the war had written a joint report on this which may still be classified.

As a very young physicist Tuck was for a time assistant to Lindemann, who later became Lord Cherwell, Churchill’s science advisor. He has a fund of interesting and amusing stories about this experience, and he still defends Cherwell vigorously against accusations or criticisms. He reminds me of the English eccentrics described by Jules Verne and by Karl May. Very tall, moving in an abrupt, somewhat uncoordinated way, by his awkwardness he causes many amusing incidents that are always the delight of his friends. For many years Tuck directed a Los Alamos program for the peaceful uses of fusion. The laboratory is still vigorously engaged in a large effort to find methods to extract energy “peacefully” from the fusion of deuterium.

There was another problem which Fermi wanted to study but which we somehow never came to formulate well or to work on. He said one day, “It would be interesting to do something purely kinematical. Imagine a chain consisting of very many links, rigid, but free to rotate around each other. It would be curious to see what shapes the chain would assume when it was thrown on a table, by studying purely the effects of the initial energy and the constraints, no forces.”

During these years we and the von Neumanns started the practice of spending Christmas together. Claire, our daughter, was a small child, and it became a tradition that on Christmas Eve Johnny and Klari would help us assemble her toys. I remember a large cardboard dollhouse which took many hours; both Johnny and I, especially I, being inept at following the instructions which called for inserting tab A into slot B. To this day I am incapable of following written instructions, whether for filling out forms or assembling parts. Johnny, on the other hand, loved it. In Princeton he actively followed the smallest details of the construction of the Princeton MANIAC. According to Bigelow, its engineer, Johnny had learned all the electronic parts and supervised their assembly. When the machine neared completion, I remember how once he made fun of it at his own expense. He told me, “I don’t know how really useful this will be. But at any rate it will be possible to get a lot of credit in Tibet by coding ’Om Mane Padme Hum’ [Oh, thou flower of lotus] a hundred million times in an hour. It will far exceed anything prayer wheels can do.”

Another Christmas we spent together was that of 1950. To celebrate the end of the decade and the first half of the century, Françoise, Claire, and I took a short vacation with the von Neumanns at Guayamas, Mexico. They drove all the way from Princeton, and we arranged to meet in Las Cruces in the southern part of New Mexico to continue the trip together. Las Cruces had an old 1890 brothel which had been remodeled into a hotel after the war, and we all stayed there. The rooms were furnished in period style and on each door, instead of a room number, the name of a girl was inscribed: Juanita, Rosalia, Maria. In the middle of the lobby, a swing was suspended from the ceiling. The ladies apparently climbed on it from the interior balcony. To Johnny and me it looked like the well-known Foucault pendulum, and we indulged in a learned and improper bilingual joke which I will refrain from repeating.

On the drive to Guayamas we also amused ourselves with the developing of a language which we called “neo-castillian.” In our ignorance of Spanish, it consisted of English words with Latin endings, for example el glaso, for glass. To our great surprise and fun we found out that it worked for some words. Terry’s guide to Mexico, particularly its prose, provided us with many hours of fun too. There was an especially eloquent page about the enchanted “paradise bosque” of Sonora, which on driving across we found to be a miserable grove of trees on a dry sandy terrain, unoccupied by any ’’numerous and diverse exotic tropical birds.” This became a proverbial expression denoting disappointment. Whenever we heard something which did not quite measure up to expectations either in mathematics or physics, we exchanged knowingly the words “bosque encantado.”

Long before Sputnik, around 1951 or 1952 I attended an early ICBM rocketry meeting in Washington. Altogether there must have been twenty or more people present. Gamow was one of the important participants. Johnny and Teller were there, too. It was a classified meeting in one of the rooms in the Pentagon. Johnny was sitting next to me at a long table. One problem under discussion was on how to guide rockets. Teller suggested a chemical path to a target. Gamow called it “smelling” the way. Other people suggested other schemes. I proposed “ballistic” projectiles, whose trajectory could be corrected if need be several times along the way. I remember Johnny asking me, “Why isn’t it just as good or better to aim well from the starting point?” I reminded him of Gauss’s famous work on planetary orbits calculated from several observations. He quickly thought about this for a few minutes and came to the conclusion that indeed this was a superior method.

I also noticed that at my mention of ballistic projectiles some people made embarrassed noises and I guessed that there was already some work going on on this. People would not disclose everything that was being worked on and clearances were not uniform among the participants. This brings me to a point about von Neumann that seems to have puzzled many people. It concerns his relations with the military. He seemed to admire generals and admirals and got along well with them. Even before he became an official himself, an AEC commissioner, he spent an increasing amount of time in consultation with the military establishment. Once I asked him: “How is it, Johnny, that you seem to be so impressed by even relatively minor officers who sometimes are not so very remarkable?” And I added, in order to say something a little derogatory about myself too, that what impressed me more were symbols of wealth and influence, like the sight of J. P. Morgan marching in an alumni procession at the Harvard Centennial Ceremonies in 1936. I had seen very many wonderful and eminent scientists and artists in my life before, but the sight of this man who was a billionaire and wielded enormous power really awed me. But to go back to Johnny’s fascination with the military, I believe it was due more generally to his admiration for people who had power. This is not uncommon with those whose life is spent in contemplation. At any rate, it was clear that he admired people who could influence events. In addition, being softhearted, I think he had a hidden admiration for people or organizations that could be tough and ruthless. He appreciated or even envied those who at meetings could act or present their views in a way to influence not only others’ thoughts, but concrete decision-making. He himself was not a very strong or active debater in committee meetings, yielding to those who insisted more forcefully. On the whole he preferred to avoid controversy.

These were the days of defense research contracts. Even mathematicians frequently were recipients. Johnny and I commented on how in some of their proposals scientists sometimes described how useful their intended research was for the national interest, whereas in reality they were motivated by bonafide scientific curiosity and an urge to write a few papers. Sometimes the utilitarian goal was mainly a pretext. This reminded us of the story of the Jew who wanted to enter a synagogue on Yom Kippur. In order to sit in a pew he had to pay for his seat, so he tried to sneak in by telling the guard he only wanted to tell Mr. Blum inside that his grandfather was very ill. But the guard refused, telling him: “Ganev, Sie wollen beten” [“You thief! You really want to pray”]. This, we liked to think, was a nice abstract illustration of the point.

Gamow, who lived in Washington, was a consultant at the Naval Research Laboratory. One of my early so-called business trips to Washington involved a consultation with him. He asked me to talk about Monte Carlo and we discussed modeling land-battle situations. He was interested in and did a lot of work on tank battles. He used Monte Carlo, for example, to simulate landscapes, which he dubbed Stanscapes.

He lived in the suburbs with his first wife Rho and would say, “Let us meet at Chebyshev Circle.” Of course, he meant Chevy Chase. (Chebyshev was a Russian mathematician, and this is how he pronounced it.) Gradually he and Rho had increasing marital difficulties and finally separated and divorced. He moved to the spartan surroundings of the Cosmos Club, where the only good thing was the profusion of newspapers and magazines available to the members. One day I received a sad letter from him saying he was living alone and that on his house was a sign saying, “For Sell [sic].”

In 1954 the Fermis were spending the summer in Europe, partly at the French Physics Institute in Les Houches near Chamonix, partly at Varenna in Italy, where the Enrico Fermi Institute was founded after his death. It now holds conferences on current topics in high-energy physics and in particle physics, both fields just beginning towards the end of Fermi’s life.

If I recall correctly Fermi had applied for a research grant that summer and had not obtained it, which irritated him somewhat. This seemed very strange to me. Just like the incredible affair of the government’s niggardly compensation for the use of his patent on the manufacture of isotopes. He told me once that he believed he and his collaborators would receive perhaps some ten million dollars from the government. With this money they wanted to establish a fund for Italians to study in the United States. But at that time they still had not received “a red cent,” as he said. Eventually a settlement was made but it was so small that it barely covered the lawyers’ fees, if I remember correctly.

We arranged to meet the Fermis in Paris, where they were to stay a few days, and to drive together in two cars part of the way south. They planned to rent a small Fiat but the director of Fiat in Paris made a great point of giving them a very special eight-speed car. I remember Fermi inviting me to try the car with all its speed changes along the quais and the Rue de Rivoli.

Enrico’s health was by now not the best. The preceding summer in Los Alamos, his wife Laura had noticed that his appetite was poor, and this began to worry her. He also showed less energy for exercise and in the tennis games he loved to play. But there were no other physical symptoms, and Laura thought that this was possibly due to his involvement in the H-bomb controversy and the Oppenheimer affair, and to his skepticism and pessimism about the general state of world politics. She hoped the summer’s rest away from home would do him good.

The Fermis always lived simply and frugally, and in Paris we noticed that they were reluctant to frequent the “good” and expensive French restaurants. Enrico did not really enjoy food that summer. Neither could we persuade them to stay in first-class hotels, which they certainly could afford better than we could in those days. On our little overnight joint trip we followed suit and took simple lodgings with them in a modest, small inn in the Vallée du Cousin some hundred fifty miles south of Paris. It is curious how one remembers physical settings. It was late evening, there were stars in the sky and we sat on a terrace next to a murmuring stream discussing the Oppenheimer Affair. Some electrical wires were strung between two houses and all the while we talked Fermi was looking at a bright star, and by moving his head so the wires would hide it from sight, he was observing the scintillation.

We agreed that the affair would ultimately lead to a beatification of Oppenheimer; he would become a great martyr and his accusers would be damned. Both Fermi and von Neumann were, in the hearings, fully on Oppenheimer’s side and defended him against the accusations, though neither was a great personal friend or special admirer of his. Fermi was not greatly impressed by his physics and had some reservations about his political leanings. He felt however that Oppenheimer had been treated very shabbily. We also discussed the attitude of Edward Teller, and I asked Fermi how he viewed the future. Suddenly he looked at me and said: “I don’t know, I’ll look at it from up there,” pointing at the sky. Did he have some premonition that he was dangerously sick? If so, he never admitted it in so many words nor did he look it. But this struck me as a bolt from the blue, especially since he repeated it once more as we discussed the foundations of physics, the mysteries of particles, the behavior of mesons, and his changing interests from nuclear structure to the supposedly more fundamental parts of the physics of particles. Again he said: “I’ll know from up there.” The next day we separated, the Fermis driving east to Grenoble and Les Houches, and we, Claire, and Françoise’s brother south, to spend a vacation in La Napoule, near Cannes on the French Riviera.

When we returned to the United States at the end of the summer, the news was that Fermi was very ill, that an exploratory operation had been performed immediately upon his return to Chicago and that a generalized cancer of the esophagus and stomach had been found. Some of his friends thought the cancer might have been caused by his early work with radioactive materials at a time when precautions were not very carefully observed. I wondered then whether a habit of his which I had noticed of occasionally swallowing hard, and which I thought was a deliberate form of self-control, might have been connected all along with a physical difficulty.

His illness progressed rapidly. I went to Chicago to visit him. In the hospital I found him sitting up in bed with tubes in the veins of his arms. But he could talk. Seeing me, he smiled as I came in and said: “Stan, things are coming to an end.” It is impossible for me to describe how shattering it was to hear this sentence. I tried to keep composed, made a feeble attempt at a joke, then for about an hour we talked about many subjects, and all along he spoke with serenity, and under the circumstances really a superhuman calm. He mentioned that Teller had visited him the previous day, and joked that he had “tried to save his soul.” Normally it is the priest who wants to save the soul of the dying man; Fermi put it the other way round, alluding to the public hullabaloo about Teller and the H-bomb. Perhaps their conversation had an effect, for shortly after Fermi died Teller published an article entitled “The Work of Many People,” toning down the assertions of Shepley and Blair. During my visit to Fermi Laura dropped in and I was amazed at the ordinary nature of their conversation about some household appliance.

We talked on and I remember his saying that he believed he had already done about two-thirds of his life’s work, no matter how long he might have lived. He added that he regretted a little not having become more involved in public affairs. It was very strange to hear him evaluating his own activity — from the outside, as it were. Again I felt that he achieved this superobjectivity through sheer will power.

Somehow the conversation turned to the progress of medicine. He said, “Well Stan, you know, my chance of living through this is perhaps not zero but it is less than one in a hundred.” I looked at him questioningly and he continued, “I believe that in twenty years or so a chemical cure for cancer will be found. Now I have only two or three months, and assuming uniform probabilities, the ratio of these times is one hundred to one.” This was his characteristic way of trying to be quantitative, even in situations where it is not possible. Then half seriously I raised the question whether in a thousand years so much progress will be made that it may be possible to reconstruct people who had lived earlier by tracing the genes of the descendants, collecting all the characteristics that make tip a person and reconstructing them physically. Fermi agreed, but he added: “How about the memory? How will they put back in the brain all the memories which are the makeup of any given individual?” This discussion now seems rather unreal and even weird, and it was partly my fault to have put us on such a subject, but at the time it came quite naturally from his super-detachment about himself and death. I paid him one more visit, this time with Metropolis; when we came out of his room I was moved to tears. Only Plato’s account of the death of Socrates could apply to the scene, and paraphrasing some of the words of Krito I told Nick, “That now was the death of one of the wisest men known.”

Fermi died shortly after. A short time later I was passing through Chicago again and called on Laura. I gave the address to the driver and added that this was the house of the widow of the famous Italian scientist who had just died. The driver, who happened to be Italian and who had read about it in the papers, absolutely refused to let me pay the fare. Only when I told him he could give the money to charity did he take it.

Just after Johnny was offered the post of AEC Commissioner and before he accepted and became one in 1954 we had a long conversation. He had profound reservations about his acceptance because of the ramifications of the Oppenheimer Affair. He knew that the majority of scientists did not like Admiral Strauss’s actions and did not share the extreme views of Teller. Some of the more liberal members of the scientific community did not like Johnny’s pragmatic and rather pro-military views nor did they appreciate his association with the atomic energy work in general and with Los Alamos in particular, especially his contributions to the work on the A and H bombs. He recognized this feeling even among some of his Princeton associates, and he was afraid that it would become stronger when he joined the Atomic Energy Commission. This despite the fact that in the Oppenheimer Affair, even though he did not especially like Oppenheimer personally, he defended him with great objectivity and gave very correct, courageous, and intelligent testimony.

The decision to join the AEC had caused Johnny many sleepless nights, he said, and in a two-hour visit to Frijoles Canyon one afternoon he bared his doubts and asked me how I felt about it. He joked, “I’ll become a commissionnaire.” (In French the term is used to mean errand boy.) But he was flattered and proud that although foreign born he would be entrusted with a high governmental position of great potential influence in directing large areas of technology and science. He knew this could be an activity of great national importance. Indeed, with his supreme intelligence, he could have done an enormous amount of good in seeing what was valuable in certain programs and in initiating new ones. As a friend of his and having pressed him to accept the offer, Strauss would be obligated to support his views and ideas. Besides, Johnny had a bit of the Teutonic trait of being easily impressed by officialdom. At any rate, he was torn between two poles: a feeling of pride with the hope of doing something good and useful and the fear of becoming associated in the minds of his colleagues with a small minority of the scientific community and of career-oriented persons. Acceptance required taking a leave of absence from the Institute and some financial sacrifice as well. I do not know the details of the promises that Strauss may have made or the pressures he may have exerted.

I wondered later whether this decision and the anguish and nervous tension it caused him had perhaps predisposed him to the onset of the fatal illness that came not long after. Obviously taking this step did have some physical impact, for he looked wan and showed the effects of stress. Besides, there was a lot more physical work involved. I don’t think that ever before he had worked from eight in the morning to five in the afternoon in the same place and with several meetings every day. No matter how hard he had worked before it had been on his own time and choosing. The first indication that something was very wrong with his health appeared some time after he became a commissioner.

As I had known him over the years he always seemed in good health. He only had infrequent colds, slept well, worked hard, could eat and drink liberally without showing any effects. I don’t think he was hypochondriac. On the contrary, except for an occasional cold or toothache, he was very little preoccupied by his own physical state, although he once showed me some correspondence he had had with Dr. Janos Plesch about kidney function. Once on one of our many walks in Frijoles Canyon he remarked in passing a tree throttled by a vine, how horrible it must feel to be surrounded and trapped and unable to get away. This remark came back to my mind later when he became paralyzed.

I got wind of some vague rumors that he was ill. I asked Teller about it, but he gave me evasive answers and said something I could not interpret. I telephoned the house in Georgetown, and Klari told me a noncommittal little story. I could not help but suspect that something was very wrong, and later found out that Johnny had given specific orders that I should not be told that he had developed cancer. One day sitting in his office he had been seized by a violent pain in the shoulder, so strong that he almost fainted. This pain disappeared, but he went to Massachusetts General Hospital in Boston where a small cancerous growth was removed from his clavicle, probably already a secondary growth. He soon recovered from this surgical intervention and came to Los Alamos for what was to be his last visit there. I still had not been told what was wrong with him.

He came to our house and I noticed that he limped slightly. He seemed obviously preoccupied and perturbed. There was a sadness in him and he frequently seemed to look around, as if, it occurred to me later, he might have been thinking that this was perhaps his last visit and he wanted to remember the scenery, the mountains, the places he knew so well and where he had so often had interesting and pleasant times. Yet at the same time he joked about his presence in Los Alamos as a commissioner. Now he was there not only to think about scientific matters but about very prosaic administrative ones. And Rabi who was in town also chimed in that it was no longer a scientific visit but an inspection tour. Before he left, Françoise showed him a recent snapshot of Claire on her bicycle. He asked if he could take the photo with him. He walked back to the Lodge through the garden, and watching him through the window I definitely had the feeling that somber and melancholy thoughts were in his head.

A few weeks later on one of my visits to Washington Johnny took me to lunch. During the meal he told me that doctors had discovered he had cancer and he described what kind. This was a tremendous shock for me. I told him my suspicions that something was wrong and that for some reason I had wondered if it could be diabetes or his heart. I turned away so as not to show how upset I was, but he noticed it anyway and started telling a joke about a woman in Budapest whose maid had fallen ill. She sent for a doctor who told her that her maid had syphilis. ’’Thank God,” the woman said, “I was afraid it was measles and she would infect the children.” During this dramatic lunch he still showed great strength of will and no signs of knuckling under. I was shattered and wondered whether he would ever recover.

On my next trip I visited Johnny at home. The Georgetown house he had rented was very different from his Princeton one. It was small, very seventeenth-century Dutch with a black-and-white-tiled vestibule as in some of Vermeer’s paintings. He was still working at the AEC but walked with increasing difficulty and soon had to take to a wheelchair. Friends and even doctors wondered whether some of it was psychosomatic. It was never clear what kind of cancer he actually had. I never learned the whole story; I don’t think many people knew it. Klari would never say much about it. I was told it started in the prostate and ultimately metastasized so that he became partly paralyzed.

During his illness Johnny did not talk to me about his important work on the ICBM Committee; only later I learned that he was Chairman and that it was called the von Neumann Committee. As he grew increasingly ill, some of the meetings were held in his house and later at the Woodner Hotel to which the von Neumanns had moved so as to be closer to Walter Reed Hospital, where he was undergoing treatment. To the end he maintained this complete discretion. Even though I was perhaps one of his closest friends he never broached to me classified or military subjects in which I was not involved. Our usual conversations were either about mathematics or about his new interest in a theory of automata. These conversations had started in a sporadic and superficial way before the war at a time when such subjects hardly existed. After the war and before his illness we held many discussions on these problems. I proposed to him some of my own ideas about automata consisting of cells in a crystal-like arrangement. This model is described in the book edited by Arthur Burks, Cellular Automata, and in Burks’s own book on the theory of automata. At that time it was believed that there were 1010 neurons in the small space of the human skull and that from some neurons there issued some hundreds and perhaps in the center region a thousand connections with other neurons. We used to marvel at the complication of the organization of the brain. Now I understand that it has been found that there are thousands of connections from each neuron to others and in some areas fifty thousand and even more. And each neuron, which at that time was believed to be just a rather simple “flipflop.” “yes or no” machine, is now believed to be a complicated organ with many more functions. In the space of fifteen years, since von Neumann’s death, the facts have become amplified; the whole structure is even more amazing, more incredible than it seemed at the time. Johnny did not live to see the developments following Crick and Watson’s work on the structure of the DNA chains in the nucleus of cells and the code which they contain.

It is evident that Johnny’s ideas on a future theory of automata and organisms had roots that went back in time, but his more concrete ideas developed after his involvement with electronic machines. I think that one of his motives for pressing for the development of electronic computers was his fascination with the working of the nervous system and the organization of the brain itself. After his death some of his collaborators collected his writings on the outlines of the theory of automata. Published posthumously, his book on the brain had merely the barest sketches of what he planned to think about. He died so prematurely, seeing the promised land but hardly entering it. The great developments in molecular biology really came too late for him to learn much about it and to enter a field which I know fascinated him.

Another source of stimulation came from his interest in the theory of games. This was initially perhaps an independent curiosity, but in my opinion, a general theory of contests, fights for survival, and evolution will furnish in the near future a whole class of new mathematical problems and new patterns of thought concerning the schemata of the development of biological processes through what is now called evolutionary and “survival of the fittest” competition. In that area one of his major undertakings was the elaboration and creation of new models of probabilistic theory of games, in particular the study of the rules of coalitions. He developed these ideas with Oskar Morgenstern, a Princeton economist, in a monumental book entitled Theory of Games and Economic Behavior.

In the space of fifteen years since von Neumann’s death the new facts discovered have become more perplexing, the whole structure is even more amazing, more incredible than it seemed at the time. It will go on increasing as our understanding of anatomy and physiology improves and will lead to new fields of mathematical research.

This process of increasing complexity in science is going on with no sign as yet of slowing down. Whether it will continue indefinitely or regress is a big question. It is a part of the problem of infinity versus the finiteness of the world.

In the last months of his life, Johnny was hospitalized at Walter Reed Hospital. He occupied a very large suite reserved for high government officials. In the fall of 1956 we were living in Cambridge again, and I was a visiting professor at MIT on another leave from Los Alamos. I managed to travel to Washington and visit him a few times. On one of these visits once again we had a discussion about age. He wondered how much more original and creative work he could still do if he lived. I tried to encourage him by telling him that he still could do at least half as much again.

Curiously, three years earlier while visiting Fermi in his hospital in Chicago, our conversation had also turned to the same topic; Fermi had said calmly that he considered he had already done most of his work. What a difference in outlook, or at least in the way these two great men expressed or suppressed their feelings.

On the same visit I went by mistake to the opposite corner of the hospital but on the same floor, and walked into an antechamber where two military men were sitting. They looked at me in surprise and questioningly. I said I was there to visit a friend and their look turned incredulous. When I added, “Dr. von Neumann,” they smiled and directed me to the proper rooms. I had entered the Presidential Suite where President Eisenhower at that moment was hospitalized after his heart attack. I told this to Johnny when I regained his room. He enjoyed this. It amused him to be in a location symmetrically opposite to that of the President of the United States.

Some months before, Admiral Strauss had a conversation with me about what Johnny’s life could be should he recover sufficiently to leave the hospital but not sufficiently to rejoin the Commission. The idea was to cheer him up with new surroundings and perhaps provide him with a perspective on things other than governmental work. Strauss, though not believing that a full recovery would come to pass, was instrumental in obtaining for him an offer of a special professorship at UCLA. This prospect diverted and cheered Johnny somewhat.

He never complained about pain, but the change in his attitude, his utterances, his relations with Klari, in fact his whole mood at the end of his life were heartbreaking. At one point he became a strict Catholic. A Benedictine monk visited and talked to him. Later he asked for a Jesuit. It was obvious that there was a great gap between what he would discuss verbally and logically with others, and what his inner thoughts and worries about himself were. It was visible on his face. Johnny used to be completely agnostic even though he sometimes expressed his feelings of wonder and mystery. Once in my presence when Klari chided him for his great self-confidence and pride in his intellectual achievements, he replied that on the contrary he was full of admiration for the wonders of nature and the evolution of the brain, compared to which all we do is puny and insignificant.

By then he was very, very ill. I would sit with him and try to distract him. There was still some scientific curiosity in him; his memory still seemed to work sporadically, and on occasion almost uncannily well. I will never forget the scene a few days before he died. I was reading to him in Greek from his worn copy of Thucydides a story he liked especially about the Athenians’ attack on Melos, and also the speech of Pericles. He remembered enough to correct an occasional mistake or mispronunciation on my part.

Johnny died in Walter Reed hospital, February 8, 1957. He was buried in Princeton in a brief Catholic service with a short eulogy by Admiral Strauss. After the funeral there was a small gathering at his house. Several mathematicians were there, among them his old friend James Alexander, himself recovered from an illness not unlike the one I had had in Los Angeles. Also present were Atle Selberg, the number theorist, and Lewis Del Sasso, an engineer who had worked at building the MANIAC, and Mrs. Gorman, his long-time secretary at the Institute. After his death, Françoise went to Washington to spend a few days with Klari, taking Claire along. The presence of a child she was fond of helped momentarily to take Klari’s mind off the long grueling months that preceded Johnny’s death.

Von Neumann was remarkably universal. I have known wonderful mathematicians who were severely limited in their curiosity about other sciences but he was not.

Von Neumann’s reputation and fame as a mathematician and as a scientist have grown steadily since his death. More than his direct influence on mathematical research, the breadth of his interests and of his scientific undertakings, his personality and his fantastic brain are becoming almost legendary. True, in his lifetime he had already achieved an enormous reputation, and all the honors the mathematical world can give. But he had his detractors. He was not entirely what one might call a mathematicians’ mathematician. Purists objected to his interests outside of pure mathematics when, very early, he leaned towards applications of mathematics or when he wrote, as a young man, about problems of quantum theory.

As for myself, I was never greatly impressed by his work on Hilbert space or on continuous geometry. This is a question of taste, and when I was more of a purist myself I made good-natured fun of certain of his involvements in applications. I told him once, “When it comes to the applications of mathematics to dentistry, maybe you’ll stop.”

But there was nothing small about his interests, and his exquisite sense of humor prevented him from going off on tangents from the main edifice of mathematics. He was unique in this respect. Unique, too, were his overall intelligence, breadth of interest, and absolute feeling for the difference between the momentary technical work and the great lines of the life of the mathematical tree itself and its role in human thought.

Now Banach, Fermi, von Neumann were dead — the three great men whose intellects had impressed me the most. These were sad times indeed.

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