On Wednesday Oppenheimer returns. The atmosphere at the institute during these last days has been rather like the first scene in Murder in the Cathedral, with the women of Canterbury awaiting the return of their archbishop. In passing, I may add that Eliot [the author of Murder in the Cathedral] is now at the institute, having been invited by Oppenheimer to come for a three-month visit and do what he likes; I have not seen him yet. During these days the secretaries have been busily cleaning and tidying up the room of the great man, where we have been making ourselves at home during his absence. Next week we are to move into a new wing of the building which is now in process of completion. (Even the institute has not escaped the disease of postwar expansion.)
I had enormous admiration for T. S. Eliot as a poet and playwright, but I was too shy to start a conversation with him when I saw him drinking tea in the institute common room. I never found out whether he saw as I did the uncanny resemblance of the opening scene of Murder in the Cathedral, with the women of Canterbury awaiting the return of their archbishop, and the opening scene of the institute at Princeton, with the young physicists awaiting the return of their director.
This morning the celebrated theologian Dr. Reinhold Niebuhr was preaching in the University Chapel, and I went along to hear him and see the service. I enjoyed it very much, the last time I went to church must have been on Christmas Day in New York. The singing was enthusiastic if not polished, and the building is a pleasant one, in the style of many a Cambridge college chapel. The main attraction, the sermon, did not disappoint. Niebuhr spoke on the text “Except a grain of corn fall to the ground, and die, it abideth alone; but if it die, it bringeth forth much fruit.” He spoke fast, and it took all my wits to follow him. But what he had to say was worth the effort, and I found his words both stimulating and consoling; he did not hesitate to apply his remarks to political and international problems. The gist of them was, just as the individual man can save his soul only be ceasing to worry about himself and immersing his actions in some larger ends, so also we shall stand a better chance of saving our civilisation if we do not worry too much over the imminent destruction of the little bit of it to which we happen to belong. Niebuhr has the reputation of being gloomy, but I think to anyone who has faced facts squarely, his remarks were exceptionally cheerful.
Reinhold Niebuhr came in 1957 to spend a year as a visiting member of the institute. Unlike Eliot, he sat and ate lunch every day with the younger members, and we got to know him well. His table conversation was as illuminating as his sermons.
OCTOBER 16, 1948
Oppenheimer is unreceptive to the new ideas in general and in particular to Feynman. Oppenheimer shocked me when he arrived by taking a semidefeatist attitude to the whole business and showing complete lack of enthusiasm for a lot of the things I consider most hopeful of fruitful advances. It is this general attitude of hesitation which I now see I shall have to fight in the next few weeks; I am sure I shall have no difficulty in the long run, and the great thing at present is to avoid antagonising people by being impatient at their conservatism.
In the afternoons I have managed to explore the country around here. It is excellent walking country, and I have met numbers of strange new birds, insects, and plants. The weather could not be better, and I hope to continue this form of exercise indefinitely. My young colleagues are unwilling to join me, as they are obsessed with the American idea that you have to work from nine to five even when the work is theoretical physics. To avoid appearing superior, I have to say that it is because of bad eyes that I do not work in the afternoons.
An interesting member of our group has recently arrived, a young man called Abraham Pais from Holland. He spent several years during the war in hiding to escape being deported and probably killed by the Germans as a Jew. He is a man of wide interests and culture and a favourite of Oppenheimer for that reason. I hope to establish a friendship with him as time goes on.
I will write a letter now to counteract the last one, which was written at a moment when I felt like Elijah in the wilderness. Since then three things have happened which have transformed the situation completely. First, on Sunday I felt so irritable that I wrote the enclosed letter to Oppenheimer. So my remarks about teaching Oppenheimer some physics came true. On Sunday night I went for a walk into a field outside the town, where the sky was unobscured by lights, and sat down on the grass to make up my mind whether I should send the letter off. After some time I had decided to do it, and then suddenly the sky was filled with the most brilliant northern lights I have ever seen. They lasted only about five minutes, but were a rich bloodred and filled half the sky. Whether the show really was staged for my benefit I doubt, but certainly it produced the same psychological effect as if it had been. I sent the letter off. On Monday I heard from the editor of the Physical Review that my paper has been accepted in entirety for publication in the issue of January 15. This is remarkably quick, considering that somebody had to read through the paper and referee it in that time. Since this is one of the longest papers the Physical Review has ever published, they might well have asked me to shorten it, which would have been a horrible task. I have much to be thankful for. Later on Monday Oppenheimer ran into me, said he was delighted with my letter and will give me opportunity to expound my views publicly next week. Finally, the same night I went uninvited to call on some of the young people at the Institute Housing Project and found they were having a party. I was very glad to join them and sat around and talked for some time, about eight of us in all. After a time they asked me what I would have to drink, and I said whiskey since that was offered. Since this episode my relations with these people have been on a much more friendly basis, so the whiskey did me a good service.
The following letter to Oppenheimer contains some technical language which nonexpert readers should skip. Translated into plain language, the letter tells Oppenheimer to listen to what Feynman has to say and stop raising silly objections. I disguised this rude message by wrapping it up in polite and diplomatic phrases.
OCTOBER 17, 1948
Dear Dr. Oppenheimer:
As I disagree rather strongly with the point of view expressed in your Solvay Report (not so much with what you say as with what you do not say), and as my own opinions are not firmly enough based for me to put them up against yours in public discussion, I decided to send you a short written memorandum. This is a statement of aims and hopes, and I would be glad if you would read it before starting on the arid details of my long paper on radiation theory.
MEMORANDUM.
I. As a result of using both old-fashioned quantum electrodynamics (Heisenberg-Pauli) and Feynman electrodynamics, on problems in which no divergence difficulties arise, I am convinced that the Feynman theory is considerably easier to use, understand, and teach.
II. Therefore I believe that a correct theory, even if radically different from our present ideas, will contain more of Feynman than of Heisenberg-Pauli.
III. I believe it to be probable that the Feynman theory will provide a complete fulfilment of Heisenberg’s S-matrix program. The Feynman theory is essentially nothing more than a method of calculating the S-matrix for any physical system from the usual equations of electrodynamics. It appears as an experimental fact (not yet known for certain) that the S-matrix so calculated is always finite; the divergences only appear in the part of the theory which Heisenberg would in any case reject as meaningless. This seems to me a strong indication that Heisenberg is really right, that the localisation of physical processes is the only cause of inconsistency in present physics, and that so long as all experiments are interpreted by means of the S-matrix the theory is correct.
IV. The Feynman theory exceeds the original Heisenberg program in that it does not involve any new arbitrary hypothesis such as a fundamental length.
V. I do not see any reason for supposing the Feynman method to be less applicable to meson theory than to electrodynamics. In particular I find the argument about “open” and “closed” systems
of fields irrelevant.
VI. Whatever the truth of the foregoing assertions may be, we have now a theory of nuclear fields which can be developed to the point where it can be compared with experiment, and this is a challenge to be accepted with enthusiasm.
NOVEMBER 1, 1948, HOTEL AVERY, BOSTON
My physics goes on splendidly. What annoyed me in Oppenheimer’s initial lethargy was not that my finished work was unappreciated, but that he was making it difficult for me or anybody else to go ahead with it. What I want to do now is to get some large-scale calculations done to apply the theory to nuclear problems, and this is too big a job for me to tackle alone. So I had to begin by selling the theory to him. As soon as he understands and believes in it, he will certainly have a great deal of useful advice and experience to offer us in applying it. Also he may be able to help me to decide what I should do next, though I am fairly determined already on a thoroughgoing attempt to prove the whole theory consistent.
After my last letter to you I decided that I needed a long weekend away from Princeton. I persuaded Cécile Morette to come with me to see Feynman at Ithaca. This was a bold step on my part, but it could not have been more successful, and the weekend was just deliriously happy. Feynman himself came to meet us at the station, after our ten-hour train journey, and was in tremendous form, bubbling over with ideas and stories and entertaining us with performances on Indian drums from New Mexico until one a.m.
Cécile Morette was the brightest of the young physicists who arrived at the institute at the same time as I did. She was the only one who quickly grasped the new ideas of Feynman. We immediately became friends. The fact that she happened to be female was irrelevant to our friendship. She was a natural leader, she understood modern mathematics better than I did, and she had a great sense of humor.
The next day, Saturday, we spent in conclave discussing physics. Feynman gave a masterly account of his theory, which kept Cécile in fits of laughter and made my talk at Princeton a pale shadow by comparison. He said he had given his copy of my paper to a graduate student to read, then asked the student if he himself ought to read it. The student said no, and Feynman accordingly wasted no time on it and continued chasing his own ideas. Feynman and I really understand each other; I know that he is the one person in the world who has nothing to learn from what I have written, and he doesn’t mind telling me so. That afternoon Feynman produced more brilliant ideas per square minute than I have ever seen anywhere before or since. In the evening I mentioned that there were just two problems for which the finiteness of the theory remained to be established; both problems are well-known and feared by physicists, since many long and difficult papers running to fifty pages and more have been written about them, trying unsuccessfully to make the older theories give sensible answers to them. When I mentioned this fact, Feynman said, “We’ll see about this,” and proceeded to sit down and in two hours, before our eyes, obtain finite and sensible answers to both problems. It was the most amazing piece of lightning calculation I have ever witnessed, and the results prove, apart from some unforeseen complication, the consistency of the whole theory. The two problems were the scattering of light by an electric field, and the scattering of light by light.
After supper Feynman was working until three a.m. He has had a complete summer of vacation and has returned with unbelievable stores of suppressed energy. On the Sunday Feynman was up at his usual hour (nine a.m.), and we went down to the physics building, where he gave me another two-hour lecture of miscellaneous discoveries of his. One of these was a deduction of Maxwell’s equations of the electromagnetic field from the basic principles of quantum theory, a thing which baffles everybody including Feynman, because it ought not to be possible. Meanwhile Cécile was at mass, being a strict Catholic. At twelve on the Sunday we started our journey home, arriving finally at two a.m. and thoroughly refreshed. Cécile assured me she had enjoyed it as much as I had. I found a surprising intensity of feeling for Ithaca, its breezy open spaces and hills and its informal society. It seemed like a place which I belonged to, full of nostalgic memories. I suppose it really is my spiritual home.
Perhaps I should tell you something about Cécile, but I hardly know where to start. No doubt I will have occasion to mention her again, so this time I will confine myself to a bare chronology. 1922, Cécile born in France, of a wealthy industrial family. 1932, father died, leaving mother and six children. Mother soon remarries. 1940, family living in Caen when German occupation starts, Cécile studying at Caen university. 1942, Cécile starts studying at Paris university, travelling to and fro weekly. 1944, Cécile caught in Paris on D-day. House in Caen destroyed, mother and one sister killed. After Germans leave, Cécile seizes one of their flats reserved for American army and installs self. Later she collects stepfather and sister and installs them too. They are still there. 1945, Cécile goes to Dublin, Institute for Advanced Study, to learn theoretical physics. 1947, Cécile moves to Copenhagen to work in Bohr’s institute. 1948, Cécile comes to Princeton with institute fellowship. Future, Cécile intends to marry and have lots of children.
The town of Caen is on the Normandy coast, at the center of the region where Allied troops landed in 1944. The town was largely destroyed in two weeks of fierce fighting before the Germans were driven out.
NOVEMBER 4, 1948
First, there is this election. Everyone is immensely pleased by the result; it is clear that it will make no great difference to the way the country is governed for the next four years, but it is of great importance politically that the Democratic Party has managed to win an election without the support of the South; the worst southern states have written themselves out of the party, and the influence of the others will be much weakened. I sat up and listened to the returns coming in for about two hours; it was clear right from the start that Truman was doing much better than expected, but even so I was as surprised as everybody else by the result next morning. One has to take off one’s hat to the American voters for not being bamboozled by the newspapers and the political experts.
The 1948 election had four parties contending for the presidency, the Republicans led by Robert Dewey, the Democrats led by Harry Truman, the Progressives led by Henry Wallace, and the Dixiecrats led by Strom Thurmond. Since the Democratic voters were split into three parties, it was obvious to everybody that Truman would lose and Dewey would win.
Next piece of news. I have received a letter from Professor [Isidor Isaac] Rabi, Nobel Prizeman, brains of the Columbia Radiation Laboratory which has done all the crucial experiments of the last three years, and head of the physics department at Columbia University. Content, offer of a job on his faculty. I wrote a letter back refusing the offer and explaining my circumstances, but I must confess with bitterness in my heart. Objectively, I can think of no place in the world that would be better for me than Columbia. They have the finest experimental department in the world, and it is just in the contact with experimentalists that I have most to learn; they are weak in theorists, and so I should have a free field to cultivate in building up the theoretical side, while still being close to Bethe and Oppy for consultation; finally, Columbia is a magnificent centre where everyone visiting New York stops, and is itself in easy reach of Europe. To throw away such a chance seems madness, but it seems there is no help for it. It would not matter so much were I older, but I have not yet learnt half of what America has to teach me, and it is a grim prospect to be cut off without more than rumours and months-old reports of what Feynman or Schwinger or Columbia or Berkeley is doing. Also perhaps might be added that Cécile is intending to stay here another year.
The Harkness Foundation was generously supporting me as a student in America. When I accepted their Commonwealth Fellowship, I solemnly promised to return to England for at least two years after the fellowship. The promise was intended to ensure that the fellowship should not be used as a stepping-stone for permanent emigration of English students to America. If I accepted the Columbia job, I would clearly be breaking my
promise and violating the trust of the foundation.
I believe I have never written you anything about the appearance and character of Rabi. He is a tiny, impish little man, with a broad grin on his face, and is always making good-humoured jokes at somebody’s expense. Where he comes from I do not know; his eyes and colour are more Mongolian than anything else. There is a celebrated song which is often sung at physical gatherings, which describes Rabi receiving the Nobel Prize. The refrain goes, “It ain’t the money; it ain’t the money; it’s the principle of the thing.” The department at Columbia may fairly be said to worship the ground he treads on, and there is a general agreement among all experimental departments outside Columbia that it is useless to try to do molecular beam experiments, because it would take anybody else about five years to arrive at where Rabi is now.
Yesterday I went to New York and spent two hours profitably with Bethe, discussing physics. He is enthusiastic about the new theory and has been using it extensively. He told me the great thing with Oppy is not to be driven frantic by him (as many people are) but to exercise calm and patience. I had come to the same conclusion myself, and I think I have been putting it into effect successfully. On Tuesday I gave the second of my seminar talks, and Oppy interrupted constantly with criticisms, some relevant and some nonsensical, so that the audience was quite bewildered; as far as I could, I went steadily on and avoided argument. The next morning, the same audience without Oppenheimer asked me to give them another seminar on the same stuff, this time without interruptions, and so I did. To me, the interruptions provided many valuable new ideas.
Maker of Patterns Page 13
