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Surely Youre Joking, Mr. Feynman

ModernLib.Net / / Feynman Richard P., Hutchings Edward, Leighton Ralph / Surely Youre Joking, Mr. Feynman - (. 16)
: Feynman Richard P.,
Hutchings Edward,
Leighton Ralph
:

 

...

 


I knew the problem. In those days, the earth appeared to be older than the universe. The earth was four and a half billion, and the universe was only a couple, or three billion years old. It was a great puzzle. And this discovery resolved all that: The universe was now demonstrably older than was previously thought. And I got this information right awaythe guy came running up to me to tell me all this.

I didnt even make it across the campus to get to my office, when another guy came upMatt Meselson, a biologist who had minored in physics. (I had been on his committee for his Ph.D.) He had built the first of what they call a density gradient centrifuge-it could measure the density of molecules. He said, Look at the results of the experiment Ive been doing!

He had proved that when a bacterium makes a new one, theres a whole molecule, intact, which is passed from one bacterium to anothera molecule we now know as DNA. You see, we always think of everything dividing, dividing. So we think everything in the bacterium divides and gives half of it to the new bacterium. But thats impossible: Somewhere, the smallest molecule that contains genetic information cant divide in half; it has to make a copy of itself, and send one copy to the new bacterium, and keep one copy for the old one. And he had proved it in this way: He first grew the bacteria in heavy nitrogen, and later grew them all in ordinary nitrogen. As he went along, he weighed the molecules in his density gradient centrifuge.

The first generation of new bacteria had all of their chromosome molecules at a weight exactly in between the weight of molecules made with heavy, and molecules made with ordinary, nitrogena result that could occur if everything divided, including the chromosome molecules.

But in succeeding generations, when one might expect that the weight of the chromosome molecules would be one-fourth, one-eighth, and one-sixteenth of the difference between the heavy and ordinary molecules, the weights of the molecules fell into only two groups. One group was the same weight as the first new generation (halfway between the heavier and the lighter molecules), and the other group was lighterthe weight of molecules made in ordinary nitrogen. The percentage of heavier molecules was cut in half in each succeeding generation, but not their weights. That was tremendously exciting, and very importantit was a fundamental discovery. And I realized, as I finally got to my office, that this is where Ive got to be. Where people from all different fields of science would tell me stuff, and it was all exciting. It was exactly what I wanted, really.

So when Cornell called a little later, and said they were setting everything up, and it was nearly ready, I said, Im sorry, Ive changed my mind again. But I decided then never to decide again. Nothingabsolutely nothingwould ever change my mind again.

When youre young, you have all these things to worry aboutshould you go there, what about your mother. And you worry, and try to decide, but then something else comes up. Its much easier to just plain decide. Never mindnothing is going to change your mind. I did that once when I was a student at MIT. I got sick and tired of having to decide what kind of dessert I was going to have at the restaurant, so I decided it would always be chocolate ice cream, and never worried about it againI had the solution to that problem. Anyway, I decided it would always be Caltech.

One time someone tried to change my mind about Caltech. Fermi had just died a short time before, and the faculty at Chicago were looking for someone to take his place. Two people from Chicago came out and asked to visit me at my homeI didnt know what it was about. They began telling me all the good reasons why I ought to go to Chicago: I could do this, I could do that, they had lots of great people there, I had the opportunity to do all kinds of wonderful things. I didnt ask them how much they would pay, and they kept hinting that they would tell me if I asked. Finally, they asked me if I wanted to know the salary. Oh, no! I said. Ive already decided to stay at Caltech. My wife Mary Lou is in the other room, and if she hears how much the salary is, well get into an argument. Besides, Ive decided not to decide any more; Im staying at Caltech for good. So I didnt let them tell me the salary they were offering.

About a month later I was at a meeting, and Leona Marshall came over and said, Its funny you didnt accept our offer at Chicago. We were so disappointed, and we couldnt understand how you could turn down such a terrific offer.

It was easy, I said, because I never let them tell me what the offer was.

A week later I got a letter from her. I opened it, and the first sentence said, The salary they were offering was, a tremendous amount of money, three or four times what I was making. Staggering! Her letter continued, I told you the salary before you could read any further. Maybe now you want to reconsider, because theyve told me the position is still open, and wed very much like to have you.

So I wrote them back a letter that said, After reading the salary, Ive decided that I must refuse. The reason I have to refuse a salary like that is I would be able to do what Ive always wanted to doget a wonderful mistress, put her up in an apartment, buy her nice things... With the salary you have offered, I could actually do that, and I know what would happen to me. Id worry about her, what shes doing; Id get into arguments when I come home, and so on. All this bother would make me uncomfortable and unhappy. I wouldnt be able to do physics well, and it would be a bigmess! What Ive always wanted to do would be bad for me, so Ive decided that I cant accept your offer.

Part 5. The World of One Physicist

Would You Solve the Dirac Equation?

Near the end of the year I was in Brazil I received a letter from Professor Wheeler which said that there was going to be an international meeting of theoretical physicists in Japan, and might I like to go? Japan had some famous physicists before the warProfessor Yukawa, with a Nobel prize, Tomonaga, and Nishinabut this was the first sign of Japan coming back to life after the war, and we all thought we ought to go and help them along.

Wheeler enclosed an army phrasebook and wrote that it would he nice if we would all learn a little Japanese. I found a Japanese woman in Brazil to help me with the pronunciation, I practiced lifting little pieces of paper with chopsticks, and I read a lot about Japan. At that time, Japan was very mysterious to me, and I thought it would be interesting to go to such a strange and wonderful country, so I worked very hard.

When we got there, we were met at the airport and taken to a hotel in Tokyo designed by Frank Lloyd Wright. It was an imitation of a European hotel, right down to the little guy dressed in an outfit like the Philip Morris guy. We werent in Japan; we might as well have been in Europe or America! The guy who showed us to our rooms stalled around, pulling the shades up and down, waiting for a tip. Everything was just like America.

Our hosts had everything organized. That first night we were served dinner up at the top of the hotel by a woman dressed Japanese, but the menus were in English. I had gone to a lot of trouble to learn a few phrases in Japanese, so near the end of the meal, I said to the waitress, Kohi-o motte kite kudasai. She bowed and walked away.

My friend Marshak did a double take: What? What?

I talk Japanese, I said.

Oh, you faker! Youre always kidding around, Feynman.

What are you talkin about? I said, in a serious tone.

OK, he said. What did you ask?

I asked her to bring us coffee.

Marshak didnt believe me. Ill make a bet with you, he said. If she brings us coffee.

The waitress appeared with our coffee, and Marshak lost his bet.

It turned out I was the only guy who had learned some Japaneseeven Wheeler, who had told everybody they ought to learn Japanese, hadnt learned anyand I couldnt stand it any more. I had read about the Japanese-style hotels, which were supposed to be very different from the hotel we were staying in.

The next morning I called the Japanese guy who was organizing everything up to my room. I would like to stay in a Japanese-style hotel.

I am afraid that it is impossible, Professor Feynman.

I had read that the Japanese are very polite, but very obstinate: You have to keep working on them. So I decided to be as obstinate as they, and equally polite. It was a battle of minds: It took thirty minutes, back and forth.

Why do you want to go to a Japanese-style hotel?

Because in this hotel, I dont feel like Im in Japan.

Japanese-style hotels are no good. You have to sleep on the floor.

Thats what I want; I want to see how it is.

And there are no chairsyou sit on the floor at the table.

Its OK. That will be delightful. Thats what Im looking for.

Finally he owns up to what the situation is: If youre in another hotel, the bus will have to make an extra stop on its way to the meeting.

No, no! I say. In the morning, Ill come to this hotel, and get on the bus here.

Well, then, OK. Thats fine. Thats all there was to itexcept it took half an hour to get to the real problem.

Hes walking over to the telephone to make a call to the other hotel when suddenly he stops; everything is blocked up again. It takes another fifteen minutes to discover that this time its the mail. If there are any messages from the meeting, they already have it arranged where to deliver them.

Its OK, I say. When I come in the morning to get the bus, Ill look for any messages for me here at this hotel.

All right. Thats fine. He gets on the telephone and at last were on our way to the Japanese-style hotel.

As soon as I got there, I knew it was worth it: It was so lovely! There was a place at the front where you take your shoes off, then a girl dressed in the traditional outfitthe obiwith sandals comes shuffling out, and takes your stuff; you follow her down a hallway which has mats on the floor, past sliding doors made of paper, and shes going cht-cht-cht-cht with little steps. It was all very wonderful!

We went into my room and the guy who arranged everything got all the way down, prostrated, and touched his nose to the floor; she got down and touched her nose to the floor. I felt very awkward. Should I touch my nose to the floor, too?

They said greetings to each other, he accepted the room for me, and went out. It was a really wonderful room. There were all the regular, standard things that you know of now, but it was all new to me. There was a little alcove with a painting in it, a vase with pussywillows nicely arranged, a table along the floor with a cushion nearby, and at the end of the room were two sliding doors which opened onto a garden.

The lady who was supposed to take care of me was a middle-aged woman. She helped me undress and gave me a yukata, a simple blue and white robe, to wear at the hotel.

I pushed open the doors and admired the lovely garden, and sat down at the table to do a little work.

I wasnt there more than fifteen or twenty minutes when something caught my eye. I looked up, out towards the garden, and I saw, sitting at the entrance to the door, draped in the corner, a very beautiful young Japanese woman, in a most lovely outfit.

I had read a lot about the customs of Japan, and I had an idea of why she was sent to my room. I thought, This might be very interesting!

She knew a little English. Would you rike to see the garden? she asked.

I put on the shoes that went with the yukata I was wearing, and we went out into the garden. She took my arm and showed me everything.

It turned out that because she knew a little English, the hotel manager thought I would like her to show me the gardenthats all it was. I was a bit disappointed, of course, but this was a meeting of cultures, and I knew it was easy to get the wrong idea.

Sometime later the woman who took care of my room came in and said somethingin Japaneseabout a bath. I knew that Japanese baths were interesting and was eager to try it, so I said, Hai.

I had read that Japanese baths are very complicated. They use a lot of water thats heated from the outside, and you arent supposed to get soap into the bathwater and spoil it for the next guy.

I got up and walked into the lavatory section, where the sink was, and I could hear some guy in the next section with the door closed, taking a bath. Suddenly the door slides open: the man taking the bath looks to see who is intruding. Professor! he says to me in English. Thats a very bad error to go into the lavatory when someone else has the bath! It was Professor Yukawa!

He told me that the woman had no doubt asked do I want a bath, and if so, she would get it ready for me and tell me when the bathroom was free. But of all the people in the world to make that serious social error with, I was lucky it was Professor Yukawa!

That Japanese-style hotel was delightful, especially when people came to see me there. The other guys would come in to my room and wed sit on the floor and start to talk. We wouldnt be there more than five minutes when the woman who took care of my room would come in with a tray of candies and tea. It was as if you were a host in your own home, and the hotel staff was helping you to entertain your guests. Here, when you have guests at your hotel room, nobody cares; you have to call up for service, and so on.

Eating meals at the hotel was also different. The girl who brings in the food stays with you while you eat, so youre not alone. I couldnt have too good a conversation with her, but it was all right. And the food is wonderful. For instance, the soup comes in a bowl thats covered. You lift the cover and theres a beautiful picture: little pieces of onion floating in the soup just so; its gorgeous. How the food looks on the plate is very important.

I had decided that I was going to live Japanese as much as I could. That meant eating fish. I never liked fish when I was growing up, but I found out in Japan that it was a childish thing: I ate a lot of fish, and enjoyed it. (When I went back to the United States the first thing I did was go to a fish place. It was horriblejust like it was before. I couldnt stand it. I later discovered the answer: The fish has to be very, very freshif it isnt, it gets a certain taste that bothers me.)

One time when I was eating at the Japanese-style hotel I was served a round, hard thing, about the size of an egg yolk, in a cup of some yellow liquid. So far I had eaten everything in Japan, but this thing frightened me: it was all convoluted, like a brain looks. When I asked the girl what it was, she replied kuri. That didnt help much. I figured it was probably an octopus egg, or something. I ate it, with some trepidation, because I wanted to he as much in Japan as possible. (I also remembered the word kuri as if my life depended on itI havent forgotten it in thirty years.)

The next day I asked a Japanese guy at the conference what this convoluted thing was. I told him I had found it very difficult to eat. What the hell was kuri ?

It means chestnut. he replied.


Some of the Japanese I had learned had quite an effect. One time, when the bus was taking a long time to get started, some guy says, Hey, Feynman! You know Japanese; tell em to get going!

I said, Hayaku! Hayaku! Ikimasho! Ikimasho! which means, Lets go! Lets go! Hurry! Hurry!

I realized my Japanese was out of control. I had learned these phrases from a military phrase book, and they must have been very rude, because everyone at the hotel began to scurry like mice, saying, Yes, sir! Yes sir! and the bus left right away.

The meeting in Japan was in two parts: one was in Tokyo, and the other was in Kyoto. In the bus on the way to Kyoto I told my friend Abraham Pais about the Japanese-style hotel, and he wanted to try it. We stayed at the Hotel Miyako, which had both American-style and Japanese-style rooms, and Pais shared a Japanese-style room with me.

The next morning the young woman taking care of our room fixes the bath, which was right in our room. Sometime later she returns with a tray to deliver breakfast. Im partly dressed. She turns to me and says, politely, Ohayo, gozai masu, which means, Good morning.

Pais is just coming out of the bath, sopping wet and completely nude. She turns to him and with equal composure says, Ohayo, gozai masu, and puts the tray down for us.

Pais looks at me and says, God, are we uncivilized!

We realized that in America if the maid was delivering breakfast and the guys standing there, stark naked, there would be little screams and a big fuss. But in Japan they were completely used to it, and we felt that they were much more advanced and civilized about those things than we were.


I had been working at that time on the theory of liquid helium, and had figured out how the laws of quantum dynamics explain the strange phenomena of super-fluidity. I was very proud of this achievement, and was going to give a talk about my work at the Kyoto meeting.

The night before I gave my talk there was a dinner, and the man who sat down next to me was none other than Professor Onsager, a topnotch expert in solid-state physics and the problems of liquid helium. He was one of these guys who doesnt say very much, but any time he said anything, it was significant.

Well, Feynman, he said in a gruff voice, I hear you think you have understood liquid helium.

Well, yes..

Hoompf. And thats all he said to me during the whole dinner! So that wasnt much encouragement.

The next day I gave my talk and explained all about liquid helium. At the end, I complained that there was still something I hadnt been able to figure out: that is, whether the transition between one phase and the other phase of liquid helium was first-order (like when a solid melts or a liquid boilsthe temperature is constant) or second-order (like you see sometimes in magnetism, in which the temperature keeps changing).

Then Professor Onsager got up and said in a dour voice, Well, Professor Feynman is new in our field, and I think he needs to be educated. Theres something he ought to know, and we should tell him.

I thought, Geesus! What did I do wrong?

Onsager said, We should tell Feynman that nobody has ever figured out the order of any transition correctly from first principles, so the fact that his theory does not allow him to work out the order correctly does not mean that he hasnt understood all the other aspects of liquid helium satisfactorily. It turned out to be a compliment, but from the way he started out, I thought I was really going to get it!

It wasnt more than a day later when I was in my room and the telephone rang. It was Time magazine. The guy on the line said, Were very interested in your work. Do you have a copy of it you could send us?

I had never been in Time and was very excited. I was proud of my work, which had been received well at the meeting, so I said, Sure!

Fine. Please send it to our Tokyo bureau. The guy gave me the address. I was feeling great.

I repeated the address, and the guy said, Thats right. Thank you very much, Mr. Pais.

Oh, no! I said, startled. Im not Pais; its Pais you want? Excuse me, Ill tell him that you want to speak to him when he comes back.

A few hours later Pais came in: Hey, Pais! Pais! I said, in an excited voice. Time magazine called! They want you to send em a copy of the paper youre giving.

Aw! he says. Publicity is a whore!

I was doubly taken aback.

Ive since found out that Pais was right, but in those days, I thought it would be wonderful to have my name in Time magazine.

That was the first time I was in Japan. I was eager to go back, and said I would go to any university they wanted me to. So the Japanese arranged a whole series of places to visit for a few days at a time.

By this time I was married to Mary Lou, and we were entertained wherever we went. At one place they put on a whole ceremony with dancing, usually performed only for larger groups of tourists, especially for us. At another place we were met right at the boat by all the students. At another place, the mayor met us.

One particular place we stayed was a little, modest place in the woods, where the emperor would stay when he came by. It was a very lovely place, surrounded by woods, just beautiful, the stream selected with care. It had a certain calmness, a quiet elegance. That the emperor would go to such a place to stay showed a greater sensitivity to nature, I think, than what we were used to in the West.

At all these places everybody working in physics would tell me what they were doing and Id discuss it with them. They would tell me the general problem they were working on, and would begin to write a bunch of equations.

Wait a minute, I would say. Is there a particular example of this general problem?

Why yes; of course.

Good. Give me one example. That was for me: I cant understand anything in general unless Im carrying along in my mind a specific example and watching it go. Some people think in the beginning that Im kind of slow and I dont understand the problem, because I ask a lot of these dumb questions: Is a cathode plus or minus? Is an an-ion this way, or that way?

But later, when the guys in the middle of a bunch of equations, hell say something and Ill say, Wait a minute! Theres an error! That cant be right!

The guy looks at his equations, and sure enough, after a while, he finds the mistake and wonders, How the hell did this guy, who hardly understood at the beginning, find that mistake in the mess of all these equations?

He thinks Im following the steps mathematically, but thats not what Im doing. I have the specific, physical example of what hes trying to analyze, and I know from instinct and experience the properties of the thing. So when the equation says it should behave so-and-so, and I know thats the wrong way around, I jump up and say, Wait! Theres a mistake!

So in Japan I couldnt understand or discuss anybodys work unless they could give me a physical example, and most of them couldnt find one. Of those who could, it was often a weak example, one which could be solved by a much simpler method of analysis.

Since I was perpetually asking not for mathematical equations, but for physical circumstances of what they were trying to work out, my visit was summarized in a mimeographed paper circulated among the scientists (it was a modest but effective system of communication they had cooked up after the war) with the title, Feynmans Bombardments, and Our Reactions.

After visiting a number of universities I spent some months at the Yukawa Institute in Kyoto. I really enjoyed working there. Everything was so nice: Youd come to work, take your shoes off, and someone would come and serve you tea in the morning when you felt like it. It was very pleasant.

While in Kyoto I tried to learn Japanese with a vengeance. I worked much harder at it, and got to a point where I could go around in taxis and do things. I took lessons from a Japanese man every day for an hour.

One day he was teaching me the word for see. All right, he said. You want to say, May I see your garden? What do you say?

I made up a sentence with the word that I had just learned.

No, no! he said. When you say to someone, Would you like to see my garden? you use the first see. But when you want to see someone elses garden, you must use another see, which is more polite.

Would you like to glanceat my lousy garden? is essentially what youre saying in the first case, but when you want to look at the other fellas garden, you have to say something like, May I observe your gorgeous garden? So theres two different words you have to use.

Then he gave me another one: You go to a temple, and you want to look at the gardens

I made up a sentence, this time with the polite see.

No, no! he said. In the temple, the gardens are much more elegant. So you have to say something that would be equivalent to May I hang my eyes on your most exquisite gardens?

Three or four different words for one idea, because when Im doing it, its miserable; when youre doing it, its elegant.

I was learning Japanese mainly for technical things, so I decided to check if this same problem existed among the scientists.

At the institute the next day, I said to the guys in the office, How would I say in Japanese, I solve the Dirac Equation?

They said such-and-so.

OK. Now I want to say, Would you solve the Dirac Equation?how do I say that?

Well, you have to use a different word for solve, they say.

Why? I protested. When I solve it, I do the same damn thing as when you solve it!

Well, yes, but its a different wordits more polite.

I gave up. I decided that wasnt the language for me, and stopped learning Japanese.

The 7 Percent Solution

The problem was to find the right laws of beta decay. There appeared to be two particles, which were called a tan and a theta. They seemed to have almost exactly the same mass, but one disintegrated into two pions, and the other into three pions. Not only did they seem to have the same mass, but they also had the same lifetime, which is a funny coincidence. So everybody was concerned about this.

At a meeting I went to, it was reported that when these two particles were produced in a cyclotron at different angles and different energies, they were always produced in the same proportionsso many taus compared to so many thetas.

Now, one possibility, of course, was that it was the same particle, which sometimes decayed into two pions, and sometimes into three pions. But nobody would allow that, because there is a law called the parity rule, which is based on the assumption that all the laws of physics are mirror-image symmetrical, and says that a thing that can go into two pions cant also go into three pions.

At that particular time I was not really quite up to things: I was always a little behind. Everybody seemed to be smart, and I didnt feel I was keeping up. Anyway, I was sharing a room with a guy named Martin Block, an experimenter. And one evening he said to me, Why are you guys so insistent on this parity rule? Maybe the tau and theta are the same particle. What would be the consequences if the parity rule were wrong?

I thought a minute and said, It would mean that natures laws are different for the right hand and the left hand, that theres a way to define the right hand by physical phenomena. I dont know that thats so terrible, though there must be some bad consequences of that, but I dont know. Why dont you ask the experts tomorrow?, -

He said, No, they wont listen to me. You ask.

So the next day, at the meeting, when we were discussing the tau-theta puzzle, Oppenheimer said, We need to hear some new, wilder ideas about this problem.

So I got up and said, Im asking this question for Martin Block: What would be the consequences if the parity rule was wrong?

Murray Gell-Mann often teased me about this, saying I didnt have the nerve to ask the question for myself. But thats not the reason. I thought it might very well be an important idea.

Lee, of Lee and Yang, answered something complicated, and as usual I didnt understand very well. At the end of the meeting, Block asked me what he said, and I said I didnt know, but as far as I could tell, it was still openthere was still a possibility. I didnt think it was likely, but I thought it was possible.

Norm Ramsey asked me if I thought he should do an experiment looking for parity law violation, and I replied, The best way to explain it is, Ill bet you only fifty to one you dont find anything.

He said, Thats good enough for me. But he never did the experiment.



Anyway, the discovery of parity law violation was made, experimentally, by Wu, and this opened up a whole bunch of new possibilities for beta decay theory, It also unleashed a whole host of experiments immediately after that. Some showed electrons coming out of the nuclei spun to the left, and some to the right, and there were all kinds of experiments, all kinds of interesting discoveries about parity. But the data were so confusing that nobody could put things together.

At one point there was a meeting in Rochesterthe yearly Rochester Conference. I was still always behind, and Lee was giving his paper on the violation of parity. He and Yang had come to the conclusion that parity was violated, and flow he was giving the theory for it.

During the conference I was staying with my sister in Syracuse. I brought the paper home and said to her, I cant understand these things that Lee and Yang are saying. Its all so complicated.

No, she said, what you mean is not that you cant understand it, but that you didnt invent it. You didnt figure it out your own way, from hearing the clue. What you should do is imagine youre a student again, and take this paper upstairs, read every line of it, and check the equations. Then youll understand it very easily.


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