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 else’s garden, you must use another ‘see,’ which is more polite.”

“Would you like to glance at my lousy garden?” is essentially what you’re saying in the first case, but when you want to look at the other fella’s garden, you have to say something like, “May I observe your gorgeous garden?” So there’s 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 I’m doing it, it’s miserable; when you’re doing it, it’s 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 it’s a different word—it’s more polite.”

I gave up. I decided that wasn’t 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 proportions—so 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 can’t 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 didn’t 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 nature’s laws are different for the right hand and the left hand, that there’s a way to define the right hand by physical phenomena. I don’t know that that’s so terrible, though there must be some bad consequences of that, but I don’t know. Why don’t you ask the experts tomorrow?”

He said, “No, they won’t 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, “I’m 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 didn’t have the nerve to ask the question for myself. But that’s 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 didn’t understand very well. At the end of the meeting, Block asked me what he said, and I said I didn’t know, but as far as I could tell, it was still open—there was still a possibility. I didn’t 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, I’ll bet you only fifty to one you don’t find anything.”

He said, “That’s 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 Rochester—the 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 can’t understand these things that Lee and Yang are saying. It’s all so complicated.”

“No,” she said, “what you mean is not that you can’t understand it, but that you didn’t invent it. You didn’t figure it out your own way, from hearing the clue. What you should do is imagine you’re a student again, and take this paper upstairs, read every line of it, and check the equations. Then you’ll understand it very easily.”

I took her advice, and checked through the whole thing, and found it to be very obvious and simple. I had been afraid to read it, thinking it was too difficult.

It reminded me of something I had done a long time ago with left and right unsymmetrical equations, Now it became kind of clear, when I looked at Lee’s formulas, that the solution to it all was much simpler: Everything comes out coupled to the left. For the electron and the muon, my predictions were the same as Lee’s, except I changed some signs around. I didn’t realize it at the time, but Lee had taken only the simplest example of muon coupling, and hadn’t proved that all muons would be full to the right, whereas according to my theory, all muons would have to be full automatically. Therefore, I had, in fact, a prediction on top of what he had. I had different signs, but I didn’t realize that I also had this quantity right.

I predicted a few things that nobody had experiments for yet, but when it came to the neutron and proton, I couldn’t make it fit well with what was then known about neutron and proton coupling: it was kind of messy.

The next day, when I went back to the meeting, a very kind man named Ken Case, who was going to give a paper on something, gave me five minutes of his allotted time to present my idea. I said I was convinced that everything was coupled to the left, and that the signs for the electron and muon are reversed, but I was struggling with the neutron. Later the experimenters asked me some questions about my predictions, and then I went to Brazil for the summer.