Source: American Institute of Physics, Jun 1966
Let’s start first, for example, with Fermi.
When I was at Los Alamos, I knew many of these great guys. Fermi was at Chicago all the time, but about half way through, somewhere, I don’t know exactly, he came to consult from time to time, to help out by consulting, at Los Alamos.
One of the early times, perhaps the first time, I don’t know, he was in a room, and we were supposed to be discussing some problem involving mixing uranium and hydrogen which I had been working on with my group. He wanted the results of it.
Now, for everybody else in the lab I was particularly good at, or I seemed to be good at, understanding the results of a calculation. So when somebody would make a calculation, I could see why it ought to be more or less like it was without actually calculating it by some physical reasoning. I was the expert, the guy they’d usually try to ask if he could see why it came out that way, and I was fairly successful.
As far as my own calculation for this hydrogen business, it was rather complicated for me to see why it came out the way it did. It was only to me the result of calculations I could give, rather than a real understanding.
So, Fermi was in this conference, this little group. It was in a small room, and there must have been eight or ten people or something like that, and he asked what about this stuff with hydrogen. He wanted me to report so he could think about it. So I thought it out.
I told the problem and he said, “Ah, let me see what I think might happen.” Then he started to give the kind of physical argument I’m always giving, and he went along; it would be this way and then it would be that way. I said, “No, you left out a feature. You see, there’s this extra complication.” “Oh, yes,” says he, and then he went a little bit further, and he worked it out and explained the results of my calculation, which I hadn’t previously understood.
It was very impressive to me, because he was able to do to me what I was able to do to somebody else. So he was just that much beyond me as I was beyond a lot of other people. So I remember that very distinctly, as a very clear thinking, clear physical thinking man.
Another story of this kind is that I wrote some kind of report on something, and when he was visiting — this was later, I know this was later — he was visiting, and he calls up on the telephone.
He says, “Hey, Feynman, I’ve been reading LADC l62” — whatever the number was -– “this article of yours,” and he says, “I wonder why you bother to print it, because couldn’t even a child see that this result has to come out this way?”
So I say, “Yes, if that child’s name was Enrico Fermi.” “No,” he says, “even an ordinary child.” It turned out at the end it wasn’t as obvious as he thought, but anyway, that’s the way we talked to each other. He’s a very nice fellow. I was often at his home, and his wife made us dinner — you know we had parties at his home and everything. I liked him very much.
How did you feel about him as to his relative position in physics? By this time, or even in Los Alamos, you began to know a lot of people. How did you regard him as to his relative standing in the world of physics?
One of the very great physicists. Yes. You must appreciate that I don’t put them in order. There’s no order, because their qualities are different, you know. I mean, each one has a way, and his was clarity of physical reasoning, which was his expertness, you see. So I don’t make an order. For instance, I couldn’t say which is the better physicist, Bethe or Fermi. That is to me an impossible assignment; Oppenheimer or Bethe, Pauli versus someone. They’re all very great guys. And Fermi to me was someone I loved to talk to, that I thought was marvelous, a very great physicist. Very great.