Boston Public Library, April 2005
in connection with the publication of his Collected Letters This essay is in Idea Makers: Personal Perspectives on the Lives & Ideas of Some Notable People »

I first met Richard Feynman when I was 18, and he was 60. And over the course of ten years, I think I got to know him fairly well. First when I was in the physics group at Caltech. And then later when we both consulted for a once-thriving Boston company called Thinking Machines Corporation.

I actually don’t think I’ve ever talked about Feynman in public before. And there’s really so much to say, I’m not sure where to start.

But if there’s one moment that summarizes Richard Feynman and my relationship with him, perhaps it’s this. It was probably 1982. I’d been at Feynman’s house, and our conversation had turned to some kind of unpleasant situation that was going on. I was about to leave. And Feynman stopped me and said, "You know, you and I are very lucky. Because whatever else is going on, we’ve always got our physics."

Feynman loved doing physics. I think what he loved most was the process of it. Of calculating. Of figuring things out. It didn’t seem to matter to him so much if what came out was big and important. Or esoteric and weird. What mattered to him was the process of finding it. And he was often quite competitive about it.

Some scientists (myself probably included) are driven by the ambition to build grand intellectual edifices. I think Feynman—at least in the years I knew him—was much more driven by the pure pleasure of actually doing the science. He seemed to like best to spend his time figuring things out, and calculating. And he was a great calculator. All around perhaps the best human calculator there’s ever been.

Here’s a page from my files: quintessential Feynman. Calculating a Feynman diagram.

It’s kind of interesting to look at. His style was always very much the same. He always just used regular calculus and things. Essentially nineteenth-century mathematics. He never trusted much else. But wherever one could go with that, Feynman could go. Like no one else.

I always found it incredible. He would start with some problem, and fill up pages with calculations. And at the end of it, he would actually get the right answer! But he usually wasn’t satisfied with that. Once he’d gotten the answer, he’d go back and try to figure out why it was obvious. And often he’d come up with one of those classic Feynman straightforward-sounding explanations. And he’d never tell people about all the calculations behind it. Sometimes it was kind of a game for him: having people be flabbergasted by his seemingly instant physical intuition, not knowing that really it was based on some long, hard calculation he’d done.

He always had a fantastic formal intuition about the innards of his calculations. Knowing what kind of result some integral should have, whether some special case should matter, and so on. And he was always trying to sharpen his intuition.

You know, I remember a time—it must have been the summer of 1985—when I’d just discovered a thing called rule 30. That’s probably my own all-time favorite scientific discovery. And that’s what launched a lot of the whole new kind of science that I’ve spent 20 years building. [See A New Kind of Science, page 27.]

Well, Feynman and I were both visiting Boston, and we’d spent much of an afternoon talking about rule 30. About how it manages to go from that little black square at the top to make all this complicated stuff. And about what that means for physics and so on. [See A New Kind of Science, page 30.]

Well, we’d just been crawling around the floor—with help from some other people—trying to use meter rules to measure some feature of a giant printout of it. And Feynman took me aside, rather conspiratorially, and said, "Look, I just want to ask you one thing: how did you know rule 30 would do all this crazy stuff?" "You know me," I said. "I didn’t. I just had a computer try all the possible rules. And I found it." "Ah," he said, "now I feel much better. I was worried you had some way to figure it out."

Feynman and I talked a bunch more about rule 30. He really wanted to get an intuition for how it worked. He tried bashing it with all his usual tools. Like he tried to work out what the slope of the line between order and chaos is. And he calculated. Using all his usual calculus and so on. He and his son Carl even spent a bunch of time trying to crack rule 30 using a computer.

And one day he calls me and says: "OK, Wolfram, I can’t crack it. I think you’re on to something." Which was very encouraging.

Feynman and I tried to work together on a bunch of things over the years. On quantum computers before anyone had ever heard of those. On trying to make a chip that would generate perfect physical randomness—or eventually showing that that wasn’t possible. On whether all the computation needed to evaluate Feynman diagrams really was necessary. On whether it was a coincidence or not that there’s an e^{–H t} in statistical mechanics and an e^{i H t} in quantum mechanics. On what the simplest essential phenomenon of quantum mechanics really is.

I remember often when we were both consulting for Thinking Machines in Boston, Feynman would say, "Let’s hide away and do some physics." This was a typical scenario. Yes, I think we thought nobody was noticing that we were off at the back of a press conference about a new computer system talking about the nonlinear sigma model. Typically, Feynman would do some calculation. With me continually protesting that we should just go and use a computer. Eventually I’d do that. Then I’d get some results. And he’d get some results. And then we’d have an argument about whose intuition about the results was better.

I should say, by the way, that it wasn’t that Feynman didn’t like computers. He even had gone to some trouble to get an early Commodore PET personal computer. And enjoyed doing things with it. And in 1979, when I started working on the forerunner of what would become Mathematica, he was very interested. We talked a lot about how it should work. He was keen to explain his methodologies for solving problems: for doing integrals, for notation, for organizing his work. I even managed to get him a little interested in the problem of language design. Though I don’t think there’s anything directly from Feynman that has survived in Mathematica. But his favorite integrals we can certainly do.

You know, it was sometimes a bit of a liability having Feynman involved. Like when I was working on SMP—the forerunner of Mathematica—I organized some seminars by people who’d worked on other systems. And Feynman used to come. And one day a chap from a well-known computer science department came to speak. I think he was a little tired, and he ended up giving what was admittedly not a good talk. And it degenerated at some point into essentially telling puns about the name of the system they’d built. Well, Feynman got more and more annoyed. And eventually stood up and gave a whole speech about how "If this is what computer science is about, it’s all nonsense…." I think the chap who gave the talk thought I’d put Feynman up to this. And has hated me for 25 years….

You know, in many ways, Feynman was a loner. Other than for social reasons, he really didn’t like to work with other people. And he was mostly interested in his own work. He didn’t read or listen too much; he wanted the pleasure of doing things himself. He did used to come to physics seminars, though. Although he had rather a habit of using them as problem-solving exercises. And he wasn’t always incredibly sensitive to the speakers. In fact, there was a period of time when I organized the theoretical physics seminars at Caltech. And he often egged me on to compete to find fatal flaws in what the speakers were saying. Which led to some very unfortunate incidents. But also led to some interesting science.

One thing about Feynman is that he went to some trouble to arrange his life so that he wasn’t particularly busy—and so he could just work on what he felt like. Usually he had a good supply of problems. Though sometimes his long-time assistant would say: "You should go and talk to him. Or he’s going to start working on trying to decode Mayan hieroglyphs again." He always cultivated an air of irresponsibility. Though I would say more towards institutions than people.

And I was certainly very grateful that he spent considerable time trying to give me advice—even if I was not always great at taking it. One of the things he often said was that "peace of mind is the most important prerequisite for creative work." And he thought one should do everything one could to achieve that. And he thought that meant, among other things, that one should always stay away from anything worldly, like management.

Feynman himself, of course, spent his life in academia—though I think he found most academics rather dull. And I don’t think he liked their standard view of the outside world very much. And he himself often preferred more unusual folk.

Quite often he’d introduce me to the odd characters who’d visit him. I remember once we ended up having dinner with the rather charismatic founder of a semi-cult called EST. It was a curious dinner. And afterwards, Feynman and I talked for hours about leadership. About leaders like Robert Oppenheimer. And Brigham Young. He was fascinated—and mystified—by what it is that lets great leaders lead people to do incredible things. He wanted to get an intuition for that.

You know, it’s funny. For all Feynman’s independence, he was surprisingly diligent. I remember once he was preparing some fairly minor conference talk. He was quite concerned about it. I said, "You’re a great speaker; what are you worrying about?" He said, "Yes, everyone thinks I’m a great speaker. So that means they expect more from me." And in fact, sometimes it was those throwaway conference talks that have ended up being some of Feynman’s most popular pieces. On nanotechnology. Or foundations of quantum theory. Or other things.

You know, Feynman spent most of his life working on prominent current problems in physics. But he was a confident problem solver. And occasionally he would venture outside, bringing his "one can solve any problem just by thinking about it" attitude with him. It did have some limits, though. I think he never really believed it applied to human affairs, for example. Like when we were both consulting for Thinking Machines in Boston, I would always be jumping up and down about how if the management of the company didn’t do this or that, they would fail. He would just say, "Why don’t you let these people run their company; we can’t figure out this kind of stuff." Sadly, the company did in the end fail. But that’s another story.

Well, there’s lots more I could say about Feynman. But let me stop here. It’s really fun to read his letters. I’d seen a small sampling before. But together they make a fascinating portrait of a terrific man. And it was nice of him to write such nice things about me.