In a new biography, Graham Farmelo digs deep into the archives and personal papers of a little-known Nobel-winning physicist. Farmelo discusses The Strangest Man: The Hidden Life of Paul Dirac, Mystic of the Atom and his theory that Dirac may have been autistic.
IRA FLATOW, host: Up next, the strangest physicist you probably never heard of. At age 31 in 1933, Paul Dirac won the Nobel Prize. And at the time, he was the youngest person ever to receive that honor. His work figuring out the mathematical equations that describe the universe is right up there with the work of Einstein in terms of its importance and elegance.</s>IRA FLATOW, host: Ask someone on the street if they've ever heard of Paul Dirac, and the answer probably is, no. The reason? Well, it probably has a lot to do with Dirac himself, by most accounts, a strange man.</s>IRA FLATOW, host: My next guest has poured over the personal papers and archives of Paul Dirac and stitched them together into a great biography. He joins me now to talk about it. Graham Farmelo, the author of "The Strangest Man: The Hidden Life of Paul Dirac, Mystic of the Atom." He's adjunct professor of physics at Northeastern University, senior research fellow at the Science Museum in London. He joins us from the studios of WBGO in Newark.</s>IRA FLATOW, host: Welcome to SCIENCE FRIDAY, Dr. Farmelo.</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): Oh, it's a great pleasure to be here.</s>IRA FLATOW, host: Tell us why you chose such a, you know, a person that no one knows about? Is it because no one knows about him?</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): Well, that's part of the reason. Dirac is sometimes called the theoretician's theoretician. And in my misspent youth, I attempted to be a theoretical physicist. And like all the people in that profession, I looked up to Paul Dirac. I mean, he was a hero, as he was to the greats of 20th century physics. And that and knowing that he have this rather opaque life that didn't seem to make any sense, I thought it was a challenge to try to bring the life of this fantastic physicist…</s>IRA FLATOW, host: Yeah.</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): …to not just scientists, but to, you know, to people who are just curious about what would make someone like that tick.</s>IRA FLATOW, host: You know, because when you look, you know, you look - you thumb through science books of great scientist of that era…</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): Mm-hmm.</s>IRA FLATOW, host: …you never see pictures of him in groups with people and stuff like that. He's always sort of missing from photos.</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): Well, I think that's true. He didn't like to be photographed. He was very, very retiring. But, you know, on set pieces, he liked to be in the action. When he went to the first big European meeting when he was a 20-odd-year-old, he made absolutely certain that he was standing right behind Einstein's right shoulder.</s>IRA FLATOW, host: We're talking about Paul Dirac this hour on SCIENCE FRIDAY from NPR News. I'm Ira Flatow talking with Graham Farmelo, author of "The Strangest Man: The Hidden Life of Paul Dirac, Mystic of the Atom." Why mystic of the atom?</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): Well, he had this faith - you could really call it a faith - that if you had a beautiful mathematical equation, that it had a truth that you could extract from it. So when he set out his incredibly beautiful equation for the electron, that equation had problems. There's no doubt about it. He knew that. But he had tremendous faith, a mystical faith…</s>IRA FLATOW, host: Mm-hmm.</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): …that if you stuck with that equation and worked at it, it would continue to yield fruit. So he had that kind of mystical approach to theoretical physics.</s>IRA FLATOW, host: So he went from the mathematical side?</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): Yeah, very much so.</s>IRA FLATOW, host: Yeah. He didn't have a theory. He had math and then tried to find a theory to fit the math? Would that be fair?</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): Yeah. Well, that's a pretty good way of summarizing it, yeah. I mean, Dirac was very mathematically minded. That is true. But he was actually trained as an engineer.</s>IRA FLATOW, host: Yeah.</s>IRA FLATOW, host: Dr. FARMELO  He had a very down-to-earth attitude. He wasn't in the game of physics to do just fancy mathematics. He wanted to set out the fundamental laws of nature in the most beautiful possible way in order to agree with experiment. His project was to set out those great laws of physics, just exactly the same as Einstein wanted to do.</s>IRA FLATOW, host: But he never got the celebrity that Einstein did.</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): Oh, no. That's absolutely right. He didn't want it. He would actually pose as an ordinary member of the public when officials came looking for him, really. I mean, Heisenberg would actually - one of his colleagues in quantum physics would actually lie and say that he's nowhere to be seen, whereas Dirac was actually sitting behind the photographers, right?</s>IRA FLATOW, host: Wow.</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): He just didn't want anything to do with it. You know, and part of the reason, you know, that Dirac wasn't famous is he had no great moment where a scientist is suddenly propelled into celebrity. I mean, Einstein had one in 1919. He was famous to his colleagues, but the public knew nothing about him. But then, it was arranged that there would be this great conflict between Einstein and Newton over the bending of starlight. And then overnight, Einstein became a world celebrity.</s>IRA FLATOW, host: Right.</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): Likewise, Hawking with his book - you know, he was not famous until his incredibly popular book came out, and then he was propelled onto the stage.</s>IRA FLATOW, host: Mm-hmm. So he - so did he go lead his whole life unknown, but well-respected among his colleagues?</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): Oh, yeah. If I may say, well-respected is an understatement.</s>IRA FLATOW, host: Yeah.</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): I mean, as I said, people like, you know, Richard Feynman and - these have gone on the records saying he was their hero. He was the person they looked up to.</s>IRA FLATOW, host: Mm-hmm. If - in 1933, he won the Nobel Prize. And as I said before, he was the youngest theoretician to do that. What did he actually win it for?</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): That's right. Well, he won it for his contributions to quantum mechanics. Now, quantum mechanics is the theory of the - roughly speaking - of the micro world. Newton's theories, that covers bridges and planets and things like that, that doesn't work when you try to use it right down at the atomic level. And quantum mechanics, which is the most revolutionary theory of the 20th century, was developed, discovered by a handful of physicists, one of whom was Paul Dirac.</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): Now, the Nobel Committee were actually quite slow to recognize - reward quantum mechanics because there was actually rather little evidence that it was correct, at least in the eyes of the conservatives who were running the Nobel Academy at that time. But Dirac had this fantastic success when he made his prediction of the anti-electron, the antiparticle of the electron. And it was - and then it was discovered in America in 1932. And that was such a success that they decided that he should be given the Nobel Prize in 1933.</s>IRA FLATOW, host: Wow. Talking with, well, with Graham Farmelo, author of "The Strangest Man: The Hidden Life of Paul Dirac, Mystic of the Atom." Our number: 1-800-989-8255.</s>IRA FLATOW, host: And he lived in this era of great discovery in physics, in quantum mechanics. If you'd like to ask our author, Graham Farmelo, a question about Dirac or any other great physicists who were alive at that time -that was some time to be alive back then - our number: 1-800-989-8255. Or also, you can tweet us at @scifi, @-S-C-I-F-R-I.</s>IRA FLATOW, host: We have to take a short break, but stay with us. We'll be right back with "The Strangest Man: The Hidden Life of Paul Dirac, Mystic of the Atom," Graham Farmelo. We'll be right back.</s>IRA FLATOW, host: You're listening to SCIENCE FRIDAY from NPR News. I'm Ira Flatow, talking with Graham Farmelo, author of "The Strangest Man: The Hidden Life of Paul Dirac, Mystic of the Atom." 1-800-989-8255.</s>IRA FLATOW, host: And Graham, you talk about how Dirac just was like a humorless guy, speaking in monosyllables, a couple of syllables at a time. And he was sort of all the butt of jokes among physicists about, you know, being Dirac-like?</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): Mm-hmm.</s>IRA FLATOW, host: And then there is a chapter at the - near the end of your book where you explain that you think that Dirac may have been autistic.</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): Mm-hmm.</s>IRA FLATOW, host: There were symptoms of being - that must be very controversial…</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): Yeah. Yeah.</s>IRA FLATOW, host: …for you to come to a conclusion like that.</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): Yeah. Well, I have to say, I wouldn't say he was humorless. He actually did like jokes, and some of them quite - some quite racy jokes. But taken as a whole, if you look at his behavior, and I did -honestly, I did not start out the book thinking that he was autistic. I mean, but when I look back after several years of research and looked at all the evidence, then in my view, you take the definition of autism, the medical definition of autism, and you compare it to every single aspect of his behavior, then I would say the evidence is very compelling that Dirac is - or was a classic example of someone who is autistic.</s>IRA FLATOW, host: What kind of evidence are you talking about? Give us an idea.</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): Well, you look at all the classic symptoms, so to speak: very repetitive behavior, found empathy extremely, extremely difficult, man of extremely few words. I mean, is it - Dirac is someone who - there was actually a unit called a Dirac, which was one word an hour, which was used in Cambridge.</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): Someone of an extremely narrow range of interests, or at least, it certainly appeared like that in his younger years. Later on, when he was at Florida State University on the faculty there, I mean, he did loosen up, somewhat. But if you go through it systematically…</s>IRA FLATOW, host: Yeah.</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): …it's really - I think the evidence is very compelling.</s>IRA FLATOW, host: Hmm. 1-800-989-8255. Bill in California. Hi. Welcome to SCIENCE FRIDAY.</s>BILL (Caller): Hi. Thank you. I just wanted to ask your guest. There's a famous picture of Richard Feynman and Dirac outside of, I think, one of the institutes of physics in France, if he knew what the circumstances were of that picture? And also, if he could comment on Dirac's influence on Feynman, who I think was actually pretty great.</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): Yeah. Well, I think the picture you're talking about is - was taken in Poland. And that was one of the times where Feynman tried to pin Dirac down, something he often wanted to do, because as I said earlier, Dirac was a hero to Feynman. Feynman was working on a theory in photons, electrons, building on Dirac's great work in the mid-1920s. But he found as he - Feynman often said to friends - extremely difficult to get anything out of Dirac. He was a person of such - he was so inward, so to speak…</s>IRA FLATOW, host: Yeah.</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): …so unwilling to open up that Feynman found it virtually hopeless.</s>IRA FLATOW, host: What would - what - if he were alive today - and it may be an unfair question, but I'll ask it anyhow. What do you think he would make of string theory and these other mathematical models? And he loved math. Would he be in favor of something like string theory?</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): I personally - obviously it's difficult to talk about somebody who's dead.</s>IRA FLATOW, host: Yeah. Yeah.</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): But, if you ask me.</s>IRA FLATOW, host: Yeah.</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): I mean, the key thing here, in my opinion, is that what Dirac believed more than anything else, right, is that beauty is the lodestar of fundamental theories of nature, that he really believed that fundamental theories advance from one to the next, each subsequent theory being more beautiful than the one that preceded it. This, to him, and I quote, was like a religion. He said at one point that for him, the beauty of the mathematical equations was more important than the agreement they give with experiment. Very controversial statement.</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): Now, if you look at string theory now, if we take what the great practitioners of that theory are saying at face value, then it appears that, all right. There's no direct experimental evidence for that. That...</s>IRA FLATOW, host: Yeah. Yeah.</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): …that's impossible to deny. But it's an enormously rich theory, a generalization of a theory that we know works well and has enormous potential. And Dirac, in my view, would be urging those theories to persist, persist with the - with what beauty is telling them, so to speak in - and have faith that eventually you will get agreement with experiment.</s>IRA FLATOW, host: Let's go to Darcy in Columbus, Ohio. Hi, Darcy.</s>DARCY (Caller): Hi. I was wondering, why wasn't he more recognized for his discovery of the anti-electron and other particles…</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): Well…</s>DARCY (Caller): …in modern society?</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): Yeah, yeah. I think that's a really good question. Just look at what that discovery is. I mean, Heisenberg, Dirac's friend and competitor, said that the discovery of the anti-electron, the first example of antimatter, was, in Heisenberg's view, perhaps the most important of all the leaps forward in 20th century physics. Just let's get this in perspective a second. Dirac, as I said, predicted on the basis of beautiful mathematics, not on the basis of experiment, that there should exist this stuff called antimatter.</s>IRA FLATOW, host: Mm-hmm.</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): If you look at the theories of the early universe now, then at the very beginning of the universe, you have half matter, half antimatter. So, by that notion, Dirac conceived half the universe in his head. Unbelievable achievement.</s>IRA FLATOW, host: That was a very Einsteinian sort of thing that...</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): Absolutely.</s>IRA FLATOW, host: Yeah. Yeah.</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): I mean, I think it's incredible. But our caller asks, why wasn't he recognized? Well, I think we go back, you know, Dirac didn't want public fame. There was nobody who had the - who was an impresario for Dirac, so to speak, who wanted to project him as a great genius. Right? And consequently, with his modesty and what have you, his name never got into the public eye.</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): I will say another thing, too, a very important thing, that although we talk about the discovery of antimatter as being a great drama, it was not seen like that at that time because Dirac's theory was seen as so way out, right, that people didn't actually take much notice of it. And it's only today that we've - if you like, we dramatize it in retrospect. So, you know, I think that's a big part of it, too.</s>IRA FLATOW, host: Hmm. Okay, Darcy. Thanks for calling. 1-800-989-8255.</s>IRA FLATOW, host: You didn't talk much about his upbringing, but there's a part in your book, one night in Tallahassee, he opens up to a friend, another teacher at Florida State, and a strange thing happened. Tell us about that night.</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): Mm-hmm. Well, he opened up, yes, to Kurt Hofer at FSU, but also to a group of other friends…</s>IRA FLATOW, host: Hmm.</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): ...each time giving the same account. I was very, very careful to - that's typical of Dirac. Once he found a way of presenting something, he stuck to it, like his lectures and all the rest of it. Dirac's account of his childhood was R-rated. He had a very domineering father, Charles, who was Swiss. And he's - and a rather shrinking violet of a mother, Flo.</s>IRA FLATOW, host: Mm-hmm.</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): And their - the father insisted on speaking to his children only in French. And at meal times, they split into two: the father and Paul Dirac, and mother and the other two children, so that Charles and Paul were only talking in French, the others only speaking in English. Most bizarre family setup.</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): In fact, in 1933, a well-informed article says that the young Dirac thought that men spoke French and women spoke English.</s>IRA FLATOW, host: Wow.</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): But his father was absolutely ruthless with his son. Any kind of grammatical error and Dirac would be denied his next wish. And according to Paul Dirac, that so frightened, intimated the young Paul that he withdrew into himself and spoke only when spoken to, and very sparingly.</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): I personally don't think that's the right reading of it, but that was how he saw his terrible childhood and how a man like Dirac never said a bad word about anyone, hardly. The one person he loathed was his father.</s>IRA FLATOW, host: Hmm. And that night in Florida State?</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): That's when he opened up to Kurt Hofer. Yeah.</s>IRA FLATOW, host: Yeah. He just spewed out, just spewed for a couple hours.</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): Well, he did, absolutely.</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): I mean, absolutely. I…</s>IRA FLATOW, host: You know, it's - somebody said, he had nothing to say until then, and then he just opened up.</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): Yeah. And, you know, he did this. He would say nothing for hours on end, people would find it painful.</s>IRA FLATOW, host: Yeah.</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): And then, once he had something he wanted to tell…</s>IRA FLATOW, host: Right.</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): …to talk about, then he would open up and he would talk for an hour - sometime - on one occasion, two hours, like with Kurt Hofer, taking in - rather like Laurence Olivier declaiming from Shakespeare in perfectly carved sentences…</s>IRA FLATOW, host: Hmm.</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): …that would just - that would spell out…</s>IRA FLATOW, host: Wow.</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): …in this case, the pain of his childhood.</s>IRA FLATOW, host: Did he make any predictions about antimatter that we're still trying to test today or look for? Or is - is his work still relevant today, or was it too long ago?</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): Oh, my goodness gracious. I mean, Dirac is like all really great minds. He's posthumously productive. I mean, the stuff that Dirac did on quantum mechanics, quantum theory, is still an inspiration to physicists today. And incidentally, not just his spirit, the spirit of mathematical beauty. But if you look at the way he treated, for example, his theory of the monopole. In 1931, in the same paper where he predicted the anti-electron, he set out a quantum theory of the single magnetic pole called the magnetic monopole.</s>IRA FLATOW, host: Hmm.</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): Now, that's not been discovered. But most physicists think that one day it will be discovered. And the geometric theory that he set out on that is extremely influential. In fact, I'll tell you, Ira.</s>IRA FLATOW, host: Yeah.</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): I was working - this summer, I was the director of physics at the Institute for Advanced Study. And I found out just recently that the biggest advance in quantum field theory in the last - in the 1990s, right, technically is called the Ads/CFT correspondence. Talking to the person that did that, Juan Maldacena, it turned out that the precursor of that paper was written in 1963 by Paul Dirac.</s>IRA FLATOW, host: Wow.</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): So I was amazed. It wasn't even in the first edition of my book. I really hadn't realized it. So Dirac is still productive, still - his papers can still be read. Often people say, the more you read Dirac…</s>IRA FLATOW, host: Right.</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): …the more you understand quantum mechanics.</s>IRA FLATOW, host: All right. A tweet from Steve DH(ph). He wants to know whatever happened to Dirac's graduate students.</s>IRA FLATOW, host: Are they still out there?</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): He didn't have that many, you know? In fact, he didn't know much about teaching. On one occasion at Cambridge, they were talking about the art of teaching. And after about an hour and a half of saying nothing, Paul Dirac piped up and said: What is supervision?</s>IRA FLATOW, host: That was it?</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): That was it. He had no idea, right? But…</s>IRA FLATOW, host: Right.</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): ...he, nonetheless, had some very successful graduate students, nearly all of whom, incidentally, were very, very bright. Dirac was a hands-off graduate student. He had people like Harish-Chandra, the great mathematician, one of his students. Dennis Sciama, Stephen Hawking's supervisor, was supervised by Dirac. So, he did have successful students. But I don't think he'd be most...</s>IRA FLATOW, host: Right.</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): …people's idea of a successful supervisor.</s>IRA FLATOW, host: Well, did he talk to them mathematically? With the trouble speaking verbally to anybody, did he open up to them verbally, or did he - you know, just one who gets to the blackboard and puts the equations or explains the math to them?</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): He wouldn't open up in the same way that you or I would open up. But he did - he had the rudiments of supervision in a sense that he knew you had to give your students soluble problems. But the idea of being a support and an enthuser, that was lost on Paul Dirac.</s>IRA FLATOW, host: And put all this together, that's why you're thinking that he might have been autistic.</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): Well, yes. I mean, as I said, I looked at his whole behavior when making that speculation.</s>IRA FLATOW, host: Yeah. Yeah.</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): And it is a speculation.</s>IRA FLATOW, host: Yeah. Yeah. We're talking about Paul Dirac with Graham Farmelo, author of "The Strangest Man: The Hidden Life of Paul Dirac, Mystic of the Atom" on SCIENCE FRIDAY from NPR News. I'm Ira Flatow. Our number is 1-800-989-8255.</s>IRA FLATOW, host: Let's see if we can get a phone to - a phone call or two in before we have to leave. Ben in Louisville.</s>BEN (Caller): Hi. I have a question about the discovery of antimatter. And can you describe what led him to predict its existence before it had been detected?</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): Yes. Well, he had this equation, perhaps his most famous contribution to physics, which was the Dirac - called the Dirac equation. Now, that equation describes the electron. Now, the reason why it's so special is that it was an arranged marriage between quantum theory and Einstein's special theory of relativity.</s>IRA FLATOW, host: Mm-hmm.</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): It was - it actually combined those two in giving a description of the electron. Now, the equation was a complete triumph, right? Because it explained, for example, why the electron has spin, something that was seen as completely magical. The problem is it did have problems, right? And what Dirac did after a long chain of reasoning was to say that his equation was right if - and he deduced this from his mathematics - there existed another particle that has the same mass as the electron but the opposite charge. And that was the particle that showed up in the cosmic rays raining down in California on the 2nd of August, 1932, when the great American experimenter Carl Anderson actually saw that first antiparticle.</s>IRA FLATOW, host: Mm-hmm. Did he - was he able to predict where all these antimatter went to after the Big Bang?</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): No, no. What he did correctly say was that the fundamental property of antimatter is that when you have, say, an electron and anti-electron, when you bring them together, they annihilate each other…</s>IRA FLATOW, host: Right.</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): …into radiation. That's the fundamental thing about matter and antimatter.</s>IRA FLATOW, host: One last question from Philip at FSU. Hi, Philip.</s>PHILIP (Caller): Hi. How are you?</s>IRA FLATOW, host: Hi, there.</s>PHILIP (Caller): I wanted to know what was the last thing Paul Dirac was working on, like his last publication or his last science paper.</s>IRA FLATOW, host: Before he died. Yeah.</s>PHILIP (Caller): Yeah.</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): Well, the last paper he was - he wrote was a paper that told people to move on from his theory.</s>IRA FLATOW, host: Hmm.</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): He had a theory of photons and electrons. He discovered that way back in 1926. But he thought that theory was fundamentally flawed, and he urged young physicists to be revolutionaries and go beyond that theory. So - it's amazingly selfless, in a way. He wasn't trying to back up his own stuff. Rather, he was urging other people to move on and do dramatically new things.</s>IRA FLATOW, host: So he had to tell people, you know, this was my time, now it's your time.</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): Absolutely.</s>IRA FLATOW, host: Find your own idea.</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): That's right. And I must say, what upset him about those theories was the presence of these infinities in the equations that describe these electron-photon interactions. And if you look at string theory today, that is a finite theory. So you could say that Dirac was validated there in that we - that his hatred of those infinities is borne out by having a theory now that is finite.</s>IRA FLATOW, host: But he'd have to have 11 dimensions or something like that.</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): That's true. But hold on. You know, we may discover these extra dimensions with the Large Hadron Collider, you know?</s>IRA FLATOW, host: Yeah. But would that be - and that would be satisfying to him, and he would accept that we have these weird 11 dimensions, and that would fit mathematically for him.</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): Oh, yeah. But ultimately, experiment has to be the thing that has to be followed. But yeah, you can be as mathematically adventurous as you like, as long as your feet are on the ground with experiment.</s>IRA FLATOW, host: Mm-hmm. So the theory has to predict an experiment that you can do.</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): Yeah, yeah. I mean, that's what Dirac would insist, that you have to be able to compare - and that causes a difficulty with string theory.</s>IRA FLATOW, host: Right.</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): But I don't think it's an insuperable one.</s>IRA FLATOW, host: Oh, you think that these - the experiments will find something there, do you think?</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): Oh, I don't know. I hope so.</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): We're all looking forward to the Large Hadron Collider, aren't we? Because then we - it really will sort out, you know, how good our theories are. It's going to be fantastic.</s>IRA FLATOW, host: I'm hoping they get it fixed and fire it up real soon.</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): Yeah. Me, too. And, you know, at CERN, there is a Dirac road. I mean, Dirac actually - well, he wouldn't go to Switzerland because he hated his Swiss father so much. But he did go back there in the 1970s, and there is a Rue Dirac. And that beam passes through Rue Dirac there.</s>IRA FLATOW, host: That's poetic justice. Thank you very much, Graham, for taking time to be with us.</s>Dr. GRAHAM FARMELO (Senior Research Fellow, Science Museum in London; Author): Hey, it's my pleasure, Ira.</s>IRA FLATOW, host: Yeah. Graham Farmelo, author of the "The Strangest Man: The Hidden Life of Paul Dirac, Mystic of the Atom." Very easy read, very nice history book, the history of science book about someone you may never have known about before.