Omni: There’s another thing that seems to happen a lot in modern physics: the discovery of applications for kinds of mathematics that were previously “pure,” such as matrix algebra or group theory. Are physicists more receptive now than they used to be? Is the time lag less?
Feynman: There never was any time lag. Take Hamilton’s* quaternions: the physicists threw away most of this very powerful mathematical system, and kept only the part–the mathematically almost trivial part–that became vector analysis. But when the whole power of quaternions was needed, for quantum mechanics, Pauli† re-invented the system on the spot in a new form. Now, you can look back and say that Pauli’s spin matrices and operators were nothing but Hamilton’s quaternions . . . but even if physicists had kept the system in mind for ninety years, it wouldn’t have made more than a few weeks’ difference.
Say you’ve got a disease, Werner’s granulomatosis or whatever, and you look it up in a medical reference book. You may well find that you then know more about it than your doctor does, although he spent all that time in medical school . . . you see? It’s much easier to learn about some special, restricted topic than a whole field. The mathematicians are exploring in all directions, and it’s quicker for a physicist to catch up on what he needs than to try to keep up with everything that might conceivably be useful. The problem I was mentioning earlier, the difficulties with the equations in the quark theories–it’s the physicists’ problem, and we’re going to solve it, and maybe when we solve it we’ll be doing mathematics. It’s a marvelous fact, and one I don’t understand, that the mathematicians had investigated groups and so on before they turned up in physics–but in regard to the speed of progress in physics, I don’t think it’s all that significant.
Omni: One more question from your lectures: you say there that “the next great era of awakening of human intellect may well produce a method of understanding the qualitative content of equations.” What do you mean by that?
Feynman: In that passage I was talking about the Schrödinger* equation. Now, you can get from that equation to atoms bonding in molecules, chemical valences–but when you look at the equation, you can see nothing of the wealth of phenomena that the chemists know about; or the idea that quarks are permanently bound so you can’t get a free quark–maybe you can and maybe you can’t, but the point is that when you look at the equations that supposedly describe quark behavior, you can’t see why it should be so. Look at the equations for the atomic and molecular forces in water, and you can’t see the way water behaves; you can’t see turbulence.
Omni: That leaves the people with questions about turbulence–the meteorologists and oceanographers and geologists and airplane designers–kind of up the creek, doesn’t it?
Feynman: Absolutely. And it might be one of those up-the-creek people who’ll get so frustrated he’ll figure it out, and at that point he’ll be doing physics. With turbulence, it’s not just a case of physical theory being able to handle only simple cases–we can’t do any. We have no good fundamental theory at all.
Omni: Maybe it’s the way the textbooks are written, but few people outside science appear to know just how quickly real, complicated physical problems get out of hand as far as theory is concerned.
Feynman: That’s very bad education. The lesson you learn as you grow older in physics is that what we can do is a very small fraction of what there is. Our theories are really very limited.
Omni: Do physicists vary greatly in their ability to see the qualitative consequences of an equation?
Feynman: Oh, yes–but nobody is very good at it. Dirac said that to understand a physical problem means to be able to see the answer without solving equations. Maybe he exaggerated; maybe solving equations is experience you need to gain understanding–but until you do understand, you’re just solving equations.
Omni: As a teacher, what can you do to encourage that ability?
Feynman: I don’t know. I have no way to judge the degree to which I’m getting across to my students.
Omni: Will a historian of science someday trace the careers of your students as others have done with the students of Retherford and Niels Bohr and Fermi?
Feynman: I doubt it. I’m disappointed with my students all the time. I’m not a teacher who knows what he’s doing.
Omni: But you can trace influences the other way, say, the influence on you of Hans Bethe or John Wheeler . . .?
Feynman: Sure. But I don’t know the effect I’m having. Maybe it’s just my character: I don’t know. I’m not a psychologist or sociologist, I don’t know how to understand people, including myself. You ask, how can this guy teach, how can he be motivated if he doesn’t know what he’s doing? As a matter of fact, I love to teach. I like to think of new ways of looking at things as I explain them, to make them clearer–but maybe I’m not making them clearer. Probably what I’m doing is entertaining myself.
I’ve learned how to live without knowing. I don’t have to be sure I’m succeeding, and as I said before about science, I think my life is fuller because I realize that I don’t know what I’m doing. I’m delighted with the width of the world!
Omni: As we came back to the office, you stopped to discuss a lecture on color vision you’ll be giving. That’s pretty far from fundamental physics, isn’t it? Wouldn’t a physiologist say you were “poaching”?
Feynman: Physiology? It has to be physiology? Look, give me a little time and I’ll give a lecture on anything in physiology. I’d be delighted to study it and find out all about it, because I can guarantee you it would be very interesting. I don’t know anything, but I do know that everything is interesting if you go into it deeply enough.
My son is like that, too, although he’s much wider in his interests than I was at his age. He’s interested in magic, in computer programming, in the history of the early church, in topology–oh, he’s going to have a terrible time, there are so many interesting things. We like to sit down and talk about how different things could be from what we expected; take the Viking landers on Mars, for example, we were trying to think how many ways there could be life that they couldn’t find with that equipment. Yeah, he’s a lot like me, so at least I’ve passed on this idea that everything is interesting to at least one other person.
Of course, I don’t know if that’s a good thing or not. . . . You see?
______
*(1929– ) Winner of the 1969 Nobel Prize in Physics for his contributions and discoveries concerning the classification of elementary particles and their interactions. In 1964 Gell-Mann and G. Zweig introduced the concept of quarks. Ed.
*Theories in particle physics that describe the various interactions between subatomic particles. Ed.
*Willis Lamb (1913– ), winner of the 1955 Nobel Prize in Physics for his discoveries concerning the fine structure of the hydrogen spectrum. Ed.
†Robert C. Retherford, American physicist, whose 1947 experiments with Willis Lamb demonstrated the energy separation in hydrogen (the Lamb shift), and contributed to the development of quantum electrodynamics. Ed.
*“Color” is actually a name physicists gave to a certain property of quarks and gluons not because they have any actual color, but for want of a better name for a new property of elementary particles. Ed.
*Sir William Rowan Hamilton (1805–1865), Irish mathematician who invented quaternions, an alternate construct to tensor and vector analysis. Ed.
†Wolfgang Pauli (1900–1958), winner of the 1945 Nobel Prize in Physics for his discovery of exclusion principle. Ed.
*Erwin Schrödinger (1887–1961), winner (with P.A.M. Dirac) of the 1933 Nobel Prize in Physics for the discovery of new, productive forms of atomic theory. Ed.
10
CARGO CULT SCIENCE: SOME REMARKS ON SCIENCE, PSEUDOSCIENCE, AND LEARNING HOW TO NOT FOOL YOURSELF
The 1974 Caltech Commencement Address
Question: What do witch doctors, ESP, South Sea Islanders, rhinoceros horns, and Wesson Oil have to do with college graduation? Answ
er: They’re all examples the crafty Feynman uses to convince departing graduates that honesty in science is more rewarding than all the kudos and temporary successes in the world. In this address to Caltech’s class of 1974, Feynman gives a lesson in scientific integrity in the face of peer pressure and glowering funding agencies.
During the Middle Ages there were all kinds of crazy ideas, such as that a piece of rhinoceros horn would increase potency. (Another crazy idea of the Middle Ages is these hats we have on today–which is too loose in my case.) Then a method was discovered for separating the ideas–which was to try one to see if it worked, and if it didn’t work, to eliminate it. This method became organized, of course, into science. And it developed very well, so that we are now in the scientific age. It is such a scientific age, in fact, that we have difficulty in understanding how witch doctors could ever have existed, when nothing that they proposed ever really worked–or very little of it did.
But even today I meet lots of people who sooner or later get me into a conversation about UFOs, or astrology, or some form of mysticism, expanded consciousness, new types of awareness, ESP, and so forth. And I’ve concluded that it’s not a scientific world.
Most people believe so many wonderful things that I decided to investigate why they did. And what has been referred to as my curiosity for investigation has landed me in a difficulty where I found so much junk to talk about that I can’t do it in this talk. I’m overwhelmed. First I started out by investigating various ideas of mysticism, and mystic experiences. I went into isolation tanks (they’re dark and quiet and you float in Epsom salts) and got many hours of hallucinations, so I know something about that. Then I went to Esalen, which is a hotbed of this kind of thought (it’s a wonderful place; you should go visit there). Then I became over-whelmed. I didn’t realize how much there was.
I was sitting, for example, in a hot bath and there’s another guy and a girl in the bath. He says to the girl, “I’m learning massage and I wonder if I could practice on you?” She says OK, so she gets up on a table and he starts off on her foot–working on her big toe and pushing it around. Then he turns to what is apparently his instructor, and says, “I feel a kind of dent. Is that the pituitary?” And she says, “No, that’s not the way it feels.” I say, “You’re a hell of a long way from the pituitary, man.” And they both looked at me–I had blown my cover, you see–and she said, “It’s reflexology.” So I closed my eyes and appeared to be meditating.
That’s just an example of the kind of things that overwhelm me. I also looked into extrasensory perception and PSI phenomena, and the latest craze there was Uri Geller, a man who is supposed to be able to bend keys by rubbing them with his finger. So I went to his hotel room, on his invitation, to see a demonstration of both mind reading and bending keys. He didn’t do any mind reading that succeeded; nobody can read my mind, I guess. And my boy held a key and Geller rubbed it, and nothing happened. Then he told us it works better under water, and so you can picture all of us standing in the bathroom with the water turned on and the key under it, and him rubbing the key with his finger. Nothing happened. So I was unable to investigate that phenomenon.
But then I began to think, what else is there that we believe? (And I thought then about the witch doctors, and how easy it would have been to check on them by noticing that nothing really worked.) So I found things that even more people believe, such as that we have some knowledge of how to educate. There are big schools of reading methods and mathematics methods, and so forth, but if you notice, you’ll see the reading scores keep going down–or hardly going up–in spite of the fact that we continually use these same people to improve the methods. There’s a witch doctor remedy that doesn’t work. It ought to be looked into; how do they know that their method should work? Another example is how to treat criminals. We obviously have made no progress–lots of theory, but no progress–in decreasing the amount of crime by the method that we use to handle criminals.
Yet these things are said to be scientific. We study them. And I think ordinary people with commonsense ideas are intimidated by this pseudoscience. A teacher who has some good idea of how to teach her children to read is forced by the school system to do it some other way–or is even fooled by the school system into thinking that her method is not necessarily a good one. Or a parent of bad boys, after disciplining them in one way or another, feels guilty for the rest of her life because she didn’t do “the right thing,” according to the experts.
So we really ought to look into theories that don’t work, and science that isn’t science.
I tried to find a principle for discovering more of these kinds of things, and came up with the following system. Anytime you find yourself in a conversation at a cocktail party in which you do not feel uncomfortable that the hostess might come around and say, “Why are you fellows talking shop?” or that your wife will come around and say, “Why are you flirting again?”–then you can be sure you are talking about something about which nobody knows anything.
Using this method, I discovered a few more topics that I had forgotten–among them the efficacy of various forms of psychotherapy. So I began to investigate through the library, and so on, and I have so much to tell you that I can’t do it all. I will have to limit myself to just a few little things. I’ll concentrate on the things more people believe in. Maybe I will give a series of speeches next year on all these subjects. It will take a long time.
I think the educational and psychological studies I mentioned are examples of what I would like to call Cargo Cult Science. In the South Seas there is a Cargo Cult of people. During the war they saw airplanes land with lots of good materials, and they want the same thing to happen now. So they’ve arranged to make things like runways, to put fires along the sides of the runways, to make a wooden hut for a man to sit in, with two wooden pieces on his head like headphones and bars of bamboo sticking out like antennas–he’s the controller–and they wait for the airplanes to land. They’re doing everything right. The form is perfect. It looks exactly the way it looked before. But it doesn’t work. No airplanes land. So I call these things Cargo Cult Science, because they follow all the apparent precepts and forms of scientific investigation, but they’re missing something essential, because the planes don’t land.
Now it behooves me, of course, to tell you what they’re missing. But it would be just about as difficult to explain to the South Sea Islanders how they have to arrange things so that they get some wealth in their system. It is not something simple like telling them how to improve the shapes of the earphones. But there is one feature I notice that is generally missing in Cargo Cult Science. That is the idea that we all hope you have learned in studying science in school–we never explicitly say what this is, but just hope that you catch on by all the examples of scientific investigation. It is interesting, therefore, to bring it out now and speak of it explicitly. It’s a kind of scientific integrity, a principle of scientific thought that corresponds to a kind of utter honesty–a kind of leaning over backwards. For example, if you’re doing an experiment, you should report everything that you think might make it invalid–not only what you think is right about it: other causes that could possibly explain your results; and things you thought of that you’ve eliminated by some other experiment, and how they worked–to make sure the other fellow can tell they have been eliminated.
Details that could throw doubt on your interpretation must be given, if you know them. You must do the best you can–if you know anything at all wrong, or possibly wrong–to explain it. If you make a theory, for example, and advertise it, or put it out, then you must also put down all the facts that disagree with it, as well as those that agree with it. There is also a more subtle problem. When you have put a lot of ideas together to make an elaborate theory, you want to make sure, when explaining what it fits, that those things it fits are not just the things that gave you the idea for the theory; but that the finished theory makes something else come out right, in addition.
In summary, the idea is to try to give all of the information to help others to judge the value of your contribution; not just the information that leads to judgment in one particular direction or another.
The easiest way to explain this idea is to contrast it, for example, with advertising. Last night I heard that Wesson Oil doesn’t soak through food. Well, that’s true. It’s not dishonest; but the thing I’m talking about is not just a matter of not being dishonest, it’s a matter of scientific integrity, which is another level. The fact that should be added to that advertising statement is that no oils soak through food, if operated at a certain temperature. If operated at another temperature, they all will–including Wesson Oil. So it’s the implication which has been conveyed, not the fact, which is true, and the difference is what we have to deal with.
We’ve learned from experience that the truth will out. Other experimenters will repeat your experiment and find out whether you were wrong or right. Nature’s phenomena will agree or they’ll disagree with your theory. And, although you may gain some temporary fame and excitement, you will not gain a good reputation as a scientist if you haven’t tried to be very careful in this kind of work. And it’s this type of integrity, this kind of care not to fool yourself, that is missing to a large extent in much of the research in Cargo Cult Science.
A great deal of their difficulty is, of course, the difficulty of the subject and the inapplicability of the scientific method to the subject. Nevertheless, it should be remarked that this is not the only difficulty. That’s why the planes don’t land–but they don’t land.
We have learned a lot from experience about how to handle some of the ways we fool ourselves. One example: Millikan measured the charge on an electron by an experiment with falling oil drops and got an answer which we now know not to be quite right. It’s a little bit off, because he had the incorrect value for the viscosity of air. It’s interesting to look at the history of measurements of the charge of the electron, after Millikan. If you plot them as a function of time, you find that one is a little bigger than Millikan’s, and the next one’s a little bit bigger than that, and the next one’s a little bit bigger than that, until finally they settle down to a number which is higher.
The Pleasure of Finding Things Out Page 20
