FEYNMAN:
One of the biggest and most important tools of theoretical physics is the wastebasket. You have to know when to leave it alone, hmmm? In fact, I learned almost everything I know about electricity, magnetism, and quantum mechanics and everything else in attempting to develop that theory. And what I got a Nobel Prize for ultimately was that in 1947, the regular people’s theory, the ordinary theory which I was trying to fix by changing it, was in some trouble so I was trying to fix it, but Bethe had found out that if you do just the right things, if you kind of forget some things and don’t forget other things, do it just right, you can get the right answers compared to experiment and he made some suggestions to me. And I knew so much about electrodynamics by this time from having tried this crazy theory and written it in some 655 different forms that I knew how to do what he wanted, how to control and organize this calculation in a very smooth and convenient way and have powerful methods to do it. In other words, I used the stuff, the machinery which I had developed to evolve my own theory on the old theory–sounds like the obvious thing to do, but I didn’t think of it for years–and found out it was extremely powerful by that time and I could do things by the old theory much faster than anyone else had before.
NARRATOR:
In addition to a lot of other things, Dr. Feynman’s theory of quantum electrodynamics provides new insights into understanding the forces that hold matter together. It also adds a little bit more to what we know about the properties of the infinitesimally small, short-lived particles from which everything else in the universe is composed. As physicists have probed deeper and deeper into the structure of nature, they have found that what once seemed very simple may be very complex and what once seemed very complex may be very simple. Their tools are the high-powered atom smashers that can fracture atomic particles into smaller and smaller fragments.
FEYNMAN:
When we start out, we look at matter and we see many different phenomena–winds and waves and moon and all that kind of stuff. And we try to reorganize it. Is the motion of the wind like the motion of the waves and so forth? Gradually we find that many, many things are similar. It’s not as big a variety as we think. We get all the phenomena and we get the principles underneath, and one of the most useful principles seemed to be the idea that things are made of other things. We found, for example, that all matter was made out of atoms, and then a large amount is understood as long as you understand the properties of atoms. And at first the atoms are supposed to be simple, but it turns out that in order to explain all the varieties, the phenomena of matter, the atoms have to be more complicated, and that there are 92 atoms. In fact, there are many more, because they have different weights. Then to understand the variety of the properties of atoms is the next problem. And we find that we can understand that if we make out that the atoms themselves are made of constituents–in this particular case, the nucleus around which the electrons go. And that all the different atoms are just different numbers of electrons. It’s a beautifully unifying system that works.
All the different atoms are just the same thing with different numbers of electrons. However, the nuclei then differ. And so we start to study the nuclei. And there was a great variety as soon as we started experiments hitting nuclei together–Rutherford and so forth. From 1914 on, they discovered that they were complicated at first. But then it was realized that they could be understood if they’re made of constituents, too. They are made of protons and neutrons. And they interact with some force that holds them together. In order to understand the nuclei, we have to understand that force a little bit better. Incidentally, in the case of atoms there was also a force; that’s an electrical force and that we understood. So besides electrons there was also the electrical force, which we represent by photons of light. The light and electrical force are integrated into one thing called photons, so the outside world, so to speak, outside the nucleus is electrons and photons. And the theory of the behavior of electrons is quantum electrodynamics and that’s what I got the Nobel Prize for working on.
But now we go into the nucleus and find that they could be made of protons and neutrons, but there’s this strange force. Trying to understand that force is the next problem. And various suggestions that there might be other particles were made by Yukawa,* and so we did experiments hitting the protons and neutrons together with higher energy and indeed new things came out, just like when you hit electrons together with high enough energy, photons came out. So we have these new things coming out. They were mesons. So it looked like Yukawa was right. We continued the experiment. And then what happened to us was that we got a tremendous variety of particles; not just one kind of photon, you see, but we hit photons and neutrons together and we got over 400 different kinds of particles–lambda particles and sigma particles. They’re all different. And π mesons and K mesons and so on. Well, we incidentally also made muons, but they have nothing to do with neutrons and protons apparently. At least no more than electrons do. That’s a strange extra part that we don’t understand where it goes. It’s just like an electron but heavier. So we have electrons and muons out here which don’t interact strongly with these other things. These other things we call strongly interacting particles, or hadrons. And they include protons and neutrons and all the things you get immediately when you hit them together very hard. So now the problem is to try and represent the properties of all these particles in some organizing fashion. And that’s a great game and we’re all working on it. It’s called high-energy physics or fundamental particle physics. It used to be called fundamental particle physics, but nobody can believe that 400 different constituents are fundamental. Another possibility is that they are themselves made of some deeper constituent. And that seems to be a reasonable possibility. And so it turns out that a theory has been invented–the theory of quarks; that certain of these things like the proton, for instance, or neutron, are made of three objects called quarks.
NARRATOR:
No one has yet seen a quark, which is too bad, because they may represent the fundamental building block for all the other more complicated atoms and molecules that make up the universe. The name was chosen for no particular reason by Dr. Feynman’s colleague, Murray Gell-Mann, some years ago. Somewhat to Dr. Gell-Mann’s surprise, the Irish novel writer James Joyce had already anticipated that name thirty years earlier in his book, Finnegan’s Wake. The key phrase was “three quarks for Muster Mark.” This was even a bigger coincidence since, as Dr. Feynman explained, the quarks that make up the particles of the universe seem to come in threes. In the search for quarks, physicists are knocking protons and neutrons together at such high energies with the hope that they will break apart into their quark components in the process.
FEYNMAN:
All true, and one of the things that’s been holding up the quark theory was that it’s obviously cockeyed, because if the things were made of quarks, if we hit two protons together, we ought to produce three quarks sometimes. It turns out that in this quark model that we are talking about, the quarks carry very peculiar electrical charges. All the particles in the world that we know contain integral charges. Usually one electric charge plus or minus or nothing. But the theory of quarks has it that the quarks carry charges like minus a third or plus two thirds of an electric charge. And if such a particle exists, it would be obvious, because the number of bubbles it would leave in a bubble chamber when it made a track would be much [smaller]. Say you had a charge of a third; then it whips up one ninth as many atoms as it turns out–the square–along the track, so there would be one ninth as many bubbles along the track as you would get for an ordinary particle. And that’s obvious; if you see a lightly drawn track, there’s something wrong. And they’ve looked and looked for such a track, and they haven’t found them yet. So that’s one of the serious problems. That’s the excitement. Are we on the right track or are we walking around in the utter darkness when the answer is way over here to the right, or are we smelling it closely and just have
n’t quite got it right? And if we just get it right, we’ll suddenly understand why that experiment looks different.
NARRATOR:
And what if these high-powered experiments with atom smashers and bubble chambers do show that the world is made of quarks? Will we ever be able to see them in a practical way?
FEYNMAN:
Well, for the problem of understanding the hadrons and the muons and so on, I can see at the present time no practical applications at all, or virtually none. In the past many people have said that they could see no applications and then later they found applications. Many people would promise under those circumstances that something’s bound to be useful. However, to be honest–I mean he looks foolish; saying there will never be anything useful is obviously a foolish thing to do. So I’m going to be foolish and say these damn things will never have any application, as far as I can tell. I’m too dumb to see it. All right? So why do you do it? Applications aren’t the only thing in the world. It’s interesting in understanding what the world is made of. It’s the same interest, the curiosity of man that makes him build telescopes. What is the use of discovering the age of the universe? Or what are these quasars that are exploding at long distances? I mean what’s the use of all that astronomy? There isn’t any. Nonetheless, it’s interesting. So it’s the same kind of exploration of our world that I’m following and it’s curiosity that I’m satisfying. If human curiosity represents a need, the attempt to satisfy curiosity, then this is practical in the sense that it is that. That’s the way I would look at it at the present time. I would not put out any promise that it would be practical in some economic sense.
NARRATOR:
As for science itself and what it means to all of us, Dr. Feynman says he is reluctant to philosophize on the subject. Nevertheless, that does not prevent him from coming up with some interesting and provocative ideas about what he believes science is and what it is not.
FEYNMAN:
Well, I’ll say it is the same as it always was from the day it began. It’s the pursuit of understanding of some subject or some thing based on the principle that what happens in nature is true and is the judge of the validity of any theory about it. If Lysenko says that you cut off rats’ tails for 500 generations, then the new rats that are born will not have tails. (I don’t know if he says that or not. Let’s say Mr. Jones says that.) Then if you try it and it doesn’t work, we know that it isn’t true. That principle, the separation of the true from the false by experiment or experience, that principle and the resultant body of knowledge which is consistent with that principle, that is science.
To science we also bring, besides the experiment, a tremendous amount of human intellectual attempt at generalization. So it’s not merely a collection of all those things which just happen to be true in experiments. It’s not just a collection of facts about what happens when you cut off [rats’] tails because it would be much too much for us to hold in our heads. We’ve found a large number of generalizations. For example, if it’s true of rats and cats, we say it’s true of mammals. Then we discover if it’s true of other animals; then we discover it’s true of plants, and finally it becomes a property of life to a certain extent that we don’t inherit as an acquired characteristic. It’s not exactly true, actually, absolutely. We later discovered experiments that show that cells can carry information through the mitochondria or something so that we modify it as we go along. But as all the principles must be as wide as possible, must be as general as possible, and still be in complete accord with experiment, that’s the challenge.
You see, the problem of obtaining facts from experience–it sounds very, very simple. You just try it and see. But man is a weak character and it turns out to be much more difficult than you think to just try it and see. For instance, you take education. Some guy comes along and he sees the way people teach mathematics. And he says, “I have a better idea. I’ll make a toy computer and teach them with it.” So he tries it with a group of children, he hasn’t got a lot of children, maybe somebody gives him a class to try it with. He loves what he’s doing. He’s excited. He understands completely what his thing is. The kids know that it’s something new, so they’re all excited. They learn very, very well and they learn the regular arithmetic better than the other kids did. So you make a test–they learn arithmetic. Then this is registered as a fact–that the teaching of arithmetic can be improved by this method. But it’s not a fact, because one of the conditions of the experiment was that the particular man who invented it was doing the teaching. What you really want to know is, if you just had this method described in a book to an average teacher (and you have to have average teachers; there are teachers all over the world and there must be many who are average), who then gets this book then tries to teach it with the method described, will it be better or not? In other words, what happens is that you get all kinds of statements of fact about education, about sociology, even psychology–all kinds of things which are, I’d say, pseudoscience. They’ve done statistics which they say they’ve done very carefully. They’ve done experiments which are not really controlled experiments. [The results] aren’t really repeatable in controlled experiments. And they report all this stuff. Because science which is done carefully has been successful; by doing something like that, they think that they get some honor. I have an example.
In the Solomon Islands, as many people know, the natives didn’t understand the airplanes which came down during the war and brought all kinds of goodies for the soldiers. So now they have airplane cults. They make artificial landing strips and they make fires along the landing strips to imitate the lights and this poor native sits in a wooden box he’s built with wooden earphones with bamboo sticks going up to represent the antenna and turning his head back and forth, and they have radar domes made of wood and all kinds of things hoping to lure the airplanes to give goods to them. They’re imitating the action. It’s just what the other guy did. Well, a hell of a lot of our modern activity in many, many fields is that kind of science. Just like aviation. That’s a science. The science of education, for example, is no science at all. It’s a lot of work. It takes a lot of work to carve those things out, those wooden airplanes. But it doesn’t mean that they are actually finding out something. Penology, prison reform–to understand why people do crimes; look at the world–we understand it more and more with our modern understanding of these things. More about education, more about crime; the scores on the tests are going down and there’s more people in prison; young people are committing crimes, we just don’t understand it at all. It just isn’t working, to discover things about these things by using the scientific method in the type of imitation which they are using now. Now whether the scientific method would work in these fields if we knew how to do it, I don’t know. It’s particularly weak in this way. There may be some other method. For example, to listen to the ideas of the past and the experience of people for a long time might be a good idea. It’s only a good idea not to pay attention to the past when you have another independent source of information that you’ve decided to follow. But you’ve got to watch out who it is you’re following if you’re going to [ignore] the wisdom of the people who’ve looked at this thing and thought about it and unscientifically came to a conclusion. They have no less right to be right than you have to be right in modern times; to equally unscientifically come to a conclusion.
Well, how’s that? Am I doing okay as a philosopher?
NARRATOR:
In this edition of the Future for Science–a taped series of interviews with Nobel laureates–you’ve heard Dr. Richard Feynman of the California Institute of Technology. The series has been prepared under the auspices of the American Association for the Advancement of Science.
______
*John Archibald Wheeler (1911– ), physicist, best known to the general public for having coined the term “black hole.” Ed.
†Eugene P. Wigner (1902–1995), 1963 Nobel Prize in Physics, for his contributions to the theory of t
he atomic nucleus and elementary particles, through his work on symmetry principles. Ed.
*Hideki Yukawa (1907–1981), winner of the 1949 Nobel Prize in Physics for predicting the existence of mesons. Ed.
13
THE RELATION OF SCIENCE AND RELIGION
In a kind of thought experiment, Feynman takes the various points of view of an imaginary panel to represent the thinking of scientists and spiritualists and discusses the points of agreement and of disagreement between science and religion, anticipating by two decades, the current active debate between these two fundamentally different ways of searching for truth. Among other questions, he wonders whether atheists can have morals based on what science tells them, in the way that spiritualists can have morals based on their belief in God–an unusually philosophical topic for pragmatic Feynman.
In this age of specialization, men who thoroughly know one field are often incompetent to discuss another. The great problems of the relations between one and another aspect of human activity have for this reason been discussed less and less in public. When we look at the past great debates on these subjects, we feel jealous of those times, for we should have liked the excitement of such argument. The old problems, such as the relation of science and religion, are still with us, and I believe present as difficult dilemmas as ever, but they are not often publicly discussed because of the limitations of specialization.
The Pleasure of Finding Things Out Page 23
