The search for truth – Richard Feynman and the Challenger disaster
On Monday 18 March BBC 2 broadcast a riveting docu-drama entitled The Challenger. It was a factual drama about the famous scientist Richard Feynman and his search for truth in the wake of the NASA Challenger disaster. When Challenger exploded 73 seconds into its flight on the morning of 28 January 1986, it represented one of the most tragic events in the history of American spaceflight. A Presidential Commission was rapidly convened to explore what had gone wrong, but with the vast complexity of the space shuttle and so many vested interests involved in the investigation, discovering the truth looked as if it was going to be an impossible challenge. However, against the background of a deeply flawed inquiry process, Feyman’s relentless investigation eventually helped to uncover the first cause of the disaster. The film is well-worth seeing. It goes some way towards demonstrating what a search for the truth actually entails: it shows, for example, how Feyman’s particular quest was severely impeded by sectional interests, all of whom had something to lose if the truth were to be uncovered. But the film also reflects Feyman’s distinction between the nature of proper science and phoney or what he called ‘cargo cult science’. He had outlined such a distinction in a famous address given to students at Caltech in 1974.
I’ve picked out some notes from Feynman’s address. Each note is important in its own right but, given the extraordinary proliferation of psychology degrees, I think the third note warrants particularly close attention. It’s also a great story.
1. “There is one feature I notice that is generally missing in “cargo cult science.” 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.”
2. “We’ve learned from experience that the truth will come 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.”
3. “All experiments in psychology are not of this [cargo cult] type, however. For example there have been many experiments running rats through all kinds of mazes, and so on — with little clear result. But in 1937 a man named Young did a very interesting one. He had a long corridor with doors all along one side where the rats came in, and doors along the other side where the food was. He wanted to see if he could train rats to go to the third door down from wherever he started them off. No. The rats went immediately to the door where the food had been the time before.
The question was, how did the rats know, because the corridor was so beautifully built and so uniform, that this was the same door as before? Obviously there was something about the door that was different from the other doors. So he painted the doors very carefully, arranging the textures on the faces of the doors exactly the same. Still the rats could tell. Then he thought maybe they were smelling the food, so he used chemicals to change the smell after each run. Still the rats could tell. Then he realized the rats might be able to tell by seeing the lights and the arrangement in the laboratory like any commonsense person. So he covered the corridor, and still the rats could tell.
He finally found that they could tell by the way the floor sounded when they ran over it. And he could only fix that by putting his corridor in sand. So he covered one after another of all possible clues and finally was able to fool the rats so that they had to learn to go to the third door. If he relaxed any of his conditions, the rats could tell.
Now, from a scientific standpoint that is an A-number-one experiment. That is the experiment that makes rat-running experiments sensible, because it uncovers the clues that the rat is really using — not what you think it’s using. And that is the experiment that tells exactly what conditions you have to use in order to be careful and control everything in an experiment with rat-running.
I looked into the subsequent history of this research. The next experiment, and the one after that, never referred to Mr. Young. They never used any of his criteria of putting the corridor on sand, or of being very careful. They just went right on running rats in the same old way, and paid no attention to the great discoveries of Mr. Young, and his papers are not referred to, because he didn’t discover anything about rats. In fact, he discovered all the things you have to do to discover something about rats. But not paying attention to experiments like that is a characteristic of cargo cult science.”
From: Feyman, R. “Cargo Cult Science”, adapted from a commencement address given at Caltech in 1974