Cargo Cult Science (Caltech Commencement)

During the Middle Ages there were all kinds of crazy ideas, such as that a piece of rhinoceros horn would increase potency. 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.

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. They’re waiting for the airplanes to land. They’re doing everything right. The form is perfect. It looks just 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 a essential feature, because the planes don’t land.

The first principle is that you must not fool yourself—and you are the easiest person to fool. So you have to be very careful about that. After you’ve not fooled yourself, it’s easy not to fool other scientists.

I wish for you the good luck to be in a place where you are free to maintain the kind of integrity I have described, and where you do not feel forced by a need to maintain your position or financial support to lose your integrity.