# Cargo cult science

Cargo cult science is a classic essay written by Richard Feynman, and presented as a commencement address at the California Institute of Technology (Caltech) in 1974. It was subsequently reprinted in Surely You're Joking, Mr. Feynman! in 1985, and in The Pleasure of Finding Things Out in 1999.
The essay instructs scientists on how not to fool themselves when performing experiments and drawing conclusions. It is also a critique of the the fallacy of attempting to achieve an outcome by engaging in a process which has been previously observed to precede a desired outcome without properly analysing or understanding the process, and where the process has not been proven to produce the outcome. In the essay Feynman references the belief in the middle ages that a piece of rhinoceros horn would increase potency, and lists analogous modern beliefs, phenomena, and practices, including witch doctors, the belief that unidentified flying objects are of extraterrestrial origin, extrasensory perception, astrology, parapsychology, and some forms of psychotherapy. Feynman also names methods of teaching reading and mathematics, and the administration of criminal justice as examples of methods and practices that are unproven, and names this pattern Cargo cult science after the cargo cults that arose in the South Pacific islands after World War II.
The essay is not strictly about practice of pseudoscience, but about about proving methods before adopting them into practice. Its purpose is not to critically examine the things mentioned as examples of cargo cult science, but to remind scientists that they must vigilantly practice the art of not fooling themselves if they want to produce credible results. Feynman argues that a scientist must report everything that might an the experiment invalid, including other causes that could possibly explain the results, and things that have already been eliminated by some other experiment, including a description of how they worked so that others can examine the flaws and come independently to the conclusion that the other possible causes have indeed been eliminated. Finally, Others should be able to judge the full value of a contribution, not just the information that leads to a judgement.
Feynman emphasizes that it is all too easy for scientists to fool themselves, and references the Oil drop experiment of Robert Andrews Millikan as an example of an experiment whose results were accepted for too long because others didn't scrutinize the information relevant to the experiment. Feynman contrasts advertising with what he calls scientific integrity: The statements in an advertisement might all be true, but additional information that might qualify the statements is omitted, and the audience is thereby lead to a conclusion other than what they might have come to if all the facts had been stated. Scientific integrity entails providing the audience all of the facts that might be relevant to their judgement, not just those that support the hypothesis. In the words of Feynman, "I’m talking about a specific, extra type of integrity that is not lying, but bending over backwards to show how you’re maybe wrong, that you ought to do when acting as a scientist. And this is our responsibility as scientists, certainly to other scientists, and I think to laymen." Feynman cites Publication bias as another example, stating that in order to maintain scientific integrity, a scientist must commit to publishing regardless of the outcome of the experiment.
Since its publication the essay has been continuously cited and discussed, and the term "cargo cult science" has inspired other terms such as "cargo cult programming", "cargo cult software engineering", "cargo cult investing", and simply "cargo culting".