Introduction to our discussion of “When Prophecy Fails”


The term “cognitive dissonance” has entered our popular vocabulary, and people use it often, more or less correctly; this is the book that introduced the concept to the reading public. It was published in 1956, the year before the 1957 publication of A Theory Of Cognitive Dissonance by the same chief author.

“When Prophecy Fails” is a case study of a religious cult whose core belief (there will be a cataclysm from which the faithful will be rescued by aliens in flying saucers) was — spoiler alert — disconfirmed. What happens when people commit themselves to a strong belief, which is then clearly contradicted by reality? As you might expect, the belief (among the people who were the most strongly committed to it) persists. What you might not have expected — but fully predicted by dissonance theory — is that people who never sought proselytes before their belief was disconfirmed, will begin to proselytize, and to seek converts, after their belief is disconfirmed.

The obvious comparison (although it is never stated in the book, but it is the “elephant in the room”) is to Christianity. Christianity and Islam, the two most popular religions in the world, are so popular, so dominant, that people don't realize how unusual they are. They are the only two religions in the world that have a core doctrine of proselytization, a core doctrine that nonbelievers must become believers. Islam has a slightly different story, but Christianity started out as a small religious cult, which never sought converts, until its core belief — that their leader was the Messiah — was disconfirmed, and disconfirmed in the starkest possible way, by his execution by the Romans. Only then did they begin to exhibit the phenomena — the same reinterpretations, the same redefinition of terms (“My kingdom is not of this world”) — that are documented in this book; and only then, like the flying-saucer cult after its core belief was disconfirmed, did they begin aggressively to seek to convert other people to their beliefs.

(In one of those dazzling coincidences that logicians loathe and poets love, I am listening to an episode of “Hidden Brain” that actually talks about this book, while I am editing this page. You can find it at https://hiddenbrain.org/podcast/when-you-need-it-to-be-true )

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