PhD thesis

"How beliefs contrary to common sense used to be discarded", PhD dissertation: Sociology, Strasbourg, University of Strasbourg, 427 p.

Advisor: Gérald Bronner. 

This PhD was defended on 17 november 2020 at Strasbourg University.


This thesis proposes addressing the dynamics of belief change using a mystery described by social psychologists Festinger, Riecken, and Schachter (1956) as a starting point. They followed a UFO cult movement whose prophecy had been contradicted by the facts. Two aspects of what we call the "Festinger mystery" will therefore be investigated. Firstly, that the factual denial of a belief is not sufficient for it to be abandoned and, secondly, that there is a threshold beyond which the belief buckles under the weight of evidence. This mystery has both a static and a dynamic dimension. The "Festinger mystery" will be explained by modelling the cognitive mechanisms at work within a particular population of convinced followers who harbour unconditional beliefs defying common sense and promoted by a cult movement. The logic behind these beliefs, often perceived as counter-intuitive, to such an extent that the believers are considered irrational, will prove to be most understandable and rational.

Keywords: belief change, revision, emotion, knowledge, value, social norms, rationality of action, confidence, cults, new religious movements, perception, sensory experience, argumentation, logic.