In this post, Scott Alexander investigates the “sun miracles” associated with Fatima and Medjugorje, travelling to Bosnia in search of firsthand evidence and ending up with something stranger than either simple faith or simple debunking. Part travelogue, part epistemic self-experiment, and part perceptual psychology essay, it follows his attempt to explain how crowds of people can sincerely report seeing the sun spin, pulse, and change colour, and why the answer may lie less in fraud or mass hallucination than in the unsettling quirks of human vision.
