Via Robin Hanson comes a great story of just how difficult it is for some people to move their dogma:
In the late 1950s, psychologist Milton Rokeach … gathered three psychiatric patients, each with the delusion that they were Jesus Christ, to live together for two years in Ypsilanti State Hospital to see if their beliefs would change. The early meetings were stormy. “You oughta worship me, I’ll tell you that!” one of the Christs yelled. “I will not worship you! You’re a creature! You better live your own life and wake up to the facts!” another snapped back. “No two men are Jesus Christs. … I am the Good Lord!” the third interjected, barely concealing his anger. …
Very little seems to shift the identities of the self-appointed Messiahs. They debate, argue, at one point come to blows, but show few signs that their beliefs have become any less intense. Only Leon seems to waver, eventually asking to be addressed as “Dr Righteous Idealed Dung” instead of his previous moniker of “Dr Domino dominorum et Rex rexarum, Simplis Christianus Puer Mentalis Doctor, reincarnation of Jesus Christ of Nazareth.” Rokeach interprets this more as an attempt to avoid conflict than a reflection of any genuine identity change. The Christs explain one another’s claims to divinity in predictably idiosyncratic ways: Clyde, an elderly gentleman, declares that his companions are, in fact, dead, and that it is the “machines” inside them that produce their false claims, while the other two explain the contradiction by noting that their companions are “crazy” or “duped” or that they don’t really mean what they say. …
Yet another case of science confirming what everyone already knows - if you've read the news over the past, say 50 years, you'd already know that people don't give up cherished beliefs about anything (religion, politics, ...) very easily.