Some cults in our day are built on speculation. Someone let the imagination run wild and invented things that are somehow attractive to others. Multitudes of people hold fast to beliefs that can neither be refuted nor verified. Walking through the drug store you find a sign over a counter that says Notions. It means various and sundry items that you might buy.
People can come to think that their notions are true.
A cultic group recently commited because they though there was a spaceship following behind the Halle-Bopp Comet. It was supposed to pick them up and take them to a higher level, a better place. So they took their lives. I think this came from someone who just had a notion. The imagination is much more seductive and deceptive than people think.