I’ve seen this happen personally. I’ve written before about my friend’s brother, who fell into a YouTube rabbit hole and bought into the idea that the Earth is flat. His brother and I spent months conducting experiments with him, walking him through the math, demonstrating that the earth cannot be flat. As much as possible we let him conduct the experiments with his own hands. (Side note: using simple equipment to measure the circumference of the earth isn’t that difficult. The ancient Greeks could do it, and it’s actually a lot of fun.)

But this guy was so invested in his flat Earth conspiracy theory believe that he was never able to pull back from it.

And now? He believes the coronavirus vaccines are dangerous, and says he won’t take one and doesn’t want his children to.