I think the only way to convince some people that the earth is round is to send them up on a space flight. Land then on the moon so they can see it with their own eyes.
They will claim that you drugged them and they are really in a holding cell in a bunker under Hollywood.
Yeah, but why would you waste money on these idiots?
Right! You can't make anybody believe anything that he doesn't want to. Only in great pain or great joy will someone be forced to drop his irrational opinions, and start to look for reality.