How do you determine which history book is correct? How do you determine who is telling the truth in the 9/11 commission? How do you determine which scientific theory is the right one? Everyone has the ability to reject what they consider to be false. Everyone does this every day. So don't make this out to be that religion is the only case where this happens.
Data! Evidence!
Heinlein said it well:
What are the facts? Again and again and again - what are the facts? Shun wishful thinking, ignore divine revelation, forget what 'the stars foretell,' avoid opinion, care not what the neighbors think, never mind the unguessable 'verdict of history' -- what are the facts, and to how many decimal places? You pilot always into an unknown future; facts are your only clue. Get the facts!Robert A. Heinlein, Time Enough for Love, 1973