I feel like you could make a pretty good rationalist children's book, consisting only of a series of stories in which a protagonist is forced to draw an increasingly unpalatable conclusion, under increasingly hard circumstances. Show the pain of the struggle, and make a virtue out of the triumph.
And then children get the lesson that changing your mind is always a good thing. The new idea is always right.
Yvain isn't a big enough self-promoter to link to this, but I liked it a lot and I think you will too.
"The Last Temptation of Christ"