From my 3-year-old nephew: "What is a prayer?" and "Did ghosts live at the same time as people?" !?
My sister told me that my nephew (her son) asked her the question about ghosts. Apparently he had already been taught (correctly) that dinosaurs never lived at the same time as people. While reading a Halloween themed children's book with the usual Halloween entities in it he asked "Did ghosts live at the same time as people?" My sister said that this one nearly stumped her. "First of all," she told me, "Ghosts don't really live at all, but how to explain that?"
I said that MY answer, to my own child, would be: "Ghosts are imaginary and people made them up, just like the other things in the book: mummies, Frankenstein, and vampires." My mother suggested that perhaps a more appropriate answer would be "Some people believe ghosts exist, and some people don't." This is how she raised me, and I believe that I came to the right conclusions, but while I agree that would be a fine and true explanation, I have no problem telling children with certainty that ghosts are imaginary.
I got the other question from my nephew while we were playing Guitar Hero together. Well, I play the game and he sings along and plays on his own toy guitar. One of the songs is "Livin' On a Prayer" and he asked "What is a prayer?" Good one! His parents weren't around to help, and though I am pretty certain they are both (basically) atheists, I didn't want to contradict something they had said. My answer was: "A prayer is a kind of wish that you make, where you hope that someone else will take care of making it happen."
I think my answer was pretty good! That accurately describes a pretty wide variety of uses of the word "prayer" including a completely secular type of use. Later, my mother (also an atheist, but leaning much further toward new-agey beliefs than me) suggested the answer: "A prayer is positive energy that you send out into the universe." While that's all warm and fuzzy and nice, I don't think it helps at all to understand the meaning of the song "Livin' on a Prayer!" It's a little like the deistic kind of "God" in that way. It's disconnected from the way people actually use the word. My definition of prayer explains that the song lyric is about living on wishes and hopes.
What do you think?