well

I know gravity exists because apples fall

You've seen electricity when checking for a spark

I know the radio and tv signals are there because my tv works

And I know magnetism exists because i had a magnetic Thomas the Tank Engine train set when i was very small. And he would never lie to me!

I won't believe in ghosts, goblins or magical sky daddies until one jumps up and punches me on the nose. Somehow I think my ruggedly handsome face is safe