I remember particularly the Indian who was buried in the mossy mound at the base of the birch tree we could just make out, glimmering in the twilight, at the edge of the small patch of woods behind our homes. It was safe to poke at the grave during daylight but if anyone dared approach at night the Indian's outraged ghost would come flying out, all misty and amorphous and horrible, intent on doing whatever unnamable things ghosts do to the poor, foolish kids they catch. Or so Johnny and I told Tommy one evening. Unfortunately, by the time the three of us had crept to within a few yards of the tree which glowed spookily in the gathering dark, Johnny and I were more convinced in the reality of our made-up phantom than Tommy was. The phosphorescent fox fire from some rotted limbs near the mound brought our invention to full, horrifying reality and sent us running for our lives.
Adults shape their own realities too but usually more subtly.
However, writers and readers still experience some of childhood's outright reality molding. I'm not talking just about creating a bit of fiction or simply reading the words. When I'm contributing my part of the Byzantine mystery novels Mary and I have been writing, I find, to be successful, I have to work with a divided mind. A part of me has to remain outside the story, monitoring the words critically. But another part has to be immersed in the tale, has to believe that John and his friends are real, that the ancient streets they walk and the dangers they face exist.