I think this is exactly backwards. Kids "believe in" Santa Claus in the same sense they believe in school and picnics - they listen for reindeer noises and hop

I think this is exactly backwards. Kids "believe in" Santa Claus in the same sense they believe in school and picnics - they listen for reindeer noises and hope to get a glimpse of him, and as far as they are concerned he exists in the same corporeal universe. It is only adults who possess the cognitive compartmentalization to "believe in" absurdities like the transubstantiation of wine into the blood of Christ, without it ever occurring to them to wonder what blood type it is, or whether it might be a useful source for transfusions.