When we determine as reasoning adults that Santa Clause is the creation of the human imagination, we can easily trace the orgins in folklore, history, art and literature. What many "belivers" don't seem to grasp is that the orgin of the concept of God can be traced in exactly the same way. What ardent Atheist don't seem to grasp is that myths about God, or Santa Claus for that matter, are necessary to the very essence of man. If you doubt it, study the life work of Joseph Cambel. There is a meeting ground where both belivers and Athiest can dwell. It has even been introduced on this forum-the Golden Rule. We are not as far apart as it may appear. If there exist such a principle and both believers and athiest know it is right, then maybe "God" is that principle.
Joseph Cambell's research determined that we are hard wired as humans to believe in something. Or as Bob Dylan says, "Your gonna serve somebody".

"Imagination is more important than knowledge." - Albert Einstein