Prologue: I majored in Music so there is little behind what follows. Although I use the declarative, please assume "IMHO" preceding every sentence. I'd like to be instructed by people with more experience than I
How could SOOO many people believe in the magic, invisible daddy in the sky? I have an explanation. Is it plausible? Is there a commonly-accepted answer to this question?
IMHO the reason why the majority of humankind believes in supernatural beings is language.
The nature of language is duality. Just as where there is a left, there must be a right; where there is hot there must be cold; where there is an up, there must also be a down. Language, by its nature, requires the concept of a speaker and a listener, though, of course, they both need not be physically present.
The human brain is always in use (setting aside sleep). Much of that activity, maybe most, is in the form of language. Our senses keep us alive for another day but our thoughts (like thoughts about the future) are made of language. But even totally unexpressed, the duality of language remains – there is a speaker and a listener. Our thoughts are initiated either by the speaker or the listener and received by the other end. So all our thoughts are really conversations. You’re either practicing what you’re going to tell your boss in the morning or, as is more pertinent here, talking to God or listening to His replies.
Everyone with language has two people bouncing around inside their heads - and it's not schizophrenia. It's really easy, even natural, to attach some level of mysticism to this phenomenon and call the third party God.
Then comes the magic of written language. Starting, what, 20,000 years ago?, the cleverest dudes in the tribe demonstrated their ability to predict the solstices and equinoxes exactly and record other important events that allow the tribe to farm and feed itself without having to move from place to place. They could do this because they’d recorded this information using written language. The tribe can now improve their village year after year and the priests can refer to their magic tablets and tell all what crops to plant, how to construct an axle that won’t fail under load, and which mushrooms to avoid. The priests are the ones controlling the written word. This is the birth of civilization. From this time on, all knowledge is (potentially) cumulative.
“John 1:1 In the beginning was the Word, and the Word was with God, and the Word was God.”
It’s no wonder that “The Word” was/is worshiped. :-)
This continues today. Even the smartest people have some difficulty in distinguishing between “the word” and that whose meaning is being conveyed.