What @1137 is going on about asking questions relating to where humans are first taught about gods - the reasons why humans understand gods are a thing in the first place - is an important one. And it fundamentally comes down to a response to human experiences of existence - nature, reality, the universe, everything. Theism originates from humans having an experience of something in their lives. More specifically, experiences that can be called "mystical experiences" by some scholars. A sense of something greater than themselves, of something awe-inspiring, of... in short? Something worthy of worship. That's all gods are - something that a human experienced out there in the world that they deem worthy of worship. And it all derives from indisputably real experience that they had.
Calling something a "god" is like applying a title to something. It indicates a particular relationship or character of that thing we've experienced. Sometimes a different word gets used in other cultures, and sometimes a word like "god" isn't used at all. Doesn't matter - gotta look at what the word/placeholder is actually pointing at. Gods are understood differently across cultures. In some, our own human ancestors are worthy of worship as an expression of our deep gratitude for our origins. In others, it's the very air we breathe and the very land we walk on, for without it we wouldn't be here. In others still, it's a numinous transcendent ideal that is so beyond our material universe that it is scarcely comprehensible other than a feeling of unity and oneness. And all of these are inspired by human experiences of existence.
The problem, for many of us, is that word "experience." You mention "from indisputably real experience that they had." And I will agree, the "experience" was real -- they experienced it. The problem is, what was the origin of those experiences. Can they be, in any sense, reified -- explained as caused by something outside of a malfunction of that most complex organ, the human brain.
When I read the works of Dr. Oliver Sacks, such as
The Man who Mistook His Wife for a Hat or
A Leg to Stand On, or
Hallucinations or
An Anthropologist on Mars, I am ceaselessly amazed at just how much our brains are capable of cooking up, all on their own. And at just how much they actually do it! Much of what we think we remember, you know, is actually less what really happened but more what story our brain wove to explain what it perceived.
I wrote a fairly long essay on this forum several years ago, called
Joan of Arc's Voices, which provides some insight into just how much I think the brain is capable of inventing. It's interesting to ponder that many of those who doubt the authorship of Shakespeare's works doubt it because they though he couldn't possibly have known as much as he did about court life. But in fact, that's simply not true. He was a voracious read of Holinshed and other historians, for example, and even today, common people know much more about the life of monarchies like the Windsors than might be suspected. We see all sorts of stuff, and we store it away -- and it can get used, sometimes not even consciously.
