In Linda Moulton Howe's Glimpses of Other Realities, Volume II: High Strangeness, Author's Introduction, she has a few paragraphs relating a story that comes from an elderly Colonel who may have spent time with an extra-terrestrial who's disc had crashed somewhere in New Mexico.
The being explained telepathically that this was not the only universe.
He continued with: "Imagine a large island of sand and that each sand grain is a separate universe separated from the others by an electromagnetic membrane. And surrounding the island is a cold dark sea."
The intelligence officer relating the story to the author refused to explain what the cold dark sea was, he said that it would forever change her.
Somewhere in the volumes of books produced by Jane Roberts pertaining to a channeled entity named Seth, Seth explains something that relates to the above in that each of us is really an electrical field that creates it's own universe.
My thought is how much that sounds like the universe in each of those grains of sand.
A very long time ago, I dreamed about a life as an electrical entity in a container of some sort. Admittedly a strange thing to dream about, but that thing would dream about real life. It had no sense of time really, its only sense was whether it was existing as an electrical blob on the floor of the cell, or whether it was powering up to a dream somewhere.
And it put the things it was interested in into its dreams.
Sadly, we're something different than what we suppose we are. We're not any particular race, culture or anything else, except thinking makes it so. Thinking by that thing in the box.
That box looked very much like a cave and the story of the cave has been around a very long time.
I first heard about it from Sigrid, the lovely young woman who taught me so much about mysticism, and then found myself coming across it in a work of fiction by John Garner.
I still stumble across it occasionally in casual reading as the cave "of life and death".