In THE HISTORY OF RELIGION, an old book, it says that many many many many years ago, before any book was written, before any religion was started or created, hypothetically, someone looked at a dead SOMETHING, a dead man or a dead cat, it doesn't matter what, and after it died, they asked themselves, WHERE DOES IT GO AFTER IT IS DEAD? And so with logic and reasoning, they watched it and watched it until they came to the conclusion or realization that it goes back to the earth, where it came from. (Dust to Dust theory). hey reasoned all dead things go back to the earth from whence it came. This became a common belief amoung all human beings.
But then someone asked WHAT ABOUT ITS SPIRIT? WHAT ABOUT ITS PERSONALITY? WHAT ABOUT THE ACTUAL PERSON THAT DIED? WHERE DOES HE GO?
And after much comtemplation, it was reasoned if the body went to the earth, or downward, the spirit must go upward to the sky, or later called the heavens.
And religion was born from that.