

This kind of thing happens even if you don’t assume time repeats. As far as we can measure, the universe is spacially infinite. Finite age, infinite spacial extent. If you ever hear someone talk about the diameter of the universe, they’re talking about the diameter of the observable universe - the part of the universe close enough for its light to actually reach us. But as far as we can measure (based on measurements of large scale spacial curvature), the universe is truly, literally infinite. It’s possible it curves back on itself with a radius much larger than the diameter of the visible universe. But if it truly is infinite, infinities make some very weird things possible.
For example, a diameter the size of the observable universe has a finite number of states. There are only so many atoms and so many ways to arrange those atoms. This number is unfathomably large, but it’s not infinite. But in an infinite universe, on a large enough distance, everything repeats. It doesn’t repeat in a regular pattern, but it does repeat. So get in a space ship and fly off into space. If you could go far enough, eventually you would run into an exact duplicate of yourself, with all the memories and life experiences you have - an atom-for-atom copy of yourself. Travel far enough and you’ll encounter a duplicate of our entire observable universe. And worse still, if the universe truly is infinite, there must be an infinite number of such copies.
I’m not talking about alternate realities or parallel universes here. I’m not talking about getting in a time machine and visiting an alternate timeline. I’m not talking about the quantum many worlds theory. I’m talking about the very space you inhabit, this universe. If you go out in a space ship and could travel arbitrarily far, it would eventually seem like you had come right back home, even though you’re quintillions of light years from where you were born.
Infinity is a terrifying thing.





I always liked the “one soul” theory. The concept is toyed with in the short story The Egg.
Basically reincarnation is real. Except if a soul can jump through space between lives, there’s no reason it can’t also jump through time. Space and time are one and the same.
Imagine if when you die, you wake up being born in another life. But that life could be anywhere in the past, present or future. Your consciousness doesn’t move linearly forward through time in a series of lifetimes arranged in a line. It bounces all over the place. 21st century US one lifetime, 8300 BC Peru the next, 12000 AD Alpha Centauri after that. And the whole chain of consciousness is a closed loop. Ultimately, there is just one soul, just one consciousness, bouncing back and forth across all of the history of creation. And when the soul’s path is complete, when it has lived every life there is to live? It loops back on itself.
You are a being of this universe. You are the consciousness of this universe. As am I. You and I are literally the same mind, separated perhaps by billions of lifetimes. Or perhaps I will live your life next, or you mine. Eternal life is real, but contained entirely within our finite universe. An endless loop of awareness echoing throughout all of creation. And we need to be kind to one another, as when I hurt you, I am literally hurting myself.
I don’t really think it’s something I personally believe, but it is a really cool concept that I love.