I'm not quite sure which universe I'm living in now
The Theory of Multiverse was set forth originally by Hugh Everett in quantum mechanics. It posited that every version of our past and future histories exists, just in an alternate universe. This means that for every choice you make, an infinite number of universes exist where you made a different choice. In this way, we get to live multiple lives.
I'm not quite sure which universe I'm living in now.