A decently common theory is the idea that there are an infinite number of universes, in something called the multiverse. This implies that there is a universe for everything. If this statement is true, then that would mean that another universe managed to invade our universe at this very second, because an infinite number of universes means an infinite number of possibilities. If said theory is true, then there should be an infinite amount of universes invading our universe at this very second. Because this isn’t happening, this leads to the final conclusion that there isn’t an infinite number of universes, which means that either we’re the sole universe, or that there is a finite number of other universes. I would love to hear your thoughts on this.