Some exorbitant multiverse complications:
[Paul] Davies argued that in a multiverse, “‘fake universes’ would be even more likely to vastly outnumber real universes [than in our one universe without a multiverse], so that if we live in multiverse, we would be overwhelmingly more likely to be living in a simulated reality. But that would imply that the laws of physics in our universe are also overwhelmingly more likely to be simulations and therefore cannot be used to conclude that there is a multiverse! So there is an inconsistency at the heart of the multiverse concept.”
Let’s unpack the argument and lay it out. To Davies, “If you take seriously the possibility of a multiverse of all possible universes, including all possible variations, then there would have to be at least some of those universes where sentient civilizations would advance to the point where they would have sufficient computing power to simulate entire fake worlds (like in the ‘Matrix’ movies). Simulated universes are much cheaper to make than the real thing. So once you’ve got civilizations throughout the multiverse that can simulate universes,” Davies stressed, then this is what they will do, and do increasingly.
As a result, “the number of fake universes in a multiverse will proliferate greatly and very soon outnumber real ones.” [Is Our Universe a Fake?]
Fake universes, Davies said, “undermine all the arguments for a multiverse,” because arguments for a multiverse are based on the physics of this universe. “But if ours is a simulated universe, then our laws are simulated, too, which means that the whole of physics is a fake.” And if the whole of physics is a fake, Davies said, then the whole argument for a multiverse collapses. The reason is that while the multiverse argument proceeds from the physics humans have discovered in this universe, people cannot use this argument because it then leads, surprisingly, to the conclusion that this is a fake universe, with fake physics.