There’s some good discussion here on Nick Bostrom’s argument concerning whether our universe is or is not a simulation. We discussed that idea here. A quick recap of Bostrom’s argument:
Bostrom argues that one of the following three propositions is most likely true:
(1) the human species is very likely to go extinct before reaching a “posthuman†stage;
(2) any posthuman civilization is extremely unlikely to run a significant number of simulations of their evolutionary history (or variations thereof);
(3) we are almost certainly living in a computer simulation.
I’m starting to like Option 2. Advanced civilizations might run partial simulations of universes, but why simulate an entire universe? Assuming the Many Worlds Hypothesis to be true, any simulation you might want to create is already out there. Accessing and observing those other universes would be no easy task, but then neither would running a simulation of an entire universe.
So I think posthuman civilizations don’t run universe-level civilizations, for the same reason that nobody is trying to build a fully operational replica of Hawaii out in the Pacific. Why go to the trouble? Hawaii is already there.