Here’s a question: if the universe is directly observable- we know it’s real because we send probes out there into the solar system, wouldn’t a simulation have to simulate not only the entire universe but also the brains of every individual and every living thing for that matter? How likely that computing hat powerful would ever exist? Would this not be an argument against simulations? Don’t even get me started on multi-layer simulations. What kind of supercomputer could ever handle that?