> The smallest computer to simulate the universe would be have the size and energy requirement of the entire universe itself.
There's no reason to think those computers don't exist.
There's no reason to think those computers don't exist.
We have no idea what constraints those machines would or wouldn't have, since we have no idea what physics they'd be operating under.
I'm only arguing against partial simulation within our own universe (eg. The Matrix). Any simulation that has a night sky and telescopes must simulate the full big bang and evolution of galaxies just for the people on Earth.