[metafunctor]

Here's a thought that ends up with exactly the opposite view...

Does someone really need to build a computer that carries out the simulation for a universe to be “real”? If there is a set of rules defining a universe, one can say that the universe already exists without having to simulate it.

The same goes for universes that are capable of life that can simulate other universes nested inside them. And, indeed, universes nested three times, four times, all the way to infinity.

There number of nested universes is a much larger infinity that the number of non-nested "root" level universes. Thus, picking a universe at random (ours), the probability that it is a simulation is 1.

[simonh]

>Does someone really need to build a computer that carries out the simulation for a universe to be “real”? If there is a set of rules defining a universe, one can say that the universe already exists without having to simulate it.

Marvin Minsky made this argument and it's a compelling one. But rather than meaning all universes are simulated, it means it doesn't matter whether they are or not because for all possible universes they will exist as root universes and as simulations within more complex universes and there's no meaningful distinction between those. It's not the argument I'm making though.