By Unknown author - "How the Earth was Regarded in Old times", The Popular Science Monthly, Volume 10, part dated March 1877
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Simulations all the way down

The simulation argument states that one of the following must be 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. 

But if we could speak to our simulators, and if we asked them whether or not they think they’re living in a computer simulation, what would they say? They would presumably be aware of the simulation argument, and by running simulations they would have ruled out the first two options and so would be left with the third option, that they are almost certainly living in a computer simulation.

Though they’d know they’re not living in one of their own simulations. (Or maybe they wouldn’t.)

These simulations could take very different forms. You could for instance run a simulation of a universe but with slightly different fundamental constants, like a different speed of light or a different value of Planck’s constant as those in “reality” (ie. in the current simulation), and see how that universe evolves, looking out for any life that develops and then honing in on wherever intelligent life emerges. But then couldn’t the universe itself be running such simulations as well?

Inflationary theory suggests that inflation could be eternal, leading to a multiverse of universes each with different properties. There would be many such universes, an infinite number of them, so isn’t it as likely we’re in one of those as that we’re in a simulation created by conscious beings? This is where the probabilities get difficult. In a single universe you can reasonably argue that there would be more simulated conscious beings than there are conscious beings living in non-simulated reality, even though, in an infinite universe, both of these numbers would be infinite. One infinity can be bigger than another.

But in a multiverse with an infinite number of universes? Not just the inflationary multiverse, but perhaps also the many worlds of quantum mechanics, where the universe is constantly branching off into different versions of itself. If the simulation argument applies in each of those universes then over all you could argue that the argument holds. There are still more artificial simulations than natural realities.

Is there any way you could tell which kind of reality you were in?