"The universe behaves in a very peculiar way because it follows mathematics. Einstein said, “The most incomprehensible thing about the universe is that it’s comprehensible.” The universe does not have to work that way. It does not have to be so easy to abbreviate that I can basically write down a few pages of equations that contain enough information to simulate it.
The other interesting thing is that the natural world behaves exactly the same way as the environment of Grand Theft Auto IV. In the game, you can explore Liberty City seamlessly in phenomenal detail. I made a calculation of how big that city is, and it turns out it’s a million times larger than my PlayStation 3. You see exactly what you need to see of Liberty City when you need to see it, abbreviating the entire game universe into the console. The universe behaves in the exact same way. In quantum mechanics, particles do not have a definite state unless they’re being observed. Many theorists have spent a lot of time trying to figure out how you explain this. One explanation is that we’re living within a simulation, seeing what we need to see when we need to see it."