@ballistic: the simulation theory is interesting but no different than the god theory, there is a god out there that is simulating everything and pretending it’s all natural. The question is why and how.
My primary reason to think we are not living in a simulation is because of what we do when we make simulations, eg video games. We put both conscious and unconscious signatures, culture, in-jokes and other features that would give it away. We also tend to be lazy and eg leave buildings empty shells if we don’t expect people to go looking in them or set arbitrary limits (render distance) to conserve energy both in creation and execution. We also have to patch it and break things on a regular basis and people find workarounds and break the rules.
It is very possible that we are in a simulation; but I don’t see any jokes or signatures or any indication we can break the rules.