Yes but the point is that I am rebutting Bostrom’s argument, which is based on the premise that we are being simulated by our descendants as a historical simulation. If that is so, then the physics must be the same. If the physics are different, then the simulating world might be almost anything. As I say in the article, we might be dreams of a purple troll in Xanadu. But we also have no reason to believe that the simulating universe looks any particular way, or even that it exists. It’s not that there can’t be an enclosing reality, it’s just that Bostrom fails to provide any convincing reason for believing it.