I thought Harris' line about being afraid of being in a simulation in which the evasive abrahamic god who is infuriated by anyone who does not acknowledge his existence is reality.

As for whether this is physics or not... is it not called theoretical physics or something? Am I just confused in thinking that the type of people I come across talking about this are some sort of physicist?

Also, even if things outside of our observable universe cannot be observed, aren't multiverse theories predicated on observations in our observable universe? I guess what I'm trying to say is, can't we be observing them by way or some apparent fluke in our observable universe, such as gravity being weaker than would be expected (I have no clue if this is actually a good example...)?