The point is not to prove one way or another whether the universe is a simulation, just like there is no point trying to prove the law of conservation of energy as universal for all forms of phenomena, discovered and undiscovered.
It's just if we can show that all known phenomena can be the result of a very limited simulation, then when analyzing new phenomena, we can also expect it to be runnable on a very limited simulation, too.
It's the same as assuming that the law of conservation of energy would apply to any new phenomena we discover. There is no proof, but it's a good starting point.
The bottom line is that it is possible to devise experiments or observations which would give different outcome if the theory holds and if the theory doesn't hold.
But you cannot devise an experiment which would give different outcomes if the universe is a simulation versus if it isn't. More specifically, you cannot imagine an observation which would prove that the universe isn't a simulation. Therefore it is not a legitimate scientific theory. At best it is a fun thought experiment.
I've already mentioned 5 times in this thread that the theory I'm talking about is of a simulation with very limited resources, but you seem to be ignoring this point.
Show that a particular phenomenon can't be simulated using extremely limited hardware (compared to the size of the universe) and you can falsify this theory.
Does this or does this not apply to a simulation with very limited resources (compared to what it would take to model all the atoms of the universe) or not, then?
Sorry I just didn't want to quote the whole comment, didn't mean to imply I was only responding to the first part of the sentence.
I understand you can hypothetically prove that a simulation of the universe would require a simulation engine of at least a certain complexity. But since the simulation engine does not exist in this universe, we have no idea about what limitations or laws of nature (if any) it is subject to. You will never be able to prove or disprove the existence if this hypothetical simulator.