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Comment by olavk | Hacker News Reader

> Why did you quote half my sentence, leaving out the part where I explain why, and then ask why?

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.

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Well, a Turing complete computer is about as abstract as you can get, and so is the concept of memory, regardless of the natural laws of some outer universe, it'd probably be a good starting point to consider a turing computer except with limited memory.

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.

You cannot through experiments prove that the law of conservation of energy holds in all cases. Indeed you cannot through observation prove that any law of nature holds in all cases. But you only need a single counterexample to show that a law doesn't hold in all cases. This is exactly the rationale behind the principle of falsification. You cannot prove through observation that all swans are white. But you can prove that not all swans are white by a single observation of a black swan.

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.

> But you cannot devise an experiment which would give different outcomes if the universe is a simulation versus if it isn't.

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.

I didn't ignore that, I mentionend the "limited resources" scenario with the 16GB example a few posts back.

> But you cannot devise an experiment which would give different outcomes if the universe is a simulation versus if it isn't.

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?

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