The luminiferous ether was a falsifiable theory - indeed it was a breakthrough for physics because it was falsified (experiments failed to detect it) so new theories had to be developed. So this is completely different from unfalsifiable metaphysics.
But it effectively wasn't for the first 150 years of it's existence. The theory originated in 1720 and it wasn't disproven until 1887. It took that long for someone to come up with a conclusive experiment. Nevertheless, for those 150 years the luminiferous ether theory was widely held, shaped the field of physics, and the research had to go into finding an experiment to test the theory.
Similarly, the idea that atoms might do things when high energy particles hit them was all theory until Wilson's cloud chamber became the first particle detector and suddenly physicists could see what these particles were doing when they hit things.
> The problem is...you can even define what it means for the universe to be a simulation.
You're confusing something that hasn't been done with something that can't be done. Indeed, what they're trying to do is exactly trying to define criteria to test that the universe is a simulation. It's the first day of school and you're complaining that Newton doesn't have his Principia and Gilbert doesn't have his De Magnete.
Theories often predate the knowledge of how to test them. This isn't weird.
The idea that quantum fields exist in multiple states simultaneously until observed become evidence for a simulation, since a simulator could be deferring calculations on things not observed.
Also, the very program this article is referring to could be considered as evidence for it, since if a rough simulation can be made where the observable result is indistinguishable from a result where every atomic element in the entire universe was simulated, then, again, a simulator with limited resources would make do.
The law of conservation of energy is built the same way. There is no way we can test ways that energy is transferred that we don't yet know about, but this law is still considered true, because we have so many examples of it working.
> The idea that quantum fields exist in multiple states simultaneously until observed become evidence for a simulation,
How is that evidence? Current physics can model that without relying on a simulation hypothesis. Adding a simulation hypothesis does not simplify the model, and it is unfalsifiable.
> Adding a simulation hypothesis does not simplify the model, and it is unfalsifiable.
I explain this. It's falsifiable if it can be shown there is some extremely large and complicated process that be observed to be different than any possible rough calculation that could be accomplished by a simulator with very constrained resources (constrained in comparison to all the supposed atomic particles in the universe)
The notion that all forms of energy must be conserved, even undiscovered ones, has been used as the basis for the theory of Hawking radiation, isn't it? Yet claiming that undiscovered forms of energy are conserved, just as known ones, is unfalsifiable, too.
The law of conservation of energy, including undiscovered ones, is in the same boat as the theory that the universe is a simulation.
Until we find a form of energy that isn't conserved, it is simpler to assume all types of energy are conserved.
Similarly, until we find a process that is of large enough scale that it couldn't be simulated on a computer with resources much more limited than the size of the universe, and be observable identical to a process taking much more resources, it is simpler to assume it all is being simulated in such a way.
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.
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?
The thing is, we don't know where this line of reasoning would even lead. I mean, people used to think that light had to travel in little packets through luminiferous aether [1] and look where that investigation led: Einstein, special relativity, atomic weapons and power, nuclear medicine, etc.
Let's say the universe is fundamentally indistinguishable from a computer simulation. What consequences does that have? What does that say about the types of math that can be used to describe the universe? Or, perhaps better, the types of math that shouldn't be used to describe the universe? What does that say about our ability to model a portion of the universe and therefore predict outcomes? Does it have implications for stochastic processes? Indeed, where is the stochasticism coming from? Is everything predictable or is there some fundamental randomness?
On the other hand, what if we can show that the universe is distinguishable from a computer simulation. What does that mean for our understanding of the universe as it exists? Does it reveal a fundamental aspect of reality that we have missed, or a limitation of our mathematics, or a fault in our computer models or design, etc.? We're dogs learning calculus here, and the universe isn't obligated to make sense.
Even if we can never find a useful test for this hypothesis, the line of thinking itself potentially leads us into new areas of discovery.
[0]: https://gizmodo.com/5950832/how-to-tell-if-the-universe-is-a...
[1]: https://en.wikipedia.org/wiki/Luminiferous_aether