"We are in a simulation" is a meaningless statement. It's like saying that there are millinons of invisible unicorns on Earth.

It would be meaningless, if we lived in an undetectable simulation. But IIRC, there's a recent paper that allows us to detect if we live at least in certain kinds of simulations.

Ah, here we go: http://www.technologyreview.com/view/429561/the-measurement-...

If I understand it correctly, they basically say "Our universe is discrete, therefore we're in a simulation".

Ok, if "being in simulation" == "discreteness", than yes, "being in simulation" is meaningful. But why not just argue whether our universe is discrete? Why introduce the concept of simulation, which evokes a picture of some higher level universe with a big computer running our universe. Which is just an idea in our heads, nothing more.

"We're in a simulation" implies that our universe is discrete, nothing more, so it's meaningless in a sense.

(Other problem is that if we're in a non-discrete universe, we may be able to make non-discrete software. But that's not the main point of what I tried to say.)

Only if we assume that the "host" universe's computers are discrete, an assumption for which there is exactly no basis. We can't even speculate about the physical laws of the outer universe, much less what kind of computers it has, if "computers" as we know them even a valid concept.

Nitpick: "We are in a perfect and undetectable simulation" is a meaningless statement. If e.g. someone found a privilege escalation in our reality's VM that would be quite meaningful.

Good point, that's how I meant it :) Similarly, if the unicorns found a way to become visible, it would become a meaningul statement too.

Reality hackers? Let's badger Charlie Stross to write a novel about it. :)

There's a great novel based on this very concept: Fine Structure ( http://everything2.com/title/Fine+Structure ). Definitely worth a read.

I get what you are saying, but I disagree. If there were millions of invisible unicorns, surely we'd occassionally bump in to one. Azaleas would go missing. With the right technology, it might be possible to harvest them for ivory or meat or hoofs for glue.

If we live in a simulation, there may be experiments that would demonstrate the fact. There may be ways to 'hack' the simulation and break all kinds of physical laws.

By "invisible unicorn" I meant a unicorn that doesn't have any effect on the physical world.

Our universe could behave, in some ways, like a computer simulation (but the question is, in what specific ways?). But it is similar to light rays behaving like waves. Which is different from light rays being equivalent to waves.

That sounds suspiciously like quantum, it does.

Doesn't your explanation mean saying we live in a simulation is _exactly like_ saying there are millions of invisible unicorns?

OK, I really tried to read that, but my lack of coffee and presence of being really tired made it hard to consume. Was the entire premise of it that one day a being will have computers powerful enough to simulate humanity, so of course they will, and we are the result of it? Some of those assumptions seem pretty damn big, but again, I could just be too tired to read it.

Then it'll be turtles all the way down :)

Simulation is overkill; the Matrix approach is cheaper - run the simulation within the brain.

Maybe we are a simulation within some entities brain.

Or maybe that's just what it wants you to think.