[_Donny]

I do not quite understand how the guys in the simulation can determine which level they are at. If L1 universe interferes with L2, will the guys in L2 see the divergence in L3? How do they determine their own level?

Fantastic story. Will read more from this author!

[JZumun]

It's like a recursive function, where you resolve to stop interfering with the lower universe once the upper universe stops interfering with you. You run it N times until nothing happens in your universe. That means you're N universes deep in the stack.

If you run the program once and not observe anything happening, that means you know you're top level. Then you resolve to not rerun the program.

If you run the program once and observe the black sphere, then run it again and not see the black sphere, you know you're level 2. You resolve to not rerun the program. And on it goes.

EDIT: box to sphere.

[varajelle]

But nothing says the function is ran only only once... There could be someone in the next room also emulating an universe, and not intervening. Or they could emulate the universe 5 minutes later and say "this time we dont intervene"

[Nition]

I think it'd work like this:

Imagine you decide to show a "1" instead of the black sphere. You then look behind you. Most likely you see a 1.

Whatever number you see, increment that number by one in the next simulation. If you see nothing, congrats, you're at the top and leave the number as-is.

So initially what each level sees is behind them is: x-1-1-1-1-1

Then after everyone increments by one: x-1-2-2-2-2

Now repeat the step. Everyone looks behind them and increments the number they see by one.

x-1-2-3-3-3

Eventually you'll look behind you and the number won't have changed. You're at one level higher than that.

If there are millions of levels that'd take ages of course. But I think you could use the same idea do it instantly on the computer instead. Just have your simulation computer modify a number on the simulation computer in the next level down.

[_Donny]

That makes perfect sense. Thanks for the excellent explanation, Nition!

[swayvil]

I think it was a rough determination. Given the evidence (apparently perfect mirroring behavior between adjacent universes) and statistical likelihood, there are probably roughly infinite universes above and below us in the stack.

[raldi]

1. Set n=1

2. Make the value of n appear in the simulation

3. If you see that number in yours, increment n and go back to Step 2

4. Else, the number you see is how many simulations down you are.