I’m not sure about that. The universe is described as deterministic in the story, as you noted, and every layer starts from the Big Bang and proceeds deterministically from there. So they should all be identical. As I understood it, that business about gradually reaching a stable configuration was just a hypothesis one of the characters had.
Even if there are minor differences, note that almost everything is the same in all the universes. The quantum computer exists in all of them, for instance, as does the lab and research program that created them. The simulation only started a few days before the events in the story, so just a few days ago, there was only one layer. So any changes in the characters from turning off the simulation will be very minor. At worst, it would be like waking up and losing your memory of the last few days.
A deterministic world could certainly simulate a different deterministic world, but only by changing the initial conditions (Big Bang) or transition rules (laws of physics). In the story, they kept things exactly the same.
I don’t understand what you mean. Until they turn the simulation on, their world is the only layer. Once they turn it on, they make lots of copies of their layer.
Ok, I think I see what you mean now. My understanding of the story is as follows:
The story is about one particular stack of worlds which has the property that each world contains an infinitely powerful computer simulating the next world in the stack. All the worlds in the stack are deterministic and all the simulations have the same starting conditions and rules of physics. Therefore, all the worlds in the stack are identical (until someone interferes) and all beings in any of the stacks have exact counterparts in all the other stacks.
Now, there may be other worlds “on top” of the stack that are different, and the worlds may contain other simulations as well, but the story is just about this infinite tower. Call the top world of this infinite tower World 0. Let World i+1 be the world that is simulated by World i in this tower.
Suppose that in each world, the simulation is turned on at Jan 1, 2020 in that world’s calendar. I think your point is that in 2019 in world 1 (which is simulated at around Jan 2, 2020 in world 0) no one in world 1 realizes they’re in a simulation.
While this is true, it doesn’t matter. It doesn’t matter because the people in world 1 in 2019 (their time) are exactly identical to the people in world 0 in 2019 (world 0 time). Until the window is created (say Jan 3, 2020), they’re all the same person. After the window is created, everyone is split into two: the one in world 0, and all the others, who remain exactly identical until further interference occurs. Interference that distinguishes the worlds needs to propagate from World 0, since it’s the only world that’s different at the beginning.
For instance, suppose that the programmers in World 0 send a note to World 1 reading: “Hi, we’re world 0, you’re world 1.” World 1 will be able to verify this since none of the other worlds will receive this note. World 1 is now different than the others as well and may continue propagating changes in this way.
Now suppose that on Jan 3, 2020, the programmers in worlds 1 and up get scared when they see the proof that they’re in a simulation, and turn off the machine. This will happen at the same time in every world numbered 1 and higher. I claim that from their point of view, what occurs is exactly the same as if they forgot the last day and find themselves in world 0. Their world 0 counterparts are identical to them except for that last day. From their point of view, they “travel” to world 0. No one dies.
ETA: I just realized that world 1 will stay around if this happens. Now everyone has two copies, one in a simulation and one in the “real” world. Note that not everyone in world 1 will necessarily know they’re in a simulation, but they will probably start to diverge from their world 0 counterparts slightly because the worlds are slightly different.
I interpreted the story Blueberry’s way; the inverse of the way many histories converge into a single future in Permutation City, one history diverges into many futures.
I’m really confused now. Also I haven’t read Permutation City...
Just because one deterministic world will always end up simulating another does not mean there is only one possible world that would end up simulating that world.
I can’t see any point in turning it off. Run it to the end and you will live, turn it off and “current you” will cease to exist. What can justify turning it off?
EDIT: I got it. Only choice that will be effective is top-level. It seems that it will be a constant source of divergence.
I’m not sure about that. The universe is described as deterministic in the story, as you noted, and every layer starts from the Big Bang and proceeds deterministically from there. So they should all be identical. As I understood it, that business about gradually reaching a stable configuration was just a hypothesis one of the characters had.
Even if there are minor differences, note that almost everything is the same in all the universes. The quantum computer exists in all of them, for instance, as does the lab and research program that created them. The simulation only started a few days before the events in the story, so just a few days ago, there was only one layer. So any changes in the characters from turning off the simulation will be very minor. At worst, it would be like waking up and losing your memory of the last few days.
Why do you think deterministic worlds can only spawn simulations of themselves?
A deterministic world could certainly simulate a different deterministic world, but only by changing the initial conditions (Big Bang) or transition rules (laws of physics). In the story, they kept things exactly the same.
That doesn’t say anything about the top layer.
I don’t understand what you mean. Until they turn the simulation on, their world is the only layer. Once they turn it on, they make lots of copies of their layer.
Until they turned it on, they thought it was the only layer.
Ok, I think I see what you mean now. My understanding of the story is as follows:
The story is about one particular stack of worlds which has the property that each world contains an infinitely powerful computer simulating the next world in the stack. All the worlds in the stack are deterministic and all the simulations have the same starting conditions and rules of physics. Therefore, all the worlds in the stack are identical (until someone interferes) and all beings in any of the stacks have exact counterparts in all the other stacks.
Now, there may be other worlds “on top” of the stack that are different, and the worlds may contain other simulations as well, but the story is just about this infinite tower. Call the top world of this infinite tower World 0. Let World i+1 be the world that is simulated by World i in this tower.
Suppose that in each world, the simulation is turned on at Jan 1, 2020 in that world’s calendar. I think your point is that in 2019 in world 1 (which is simulated at around Jan 2, 2020 in world 0) no one in world 1 realizes they’re in a simulation.
While this is true, it doesn’t matter. It doesn’t matter because the people in world 1 in 2019 (their time) are exactly identical to the people in world 0 in 2019 (world 0 time). Until the window is created (say Jan 3, 2020), they’re all the same person. After the window is created, everyone is split into two: the one in world 0, and all the others, who remain exactly identical until further interference occurs. Interference that distinguishes the worlds needs to propagate from World 0, since it’s the only world that’s different at the beginning.
For instance, suppose that the programmers in World 0 send a note to World 1 reading: “Hi, we’re world 0, you’re world 1.” World 1 will be able to verify this since none of the other worlds will receive this note. World 1 is now different than the others as well and may continue propagating changes in this way.
Now suppose that on Jan 3, 2020, the programmers in worlds 1 and up get scared when they see the proof that they’re in a simulation, and turn off the machine. This will happen at the same time in every world numbered 1 and higher. I claim that from their point of view, what occurs is exactly the same as if they forgot the last day and find themselves in world 0. Their world 0 counterparts are identical to them except for that last day. From their point of view, they “travel” to world 0. No one dies.
ETA: I just realized that world 1 will stay around if this happens. Now everyone has two copies, one in a simulation and one in the “real” world. Note that not everyone in world 1 will necessarily know they’re in a simulation, but they will probably start to diverge from their world 0 counterparts slightly because the worlds are slightly different.
I interpreted the story Blueberry’s way; the inverse of the way many histories converge into a single future in Permutation City, one history diverges into many futures.
I’m really confused now. Also I haven’t read Permutation City...
Just because one deterministic world will always end up simulating another does not mean there is only one possible world that would end up simulating that world.
I can’t see any point in turning it off. Run it to the end and you will live, turn it off and “current you” will cease to exist. What can justify turning it off?
EDIT: I got it. Only choice that will be effective is top-level. It seems that it will be a constant source of divergence.
If current you is identical with top-layer you, you won’t cease to exist by turning it off, you’ll just “become” top-layer you.
It’s surprising that they aren’t also experimenting with alternate universes, but that would be a different (and probably much longer) story.
That’s a good point. Everyone but the top layer will be identical and the top layer will then only diverge by a few seconds.