But didn’t you already answer this? The computer needed to find-and-mark a universe with closed time loops is much, much larger, computationally speaking, than the one you need to, say, find-and-mark our universe. If you give me no information other than “a computer is simulating a universe”, I’ll still rate it more likely that it’s doing something that doesn’t require iterating the totality of predecessor search space.
But if the computer simulating operates in an acausal universe, the limitations on complexity we see in our causal-universe computers may not hold, and so the point may be self-defeating.
Finding that acausal universe still requires computational resources equivalent to (at least) traditional causality. It just moves the problem outwards. (If I understand this right)
No. My point is that computational complexity as understood in this universe depends on causality. Without causality, the logic falls apart.
If a universe is acausal, there could, potentially, be O(0) algorithms for basically anything. (I can just input a condition that terminates only if the answer is correct, and have the answer immediately based on the fact that it worked.) If so, the simulation could be instantaneous, and therefore any simulation would have the same cost.
My point is that it’s not very useful to know that a universe exists, if we don’t have a method for locating it in configuration space—and that method would eat the costs of causality, even if the universe itself doesn’t. Like in the GAZP.
But didn’t you already answer this? The computer needed to find-and-mark a universe with closed time loops is much, much larger, computationally speaking, than the one you need to, say, find-and-mark our universe. If you give me no information other than “a computer is simulating a universe”, I’ll still rate it more likely that it’s doing something that doesn’t require iterating the totality of predecessor search space.
But if the computer simulating operates in an acausal universe, the limitations on complexity we see in our causal-universe computers may not hold, and so the point may be self-defeating.
Finding that acausal universe still requires computational resources equivalent to (at least) traditional causality. It just moves the problem outwards. (If I understand this right)
No. My point is that computational complexity as understood in this universe depends on causality. Without causality, the logic falls apart.
If a universe is acausal, there could, potentially, be O(0) algorithms for basically anything. (I can just input a condition that terminates only if the answer is correct, and have the answer immediately based on the fact that it worked.) If so, the simulation could be instantaneous, and therefore any simulation would have the same cost.
My point is that it’s not very useful to know that a universe exists, if we don’t have a method for locating it in configuration space—and that method would eat the costs of causality, even if the universe itself doesn’t. Like in the GAZP.