I have problems to understand some aspects of this “multiverse” stuff, so my reasoning may be very confused.
My biggest problem is what makes some universes “more real” than others. For example, why is our universe more real than a universe that is exactly like the our universe until now, but exactly now some magic starts happening. Seems to me that an official answer is “Solomonoff induction”, which says that ‘our universe’ has shorter description than ‘our universe + magic starting right now’, but that answer seems to me just like passing the bucket. Why should Tegmark multiverse care about the length of description?
But the question relevant to this topic is this: Let there be a universe A to which the Solomonoff induction gives prior probability X, and an universe B with probability Y. The universe B contains a computer that runs a simulation of universe A… now is the probability of the universe A still X, or is it X+Y? I don’t even know what this question means (maybe nothing), but it seems to me that it means whether people running the simulation in the universe B are somehow responsible for what happens in universe A.
I have problems to understand some aspects of this “multiverse” stuff, so my reasoning may be very confused.
My biggest problem is what makes some universes “more real” than others. For example, why is our universe more real than a universe that is exactly like the our universe until now, but exactly now some magic starts happening. Seems to me that an official answer is “Solomonoff induction”, which says that ‘our universe’ has shorter description than ‘our universe + magic starting right now’, but that answer seems to me just like passing the bucket. Why should Tegmark multiverse care about the length of description?
But the question relevant to this topic is this: Let there be a universe A to which the Solomonoff induction gives prior probability X, and an universe B with probability Y. The universe B contains a computer that runs a simulation of universe A… now is the probability of the universe A still X, or is it X+Y? I don’t even know what this question means (maybe nothing), but it seems to me that it means whether people running the simulation in the universe B are somehow responsible for what happens in universe A.