How do I go about obtaining a probability distribution over all possible universes conditioned on nothing?
Nobody really knows, but some people have proposed Kolmogorov complexity as the basis of such a prior. In short, the longer the computer program required to simulate something, the less probable it is. (The choice of which programming language to use is still a problem, though.)
That’s not the only problem. We don’t even know whether our universe is computable, e.g. physical constants can have uncomputable decimal expansions, like Chaitin’s Omega encoded into G. Are you really damn confident in assigning this possibility a prior of zero?
It amazes me that people will start with some particular prior over universes, then mention offhand that they also give significant probability to simulation from prior universes nearly unrelated to our own (except as much as you generically expect simulators to prefer conditions close to their own). Then, should I believe that most universes that exist are simulations in infinite containing universes (that have room for all simulations of finite universes)? Yudkowsky’s recent “meta crossover” fan fiction touched on this.
Simulation is sexy in the same way that creation by gods used to be. Are there any other bridges that explain our universe in terms of some hidden variable?
How about this: leading up to the big crunch, some powerful engineer (or collective) tweaks the final conditions so that another (particular) universe is born after (I vaguely recall Asimov writing this). Does the idea of universes that restart periodically with information leakage between iterations change in any way our prior for universes-in-which-”we”-exist?
In my opinion, I only exist in this particular universe. Other universes in which similar beings exist are different. So p(universe|me) needs to be fleshed out better toward p(universe|something-like-me-in-that-xyz).
I guess we all realize that any p(universe|...) we give is incredibly flaky, which is my complaint. At least, if you haven’t considered all kinds of schemes for universes inside or caused by other universes, then you have to admit that your estimates could change wildly any time you encounter a new such idea.
Nobody really knows, but some people have proposed Kolmogorov complexity as the basis of such a prior. In short, the longer the computer program required to simulate something, the less probable it is. (The choice of which programming language to use is still a problem, though.)
That’s not the only problem. We don’t even know whether our universe is computable, e.g. physical constants can have uncomputable decimal expansions, like Chaitin’s Omega encoded into G. Are you really damn confident in assigning this possibility a prior of zero?
It amazes me that people will start with some particular prior over universes, then mention offhand that they also give significant probability to simulation from prior universes nearly unrelated to our own (except as much as you generically expect simulators to prefer conditions close to their own). Then, should I believe that most universes that exist are simulations in infinite containing universes (that have room for all simulations of finite universes)? Yudkowsky’s recent “meta crossover” fan fiction touched on this.
Simulation is sexy in the same way that creation by gods used to be. Are there any other bridges that explain our universe in terms of some hidden variable?
How about this: leading up to the big crunch, some powerful engineer (or collective) tweaks the final conditions so that another (particular) universe is born after (I vaguely recall Asimov writing this). Does the idea of universes that restart periodically with information leakage between iterations change in any way our prior for universes-in-which-”we”-exist?
In my opinion, I only exist in this particular universe. Other universes in which similar beings exist are different. So p(universe|me) needs to be fleshed out better toward p(universe|something-like-me-in-that-xyz).
I guess we all realize that any p(universe|...) we give is incredibly flaky, which is my complaint. At least, if you haven’t considered all kinds of schemes for universes inside or caused by other universes, then you have to admit that your estimates could change wildly any time you encounter a new such idea.