Hal Finney wrote:
I imagine that multiple universes could exist, a la Schmidhuber's ensemble
or Tegmark's level 4 multiverse. Time does not play a special role in
the descriptions of these universes.
Doesn't Schmidhuber consider only universes that are the results of
computations? Can't we consider any computation as having an intrinsic
"causal structure"? How would it be possible to write an algorithm that
describes a "Life" universe where there's no time, where the t-axis is
replaced by a z-axis, for example?
Tegmark in one of his papers considers universes with two or more
If this universe is computable, it can be simulated by an algorithm that can
run in a universe with only one time dimension. Perhaps the algorithm would
go back and forth between simulating time increments in different
directions, like how a regular computer can simulate a parallel computer.