Bekenstein bound

The Bekenstein bound is an upper limit on how much information a region of space can hold, given its energy. It grows with the region’s radius times its energy.

It means a simulation can’t store more state than the universe that contains it. So each nested layer has to be smaller than the one above, and the regress can’t go on forever.

Lloyd’s bound limits how fast a given mass can compute. Bekenstein’s limits how much it can store. Together they limit the regress. A simulated universe can’t hold more state than the region of the outer universe that runs it. So each layer has to be smaller than the one around it, and the nesting can’t go on forever.