Also, note that specifying a brain simulation is much more difficult (takes more bits) than specifying a universe simulation. A brain simulation needs to have m

Also, note that specifying a brain simulation is much more difficult (takes more bits) than specifying a universe simulation. A brain simulation needs to have moods, emotions, headaches, sensory processing, etc. A universe simulation just needs a few equations (our best guess at the moment is general relativity plus the standard model). The chance that a universe simulation appears at random is much higher than the chance a brain simulation appears at random, even though a universe simulation may take vastly more resources to run.