I was having a discussion with some individuals on Facebook’s Mensa page. The question posed was if there is a rule that all universes must follow. I answered that there is one, and it is this rule: that they must be permanent over a time horizon of length P such that P is greater than zero by any infinitesimally small amount.
What does this mean?
There could be universes being created and destroyed a googolplex times per second, undetectable by us because their infinitely short lifespans prevent them from growing into anything detectable by human science, or because they lack any physical properties.