Infinite regress

Infinite regress is the problem that if our reality is simulated, the reality running it might be too, with no natural place to stop.

The Regress window. Each layer has to run the one nested inside it, so the computing available sets a maximum depth.

A simulation inside a simulation isn’t free. Each layer has to run the one inside it. The Regress window does the division. For most builds the stack is shallow. For the biggest ones it has depth zero, because the outer universe can’t run even one copy.