[ExI] Time travel in simulations

[Keith Henson]

There are good reasons to expect humans will never develop time travel
in the base universe in which we live.

https://en.wikipedia.org/wiki/Niven%27s_laws#Niven's_Law_(re_Time_travel)

However, there is a way to get *subjective* time travel with an
uploaded civilization running in a simulated reality.  And no
causality violations.

All it requires is to checkpoint the hardware running the simulated
reality from time to time.  “Time travel” for an individual in such a
context would amount to reloading a previous checkpoint (perhaps on
new hardware) and entering the simulation.  From a subjective
viewpoint, this would be equivalent to time travel.

Limits, you can’t go back before the first checkpoint.

Keith