| Re: Paradoxes
There are several spacetime models that do allow information, and occasionally matter, to travel against the entropic arrow. The simplest is a totally predestined universe where if you are going to travel back in time then you have already done so, and so nothing is changed - the situation now is the summed result of all the interferences and free will is an illusion caused by our sensory perceptions.
Alternatively time travel requires a transmitter and a receiver, so one can never go back in time further than the invention of the machine (but when it's invented, chaos ensues)
Or only information can travel, not matter or energy (thus maintaining the laws of conservation of this, that and the other) and we haven't yet learn't to detect the information our distant descendents are frantically sending back ("the history books were clear; it was discovered in the twenty-first century. And despite everything we told them, they still went and invaded")
Or the "The universe spawns a new set of potential universesequal to the sum total of all the particles in the univese in the period of time in which a particle can take two different actions, but the majority of these reinforce to make a "consensus" universe before the next split" In chaos like that, the guy with the AK47 at the crucifixion is just considered too improbable by the majority of universes and "poof" |