How can time travel exist in a deterministic universe? I don't imagine it can. ok. so lets say time travel is only possible in a non-deterministic universe. What does that tell us? That 1 + 1 might not be equal to 3. So that makes sense. But does time make sense it this setting? No, because time is the casuality chain of choice, time will have no meaning in a non-detministic universe universe.