Yet quantum mechanics is full of phenomenon that operate counter to our understanding of cause and effect. Physicists accept things like double slit interference - why do they seem to consider these time travel induced causal paradoxes so off-limits?
Mostly because a bagel is not an electron, and slit experiments illustrate wave-particle duality, do they not?
Anyhow, the message was about how paradoxes make reasoning hard, not about how we can wave away the uncertainties. Next time I'll just skip all the time machine nonesense and head to the nearest rectory.
I think the point made by user jbattle is that physics already allows, for example, causal relationships that go either “back in time” or “faster than light” from certain valid reference frames. Physicists have found ways of coping with this reality. Why should the introduction of a time machine make it fundamentally any different?
