Time travel breaks causality if you assume Copenhagen interpretation of quantum mechanics. Multi-world interpretation allows it as you just end up in a self-con

Time travel breaks causality if you assume Copenhagen interpretation of quantum mechanics. Multi-world interpretation allows it as you just end up in a self-consistent "branch" and you would be stuck there. Like you can travel back in time and kill one of your ancestors before he/she had children. In that branch you wouldn't be born, but since you come from another branch the system remain consistent. (If you are interested look at David Deutsch’s quantum model of Closed Timelike Curves).