Well, here's an intuition pump for you: Suppose the universe is reset to the time of birth of a person P, and the hero (who is someone other than person P) does things differently this time so that person P grows up in a different environment. It seems to me that this act is just as bad for P as the act of killing P and then causing a genetically identical clone of P to be born, which is a bad act.
On the other hand, if the hero resets the universe to 1 millisecond ago, there is virtually no effect on person P, so it does not seem to be a bad act.
So for practical purposes, the hero can use the power for bursts of, say, an hour or less, without ethical issues involved?
This is a thread where people can ask questions that they would ordinarily feel embarrassed for not knowing the answer to. The previous thread is at close to 500 comments.