Bear with me as I try to decide whether I believe this. Here's a principle on wronging persons/person-stages that I think is true.
P. For each additional, intentional and malicious moral wrong A that B freely does to person(s) S, B becomes morally worse.
After considerable discussion and dispute with PB contributors, I think I can put my worry much more clearly. Here it is.
1. Let A1 be an action of B that intentionally, maliciously and freely wrongs person S1 at time t. (Let's say that B irradiates S1 causing serious disease D.).
2. Let A1' be an action of B' that intentionally, maliciously and freely wrongs person S1' at t'. (A1' irradiates S1'.).
3. At t2, God instantaneously replaces all of S1's memories and cells resulting in S2'. (S1' is not identical to and is not an earlier stage of S2'.)
4. Had B not performed actions A1, then S1 would not have had disease D.
5. Had B' not performed A1', S1' & S2' would have had disease D.
Why do I find it next to impossible to believe (6), despite the principle P, which I think is true?
6. B' is morally worse than B (assuming, of course, that they were otherwise moral equals).
Even adding premise (7) doesn't make an important difference (to me).
7. B' knew that God would instantaneously replace all of S1's memories and cells after S1' was irradiated.
In fact, I don't that B' wronged S2' at all! That is, I don't believe there were two wrongs, one to S1' and another to S2'. And that is why B' is not worse than B. Or, I find it difficult not to see it that way.