Generally with this sort of thing it helps to be concrete.
Ask him to imagine that he’s James Bond retiring at 60 years old. He’s survived more lucky occasions then he can count. Why? Because he’s the remaining lucky one.
As to continuity of identity, this is actually a tricky part. Ask him if he identifies with himself from 1 millisecond ago. Ok, but another version of him that had had that 1 millisecond go slightly differently would also identify with the one from 1 millisecond ago. And there identification is just as reasonable. So you should identify with the one who did the last millisecond slightly differently.
This doesn’t quite work out (because presumably there’s some sufficiently different version of me that doesn’t have a goatee and thus is a goody-two shoes, and I’m not going to identify with that one.) But this detail isn’t too relevant because the real notion is observers.
I’d skip the issue of continuity completely if you can and simply explain that the idea is that at any given point if you accept MWI then there will always be an observer who shares an identical history up to you at the current time.
Generally with this sort of thing it helps to be concrete.
Ask him to imagine that he’s James Bond retiring at 60 years old. He’s survived more lucky occasions then he can count. Why? Because he’s the remaining lucky one.
As to continuity of identity, this is actually a tricky part. Ask him if he identifies with himself from 1 millisecond ago. Ok, but another version of him that had had that 1 millisecond go slightly differently would also identify with the one from 1 millisecond ago. And there identification is just as reasonable. So you should identify with the one who did the last millisecond slightly differently.
This doesn’t quite work out (because presumably there’s some sufficiently different version of me that doesn’t have a goatee and thus is a goody-two shoes, and I’m not going to identify with that one.) But this detail isn’t too relevant because the real notion is observers.
I’d skip the issue of continuity completely if you can and simply explain that the idea is that at any given point if you accept MWI then there will always be an observer who shares an identical history up to you at the current time.
Sounds promising, upvoted.