(Will be using “UDT” below but I think the same issue applies to all subsequent variants such as FDT that kept the “updateless” feature.)
I think this is a fair point. It’s not the only difference between CDT and UDT but does seem to account for why many people find UDT counterintuitive. I made a similar point in this comment. I do disagree with “As such the debate over which is more “rational” mostly comes down to a semantic dispute.” though. There are definitely some substantial issues here.
(A nit first: it’s not that UDT must value all copies of oneself equally but it is incompatible with indexical values. You can have a UDT utility function that values different copies differently, it just has to be fixed for all time instead of changing based on what you observe.)
I think humans do seem to have indexical values, but what to do about it is a big open problem in decision theory. “Just use CDT” is unsatisfactory because as soon as someone could self-modify, they would have incentive to modify themselves to no longer use CDT (and no longer have indexical values). I’m not sure what further implications that has though. (See above linked post where I talked about this puzzle in a bit more detail.)
(Will be using “UDT” below but I think the same issue applies to all subsequent variants such as FDT that kept the “updateless” feature.)
I think this is a fair point. It’s not the only difference between CDT and UDT but does seem to account for why many people find UDT counterintuitive. I made a similar point in this comment. I do disagree with “As such the debate over which is more “rational” mostly comes down to a semantic dispute.” though. There are definitely some substantial issues here.
(A nit first: it’s not that UDT must value all copies of oneself equally but it is incompatible with indexical values. You can have a UDT utility function that values different copies differently, it just has to be fixed for all time instead of changing based on what you observe.)
I think humans do seem to have indexical values, but what to do about it is a big open problem in decision theory. “Just use CDT” is unsatisfactory because as soon as someone could self-modify, they would have incentive to modify themselves to no longer use CDT (and no longer have indexical values). I’m not sure what further implications that has though. (See above linked post where I talked about this puzzle in a bit more detail.)