According to Jennifer Whiting, our relation to our future selves is like that to our friends. But this view is subject to a particularly clear form of the self-sacrifice objection. For suppose that I can rescue a stranger from a bear, but I foresee that in doing so I will acquire fatal wounds that will cause death within a few hours. If I had no conflicting duties, e.g., to my children, this would be a heroic and laudable thing to do. But if Whiting is right, then it seems this action is analogous to sacrificing the life of a friend for that of a stranger, without having asked the friend, since the future self who will die in a few hours is like a friend. But it's surely wrong to sacrifice the life of a friend, without special permission, to save a stranger.
Objection: The future self has the same values as I do, and hence if it were the case that I am such that I would choose to die for the stranger, I can assume that he, too, would choose to die for the stranger.
Response: There are several problems with this objection. First, the relevant future self is the one who is going to be dying from the fatal wounds. Can I really be sure that at that time there will be no regrets, but consent? Second, this answer assumes that anybody with the same values as me would have chosen the same thing. But that assumption is plausibly false. I have certain values which imply that it would be a fine thing to give up my life for the stranger. But it is not certain that each time I would act on those values. It could well be that I would only sometimes choose to act on those values. But that fact would not affect the permissibility of acting on the values. Third, consider this. What if in fact I do not love my future self as much as I love myself? Plausibly, the self-sacrifice would still be permissible. But in that case, it cannot be presumed that my future self would choose to have himself be sacrificed—for, presumably, he loves himself more than I love him. Fourth, when it comes to sacrificing the life of a friend to save a stranger, more than merely knowing that the friend has values that make the sacrifice likely is needed. The choice has to be made by the friend.