From a comment on the Mises blog from a while back:
One thing to keep in mind is there is a difference between being immortal and knowing you are immortal. I have noted this before (where, I cannot find) regarding Ayn Rand’s views about the nature of value. In Virtue of Selfishness she writes:
It is only the concept of ‘Life’ that makes the concept of ‘Value’ possible. It is only to a living entity that things can be good or evil. … To make this point fully clear, try to imagine an immortal, indestructible robot, an entity which moves and acts, but which cannot be affected by anything, which cannot be changed in any respect, which cannot be damaged, injured, or destroyed. Such an entity would not be able to have any values; it would have nothing to gain or to lose; It could not regard anything as for or against it, as serving or threatening its welfare, as fulfilling or frustrating its interests. It could have no interests and no goalsâ€¦ Only a living entity can have goals or can originate them. And it is only a living organism that has the capacity for self-generated, goal-directed action.
(See this Randian essay on related matters.)
The problem here, it seems to me, is the assumption that IF you are immortal, then you would be absolutely sure of this fact. Because the argument seems to rely not so much on *being* immortal, but in believing you are immortal. (I think the argument is fallacious in either case.)
What really matters, for action, is what one believes to be the case. This seems to me to apply to Rand’s hypo about “valuing” as much as it does this little discussion about time preference. Now in my view, we would still have time preference, and still value, even if we were immortal and knew it.
But even from the perspective of those here arguing about whether immortality affects time preference (or, in Rand’s case, the capacity to have values), the focus has to be on what the actor thinks or believes, not on what is really the case. Suppose A is immortal but does not know it. He only knows he is older than others and has not yet died. He assumes he has some weird gene that makes him live longer but he has no way of knowing or proving he is really immortal. In this case, he would not act as if he is immortal (whatever the implications of that are) since he does not think he is.
Also assume this: A is not immortal but falsely believes he is. Presumably he would act as if he is immortal. But note: today, many people, e.g. Christians, do in effect believe they are immortal; they believe they don’t really “die” but their soul goes to heaven and exists forever. These people evidently are (from their point of view) immortal, yet still value, and still have time preference.
So clearly, this entire focus on “immortality” is doubly mistaken. First, it is not immortality that matters–it is one’s beliefs about one’s own mortality. And second, apparently even a belief in immortality does not undercut the capacity to have values of time preference.
I really think a big flaw in this entire hypo is that no one can ever know they are immortal–even an immortal person could not know it. In fact, it’s probably impossible to be immortal anyway, given entropy and the universe’s ultimate collapse.