I don't agree that preferring utilitarianism is necessarily a moral intuition, though I agree that it can be.
Suppose I have moral intuitions about various (real and hypothetical) situations that lead me to make certain judgments about those situations. Call the ordered set of situations S and the ordered set of judgments J.
Suppose you come along and articulate a formal moral theory T which also (and independently) produces J when evaluated in the context of S.
In this case, I wouldn't call my preference for T a moral intuition at all. I'm simply choosing T over its competitors because it better predicts my observations of the world; the fact that those observations are about moral judgments is beside the point.
If I subsequently make judgment Jn about situation Sn, and then evaluate T in the context of Sn and get Jn' instead, there's no particular reason for me to change my judgment of Sn (assuming I even could). I would only do that if I had substituted T for my moral intuitions... but I haven't done that. I've merely observed that evaluating T does a good job of predicting my moral intuitions (despite failing in the case of Sn).
If you come along with an alternate theory T2 that gets the same results T did except that it predicts Jn given Sn, I might prefer T2 to T for the same reason I previously preferred T to its competitors. This, too, would not be a moral intuition.
Has anyone here ever addressed the question of why we should prefer
(1) Life Extension: Extend the life of an existing person 100 years
to
(2) Replacement: Create a new person who will live for 100 years?
I've seen some discussion of how the utility of potential people fits into a utilitarian calculus. Eliezer has raised the Repugnant Conclusion, in which 1,000,000 people who each have 1 util is preferable to 1,000 people who each have 100 utils. He rejected it, he said, because he's an average utilitarian.
Fine. But in my thought experiment, average utility remains unchanged. So an average utilitarian should be indifferent between Life Extension and Replacement, right? Or is the harm done by depriving an existing person of life greater in magnitude than the benefit of creating a new life of equivalent utility? If so, why?
Or is the transhumanist indifferent between Life Extension and Replacement, but feels that his efforts towards radical life extension have a much greater expected value than trying to increase the birth rate?
(EDITED to make the thought experiment cleaner. Originally the options were: (1) Life Extension: Extend the life of an existing person for 800 years, and (2) Replacement: Create 10 new people who will each live for 80 years. But that version didn't maintain equal average utility.)
*Optional addendum: Gustaf Arrhenius is a philosopher who has written a lot about this subject; I found him via this comment by utilitymonster. Here's his 2008 paper, "Life Extension versus Replacement," which explores an amendment to utilitarianism that would allow us to prefer Life Extension. Essentially, we begin by comparing potential outcomes according to overall utility, as usual, but we then penalize outcomes if they make any existing people worse off.
So even though the overall utility of Life Extension is the same as Replacement, the latter is worse, because the existing person is worse off than he would have been in Life Extension. By contrast, the potential new person is not worse off in Life Extension, because in that scenario he doesn't exist, and non-existent people can't be harmed. Arrhenius goes through a whole list of problems with this moral theory, however, and by the end of the paper we aren't left with anything workable that would prioritize Life Extension over Replacement.