Of course, the premise that “humans are the only beings who can reason about their own preferences” could only justify the conclusion that some human beings are special, since there are members of the human species who lack that ability.
In our society we don’t really respect the volition of those human beings. We give them legal guardians who are supposed to decide in their interests instead of letting them make their own decisions. We don’t let them vote in our elections.
That is not because we don’t regard their preferences as valuable in themselves, but simply because these beings lack the means to do the kinds of things that would allow them to satisfy those preferences. In any case, CEV does not exclude such humans from the class of creatures whose volitions are to be coherently extrapolated.
In our society we don’t really respect the volition of those human beings. We give them legal guardians who are supposed to decide in their interests instead of letting them make their own decisions. We don’t let them vote in our elections.
That is not because we don’t regard their preferences as valuable in themselves, but simply because these beings lack the means to do the kinds of things that would allow them to satisfy those preferences. In any case, CEV does not exclude such humans from the class of creatures whose volitions are to be coherently extrapolated.