"What's the worst that can happen?" goes the optimistic saying. It's probably a bad question to ask anyone with a creative imagination. Let's consider the problem on an individual level: it's not really the worst that can happen, but would nonetheless be fairly bad, if you were horribly tortured for a number of years. This is one of the worse things that can realistically happen to one person in today's world.
What's the least bad, bad thing that can happen? Well, suppose a dust speck floated into your eye and irritated it just a little, for a fraction of a second, barely enough to make you notice before you blink and wipe away the dust speck.
For our next ingredient, we need a large number. Let's use 3^^^3, written in Knuth's up-arrow notation:
- 3^3 = 27.
- 3^^3 = (3^(3^3)) = 3^27 = 7625597484987.
- 3^^^3 = (3^^(3^^3)) = 3^^7625597484987 = (3^(3^(3^(... 7625597484987 times ...)))).
3^^^3 is an exponential tower of 3s which is 7,625,597,484,987 layers tall. You start with 1; raise 3 to the power of 1 to get 3; raise 3 to the power of 3 to get 27; raise 3 to the power of 27 to get 7625597484987; raise 3 to the power of 7625597484987 to get a number much larger than the number of atoms in the universe, but which could still be written down in base 10, on 100 square kilometers of paper; then raise 3 to that power; and continue until you've exponentiated 7625597484987 times. That's 3^^^3. It's the smallest simple inconceivably huge number I know.
Now here's the moral dilemma. If neither event is going to happen to you personally, but you still had to choose one or the other:
Would you prefer that one person be horribly tortured for fifty years without hope or rest, or that 3^^^3 people get dust specks in their eyes?
I think the answer is obvious. How about you?
Since Robin is interested in data... I chose SPECKS, and was shocked by the people who chose TORTURE on grounds of aggregated utility. I had not considered the possibility that a speck in the eye might cause a car crash (etc) for some of those 3^^^3 people, and it is the only reason I see for revising my original choice. I have no accredited expertise in anything relevant, but I know what decision theory is.
I see a widespread assumption that everything has a finite utility, and so no matter how much worse X is than Y, there must be a situation in which it is better to have one person experiencing X, rather than a large number of people experiencing Y. And it looks to me as if this assumption derives from nothing more than a particular formalism. In fact, it is extremely easy to have a utility function in which X unconditionally trumps Y, while still being quantitatively commensurable with some other option X'. You could do it with delta functions, for example. You would use ordinary scalars to represent the least important things to have preferences about, scalar multiples of a delta function to represent the utilities of things which are unconditionally more important than those, scalar multiples of a delta function squared to represent things that are even more important, and so on.
The qualitative distinction I would appeal to here could be dubbed pain versus inconvenience. A speck of dust in your eye is not pain. Torture, especially fifty years of it, is.