"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?
@Paul, I was trying to find a solution that didn't assume "b) all types of pleasures and pains are commensurable such that for all i, j, given a quantity of pleasure/pain experience i, you can find a quantity of pleasure/pain experience j that is equal to (or greater or less than) it. (i.e. that pleasures and pains exist on one dimension).", but rather established it for the case at hand. Unless it's specifically stated in the hypothetical that this is a true 1-shot choice (which we know it isn't in the real world, as we make analogous choices all the time), I think it's legitimate to assume the aggregate result of the test repeated by everyone. Thus, I'm not invoking utilitarian calculation, but Kantian absolutism! ;) I mean to appeal to your practical intuition by suggesting that a constant barrage of specks will create an experience of a like kind with torture.
@Robin Hanson, what little expertise I have is in the liberal arts and sciences; Euclid and Ptolemy, Aristotle and Kant, Einstein and Sophocles, etc.