"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?
This "moral dilemma" only has force if you accept strict Bentham-style utilitarianism, which treats all benefits and harms as vectors on a one-dimensional line, and cares about nothing except the net total of benefits and harms. That was the state of the art of moral philosophy in the year 1800, but it's 2012 now.
There are published moral philosophies which handle the speck/torture scenario without undue problems. For example if you accepted Rawls-style, risk-averse choice from a position where you are unaware whether you will be one of the speck-victims or the torture victim, you would immediately choose the specks. Choosing the specks maximises the welfare of the least well off (they are subject to a speck, not torture) and, if you don't know which role you will play, eliminates the risk you might be the torture victim.
(Bentham-style utility calculations are completely risk-neutral and care only about expected return on investment. However nothing about the universe I'm aware of requires you to be this way, as opposed to being risk-averse).
Or for that matter if you held a modified version of utilitarianism that subscribed to some notion of "justice" or "what people deserve", and cared about how utility was distributed between persons instead of being solely concerned with the strict mathematical sum of all utility and disutility, you could just say that you don't care how many dust specks you pile up, the degree of unfairness in a distribution where 3^^^3 people get out of a dust speck and one person gets tortured makes the torture scenario a less preferable distribution.
I know Eliezer's on record as advising people not to read philosophy, but I think this is a case where that advice is misguided.
Rawls's Wager: the least well-off person lives in a different part of the multiverse than we do, so we should spend all our resources researching trans-multiverse travel in a hopeless attempt to rescue that person. Nobody else matters anyway.