"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?
Bogdan's presented almost exactly the argument that I too came up with while reading this thread. I would choose the specks in that argument and also in the original scenario (as long as I am not committing to the same choice being repeated an arbitrary number of times, and I am not causing more people to crash their cars than I cause not to crash their cars; the latter seems like an unlikely assumption, but thought experiments are allowed to make unlikely assumptions, and I'm interested in the moral question posed when we accept the assumption). Based on the comments above, I expect that Eliezer is perfectly consistent and would choose torture, though (as in the scenario with 3^^^3 repeated lives).
Eliezer and Marcello do seem to be correct in that, in order to be consistent, I would have to choose a cut-off point such that n dust specks in 3^^^3 eyes would be less bad than one torture, but n+1 dust specks would be worse. I agree that it seems counterintuitive that adding just one speck could make the situation "infinitely" worse, especially since the speckists won't be able to agree exactly where the cut-off point is.
But it's only the infinity that's unique to speckism. Suppose that you had to choose between inflicting one minute of torture on one person, or putting n dust specks into that person's eye over the next fifty years. If you're a consistent expected utility altruist, there must be some n such that you would choose n specks, but not n+1 specks. What makes the n+1st speck different? Nothing, it just happens to be the cut-off point you must choose if you don't want to choose 10^57 specks over torture, nor torture over zero specks. If you make ten altruists consider the question independently, will they arrive at exactly the same value of n? Prolly not.
The above argument does not destroy my faith in decision theory, so it doesn't destroy my provisional acceptance of speckism, either.