"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?
I don't see that it's necessary -- or possible, for that matter -- for me to assign dust specks and torture to a single, continuous utility function. On a scale of disutility that includes such events as "being horribly tortured," the disutility of a momentary irritation such as a dust speck in the eye has a value of precisely zero -- not 0.000...0001, but just plain 0, and of course, 0 x 3^^^3 = 0.
Furthermore, I think the "minor irritations" scale on which dust specks fall might increase linearly with the time of exposure, and would certainly increase linearly with number of individuals exposed to it. On the other hand, the disutility of torture, given my understanding of how memory and anticipation affect people's experience of pain, would increase exponentially over time from a range of a few microseconds to a few days, then level off to something less than a linear increase with acclimatization over the range of days to years. It would increase linearly with the number of people suffering a given degree of pain for a given amount of time. (All other things being equal, of course. People's pain tolerance varies with age, experience, and genetics; it would be much worse to inflict any given amount of pain on a young child than on an adult who's already gone through, say, Navy S.E.A.L. training, and thus demonstrated a far higher-than-average pain tolerance.)
Thus, it would be enormously worse to inflict X amount of pain on one individual for sixty minutes than on 60 individuals for one minute each, which in turn would be much worse than inflicting the same pain on 3600 individuals for one second each -- and if we could spread it out to a microsecond each for 36,000,000 people, the disutility might vanish altogether as the "experience" becomes too brief for the human nervous system to register at all, and thus ceases to be an experience. However, once we get past where acclimatization inflects the curve, it would be much worse to torture 52 people for one week each than to torture one person for an entire year. It might even be worse to torture ten people for one week each than one for an entire year -- I'm not sure of the precise values involved in this utility function, and happily, at the fine scale, I'll probably never need to work them out (the empirical test is possible in principle, of course, but could only be performed in practice by a fiend like Josef Mengele).
There's also the fact that knowing many people can and have endured a particular pain seems to make it more endurable for others who are aware of that fact. As Spider Robinson says, "Shared joy is increased, shared pain is lessened" -- I don't know if that really "refutes entropy," but both of those clauses are true individually. That's part of the reason egalitarianism, as other commenters have pointed out, has positive utility value.
If getting hit by a dust speck has u = 0, then air pressure great enough to crush you has u = 0.