Ben: suppose the lever has a continuous scale of values between 1 and 3^^^3. When the lever is set to 1, 1 person is being tortured (and the torture will last for 50 years.). If you set it to 2, two people will be tortured by an amount less the first person by 1/3^^^3 of the difference between the 50 years and a dust speck. If you set it to 3, three people will be tortured by an amount less than the first person by 2/3^^^3 of the difference between the 50 years and the dust speck. Naturally, if you pull the lever all the way to 3^^^3, that number of people will suffer the dust specks.
Will you pull the lever over to 3^^^3? And if so, will you assert that things are getting better during the intermediate stages (for example when you are torturing a google persons by an amount less than the first person by an entirely insignificant quantity?) And if things first get worse and then get better, where does it change?
Will you try to pull the lever over to 3^^^3 if there’s a significant chance the lever might get stuck somewhere in the middle?
To your voting scenario: I vote to torture the terrorist who proposes this choice to everyone. In other words, asking each one personally, “Would you rather be dust specked or have someone randomly tortured?” would be much like a terrorist demanding $1 per person (from the whole world), otherwise he will kill someone. In this case, of course, one would kill the terrorist.
I’m still thinking about the best way to set up the lever to make the point the most obvious.