Digital Cabinet

Polevaulter Donkeyman's rants, raves musings and flame wars

Nightmare Scenarios

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Steven Landsburg blogs about some interesting nightmare scenarios

Q1. Which one of the two do you prefer?

Scenario A: An evil alien flips a coin. If it comes up heads, he destroys all human life; otherwise he goes home. Scenario B: The same evil alien flips 7 billion coins, one for each person on earth. He destroys anyone whose coin comes up heads.

I would choose Scenario B because:

  1. The probability of a significant number of humans surviving is greater in scenario B.
  2. I like the logic of the poster above who said that the utility of the last 1000 humans surviving is greater than that if subsequent 1000s (though due to network effects the 1000 should be revised upward to a million or 10s of millions)
  3. If the most likely outcome of scenario B is 3.5 B people, that takes us back to 1950-1970. That is still a pretty good era to live in.
  4. I like humans, I enjoy being around other humans and I am sure other humans like other humans and like to be around other humans.

Q2. Suppose you’re happily married. If forced to choose, which of these scenarios would you prefer?

Scenario A: An evil alien flips a coin. If it comes up heads, he kills you and your spouse; otherwise he goes home. Scenario B: The same evil alien flips a coin. If it comes up heads, he kills just you; if it comes up tails, he kills just your spouse.

I would choose scenario B irrespective of the age of spouses, or whether they have children or not. In fact it is a very simple choice. My question to those who choose A, those who cannot imagine living without their spouses is how many of them would commit suicide if their spouse predeceases them?

Q3. In front of you are two childless married couples. For some reason, it’s imperative that you kill two of the four people. Your choices are:

Scenario A. Kill one randomly chosen member from each couple. Scenario B: Kill both members of a randomly chosen couple.

All four people agree that if they die, they want to be well remembered. Therefore all four ask you, please, to choose A so that anyone who dies will be remembered by a loving spouse.

I choose A. For goodness’s sake, they’ve told me what to do.

  1. They’ve told me. Presumably all 4 people are better placed to evaluate the post-killing situation since they would be doing the dying, surviving and remembering


  1. each couple has discussed it amongst themselves. I am not sure if it matters the two couples have discussed the matter with each other. Of course if one couple wants A and the other wants B, I would shoot the one which chose B (but that would not be random then, would it?)
  2. Alan Wexelblat’s assumptions
  3. No externalities imposed on anyone outside the 5 people involved (the 2 couples and the executioner)

As for Harold’s hypothetical I would still choose A (given everything else is the same).


Written by Polevaulter Donkeyman

March 26, 2012 at 15:24

Posted in Uncategorized

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