Pascal's Mugging

Pascal's Mugging is a hypothetical incident designed to illustrate the problems with the application of expected value calculations to some types of situations, namely: ones with very low probability and very high utility.

The scenario runs like this:

'' Now suppose someone comes to me and says, "Give me five dollars, or I'll use my magic powers from outside the Matrix to run a Turing machine that simulates and kills 3^^^^3 people." ''

The expected value of this action is very high, and yet most people would reject the offer. It could be an example of where our tools for reasoning break and our intuitions do better. Another interpretation is that people fail to accept the logical task. For example, people might perceive the stated probability as arbitrary, meaningless, or beyond the capability of humans to calculate and thereby reject the task of following the instructions.

It is often invoked when talking about low probability, high utility actions, as a reductio ad absurdum of these lines of reasoning.

Further Reading:

 * Pascal's Mugging: Entry on Less Wrong Wiki.