Pascal's mugging refers to a thought experiment in decision theory, named in analogy to Pascal's wager. An agent with an unbounded utility function can potentially be exploited by bets offering tiny probabilities of vast utilities: describable utilities can get large faster than the probabilities of corresponding situations given by the Solomonoff-like priors get small. The situation is dramatized by a mugger:
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."
Intuitively, one is not inclined to acquiesce to the mugger's demands, and yet it's not clear how this intuition can be justified in decision theory.
- Nick Bostrom (2009). "Pascal's Mugging". Analysis 69 (3): 443-445. (PDF)